BIKE FIT GUIDE

1. Stand barefoot with your back against a wall, feet about 15cm apart.
2. Pull a hardback book firmly up between your legs, spine level, as high as you can comfortably tolerate.
3. Mark the top of the book on the wall and measure to the floor.
4. Do it three times and take the largest number. That is your inseam.

Then use the saddle height calculator to turn it into a starting saddle height.

Set it

Measure from the centre of the bottom bracket to the top of the saddle along the line of the seat tube. Set it to roughly 0.883 x inseam. Then check it on the bike: with your heel on the pedal at the bottom of the stroke, your leg should be almost straight, with your hips staying level.

Read the symptoms

• Put the cranks horizontal. Drop a plumb line from the front of your forward kneecap — it should fall roughly at the pedal axle.
• Ahead of the axle loads the front of the knee. Well behind it loads the back of the knee and the hamstrings.
• Tilt: level, or the nose 1-2 degrees down at most. Nose-up creates soft tissue pressure, nose-down makes you brace with arms and lower back.
• Moving the saddle back or forward changes your effective saddle height, so re-check height afterwards.

• Fore-aft: the ball of your foot at or just behind the pedal axle. Slightly rearward reduces load on the calf and front of the knee.
• Rotation: match your natural foot angle. If your heels want to sit out, let them. Forcing straight feet is a classic cause of outer knee pain.
• Float: keep some. Zero-float cleats belong to riders who have already had their fit measured properly.
• Stance width: if your knees splay out or brush the top tube, look at pedal spacers or a different pedal axle length.
• Insoles: arch support helps riders whose feet collapse inwards under load.

• You should be able to ride your normal position for a full hour without the lower back complaining. If not, the front end is too low or too long.
• Raise bars before shortening the stem. Spacers are free; stems are not.
• Aim for a slight bend at the elbows and shoulders that are not shrugged.
• Bar width roughly matches shoulder width. Too wide opens the chest but adds strain to the shoulders.
• Numb hands mean too much weight through the bars — usually a reach or core problem, not a glove problem.

Copy your outdoor numbers across: saddle height, setback, saddle-to-bar drop and saddle-to-bar reach. On a smart bike, write those four numbers down once and you can rebuild the position in a minute. Two indoor-specific notes: keep the whole bike level, because a mismatched front block quietly changes every angle, and remember that never coasting means your position is held for the entire session, so small errors feel much bigger indoors.