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Saddle height and cycling inseam(7 posts)

Saddle height and cycling inseamaltidude
Jan 20, 2003 11:02 AM
I have read that once you determine your true cycling inseam, not your pants inseam, that you can then subtract 10 cm's from this measurement to achieve a length at which your saddle top should be above the center of your bottom bracket as measured up your seatube incline, give or take a cm or two. Is there any validity to this approximation for correct saddle height above BB?
ballpark figure...C-40
Jan 20, 2003 11:20 AM
There are lots of formulas that will get you in the ballpark, but none of them can take into account things like the stack height of the pedal system and shoes that are being used.

The method you mention comes close to another popular formula: .883 x inseam.

I prefer to sit on the bike, clip into the pedals and adjust the saddle to permit my heel to drop 2-3cm below horizontal with the leg locked out at the bottom of the stroke as a starter. This assures that you won't be pedaling with the toes pointed down or overextending your leg. It also takes into account the pedal system and shoes being used. Fine tuning the height follows this initial setting.

One of the old school ideas that got me in trouble was raising the saddle a little at a time until my hips rocked at high rpm. This resulted is a saddle position that was several centimeters too high. If the saddle is set too high it can cause back pain, and a slow choppy cadence.
Good point C-40 - also ...GrabTheBarsAndHurt
Jan 20, 2003 11:32 AM
You should take into account personal characteristics that can influence your positioning - any knee operations? Back problems? Leg length discrepencies? Hip problems? Do you come from a running background? Etc.

I will reiterate what I think C-40 is trying to say - all of the methods (10 cm shorter than leg length, .883 * inseam, X% knee bend, etc.) are a good starting point, but personal issues and / or preferences will override any generic measurement.

Also, I read one time something about a fit, limber cyclist is one of the toughest people to correctly determine saddle position because their 'proper' saddle position usually feels too low for them.

The last thing you want to do is cause permanent damage by trying to look cool with the ultra high saddle and the saddle jammed back in a laid back post.
Check this out, especially diagram 8 . . .mja
Jan 20, 2003 2:56 PM
http://www.cyfacusa.com/FIT%20SADDLE.htm
and diagram 7...C-40
Jan 20, 2003 3:17 PM
Diagram 7 illustrates the initial saddle height setting that I described.
One other thing.........Len J
Jan 20, 2003 3:27 PM
be careful of making major changes in saddle height all at one time. If you find that your seat is significantly too high or too low, make small changes over a several rides to zero it in. Too big a change can put undo stress on (in my case) your knees.

Len
109-110%Kerry
Jan 20, 2003 5:10 PM
The trouble with the 0.883-0.885 guidance is that ignores both your crank length and the cleat/shoe offset from the pedal axle. It's hard to compensate for the cleat/shoe thing, but at least you can compensate for crank length. If you put your saddle top to pedal axle distance at 109-110% of your cycling inseam, you'll be pretty close. Personal preference and the shoe/cleat thing will cause some tweaking from there.