A professional bike fit will help you stay comfortable and injury-free when riding, perhaps improving efficiency and handling, but it's not all good news. Forewarned is forearmed, and all that!
A bike fitter will look at your body's peculiarities and areas of weakness, so prepare yourself for a blunt assessment. You might learn that your quads or hamstrings are tight, your knees are moving out to the sides as you pedal, you slouch in the saddle or that your core strength needs to improve.
Chances are that the bike fitter will break the news gently and it's all part of the process, so don't let it get to you!
You've been riding a long time and you know a thing or two about this cycling lark, so you're bound to have ended up with a position that's there or thereabouts, right? Not necessarily. Some very experienced cyclists have setups that aren't doing them any favours in terms of comfort, efficiency or injury prevention.
We'd suggest that you go into a bike fit with an open mind and don't get defensive if your current position is pulled apart.
Minor tweaks to your riding position can feel large. Dropping your saddle by a centimetre, removing a 10mm headset spacer from underneath your stem, or even something as small as shifting your cleats a few millimetres can made a big difference to the way your bike feels.
A lot of people are prompted to go for a bike fit by pain or discomfort, often from the foot or knee. Sometimes the issue can be as simple as poorly positioned or worn out cleats.
As a cleat wears, the position of your shoe on the pedal can alter. This can affect the alignment of your ankle, knee or hip and lead to problems.
For this reason you should regularly check your cleats for wear and damage and replace them when necessary.
Some people see a bike going cheap – perhaps in an online sale or secondhand from a friend – they snap it up and then ask a bike fitter to sort out their position.
That's really not the way to do it! You need to know your bike size and key measurements before doing the shopping. It's not a bargain if it's not the right size!
You might be able to get the right saddle height with masses of seatpost extending out of the frame, and you might be able to sort the right handlebar position, perhaps with a huge stack of headset spacers and a super-long stem, but if you're on the wrong sized bike the handling is going to suffer.
Do yourself a favour and buy the right sized frame to start with, and that might mean having a bike fit first.
The guys at CycleFit are obsessed with feet and will have you walking backwards and forwards before sitting you on a bike. They start with foot control and move on from there.
A successful bike fit requires lots of input from you. You need to go armed with relevant information – there's no point realising on the way home that you forgot to mention an old ankle injury that occasionally flares up. And you need to ride on the static bike in the same way that you ride out on the road, rather than trying to look good for the bike fitter!
Some bike fits rely on a lot of technology and it can be easy to get overawed, so remember to pipe up if something doesn't feel right, and ask lots of questions.
Every rider is different in terms of physical dimensions, history, objectives, strengths and weaknesses, and a good bike fitter will take all of this into account. It's not just a case of rocking up, having a few measurements taken and being out the door 10 minutes later.
Also, two bike fitters might well suggest two different riding positions, depending on their school of thought.
Bike fits come in different depths and flavours. Many bike fitters use a system that they’ve bought into. Retül Fit, for example, is a Specialized-owned system that uses 3D motion capture technology to measure your movement, “providing you and the fitter with data to support the choices made during the fit for your cycling equipment and personal riding experience.”
Other bike fitters essentially rely on their experience and eye, and perhaps elements of other systems that they've used over the years.
Dedicated bike fitters generally charge premium prices. If you just want someone in a bike shop to have a quick look at your position and give it a thumbs up or thumbs down, fine, but this is very different.
Make sure you know what you're buying into and ask about the credentials, knowledge and skills of any bike fitter that you’re considering.
One traditional method of helping to determine your ride position was to set the saddle so that the front of the knee was directly over the pedal axle (measured with a plumb line) with the crank in a horizontal position. You still hear that said, but things have moved on a long way since then.
Today's bike fit systems are based on much more data than that, but – who knows? – maybe they'll also be outdated before long too.
A bike fitter could recommend that you change your stem, handlebar, saddle, shoes or some other component/accessory – perhaps even your frame. That's going to cost some money.
Bear in mind that most (not all) bike fitters are also in the business of selling bikes and components. There's nothing at all wrong with that, of course, but the more cynical might point out that it's in their financial interest to suggest a new setup that involves buying from them.
On the other hand, the bike fitter might tell you that your current ride position is spot on, in which case you'll have paid out and got little back.
A bike fit can take into account any aches and niggles you have but it's not a panacea for every ill. You might have a knee or ankle ailment that no amount of tinkering with fit can cure, meaning that it's a case of managing the condition.
Many issues demand extra work following a bike fit. If your back pain is caused by tight hamstrings you're going to have to stretch them out regularly. If you're lacking core strength you're going to need to do some conditioning.
A good bike fitter will give you detailed follow-up instructions.
You might have been using a certain setup for months or even years, so when changes are made during a bike fit everything can suddenly feel strange... Really strange. A new position might work your muscles differently, it could demand more flex in your lower back or put more weight on your arms. The bike fitter might suggest that you alter your riding style or increase your cadence.
It takes time to adjust to these changes. A bike fit session is usually the start of a process of change rather than an instant solution.
If you really can't get on with a new ride position, you might need to return to your bike fitter for a follow-up appointment.
“[Having a bike fit] every year should be a good aim, but obviously that isn’t always realistic for some people," says Jake Yarranton from Precise Performance. "Your fitness levels might improve or decrease, you may have suffered an injury, or your targets may have changed so you have to reassess what your position looks like.” he adds.
Your flexibility or weight could alter and if you're a woman you could have a baby. Any of these things could affect your optimum riding position and mean that it's time to go and get yourself a fresh bike fit.
Once you've had a bike fit, bear in mind that replacing components and accessories can make a big difference. A change in seatpost setback, stem length or handlebar width is clearly going to affect fit, but other variables are less obvious.
Saddles have different stack heights (distance from the rails to the top of the padding), for example, meaning that a new perch could leave you sitting higher than before. We're not talking about a couple of millimetres here; some saddles are well over a centimetre taller than others, and not many brands give you this measurement on their product information.
Saddles are also very different shapes. A bike fitter might use a pressure-mapping system to help you select the most suitable model. Ditching it because you fancy something lighter could be a big mistake in terms of comfort and might have a knock-on effect on the rest of your bike fit too.
Similarly, shoe soles vary considerably in thickness, altering your knee angle at full flexion and extension. There are loads of other variables when it comes to shoes: the angle of the sole, the level of stability, the arch support, and so on.
Even things like the lever hood length varies between different brands, so if you're happy with your current bike fit and something wears out, it's worth replacing like with like.
If you've had experience of a bike fit – good or bad – let us know about it in the comments below.
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.