Setting saddle height without the guesswork

Almost every bike that comes through here for the first time has the saddle too low. It happens because a low saddle feels reassuring when you are stationary, since you can get a foot down flat. But you spend almost no time stationary and a great deal of time pedalling, and pedalling with a saddle an inch too low is both slower and harder on your knees.

Here are two methods. Use the first to get close, and the second to check.

The heel method, for getting close

Sit on the bike, leaning against a wall or with someone holding it. Put your heel on the pedal and turn the cranks until that pedal is at the very bottom, in line with the seat tube rather than straight down.

With your heel on the pedal in that position, your leg should be completely straight, and your hips should stay level. If you have to rock or tip a hip to reach, the saddle is too high. If your knee is still bent with your heel down, it is too low.

When you then move to the ball of your foot, which is where it actually belongs, you will have the right amount of bend. This gets you within a centimetre in about two minutes.

The measurement method, for checking

Stand with your back against a wall, no shoes, feet about fifteen centimetres apart. Put a book between your legs and pull it up firmly, the way a saddle would sit. Have someone measure from the top edge of the book straight down to the floor. That is your inseam.

Multiply it by 0.883. That number is the distance from the centre of the bottom bracket to the top of the saddle, measured along the seat tube.

It is a starting point rather than an answer, and it will usually land within a few millimetres of what the heel method gave you. If the two disagree by more than a centimetre, measure the inseam again, because that is the step people get wrong.

Then adjust it by how it feels, over a week

Neither method knows anything about your hips, your flexibility or your shoes. Both get you close, and then you refine.

Move it in three or four millimetre steps, no more. Ride for a few days at each setting. Changes smaller than that are not really detectable, and changes larger than that make it hard to tell what improved.

Mark the seatpost with a piece of tape at each setting so you can always get back to one that worked.

What the symptoms tell you

• Pain at the front of the knee, usually too low, or the saddle too far forward.
• Pain at the back of the knee, usually too high.
• Rocking hips, too high. This is the clearest sign and it is easy for someone to spot from behind you.
• Sore or numb sit bones, often too high, because you are sliding forward to reach.
• Feeling like you cannot get any power out, usually too low.

Two things people get wrong

First, the minimum insertion line on the seatpost is not a suggestion. If getting the right height means the post is out past that mark, you need a longer post, not a compromise. A post that snaps at the clamp takes the frame with it.

Second, grease the post before you put it back, or use the correct paste if either the post or the frame is carbon. A seatpost you adjust once and then leave for five winters can seize solid. That is covered in winter maintenance and it is a genuinely common way to write off a good frame.

When it is not the saddle height

If you have set the height carefully and something still hurts, the next things to look at are saddle fore and aft, saddle tilt, and reach to the bars. Height is the biggest single lever but it is not the only one.

We set saddle height as part of every custom build, with you sitting on the bike rather than off a chart. If you have bought a bike elsewhere and it has never felt right, bring it in and we will go through it with you.