How to do your own DIY bike fit

Try sitting more upright and further back. When you’re aiming to get more comfortable on your bike, it’s sometimes that simple.

I’m a journalist not a bike fitter but I’ve ridden hundreds of bikes and had four bike fits: one more or less endorsed what I was already doing; one felt awkward but didn’t hurt; two were painfully wrong.

Bike fitters may or may not be experts on bike geometry and physiology. None of them is an expert on what you find comfortable. You are.

A good bike fitter will at least get you in the ballpark for fit; I’m not suggesting that bike fitting is snake oil. But bike fit theories tend to be extrapolations of measurements that seemed to work for racing cyclists in the prime of their lives.

Systems based on such measurements work fine for sports people in their 20s and 30s. For others, not so much.

And there’s another fly in the bike-fitting ointment when you’re primarily looking for comfort. The current trend, on road and off, is for steep seat angles, short head tubes and (particularly for mountain bikes) long top tubes. These have the effect of tipping you forward onto the handlebar.

On road this can work well for aerodynamics and for applying maximum power through the pedals. Off road it’ll help you weight the front end on climbs and descents, and a supple suspension fork will stop your hands being jackhammered.

Yet there are drawbacks. Common ones include numb or tingling hands, aching shoulders, a sore neck and lower back pain. Sound familiar?

What follows is a list of things you can try to improve comfort. If you’re comfortable on your bike, you’ll enjoy it more and you’ll ride more.

The right size bike

Your bike needs to be roughly the right size to begin with. Bikes are generally sized by the seat tube length in either inches or centimetres. A road bike might be listed as 54cm, a mountain bike 18in. Often bikes are described simply as small, medium and large, so check geometry tables for seat-tube lengths.

When bikes had horizontal top tubes, sizing by seat tube made sense. You could work out whether you could reach: a) the pedals; b) the ground. Nowadays, seat tubes are truncated to accommodate sloping top tubes and they’re seldom sized consistently between different bike types or models.

You can nevertheless get a good steer on your target bike size by using a guide that former technical officer Chris Juden wrote some time ago for Cycle magazine.

I’ll paraphrase it. The medium-sized bike in most bike ranges is designed to fit the average height man. In the UK, he’s 5ft 9in (about 176cm). If it’s a women’s-specific bike, medium will be designed for the average height woman, who in the UK is about 5ft 4in (162cm).

If you’re around average height, the medium should more or less fit. If it’s not listed as such, medium is the arithmetic mean of the available sizes – the average. So if a bike comes in sizes from 50cm to 60cm, 55cm is medium.

Bike sizes vary half as much as height. If you’re taller or shorter than Mr or Ms Average, add or subtract half the difference between your height and theirs to the medium size that Mr or Ms Average would ride.

If Mr Average needs the 55cm bike and you’re 180cm (about 4cm taller), you likely want a frame that’s 2cm bigger: 57cm. If the medium is 18in and you’re 5ft 5in (4in shorter), you probably want a bike that’s 2in smaller: 16in.

You might find yourself between sizes, wanting a 57cm bike when it’s available in 56cm and 58cm sizes. Don’t worry. Either might work for you. Bike fit is a dynamic issue that can be determined only approximately by static measurements.

People have different bodily proportions and different levels of flexibility. It’s not uncommon to find that you’re more comfortable on a bike that’s one size ‘too big’ or one size ‘too small’.

I often size up with road bikes to get a taller head tube and thus a higher handlebar position. But I once met a guy taller than me who rode a really small road bike fitted with a 140mm stem and an extremely long seatpost. He wanted a huge saddle-to-handlebar drop and was happy with the result.

Zero-cost bike fitting

You can make these checks in store if buying a new bike, or at home if your existing bike isn’t as comfortable as you’d like.

Stand over the bike

You need at least a couple of centimetres of clearance between your crotch and the top tube or you risk bruising your undercarriage when you get off the saddle. More is better if you’ll be riding off road.

Set saddle height

Many casual cyclists have the saddle too low. Many cycling enthusiasts have it too high. Sit on the bike. You’ll need an assistant or a wall.

Adjust the saddle height until, with the heel of your foot on the pedal, your extended leg is just straight when the pedal at its furthest point, with the cranks in line with the seat tube. That’s your approximate saddle height.

You can tweak it from here, depending on preferences and pedalling style: are you a heel dropper like me or a toe dipper? Be careful of putting the saddle too high to ‘gain power’ – you’ll rock your hips which may hurt your back.

Over reaching to the pedals may also squash your undercarriage as you pedal. Saddle sore? Try dropping your saddle. Start with a 5mm reduction.

As for saddle angle, start with horizontal. Some cyclists, especially taller ones with a large saddle-to-handlebar drop, find that it’s more comfortable to tilt the saddle down a few degrees.

Assess handlebar height

Many road bikes have the handlebar set very low relative to the saddle. A better starting point for non-racers is to have the top of the handlebar level with the top of the saddle (whose position you’ve just set). Can you get the handlebar this high by moving the stem up the steerer tube and/or fitting the stem the other way up?

If the steerer tube has been cut off just above where it emerges from the head tube, you can’t raise the stem any higher than that. It’s a bad idea to have an excessively long steerer tube in any case, unless it’s made of steel, as it may shear!

So a large part of being able to get the handlebar high enough is having a frame with a tall enough head tube or a fork with a steel steerer tube.

Assess handlebar reach

The saddle-to-handlebar distance determines how stretched out you’ll be on the bike. You can estimate a position you’ll find comfortable like this: put your elbow against the nose of the saddle and reach your fingers towards the centre of the handlebar, where it’s clamped by the stem.

If it’s more than two-to-four fingers’ width away, the bike is probably too big or has a stem that’s too long. If it’s closer than just-touching distance, the bike may be too small or have a stem that’s too short.

Sit on the bike to check, putting your hands on the brake hoods (drops) or grips (flats). You want at least a slight bend at your elbows, so your hands are essentially resting on the handlebar as opposed to propping you up. If your elbows are locked out, the bike is too long or low for you. Bumps and vibrations will travel up your arms.

Assess weight distribution

Many cyclists carry too much weight on their hands for comfort. Here’s a simple check, which takes account of core strength. Colin Thomson (who posts as 531colin on the Cycling UK Forum) makes this excellent suggestion whenever bike fit comes up there. You’ll need to put your bike on a turbo trainer or have someone to hold your bike.

Sit on the bike with your hands on the brake hoods. Now, without changing the angle of your torso, remove your hands and put them behind your back.

If you can’t hold the same position: the handlebar is too low and/or too far forward; the saddle is too far forward relative to the bottom bracket; or both.

One of the simplest adjustments you can make to weight distribution is to slide the saddle back on the seatpost, which slackens the effective seat tube angle. Try it. Slide it back as far as it will go just to feel the difference. You can always move it back.

More of your weight will now be carried by your backside than your hands. You may find that you want a commensurately shorter stem to maintain the saddle-to-handlebar distance, and you may need to lower the saddle slightly to maintain the saddle-to-pedal distance.

Some bike fitters will recommend that your saddle position is set so that your knee is over the pedal spindle (KOPS). That may work for you but don’t worry if it doesn’t. Keith Bontrager blew holes in it as a prescriptive measurement years ago. I prefer ‘behind KOPS’ and just slide the saddle right back on bikes with a seat tube steeper than about 72º.

Buying parts to fine-tune your fit

If your bike’s contact points (handlebar, saddle, pedals) aren’t where you want them after adjustments, you’ll need to buy new parts. Prices below are guideline minimums; you can spend much more.

New stem: from £15

A new stem may be the only extra component you need to fix your bike fit. They’re readily available in lengths from 35-120mm, and they exist in even shorter and longer lengths.

Stem angles vary from about 6º to 35º or more. There are online calculators to help you work out where your handlebar will end up. If even a steeply angled, tall stem won’t get the handlebar high enough, a stem riser – essentially a clamp-on section of extra steerer tube – may do so.

New handlebar: from £20

The width and shape needs to be comfortable. A drop handlebar wider than your shoulders can feel unwieldy but narrower ones seem OK. I ride 38cm drops as I have a fairly slight build. But Chris Hoy also rides narrow drops on his road bike because they’re aerodynamically more efficient and because he’s used to narrow bars from track racing.

Flat bars have been getting wider and wider recently, which is great for steering leverage but can feel too wide for comfort. If you’ve tried them and they feel uncomfortably wide, cut them down. Cross-country racer Nino Schurter evidently has a 700mm bar, which keyboard warriors would decry as far too narrow. He does pretty well on it!

If you don’t like a straight bar, try one with more backsweep, like one of the alternative bars we tested recently. Changing the width of the bar will also change the effective saddle-to-handlebar distance. As your hands move horizontally further apart, your body has to lean further forward to compensate.

So a new bar may necessitate a new stem. Changing between a flat-topped handlebar and a riser handlebar will affect how upright you sit. ‘Flat’ bars are readily available with up to 75mm rise, while riser drops are now a thing. You can use a riser bar as well as or instead of a higher-rise stem.

New seatpost: from £15

Seatposts have the clamp in line with the post or offset by anything up to 30mm.This layback (also called setback) lets you put the saddle that much further back – or forward if you’re switching from a layback post to an inline one.

New cranks: from £45

Although cyclists’ heights vary a lot, crank length doesn’t: you typically see 170mm, 172.5mm or 175mm – occasionally 165mm. Cranks longer than about 10% of your height may give an awkward pedalling action with lots of knee bend.

Shorter cranks suit shorter riders and anyone with limited knee articulation but can also be used by cyclists who don’t ‘need’ them. I’m 177cm tall but prefer 165mm cranks as they’re easier to spin faster, which suits how I pedal. In fact, I’ve now got some 155mm cranks on test.

New pedals: from £20

Unless you’re confident you can set clipless pedal cleats up just right, go for some with plenty of float, such as Speedplay, Time ATAC or Crank Bros Eggbeaters.

If you’ll be using pedals with less float, you could try putting your bike on a turbo trainer, closing your eyes, putting your cleatless feet on the pedals in whatever angle feels natural, then photographing the results with your phone.

You can then use this as a guide to setting up the cleat angle – bearing in mind that turning the cleats inwards angles your feet outward. However, cleat angle is one of those situations where a good bike fitter can prevent niggling problems further down the line.

For the fore-aft position of cleats, the accepted theory is to put them inline with one of the metatarsal joints to get it under the ball of your foot. I forget which as I’ve had more success by just putting the cleats as far back as they’ll go on the shoes, which seems to prevent foot fatigue and improve power generation.

Flat pedals cause few bike-fitting problems as you can place your foot however you like. The facility to do this may instantly solve knee and hip problems caused by incorrectly set cleats. I don’t get knee pain but use flats most of the time anyway as the pros (practicality, comfort) outweigh the only con (marginal efficiency loss).

And finally…

It’s tempting to think that there’s a bike fit holy grail out there, with one perfect set of measurements for you. That’s unlikely. Most of us have what bike fitter Phil Burt calls a ‘bike fit window’ – a range of measurements within which we can be comfortable.

Changes to the setup of your bike may feel odd at first, simply because it’s different from what you’re used to. Give it a few rides. If it’s not working after that, change it back or make some other adjustments.

Lastly, take any bike fit advice, including this article, with a pinch of salt. If you’re comfortable, your bike fit is fine and you’re doing it right.