The purpose of this article is to provide all the information you need to on your own make and maintain a good bike fit for your drop bar bike, that is road bike, cross bike, or a gravel / adventure bike.
First a disclaimer though: I'm no authority in bike fitting. I'm a recreational cyclist that have an interest and need to understand bike fitting and sizing, so I've studied the subject thoroughly and gained enough confidence so I dare to share my findings. I do know a thing or two about sports science and biomechanics from my experience in a number of sports, so I think I have the ability to sift through information in this sport too. I've turned to many sources, filtering and sorting, using my own judgment and experience to figure out what aspects that are important and those that are less so. Still I must stay humble and recommend anyone deeply interested turn to many sources, and consider this for what it is — a comprehensive layman's view.
There are professional bike fitters, so why do it yourself in the first place? The simple answer is to save money, which certainly can be relevant if you are on a budget, but if you have decided to spend on a higher end road bike the cost should not be a problem. Some people seem to have an infinite budget to spend on gear, but always complain about the cost of services. Please don't be one of those. If there's a great bike fitter around, do use the service if it suits you. To many of us, a professional bike fit worthy of its name is actually quite hard to find though. If you don't live in a large city you almost certainly need to travel to find one, adding cost and inconvenience.
I think the key reason to do it yourself is not to save money, but to become familiar with the subject and then have the ability to fine-tune as you develop without having to involve anyone else. It's just more practical. Real bike fitting is not a set-and-forget procedure, it's something you evaluate and tune over time, which of course is hard to do by consulting a professional if you don't have access to that person locally.
If you like me have ridden standard bikes all your life, your relation to bike fitting may be like this: all you had to do was to pick out a bike of a reasonable size (if even that), set the saddle height to something that felt comfortable, and then just ride, no problems. So when you get a drop bar road bike it may come as a surprise the almost obsessive focus on bike fit that exist in the community, where many claim that adjustments in the range of millimeters have made drastic changes to comfort or performance.
The nature of road biking, which is prolonged hard effort in a static aerodynamic position, means that bike fit does have a much greater impact than in other types of cycling. In mountain biking you do put in some hard effort too, but you are much more dynamic on the bike, constantly changing position to tackle technical terrain, and you're not bothered by being folded into a low aerodynamic position, thus fit is less troublesome.
So exactly how important is it to make a thorough bike fit for your drop bar bike? If you ask commercial bike fitters most will probably say that it's extremely important to get the bike dialed in to fractions of centimeters. While this can be true for some individuals, it's not universally true. Some will react strongly, either with under-performance or discomfort (injury in the longer term) to a sub-optimal bike fit. Others are much more adaptable and have a wide "fit window" where they perform well and are comfortable. This means that for many it actually is just setting the saddle height and go (assuming bike sizing is good). Both types are common, and there is unfortunately no other method than experience to know which type you are. Master fitter Phil Burt calls these two types "micro-adjusters" and "macro-absorbers", the first type has a tendency to constantly re-adjust their fit and the other can absorb a wide range of fits without problems.
The DIY bike fit procedure presented herein will work very well for anyone which has a reasonable fit window, and I'd say this is most people based on how many that get along well without ever having made a bike fit at all. However, if you do have special needs to have a very accurate clinically evaluated bike fit you cannot get to that level yourself. Unfortunately few "professional" bike fitters can either, certainly not the typical bike shop fitter (I dare to say that this DIY bike fit is better than what most shops do). You then need someone that is well-educated (for example has physiotherapist competence in addition to bike fitting), has advanced measurement gear, and a long proven track record of making successful fits for riders with fit-related problems.
For this DIY bike fit, getting to the appropriate position is much based on what you, the rider, feel. That is the quality is dependent on your feedback, and the more experienced you are the better you are at feeling nuances and thus can make a better fit. In any case it's wise to return and fine-tune fit further as you gain experience, not only because the ability to feel improves, but fitness and flexibility may improve too so a more aggressive fit (= more aerodynamic fit) may be appropriate.
Finally, be aware of that bike fitting is more art than science. While there indeed is some science on individual factors, putting it all together and balancing conflicting goals is an art. Inventing and applying fitting techniques in areas where there is no guiding science is an art. This means that two professional bike fitters will not get to the exact same result. There simply is no such thing as a single optimal bike fit. When studying bike fit and listening to some bike fit professionals you can get the impression that there is this one optimal bike fit that only the best fitters can find, and small deviations from it can be a disaster, and likewise that the optimal bike fit would solve all your problems. It's not like that. If you cycle harder and longer than ever before you will eventually get pains, regardless how good the bike fit is. A good bike fit can delay that, or make you ride faster or both, but it won't take away the limits of the body. And certainly, just as there is more than one bad fit, there is more than one good too.
Bike fit is not about finding the one perfect fit that you will use on all your bikes. Instead it's about balancing the following:
This balance of conflicting goals (mainly comfort vs aerodynamics) varies depending of what style of riding you will do with the bike up for fitting. If you have more than one bike for different riding styles, those will most likely end up with different fits.
Bike fitting for amateur and novice riders often focuses on improving comfort, as discomfort is a common problem and often the reason you first start thinking about a making a bike fit. While comfort certainly is important, you should know what the goal of your bike fit is. Do you go for long endurance rides of 4-6 hours or more? Or do you use your bike for shorter efforts where you like to go really fast? Obviously a bike fit intended for shorter durations and higher speeds can sacrifice some long-term comfort to gain better aerodynamics.
Improving aerodynamics in a road bike is generally about increasing the reach and/or lowering the handlebar so your back angle gets lower (making the fit more "aggressive"). More important than the static position of the handlebar is how you sit on the bike though. By bending your elbows you can get low even if the handlebar is quite high, meaning that for only temporary needs of aerodynamics, like when being in front in the group or on downhills, you can still have a fit made for comfort.
A very low position can also become a problem for your power output, so if you make your fit too aerodynamic you may actually end up slower due to difficulties delivering power.
It's worth noting that a compromise in comfort is not about making the bike immediately uncomfortable. If the bike feels uncomfortable as soon as you get on it, the fit is not good. The compromise is about what happens if you go out for a long ride, how long time your body can stay in that position without tiring and start to become uncomfortable.
Places on the bike where you can adjust for fit. Green points without changing components: saddle height, fore-aft and tilt; stem height on fork (if spacers are available), flip to get upward instead of downward angle, adjust angle of handlebar, adjust levers position. Not shown in the image: shoe cleat adjustment.
Red points adjustment through component change: saddle (shape), seat post (setback), stem (angle/length), handlebar (reach/drop/width/shape), cranks (length), pedals (stance). Not shown: cleat wedges.
Before even starting with a fit you need a properly sized bike (the frame size). Hopefully the bike shop have already got you a suitable size. If you need to evaluate size yourself, for example when buying second hand or online, you can first read the separate section on bike sizing.
Without swapping out parts this is what you can adjust for a better fit on your bike:
Often this is enough, but sometimes you need to get new parts to adjust the fit further. Here's what you can get:
There are many adjustments you can do on a bike, and for each and every one you can somewhere find someone that believes that particular adjustment is the most under-appreciated and the most important. Indeed, for some individuals there are some rarely made adjustments that can have great impact. To be able to make these right you probably need help from an experienced bike fitter with expertise in clinical adjustments. For most of us, bike fit does not need to be that complicated though, and in this overview I comment on how important or not each adjustment usually is.
For some adjustments below I mention "fit window", this is a term to indicate that there is a range of positions which all work well. These fit window sizes vary between individuals, so the values mentioned are just what you would typically expect.
What do we aim for when making all these adjustments? Broadly speaking we set the saddle position relative to the bottom bracket for best pedaling efficiency and then handlebar position in relation to saddle for a balance between comfort and aerodynamics.
Here follows a bike fit procedure. You need a trainer to put the bike on as much of the adjustments are evaluated and refined while pedaling, and a video camera is a nice accessory but not necessary, especially if you are starting off with something close to ideal. If you have never seen yourself on the bike I do recommend to mount a camera and make a video analysis too, just for sanity-checking. It's often the case that our inner picture doesn't match how we actually look in reality.
I assume that you make the fit for yourself, that is the fitter and the rider is the same person. I think this makes it more likely that the fit becomes good and that fine-tuning will happen later on as needed. While you can make a fit for a friend using these techniques, it's much harder due to the dependency on rider feedback. If you get poor feedback, it's likely that the fit will be poor. There is one drawback of making the fit for yourself though, and that is that many of us have a desire to handle more aggressive positions than we actually can, and thus push ourselves too far. Keep that in mind and be honest to yourself. Don't sacrifice fit for vanity.
You can perform the complete procedure on your own without any assistant.
To make bike fitting easier you should have the following equipment:
In this setup we record video from one side. If possible mount the camera far away and use a tele lens to minimize the amount of perspective in the frame, as that makes measurement more reliable. If you have space to have the camera at some distance but no tele lens, place the camera as far away as possible while still having enough resolution on the bike to be able to make measurements.
The video is used to establish some rough angles and position plus general observation, basically a sanity check. It's not that useful for fine-tuning though as it's not feasible to do exact measurements without proper joint markers. High-end fit systems like Retül have joint markers which does add some value, but you can make up for the lack of that (and other technical gadgets like saddle pressure mats) by carefully thinking about how it feels on the bike. Even with high-end fitting tools the feedback from the rider is still a key aspect in adjusting the fit.
If you don't have a trainer there are simpler procedures when you just take a static photo of yourself sitting on the bike leaning against a wall. You can get to a good bike fit this way, but it's much less reliable. As many parameters are fine-tuned by feel I think it's important to be able to pedal with effort while evaluating. For example I'd say it's impossible to really fine-tune the saddle position without pedaling.
Another aspect that makes actual pedaling important is that we then naturally settle on the position we will be on the saddle, while if we just jump on the bike statically there is a risk that we're not really placed on the saddle where we will end up while riding.
When pedaling it's also easier to sense and see problems, like sliding backwards or forwards on the saddle or if you have a tendency to lock out your elbows.
All bike fit adjustments are more or less interconnected, both in terms of how your body reacts, and in actual bike mechanics. If we move the saddle forward but keep the same stem we shorten the reach at the same time. If we shorten the reach, we sit more upright and we may want a different saddle setback or even slightly different saddle height.
This means that when we make one adjustment at a time we may still be off target when we have gone through all adjustments. So what to do? Go through them all again! For each round we get closer to optimal and eventually we don't need to adjust any further. This doesn't mean that you need to go through the round a lot of times, actually often just one round is still enough as we're usually starting with something that is fairly good, and most of us have at least some fit window to each adjustment. If we start further off target a couple of more rounds is likely necessary.
With the best pro bike fitters you don't just get one bike fit and then it's set for life, but you return and fine-tune as needed. One reason is that you develop as a rider (getting more flexible, adapt more to a certain position, increase fitness) and thus can optimize the fit further based on your new capabilities. Another is that some adjustment may be more experimental by nature and need long-term evaluation where you provide feedback to the fitter after some time. A good fitter can also help with adjustments to relieve from temporary pains, when recovering from an ache or injury.
This type of relation to the bike fitter is unusual as there are not many around working at that level. However when we are our own bike fitter we can and should adopt the method, making longer term evaluations of settings and fine-tune as we develop and gain experience. Just as we should relax the position on the bike if our bodies start to hurt after a tougher period of training or racing.
In other words, while you can run through the bike fit procedure here once and set everything, just as you would in a local bike shop fit, I do recommend that once you have a fit that feels good you should still consciously evaluate it while riding, and fine-tune as needed.
When you have a decent bike fit already, it's rarely necessary to redo it all over again, instead you make small adjustments one at a time and evaluate them over a few rides. In fact, it's better to make only small changes of just one setting, as if you change many at once it's much harder to feel the effect of the change. Another reason to prefer small gradual changes is that the body is adapted to the current fit and large changes implemented fast may lead to an overuse injury.
As you need to pedal during bike fitting, here's a few words on pedaling technique: although clipped in you shouldn't pull up or try pedaling in circles. It was believed to be beneficial some years ago, but has since been scientifically dis-proven. Just pedal as if you weren't clipped in. You can refine pedaling technique, but for the sake of a bike fit just pedal as relaxed and natural as possible.
We still need to be clipped in to keep the foot in our preferred position and avoid the risk of slippage.
Many aspects of the fit is about maximizing power transfer efficiency. Here I suggest to do this by feel. However, when really into the fine-tuning details of power, what feels more powerful may not be what actually is most powerful. Many turbo trainers have power meters, or your bike may have one, so instead of trusting what we feel we could thus use the power meter, right? No. The problem with that is that we compare very small differences and thus it's difficult to maintain a steady enough effort so we actually see a difference in power efficiency, and not just that you became tired, or the other way around that you are more warmed up, or just by being aware that power is tested you unconsciously put out more. To measure efficiency reliably you need to measure oxygen consumption too, gear which only advanced labs have access to. Thus I don't think it's worth considering using a power meter even if you have one, the results will just be too unreliable. We just have to accept that we can't reach perfection in this regard, or at least not know for sure if we have or not.
Note that at elite level there is also an interest to consider the balance with aerodynamics, in some cases you can gain higher speeds in a less powerful but more aerodynamic position, but it's a delicate balance.
Regardless how good and relaxed bike fit you have, you can still get overuse injuries by simply cycling too much without enough recovery. As a performance bike fit does make a compromise between comfort and aerodynamics, there is a limit to how much time you can spend in that position before it starts to hurt.
Being more dynamic on the bike can significantly increase the time you can spend riding without issues. Here's a few tips: even when not needed do stand up and pedal for a moment now and then, and don't sit in a low aero position if you don't need to (like when riding in the drag of a group), and lower your head briefly now and then when sight is clear to relieve neck muscles.
If you feel that you start to develop an overuse injury that can be relieved by relaxing your bike fit (pain in back, shoulders, neck), do relax it, it doesn't need to be forever.
When you are pedaling hard, using a higher cadence, say 90-100 instead of 80-90, is much kinder to your knees and lower back as you reduce the torque in your pedal stroke. However, while a higher cadence puts less stress on muscles and tendons it demands more capacity from heart and lungs, so it depends on what type of athlete you are what is suitable for you. Heavy strong riders may use lower cadences than light riders with high level of aerobic fitness. It's quite common among novice riders to use an unnecessarily low cadence just out of habit though, so it may be worth monitoring and if it's low try to increase it.
If you have not ridden the bike at all it's best to start with a coarse fit, as the thorough bike fit procedure will then go much faster with much less need to re-iterate.
Here's a suggested procedure:
Video analysis is interesting and I recommend that you do it if you can, but actually it's not all that important. We don't really use the video for anything other than a sanity check, and to get a documented view of exactly how aggressive we sit on the bike (which can be difficult to feel). All adjustments are fine-tuned based on what the cyclist feels when pedaling, and for that no video is required. If we just need to check our back angle a still image is fine.
For the video, make sure you are warmed up, and for the analysis segment cycle at say 70-80% effort with a cadence natural for the effort, which should be around 80-90.
Video analysis checklist:
Maybe you want to record video from both sides and also the front or back to detect any knee tracking issues or asymmetry issues (such as leg length difference). I think this is unnecessary. All riders have some asymmetry and even if strongly visible there is rarely any need to correct them, in fact correcting them (using cleat wedges etc) often leads to adding a problem that wasn't there in the first place. There are plenty of examples among professional riders that do well with clearly visible asymmetries.
Also, if you actually do need some sort of correction for asymmetry this is a question for professional clinical expertise, not something you should do yourself.
It's also worth noting that a normal bike on a trainer usually flex a bit side-to-side when cycling, which makes it hard to do any side-to-side movement analysis.
We set up cleat position first as it affects the saddle height setting.
Use cleats with some float (that is like all standard cleats have), which will allow the feet to fine-tune its optimal position throughout the pedal stroke to reduce load on the knees. Too much free-flowing float might actually cause knee problems in some individuals, but much less likely so than a cleat with no float.
The baseline fore-aft position of the cleat is to put the pedal axle over the ball of the foot. Putting it a bit farther back (closer to the heel) is also okay, safer even, it doesn't decrease power output and can compensate somewhat for a bit too long cranks, and also leads to a (slightly) lower saddle position which as a side effect reduces drop to the handlebar.
Fine-tune cleat rotation by testing on the bike. The float should be centered around the position your foot want to be in, it's easiest to test with pedals horizontal. Don't force your feet to be straight. It's common that foot orientation is a bit different between left and right.
Note that float is not only used for letting the foot find it's natural position statically, the foot rotation does change during the pedal stroke too. Forcing it not to move with a zero float cleat is thus a bad idea for most individuals. Cleats with no float are intended for elite sprinters or track cyclists which may need the locked-in feel when unleashing all their power in a sprint.
Regarding left-to-right position, keep it centered unless there is a reason not to (see the next section on stance width).
Note that depending on your shoe size, cleat position, crank length and frame geometry you may get a "toe overlap". This is when your toe in the three-o-clock position may collide with the wheel when turning. This is quite normal on road bikes with their steep head tube angles and shouldn't be considered a fit error. On some bikes it can be impossible to avoid, especially with the smaller frame sizes. It's only a problem when making sharp low-speed turns (which you rarely do on a road bike) and in those situations you simply just need to stop pedaling and keep the foot out of the way.
You can affect the stance width slightly with cleat positioning (2mm or so). Your pedal model may provide additional adjustment in the pedal itself, usually a few millimeters. For road bikes, which have narrow stance widths compared to mountain bikes, most do well with whatever stance width the bike provides, that is you usually just keep it as is. There is another reason than comfort or efficiency to adjust stance width though: if you have a heel-in foot position (splay footed) and due to that have a tendency to rub the rear of the shoe against the crank or the frame, increasing the pedal stance width can solve that problem.
The bulk of the pedal stance width is decided by the crank-set which in turn is adapted to the bottom bracket width and space required by the drive train. It's believed that a narrow stance width has efficiency advantages (within limits), but to fit tires and drive-train it must be a certain width. Due to these static technical requirements and that every manufacturer tries to make crank-sets reasonably narrow, the difference in stance width offered by different crank-sets are usually no more than a few millimeters. That is, it's almost never worthwhile to consider stance width when choosing crank-set, and there's no need to change crank-set for that reason.
There is no simple body measurement or similar to relate stance width to, so if you want to adjust it yourself you have to do it based on feel. If interested in this, start by testing the extreme ends (using pedal spacers if available and cleat adjustment, often only 5 mm or so in total), and if you feel a difference use trial-and-error until you find the position that feels best. Think of comfort and ease to produce power. Do this while pedaling with an 80% effort or so, and make the changes as quickly as possible so you have the sensation in fresh memory.
For leg length difference or knee tracking problems one can install wedges or shims under the cleats, and/or use orthotics. Wedges have a very strong effect and I strongly recommend against using them, unless recommended by clinical expertise. There is a high risk that you do more harm than good when trying to correct for bio-mechanical asymmetries (which is not the same as bio-mechanical "problems").
If you use orthotics in your normal shoes there may be a good reason to install similar orthotics in your cycling shoes (make sure the shoes have space for them). Orthotics have a weaker effect than wedges and are thus safer to use.
To adjust crank length you usually need to replace the whole crank-set, which is expensive. Fortunately it's a less important adjustment; it's more about personal preference than performance as the bike gears compensate for the leverage difference.
Being both expensive and unimportant there's little reason to change an existing crank-set, but if you build a bike from scratch you still have to choose crank length, so which one? It's safer to have cranks on the short side (both in terms of power output and comfort), than on the long. Long cranks relative to leg length require tighter hip and knee angles at the top of the stroke, that is more flexibility. If you happen to have cranks on the long side, you can however somewhat compensate by having the shoe cleats in a position further back.
The most common crank lengths are 165, 170, 172.5 and 175mm, and are on pre-assembled bikes mounted based on frame size. The traditional size range is as seen only 10mm from shortest to longest, but it does bring your foot 20mm closer to the saddle at the top of the stroke, so it does make a noticeable difference. Why 20mm when crank length difference is only 10? As the pedal sits 10mm lower below the bottom bracket you need to lower the saddle with 10mm, and then as the foot is 10mm higher above the bottom bracket at the top of the stroke and the saddle 10mm lower the total becomes 10×2mm.
A baseline formula for crank length is inseam in cm times 1.25 + 65. An example: for 85 cm inseam it gets 85 × 1.25 + 65 = 171.25, that is exactly in-between the two standard sizes. As there are some advantages to go for shorter cranks, we pick the shorter (170). Note that this formula doesn't have much if any scientific support, it's just tradition, but if you don't have any specific personal preference it's well worth using.
As shorter cranks can avoid too tight angles and has no drawback on power output, the only reason to have long cranks is if it feels nicer. Larger riders, and even some small, may simply prefer the feel of long cranks and if it doesn't give you any problems in terms of tight angles go ahead and use them.
Short cranks, below 170mm, are quite popular on time-trial bikes to open up the tight hip angle that stems from the extreme aerodynamic position. There is less need for that on normal road bikes though. However if you are a short rider it may be worthwhile to get shorter cranks also for a road bike to be more comfortable in general.
While saddle height is the most important adjustment, it's also common to have a quite wide window that suits you, say 10 - 15mm or so. Therefore using a simple static method or formula will often get you near or even within that window. Here's the most common (saddle height defined as center of bottom bracket up to top of saddle):
All those are good ways to start, and it's only coincidence if one happens to match your body better than another. One of these methods may put you right in the window, or not. There's still need to fine-tune.
While basic video analysis is a good sanity check it isn't enough for fine-tuning. Even advanced video systems with joint markers have limitations in this regard. From the starting point the remaining refinement is instead based on feel, focusing on how easy it is to deliver power. For fine-tuning this a trainer is almost necessary as you need to pedal with say a 80% effort to get the proper feel of the pedal stroke. Start with adjusting quite large steps, say 15mm at a time, and try both obviously-too-low and obviously-too-high positions to get a sense of how it should not feel. The right position is that which feels neither too high nor too low. Then you can try adjust smaller steps. For the final small-adjustment of say a 3mm step you can use a folded towel to slip in-between to make a quick A/B test, as a long pause getting on and off your bike to adjust can make it too hard to feel a difference.
Don't worry if you don't get down to 3mm precision, as said many have a quite wide window that works. It's generally safer to be lower in that window. Experienced riders with a high fitness level usually try to be higher in the window as it may give a small edge in power. When riding in technical terrain (cyclocross, gravel, adventure) you may want to set the saddle low in the window to make it a little bit less in the way.
In bullet form:
The by far most common method for saddle fore-aft adjustment (saddle setback) is the Knee-Over-Pedal-Spindle (KOPS) method, where the front of the knee just under the knee cap is aligned with the pedal axle when the cranks are horizontal. It actually has no scientific merit, but it seems that cyclists with average body proportions usually end up in a comfortable position this way. As it usually works just fine and there is no consensus on replacement method it continues to be widely used. But hang on, I'm going to recommend something else.
Most serious bike fitters don't use KOPS, but instead optimize fore-aft based on a mix between bike handling, performance and comfort.
We need to find a balance, and many bike fitters talk about using fore-aft positioning to balance the body weight over the bike although the methods (and results) vary. A good positioning must take into account many factors in the pedaling cyclist, so it's impossible to make a method as easy and repeatable as KOPS. It must to a large extent be based on feel. Here's my suggested method:
Some have suggested that having the knee in front of KOPS increases forces on the knee and should thus preferably be avoided to prevent overuse injury. There are mixed scientific results on this though, and currently I find no reason to worry if the best position for you happens to be a bit in front of KOPS.
While we can find saddle height without being affected by handlebar position (unless it's extreme), the reach adjustment side-effect of fore-aft saddle positioning can in many occasions have a larger impact on feel and comfort than the changed relative position of the bottom bracket. It makes the fitting procedure a bit more cumbersome but is something we just have to live with. By re-iterating through the complete bike fit we will eventually find both reach and saddle fore-aft optimized.
The rails of the saddle is part of its suspension. It works best if the saddle is clamped to the seat post at the midpoint of the rail. Some adjustment (say 10-20mm) shouldn't drastically change the behavior, but if you end up at an extreme end you should probably consider changing seat post to one with a setback that better matches your need.
Also note that the saddle may sag and tilt a bit when you sit on it when the rail is at an extreme position, so both saddle tilt and height settings may be affected and thus need compensation if this position is unavoidable.
Saddle discomfort can be caused by an unsuitable saddle position or tilt, or an overall poor bike fit. Always check that first before considering a new saddle. Traditional saddle setup is having it completely level (and that is what the saddle is designed for), but up to say 2 degree nose down may be beneficial, especially if you have a low handlebar. Many saddles are a bit curved back to front so it may not be entirely obvious which part that should be horizontal. For normal shaped saddles it's about 1/3 in from the nose, but do look at the manufacturer recommendations if uncertain.
Saddle tilt adjustment of just a half degree can have a large impact how pressure is distributed over the saddle, so it's certainly worth experimenting with. As the fit is related to how the pelvis is rotated, the handlebar position have an effect too, so when that is changed in relation to the saddle, you might need to revisit saddle tilt.
Saddle height adjustments usually don't have that large impact on saddle comfort, but there are exceptions as it does change how you interact with the saddle. Unlike saddle tilt you shouldn't adapt saddle height to try to improve comfort of the saddle though. It's just something to be aware of when saddle height is adjusted for other reasons.
Good saddle comfort comes from a saddle shape that suitably matches the shape of your pelvis, in the rotation it is when you sit on the bike. A more aggressive position means that the pelvis rotates more forward which means you sit less on the sit bones and more further forward on the narrower part. Your flexibility will also affect the pelvis position. If you are more flexible there will be more rotation and you have a flatter back, less flexible less rotation and a more hunched back. Standard saddles are wide at the back and narrower at the front and thus supports both a bit more upright and a more aggressive position. They are rarely perfect for all pelvic rotations though so you need to optimize for the position you will be in the most.
If you use your saddle in racing and have a high power output, more of your weight will be on your feet and less on your saddle, meaning that there can actually be less risk of saddle soreness than on slower rides. A more aggressive position shifts more weight towards the hands, which may become a problem for the hands, but does reduce pressure on the saddle. Experienced racers often have a saddle height slightly higher than common to get a bit more leg extension and may thus need a narrower saddle. In other words, there are reasons racing saddles look narrow and uncomfortable, and they actually may become exactly that when not used in a racing situation or by a rider with modest power output.
The need of cushioning is individual. You may even do without any cushioning at all. Cushioning cannot make up for a shape that doesn't work, and to make up a stable platform for high intensity pedaling there cannot be that much cushioning in any case. While the pad in your bibs is intended mostly for moisture management to avoid abrasions, it does provide some cushioning too so you need less on the saddle. The pads come in different thicknesses, so when trying saddles use your favorite bibs. Note that thick cushioning in the bibs or on the saddle can make a center cutout (if you need that) ineffective, as it gets filled up with all the softness, and if there isn't a center cutout you may actually get a center ridge forming instead. In other words, a firm saddle is preferable to start with. If that familiar beginning-of-season-saddle-soreness won't go away even after a longer period of cycling you could try a little bit more cushioning.
For some individuals almost any saddle will do, and if you belong to that lucky category you typically just use whatever saddle the bike came with, or make upgrades based on looks or weight. To others it can be quite difficult to find a saddle that works. This is a troubling situation as trial-and-error is the only reliable method on offer. If you have a saddle problem a high-end bike fit where they can test out several different saddles and have saddle pressure analysis capability can be a real money-saver, as the alternative is often to guess-and-buy saddles maybe €100 each until you find something that works. A local bike shop which can lend saddles, cycling friends with saddles you can borrow, an online shop with a generous return policy or buying second hand saddles are ways to keep down the costs of your own testing.
Note that expensive saddles are expensive due to that they are lightweight, not that they would be more comfortable. Often the same saddle exists in both a more expensive lightweight version and a budget version which is heavier but otherwise have the same properties. If you must buy to test and can't return it's advisable to use the budget alternatives when possible, and possibly upgrade to a lightweight version later on. Also note that high end metal rails are springier and usually more comfortable than carbon rails, so the carbon is just there for saving weight in this case (unlike carbon in forks and handlebars which often has a comfort advantage by being better at killing road buzz than alloy).
Many saddle manufacturers have sit bone measurement and flexibility tests to find a saddle in their range that is supposed to suit you. This may work, but just as likely it may not work at all for you. These fitting methods are far from a reliable. I can use myself as an example, the best saddle for me turned out to be one that is designed for wider sit bone spacing much more flexibility than I have.
Here's a few tips if you have a saddle fit problem:
Much more can be said about saddle fit, but the truth is that there is no other reliable method than actually testing the saddles.
The reach to the handlebar is primarily a balance between aerodynamics and comfort. The longer the reach and drop from the saddle the lower your back angle and the more aerodynamic you become. With limits in flexibility you will at some point lock out elbows or overstretch your shoulders rather than get lower, or get an overly hunched back. A too extreme position may also lead to difficulty to get power out, so you may actually lose speed even if being more aerodynamic.
Within the range your flexibility can handle there is still more or less comfort. With a low back angle you will need to lift your head more to see ahead on the road, which may cause a strained neck over longer rides. Lower back problems are also more likely. Here you need to consider what type of cycling you will do; for shorter faster rides you can often endure a bit less comfort just to get that edge in aerodynamics.
Flexibility and the ability for the back and neck to handle an aggressive position can improve over time, but it's not a fast process. You can speed it up with specific off-the-bike stretching and strength training. Your ability can also vary depending on how fresh you are. After a long hard period of cycling the body may be a bit sore and to recover it may need a less aggressive position. Likewise after a winter with little or no cycling you may need some time to adjust to a position you could deal with mid-season last year. Having some adjustability range left (or perhaps an extra stem) to be able to reduce the reach and/or drop temporarily is a good idea.
Less flexible riders will get a more hunched back for lower positions. This is okay to some extent (even some elites have quite hunched backs), but be aware that it may reduce power output and may increase risk of lower back and neck pain. For healthy people there's no risk for sudden injuries when trying a too aggressive position — your body will tell you after one or a few rides if it could handle it or not, so don't be afraid to experiment a bit.
A common misconception is that you need a really low handlebar in order to get aerodynamic. Instead it's all about the back angle, so you can have a small drop if the reach stretches you out. This can be seen in professional racing, while indeed there are many examples of really huge drops, some actually have a quite shallow drop and a longer reach instead. There still needs to be a balance with drop to avoid over-reaching, of course.
Being in the drops has traditionally been mostly for aerodynamic gain, but nowadays with modern hood and bar design holding your hands on the hoods with bent elbows so the forearm is horizontal (mimicking a time-trial position) is actually a little bit more aerodynamic — your torso gets as low (compared to normal drop position), and there is less drag from the arms. There is still a need for the drops though: to gain a lower center of gravity for better control and stability when it gets rough or when descending and going fast through corners, and an aerodynamic and powerful position with good grip when sprinting, or just to be able to vary positions on the bike.
Among amateur riders it's common that most of the time is spent on the hoods, and perhaps only 10% or so is spent in the drops. This is okay if it's a natural result of your needs during your rides. However you should avoid putting your handlebar so low that you really can't use the drops because it just becomes too uncomfortable. As the position indeed is lower, it is less comfortable to most people, so you should expect some compromise, just not so much it becomes unbearable.
After the saddle position is set, reach and drop from the saddle to where you hold your hands on the handlebar can be adjusted these ways:
You can adjust about 1-2 cm drop by angling the handlebar and fine-tuning position of the levers, but that adjustment should be used for optimizing hand comfort, not drop adjustment (except as a last resort if you can't get new gear). Likewise you can increase or reduce drop by changing saddle height (if you have a 15mm fit window it will be noticeable) but I don't think one should use saddle height fine-tuning for that reason. I do think that saddle fore-aft can be used to tune reach though, but only within your fit window. If you can't change stem or handlebar, saddle fore-aft is the only adjustment there is to adjust reach.
A new handlebar can usually only change reach (range about 7 - 10 cm) and how much lower the position in the drops becomes (range about 11 - 15 cm), but there are a few rare exceptions like the Specialized Hover bar which rises 15mm above the stem clamp, a stealthy way to further reduce drop.
A stem with adjustable angle is okay for testing out different positions, but generally they are not stiff enough for permanent use. An exception is when this adjustment is made through angled spacers/shims (like the Specialized Multi stem) rather than a joint on the stem. Shimmed stems usually have a small adjustment range which often is more suitable for road bike fitting as the required adjustments are usually quite small. Stems with a joint usually have a huge range but may be hard to fine-tune.
Reach to the handlebar is primarily adjusted with the stem length, and stems with adjustable length does not exist (except for special very expensive bike fitting-specific stems) so you need to buy the length you need. If you need to make it work with what you got now you can adjust reach by adjusting the saddle fore-aft position instead (review saddle height if you do), but if you do feel that it causes a compromise in saddle position it's certainly worth getting a new stem in the longer term.
As the hands are primarily placed on the hoods or in the drops, an alternative to adjusting the overall reach is to swap out the handlebar to one with longer or shorter reach. Today compact handlebars (short reach and drop) are very popular so it's likely your bike already have one fitted, so it may be hard to find one with even shorter reach if you need to. There are some variations though so it's certainly worth looking into. For pedaling out of the saddle when climbing it's good to have the bar far away, so shortening reach by changing handlebar rather than stem may be a good idea. Don't get a handlebar that feels too small for your hands though, which may happen for the most compact bars. Very compact bars are also less flexible when it comes to placing the levers.
Stem length (combined with handlebar reach) affects handling. Shorter stems lead to twitchier steering, and longer lead to slower more stable steering. A general recommendation is that you should not go below 9 cm or over 14 cm for the stem, and it's better (safer handling) to be on the longer side than on the shorter. Bike frames are typically designed for about 11 cm stems. Professional riders often use longer stems and may even step down a frame size to get a really low aerodynamic position. Note that frames are more or less twitchy by design, meaning that a more stable geometry can do with a shorter stem.
Some modern aerodynamic road bikes have integrated handlebar and stems with little or even no adjustment capabilities. Obviously this type of bike is not a good choice unless you already know the exact fit you need and can get a frame size that matches that, and know you won't need to change your fit anytime soon (due to improved flexibility/fitness for example). I would not recommend that as a first bike. In the most recent time (2019 models) many aero road bikes have become better in terms of cockpit adjustability, but be sure to check how it can be adjusted before buying, and indeed how much it costs. Often you need to buy frame-specific cockpit components as third-party ones won't fit.
Here's a method to find a suitable reach and drop:
Examples of three typical drop bar shapes, the modern compact, the anatomic/ergonomic and the traditional round. Note that the measurements in the image is just showing an example from one manufacturer, FSA in this case. Reach can vary between say 70mm for the smallest and 100mm for the longest, and drop from 120 in the smallest to 170 in the largest. Also note the different positioning of the levers, the compact handlebar yields significantly less drop to the hoods than a traditional bar.
The bars are shown in their neutral rotation. For the anatomic and traditional types that usually means that the bottom horizontal section is level, while the compact handlebar instead is rotated up so the top section is level, which yields a horizontal platform seamlessly transitioning into the hoods. Today the most common hoods position on compact handlebars is a bit farther back/up than shown in the figure, to yield a slight uphill slope (of about 5 degrees) for better hand comfort when in the hoods.
Example how you get less drop to the hoods and more comfortable angle for the wrists by angling up the drop bar (right) compared to keeping it neutral (left). Note that this example is showing more up angle than would typically be used, but the drops still work well thanks to the compact bar design.
The photo shows older style levers, more modern levers can generally be mounted farther back without affecting braking lever reach in the drops too much, this way a comfortable uphill slope can be achieved without angling up the bar.
The neutral position of the levers depends on handlebar design. The most popular handlebar today is (variations of) the "compact" type and it's designed to make a horizontal or near horizontal platform from top of the handlebar out to the hoods. Traditional round bars slope down with levers mounted lower, meaning that you get a lower position with the same stem. Traditional round bars (and the "anatomic" types) are today rare on pre-assembled bikes.
There is little reason not to use a compact handlebar for most riders, but if you are a flexible strong rider you may prefer a traditional design to get into lower position on the hoods and even lower in the drops, and indeed traditional bars can still quite frequently be spotted among professional riders, perhaps most among sprinters that want a low horizontal section to hold against when forcefully sprinting.
The shapes are in no way standardized, so although one can talk about the three major types compact, anatomic/ergonomic, and traditional/round, there are significant variations in shapes between manufactures, and there are many "crossover" types that sits in-between.
Levers can be mounted slightly higher or lower on the bar, but make sure they are level or pointing up slightly, never noticeably down, as it won't be as comfortable and is less safe when you have the hands on the hoods.
When fine-tuning the position of the levers you need to favor either the hands on hoods or hands in drops position. The best hoods ergonomics is often with levers slightly higher than neutral, and in the drops slightly lower (not by much, total range of reasonable positioning is a centimeter or so on the bar). It's generally not possible to have both fully optimized at the same time. Roughly speaking the neutral horizontal position is optimized 90%/90% for both positions, slightly up is 100% for the hoods and 80% for the drops, and down 80/100. How much this affects you will depend on how large hands you have and/or if the levers have good reach adjustment. If you have larger hands or you can adjust in the braking lever reach when mounted high, the drops ergonomics can still be very good despite an optimization for the hoods.
If you are the type of rider that spend very little time in the drops, angling the drop bar slightly up and/or mount hoods slightly higher is often a good idea. Observe the angle in your wrists when holding the hoods. Be careful not to angle up the bar so much that the drops position becomes awkward. How much angle the bar can take while still working in the drops depends on its shape and other factors in the fit, so you need to test. Note that if you have an aero bar with the tops shaped to a wing you should try to minimize any angling as that will affect aero performance.
A typical setup for a compact drop bar today is to have the top section fully level (or any other angle that is the manufacturer neutral position for the model used), and then mount the levers slightly high so they yield about 5 degree slope in the hoods position. This way a comfortable slope in the hoods can be combined with good ergonomics in the drops. Not all lever and bar combinations allow for this setup to work in your fit though.
The position in the drops always requires some twisting of the wrists when holding the braking levers, unless you ride very low with bent elbows and near-horizontal forearms. Modern compact handlebars are usually much better in this regard than traditional designs though. When riding on open flats when you don't need immediate access to the brakes you can use a more comfortable spot in the drops further down on the hooks where you get less twisting in the wrists.
When in the drops the reach to the braking levers may be long, especially if they have been angled up slightly. Many levers today have a reach adjustment so you can move the braking lever closer to the handlebar, a useful adjustment if you have small hands. In addition, or if reach adjustment is not available, you can adjust your brake cables so the brakes engage later (make sure you can still brake in full). When descending in the drops you can then grip the brakes and pull them to a comfortable reach without starting to break. Hydraulic brakes may not be possible to adjust in this way though. More expensive group sets often have more adjustment capabilities than the budget alternatives.
The levers can also be rotated inwards or outwards, but they should be kept straight ahead for best aerodynamics and cable routing. If you feel a need to rotate them consider to change bar width instead to get a suitable hand position.
Traditionally the width of the handlebar is set based on shoulder width. The wider shoulders, the wider handlebar. Traditional sizes for men are 40, 42 or 44 cm center-to-center (note that some manufacturers measure side-to-side rather than center-to-center).
For most this is a less important adjustment, and if you make a change it's often to change the handling rather than fit. A wider handlebar makes the steering slower and more stable and it may feel a bit easier to balance at low speeds. A narrower bar improves aerodynamics slightly and makes it easier to push through in tight spaces in a race (narrow bars are popular in professional racing), but the difference is pretty marginal. Some prefer wider bars on their gravel and cross bikes compared to their road bikes.
If you do want to match shoulder width the idea is that the hands should not need to flare in or out when holding them on the hoods. In other words, the width that naturally puts your wrists in the most comfortable alignment is the best. To relate to a measurement on the body the center-to-center handlebar width should match the bony peaks on the shoulders (that is not the maximum width). This is not that relevant though as our arms are plenty long enough to handle wider or narrower bars without twisting the wrists.
Note that a narrow bar may complicate an elbow/knee overlap situation (check when in the drops with bent elbows). A too narrow bar may also cause you to flare out with your elbows in your normal relaxed position, making you less aerodynamic rather than more.
Measure the bike using the back wall and floor as reference planes. Measure horizontally and vertically using a spirit level and a ruler (green lines) and subtract the values to get relative offsets (red lines) that you can record and use when recreating the fit on another bike.
The image only shows a set of example measurements, the same technique can be used to derive any other measurements you may need. If you want measurements for a geometry chart it's often quicker to make a quick online search to get the chart from the manufacturer, but if that is not available you can get decently accurate measurements using this technique, especially if using a dedicated Bike Geometry Calculator.
Once you have completed your bike fit you may want to record it. If the purpose is to be able to take apart re-assemble the same bike, it's easiest and most reliable to use the markings on seat-post and saddle rail etc instead of making actual measurements.
If the purpose is to replicate the saddle, bottom bracket and handlebar relative positions over to a different bike with a different geometry you need to measure those actual positions and transfer them. Without special measurement equipment (like bike fitters and pro teams have) it's quite hard to measure a bike accurately. If you just have a ruler, holding it off-level or reading it off-level will cause significant errors.
Instead of getting the traditional measurements directly it's easier to get accurate measurements by setting up perpendicular reference surfaces and then only do horizontal and vertical measurements using a ruler and a spirit level. Here's how: place the bike on a stand or on a trainer so it's perfectly level and upright. As an alternative you can very carefully lean it as close to upright as possible against a wall. Let the rear wheel touch a back wall, so the floor and back wall forms two perpendicular reference planes. Now let's measure the following:
Using these measurements we can now subtract to get the relative positions, and then copy them on to the next bike. Note that as we measure from saddle tip or rear we assume that the saddle on the other bike is of same or very similar shape. If not you need to estimate where on the saddles you will be centered and use that as a reference on both.
In this example we don't measure anything about the handlebar, thus we assume the same handlebar is being used in the same setup. You can quite easily complement with handlebar measurements though.
To get some support doing this type of measurements you can use my Bike Geometry Calculator.
To make a good bike fit you need to start with a properly sized bike frame. The most common way to buy a bike is to buy it complete with all parts mounted, with the intention to not change any part. Reach is mainly adjusted by swapping out stem and handlebar so you give up that aspect of bike fit if you keep the bike as is, thus it's then even more important that the bike is of suitable size.
However, if reach is not too long we can accept a quite wide variability in exactly how much we bend our backs, a typical range for amateur riders is 50 to 40 degrees with the hands on the hoods and that makes up for a reach difference of about 4 centimeters. That is you can indeed most often get a good fit with only saddle height and fore-aft adjustment.
Frames have different design goals. A race machine aimed at pro level cyclists generally has a lower front end for the same size when compared to an endurance or "sportive" geometry (which have a bit shorter reach and higher front end). An aggressive race bike may still fit a inflexible novice rider, but it may then need plenty of spacers under a riser stem.
Simply put, there can be frames that despite the right size for your body dimensions still won't suit you as they have a too low front end for your current flexibility and adaptation, or at least may look a bit strange when enough spacers and stem rise are added.
In other words, it's generally less risky to get an endurance or sportive geometry, than one designed for high speed racing. If you are going to approach or push the limit of what your body can handle in terms of aerodynamic position it's more important that you really take your time to evaluate the frame size and geometry.
If you're new to drop bar bikes I strongly recommend to get a endurance/sportive geometry, even if you are flexible. It's easier to make a suitable fit with these geometries and it's still possible to make a very low position as you develop. That said, there are today endurance geometries that are overly high (especially in the gravel/adventure genre), and race geometries that are not too extreme. Looking at the actual geometry charts is best.
Here's a few methods to find the right frame size:
While model-specific body-length-to-size tables work well in many cases, especially for more relaxed geometries, I do recommend to take a look at geometry charts, especially if you have a bit unusual body proportions. Then you either need an existing well-sized bike to compare to, or use a calculator (or do both).
Most calculators found online aren't that detailed, but the one found at the Competitive Cyclist website (Competitive Cyclist's Bike Fit Calculator) is good.
If you already have an existing bike that has a reasonable fit, use measurements from that as the main reference rather than a calculator. A calculator won't take into account your flexibility for example; if you are really flexible your back will be quite flat and you reach longer than if you have a more hunched back when reaching forward. This has a larger effect for more aggressive positions. With a 40 degree back angle it may differ say 2-4 cm in reach between a flatter and a more hunched back. That is generally not more than you can fix with a stem and/or handlebar exchange, but it's of course worthwhile to try to get it right to start with.
Geometry charts are often not that easy to analyze as there is no standardized way to make them, and to make things worse manufacturers often leave out measurements we'd like to have.
The easy way is to only look for horizontal top tube length which most charts have (use a bike fit calculator or an existing bike to find out what you need). Note that most frames today have sloping top tubes, so if you measure on an existing bike be sure to use a bubble level rather than measuring along the tube itself. If we only look at horizontal top tube we assume that 1) front end stack is not too low or high, 2) seat tube angle, seat post extension and stand-over height won't be a problem. If we have fairly normal body proportions and we get a sportive or endurance frame this should indeed work out fine. If you know that you have long legs and a short torso or the other way around, you should analyze the geometry in more detail.
Slightly better than only the top tube is to compare "stack" and "reach", those are however not always available in the charts and is a bit cumbersome to measure on an existing bike (but you can, see the section on measuring the bike).
The thorough way is that after you have used a simpler method to guess what size you need, you then make a complete bike drawing from the geometry chart, using my online Bike Geometry Calculator, or a dedicated bike CAD software like the free RattleCAD. With a complete drawing you can make a more detailed comparison with an existing well-fitted bike (preferred) or if lacking that, the bike fit calculator result. In addition we can make some sanity checking of a few standard measurements.
The reason for making a complete drawing (including saddle and handlebar) even if the geometry chart is detailed is that frame measurements like stack and reach doesn't provide the whole truth. The slope of the seat tube will move the saddle farther back the higher it is, thus increasing reach. You also generally need to figure out how many spacers you can fit under the stem (depending on available steerer tube length), and then experiment with stems. Also note that handlebar type (and model) can significantly change both reach and drop. Today most will choose a compact handlebar.
It is quite time-consuming to make a drawing, and you will most likely end up at exactly the same sizing as when using a simpler method. If you really want to make sure to get it right and take fine nuances into account I do recommend this method though. You may come to the conclusion that there is no size for the evaluated model that suits you so you need to look for some other model. With simpler methods you generally miss that and may buy an unsuitable frame geometry.
To be able to place the saddle properly in relation to the bottom bracket in your drawing you ideally already have a fitted bike to take measurements from, otherwise you need to make some guesswork, for example using numbers from the bike fit calculator, or just leave the saddle in its default center position which usually is fine when bike sizing is good and you have average body proportions.
When you have the drawing with the saddle placed, it's time to do some sanity checking:
If the reach is too long or short, or drop too large or small, you can experiment with stem adjustments in the drawing. A stem shorter than 9 cm or longer than 14 is not recommended due to the effect it has on handling (most pre-assembled road bikes are delivered with a 10 or 11 cm stem). Often frame sizes are spaced close enough that you should be able to find a reasonable fit with the standard stem applied.
If you know which handlebar you are going to use, you can add that to the drawing too, getting the complete reach all the way to the hoods. The difference between a compact and a traditional handlebar can be 2-4 cm in reach, that is significant. The brand of levers (Campagnolo, SRAM, Shimano) affect the reach slightly too but it's small enough so you can ignore it while sizing.
It may turn out that you are in-between sizes. Is it then better to get the smaller or the larger frame? The smaller has shorter reach, but also lower stack. If it seems more reasonable to raise the front end with spacers than to shorten the length with a shorter stem, go for the smaller size, otherwise the other way around. Or choose another model that has more on-the-spot sizing for you.
When you buy a frame set or complete bike second hand, note that there is a risk that the previous owner has cut the steerer tube very low, maybe completely "slamming the stem", that is leaving no space for spacers under the stem. This is common if you get a fairly recent second hand higher end race bike. While this can often be compensated with a riser stem it does make the bike look a bit strange, with both slamming and rising at the same time.
New frame sets come with the steerer tube uncut so you cut it to length after fitting.
New pre-assembled bikes usually have 2-3 cm of spacers under the stem, plus the bottom cone (about 1cm). Spacers can be moved and placed above, so this is thus 2-3 cm of adjustable height. Unfortunately the stack height added by headset and spacers is usually not specified in the geometry diagrams, so if you don't have access to the actual bike you need to look at photos and estimate how much stack is added on top of the frame. Note that marketing photos generally show the bikes with the steerer cut low and little or no spacers to make it look more racy. To see how many spacers the bike is actually delivered with you may need to make a broader image search to find actual consumer photos.
If you have a carbon steerer tube it needs a compression plug (also called expander plug) to avoid over-compression by the stem and to strengthen it for the forces put to it through the stem. In many cases the plug delivered with the bike is so short that you cannot have spacers above the stem. That is if you want to lower the stem you either need to cut the steerer tube so you don't need spacers above the stem or get a new longer compression plug. I suggest getting a longer compression plug.
A few exclusive brands offer custom geometry frames. Unless you have a very unusual body geometry I consider this overkill in terms of fit, as most can find several off-the-shelf bikes that through adjustment and component selection can be made to fit you as well as a custom-made frame.
Bike fit in a frame is basically just about stack and reach which yields a suitable aggressive or relaxed position for your desired riding style. The rest of the geometry is about handling and stiffness and other factors unrelated to fit. If you want an endurance bike, I recommend a frame that has from the ground and up been designed for endurance, rather than using custom geometry just to reduce reach and increase stack of a frame otherwise designed for smooth tarmac racing. And if you go for a frame designed for the style of riding you want there nearly always is a suitable size for you.
There are exceptions though of course, if you are very short or very long there may not exist sizes for the type of bike you want and then a custom geometry may be the solution. And of course, having a custom hand-built bike made just for you is something special, there is certainly a value in that even if you don't have any strict need for a custom geometry. The geometry is just one aspect of a custom bike.
It's also worth mentioning that geometry is not only about fit, it's about handling too. If you are a very experienced bike rider you may have developed a refined taste for certain aspects of bike handling, you may want a certain length of chainstays, certain amount of trail etc. If you really know what you want out of the frame in all aspects, a custom frame can be a worthwhile investment.
Cyclists often care about how they and their bikes look, and unfortunately in some cases they also vocally care about how others' bikes look, and this can become an enemy of good bike fit. The problem is that some amateur cyclists without having the required fitness and adaptation want their bikes and positions look like the professionals, very low, very aerodynamic, very aggressive. So they buy a bike that doesn't suit them, and put themselves in a very aggressive position which they simply can't hold without severe discomfort.
If you do want a racy-looking bike without the ability of handling the most aggressive positions there are a few optical illusions you can employ to maintain both a good fit and a nice look:
Finally, the best friend of a good fit is good confidence, so you don't actually care about these vanity things or what other cyclists think of you or your bike. It's unfortunately true that the cycling community have some "style police" roaming about, a phenomenon not seen as much in other sports. The best way is of course to ignore this alienating aspect of the cycling culture, and just enjoy your well-fitted ride.