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stem length, fit by numbers x feel(4 posts)

stem length, fit by numbers x feelcolker
Mar 11, 2002 9:44 AM
the formula says: torso legth + arm length divided by 2 + 4cm equals stem plus ttube(pheew...). according to the formula i should ride a 12cm stem. it feels long. since i pointed the tip of the saddle upward it felt longer. i sit better on the tilted saddle but.the front felt slow and far away when cornering. i do a lot of cornering since i commute and i like an agile bike.the bars didn't obstruct the front hub (although this is as vague a measure of fit as can be).
so i installed a 11cm stem. while sitting on the bike, it feels sharp and comfortable. i'm going for a long ride and check if it still feels good.
can i develop any kind of muscular pain from riding (theoretically) on a shorter stem?

thanks
Aargh, formulae...TJeanloz
Mar 11, 2002 9:48 AM
This is one thing that most people just don't seem to get. The formulae provide a decent STARTING point for a good fit. No formula will tell you which bike will fit, it will recommend one that is close, which will then need to be adapted to your personal tastes.

If the formula tells you that a 12cm stem is right, but an 11 feels better- the 11 is the right one.

People get too 'by the numbers' on fit, and forget what it's supposed to achieve- a comfortable position on the bike. The formulae only exist so that people can be sized without a bike- if you have a bike, you don't need a formula.
Forumlae, the curse of the riding class...cory
Mar 11, 2002 10:01 AM
I'm with Jeanloz...what works for Lance probably won't work for you, because Lance has 8 percent body fat, works out six hours a day and does this for a living. Use the formula as a GUIDE ONLY--it makes more sense to fit the bike to you than to force yourself to fit the bike. Your fit may change as the season progresses, but riding a bike that's uncomfortable discourages progress and increases the chance of injury and soreness.
One small example: I rode for nearly 30 years with my saddle two to four inches higher than my handlebars, as the fit experts recommended. I had six or seven bikes in that period, but was never comfortable.
Two years ago I read Grant Petersen's advice on bike fit and raised my bars so they're level with the saddle. I can stay on the bike far longer, and although several people warned it would slow me down, I'm going faster and farther at age 57 than I've gone since I was in my mid-20s. Don't be a slave to what the pros do.
Think of it this way.Spoke Wrench
Mar 11, 2002 10:49 AM
Imagine a room full of people doing toe touches. Some can touch their toes, some can barely touch their knees, and some can flatten their palms gainst the floor. If you are using a fit formula that diesn't account for this difference, You are going to have to adjust for it in some manner after you apply the formula.