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Testing for Correct Seat Height
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Here is my question. What methods do various board members use to check seat height? A recent postion photo post got me thinking about how we diagnosis someone as having too high a seat without watching them peddle.

I know that it is considered a truism that if your hips rock side to side then your seat is too high. Sometimes I find myself swaying side to side on my rollers. It is more of a slight shoulder sway than a hip rock. It seems more of a breathing rhythm than a cadence rhythm

What about riding on rollers with a high cadence as a guide to determining whether a seat is too high? Although I somewhat suspect my seat is too high, I can peddle at 120 rpms on the rollers for a couple of minutes at a time with no bouncing or swaying. This leads me to beleive that it is not too high.

So, anyone know of any rules of thumb concerning seat height, cadence, rollers, etc.??

Thanks. DavidK
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Re: Testing for Correct Seat Height [DavidK] [ In reply to ]
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Here's the LeMond rule of thumb.

Take your true inseam (not your pants inseam), multiply by .883. This is the distance from the center of your bottom bracket to the top of your saddle in the middle.

Adjust height by -3mm for clipless peddles. When this was written, the only (?) type of clipless were Look which were about 25mm from the center of the peddle hole in the crank to the top of the peddle platform. Also, this rule assumed the thickness of the sole of your shoe was 13mm and that you rode 170mm cranks.

If you ride a different peddle system or have different shoe sole thickness, you need to adjust accordingly.

Lemond recommeded not adjusting saddle height for changes in crank length. I don't know what the current thinking is. Also, I'm sure there are differences in foot length and God knows what else that may need to be adjusted for.

I'm not a FIST certified fitter, I just play one on this board, so if you've got question about seat height you might want to get your whole set up checked out. It's worth the cost of a fitting and a few parts if your frame is in the ball park. If not, at least you've got the justification for why you need that new bike.

Irony can be humorous, but it does not have to be.

"I've always said that an Ironman is a reflection of your character" - Kevin Moats
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Re: Testing for Correct Seat Height [east coast] [ In reply to ]
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Another approach, which sort of bypasses all of the variables that east coast mentions, is to set seat height according to knee angle at the bottom of the pedal stroke. The general range of acceptable knee positions (according to the guy that did my last fitting) is 25* - 35*. It's important that the ankle be in the position that it would normally be in when riding, so you can't just move your foot to the bottom. He had me pedal for 20-30 revolutions, and then stop as close to the bottom as I could without changing ankle angle. He then measured the knee angle. Seems like a logical approach to me. Anyone else use this method?
Last edited by: jkatsoudas: Apr 4, 03 16:31
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