How to set saddle height, reach and tyre pressure

Published 2026-10-04 · Updated 2026-10-04 · 1,229 words

Most people ride bikes that are set up wrong, and most of the discomfort they attribute to the bike is actually the setup. Three adjustments fix almost all of it, and you can do all three at home with a tape measure, a set of hex keys and a pump.

Do them in this order: saddle height, then reach, then tyre pressure. Each one affects the next.

Saddle height: the heel method

This is the single most important adjustment on a bike. Too low and your knees hurt and you lose power. Too high and your hips rock, which causes lower back pain and saddle sores.

The method:

1. Put the bike near a wall you can lean on, or put it in a stand.
2. Sit on the saddle in normal shoes, and put your heel on the pedal.
3. Rotate the pedal to the bottom of the stroke, in line with the seat tube (not forward of it).
4. Your leg should be almost straight, with a very slight bend at the knee. If your knee is locked straight, lower the saddle slightly. If the leg is visibly bent, raise it.

The heel method works because it accounts for the difference between the heel and the ball of the foot. When you pedal properly, the ball of your foot is on the pedal, which effectively lengthens your leg by a couple of centimetres. That is why the leg looks almost straight when you use the heel to measure.

Sanity checks:

• If your hips rock from side to side when you pedal, the saddle is too high.
• If you can put your whole foot flat on the ground while seated, the saddle is almost certainly too low.
• If you get pain at the front of the knee, the saddle is usually too low. Pain at the back of the knee is usually too high.

A starting number

If you want a figure to start from rather than a method: saddle height ≈ inside leg × 0.883, measured from the centre of the bottom bracket to the top of the saddle along the seat tube.

For a rider with an 85 cm inside leg, that is about 75 cm. Set it there, then fine-tune with the heel method.

Saddle position: fore, aft and angle

Fore and aft. With the cranks horizontal (three o'clock and nine o'clock), a plumb line from the front of your kneecap should fall through the pedal axle. Most riders are within a centimetre or two of this. Moving the saddle forward shifts weight onto your hands; moving it back takes weight off them and uses the glutes more.

Angle. Start level. A slight nose-down tilt (1-2 degrees) relieves pressure for some riders, but a visible downward slope means you will constantly slide forward and put weight on your hands. If you need a big tilt to be comfortable, the problem is usually saddle height or reach, not the angle.

Saddle choice. Width should match your sit bones, not your body size. Most people are on a saddle that is too narrow. A shop can measure your sit bones in a couple of minutes with a pressure pad.

Reach: bars and stem

Reach is the distance from the saddle to the bars. It decides whether your back, neck and hands are comfortable.

Signs the reach is too long:

• Locked elbows, straight arms.
• Pain between the shoulder blades or in the neck.
• Numb hands on rides over an hour.
• You find yourself sliding forward on the saddle.

Signs the reach is too short:

• Knees coming up towards the bars.
• Feeling cramped, with a rounded back.
• The bike feels twitchy and unstable at speed.

How to fix it: the stem is the cheap lever. A shorter stem (10-20 mm shorter) brings the bars closer and costs £15-40. Stem length also affects steering: shorter is quicker, longer is more stable. If the bike is a size too big, a short stem and a swept-back bar can rescue it; if it is two sizes too big, it cannot.

Bar height matters too. Raising the bars by 20-30 mm (spacers or a riser bar) takes weight off your hands and is the single best change for most commuters and leisure riders.

Tyre pressure: the numbers

Pressure is where people either follow the number printed on the tyre sidewall (which is a maximum, not a recommendation) or guess. Both are wrong.

Pressure should scale with rider weight and tyre width. A heavier rider needs more; a wider tyre needs less for the same support.

Road bikes (25-28 mm tyres)

Tubeless tyres can run 5-10 psi lower. Wider tyres (28 mm and up) run lower than 25 mm at the same weight, which is why modern road bikes have moved to wider rubber: lower pressure is faster on real roads and far more comfortable.

Mountain bikes (2.1-2.4 inch tyres)

Tubeless: 2-4 psi lower. If you are pinching the tyre against the rim on roots and rocks (snakebite punctures), you are too low; if the bike skitters and feels harsh, you are too high.

Fat bikes (3.5-5 inch tyres)

Fat tyres are extremely pressure-sensitive and the difference between 6 and 10 psi is dramatic. Run them too hard and you lose the whole point of the bike; too soft and you will burp the tyre off the rim or damage it on a sharp edge.

Hybrid, city and e-bikes (32-47 mm tyres)

E-bikes are heavier than the equivalent unpowered bike, often by 8-12 kg, so add 5-10 psi to the figures above. Running an e-bike tyre soft is a common mistake: it feels comfortable but it rolls badly and wears the sidewall.

Check pressure weekly

Tyres lose pressure over time, faster in cold weather and faster on butyl tubes than on latex. A tyre that was at 80 psi a month ago may be at 50 now, which is the difference between a fast bike and a sluggish one.

Check before every ride if you ride daily, and at least weekly otherwise. A track pump with a gauge costs £20-30 and is the best money you will spend on bike equipment after a helmet.

The order to do it in, once more

1. Saddle height with the heel method.
2. Saddle fore and aft with the knee-over-pedal check.
3. Reach by adjusting the stem, and bar height with spacers.
4. Tyre pressure last, because it is the only one you will adjust for conditions rather than for your body.

Then ride for a week before changing anything again. Small changes need time to assess; changing three things at once tells you nothing.

Written by the EplusNINE team, Croydon. Specifications quoted in this guide are taken from the manufacturers' published listings for the models we show; prices are indicative and change.