What happens during a bike fit?

Many riders feel that they know what works for them, or have got used to the way their bike was set up when they bought it. But a bike fit can help to make riding more comfortable and help you improve as a rider. Here’s what you can expect from our Ultimate Bike Fit with Nas Karimi, our in-house professional bike fitter.

Bike fit

Why you need a bike fit

Nas says that many cyclists feel that they don’t need a bike fit. Novice riders think it’s just for elite riders, while experienced cyclists think that it’s only for newbies. In reality, both will benefit from having their position assessed and adjusted by an expert. Even the pros have their position reassessed regularly.

Although cycling is a low impact sport, the fact that you’re mostly sat in the same position, often for long periods, and repeating the same limited range of motions thousands of times means that a sub-optimal position can lead to injuries or aches and pains. Your feet, hands, arms and upper body are relatively constrained in their range of movement or holding a fairly static position while riding too.

Small changes in position and components can make a significant difference to your comfort and efficiency when riding and the optimal position for you will likely change as you get older or ride more too. Your flexibility might change, you may suffer an injury. For women, pregnancy can alter the optimum position. 

But a bike fit isn’t always about solving a problem, refining your ride position can improve your cycling and your enjoyment. 

What happens during a Pearson Ultimate Bike Fit session?

Book our Ultimate Bike Fit and Nas will spend around three hours understanding your aims for your riding, working to optimise your position and finally reviewing and modifying your current bike position to fit his findings. 

Bike fit

Often a bike fit would have started by looking at how your current bike is set up and adjusting the bike fitter’s fitting bike to match that, then changing things from there or putting your bike on a turbo to look at how you currently ride. 

That’s how Nas was taught to do it, but now he prefers to start from a blank slate, then once he’s established a position, use that to adjust your bike to match the results of the fitting. He feels that this gives better feedback and a more accurate position, rather than being constrained by the range of adjustment that can be made to the bike you are riding.

Here’s what you can expect in each phase of the fit.

Phase One

The first step is to get to understand you as a rider. That starts with Nas asking you about the types of riding that you do and the frequency, intensity and duration. He’ll also ask about any injuries you’ve had or discomfort you’re suffering. 

The best position for you may be different depending on whether you’re primarily interested in comfort or performance – a lower position will be more aerodynamic, but may not be as comfortable to hold for long periods or it may prevent you from using the drops effectively.

Bike fit

Nas will also take measurements and perform a physical analysis to understand your morphology. At this stage, he might spot any asymmetries like differences in leg length that might affect your riding. 

This phase usually takes around an hour.

Phase Two

During the second hour of your Ultimate Bike Fit, Nas will look to find your optimal position and ideal set-up using the adjustable fitting bike in the fitting studio.

This starts with getting the rear of the bike set up right. It’s not just saddle height, Nas will work first on your shoes, cleat position and foot stability when riding. Getting shoes which support your feet well, don’t let your feet slip around too much and match the shape of your feet is important to ensure that your feet are fully engaged with the pedals and comfortable. Poor shoe and cleat set-up can show up in misalignment and pain further up the leg, Nas says.

Bike fit

Crank length and stance width can both affect your pedal stroke as well. Nas points out that the distance between the cranks doesn’t change between bike sizes, although a larger rider is likely to have wider hips than a shorter one. That might result in you pedalling knee-in or knee-out at the top of the pedal stroke, something that can be compensated for by fitting pedals with a different spindle length or by adjustments in the cleats’ side-to-side position on the sole of the shoes.

Next is an assessment of the best saddle type for you and its height and position, along with the best crank length. We’ve got more on how to find your perfect saddle and the different options available. 

The saddle’s fore and aft positioning will also affect the saddle height and how well you’re seated on it. Suboptimal positioning can cause you to slip forward on the saddle or may cause muscle aches and pains. Check out our post on how to set your saddle height for more.  

Bike fit

It’s only when the fit at the rear of the bike is right that fitting turns to the front, where Nas will review bar height, width and drop and the handlebar’s distance from the saddle. Handlebar position should be set up without changing the position of the saddle.

At the same time, Nas may give you pointers on your technique and how you could improve it: how you sit on the saddle, how you hold the bars and how you pedal.

Phase Three

It’s only in the third hour of the fit, once these aspects have been addressed, that Nas will look at how his findings compare to your existing set-up and the changes that need to be made to it to match the measurements from the bike fit. If you’ve previously had a bike fit, Nas will compare his measurements with the numbers from that.

For a novice rider, it’s time to look at options for a new bike purchase, while for a more experienced rider this is when changes can be made to the current set-up.

Bike fit

Nas points out that for modern, integrated bikes, it’s not as easy to change position as on bikes with separate components, particularly at the front end where there might be a one-piece bar/stem, or complex internal cable runs. 

However, it’s usually possible to change a rider’s current bike to reflect the results of the bike fit. In rare cases Nas has recommended returning the current bike, if it’s been bought recently and it’s not possible to reach the desired riding position.

A change of saddle will also affect the ride position, as a different saddle may tend to seat you more forward or aft than your previous model. The height of the saddle top above the saddle rails may be different from your current saddle too. Both can change your leg extension at the bottom of the pedal stroke and may mean that seatpost length and saddle position need to be altered to get back to your optimal position. 

The effect of changes can be gauged by riding the adjusted bike on the turbo in the store before going out and riding outdoors.


A bike fit isn’t one-and-done and you can expect to need to make microadjustments after more riding, so Nas advises scheduling an optional follow-up session after two to three months of riding. This should take around an hour and will assess how well your new position is working for you. 

Bike fit

Nas points out that many riders don’t know what riding their bike should feel like: can you cover your planned ride distances, can you recover well after a ride? Alterations in position may feel strange at first and it’s possible that you’ll feel some discomfort until you adjust to the changes. Incremental changes in a follow-up session may only be a few millimetres to optimise your set-up.

Bike sizing session

Alongside the Ultimate Bike FIt, we also offer a shorter bike sizing session. If you’re looking to buy a new bike, this makes sure that you get the right size bike for you. 

All Pearson’s bikes are custom built up from the frame and components to match the rider, rather than the more normal off-the-peg bikes from mainstream brands that come pre-fitted with standard components and component sizes. This means that we can choose the right components to suit and you’re less likely to need to change components later on to increase your riding efficiency and comfort.

Bike fit

Nas has written a further explainer on the perfect bike fit and some practical details if you want more information. 

Although a bike fit might look like a pricey option, cycling is an expensive hobby. Compared to the cost of a new bike or many components, a bike fit is good value, particularly as it can help increase your enjoyment and performance on the bike. 

It’s easy to book either an Ultimate Bike Fit or a Bike Sizing Session online via our interactive booking system, which lets you select from available dates and times. Alternatively, you can call or message us to discuss your bike fit requirements.

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