crank length?
 

so i have been TRYING to fit myself to my bike. because the cheapest bike fit around here is 130$ (and hes very experienced) so today, i have been adjusting and riding it for about 5 days.

oddly i feel more comfy in a racing style position. flipped my stem, moved my seat back, lowered my seat a little bit.

but ive been reading this article and im wondering if i need a longer crank arms?

"Some research has been done to determine the optimum percentage of leg length to crank length. I doubt that there is an optimum percentage that would apply to all people. One writer in a major magazine article quite a few years ago claimed that after considerable testing with many different riders, 18.5% of the distance from the top of the femur to the floor in bare feet should be the crank length."

http://www.peterwhitecycles.com/fitting.htm

anyone can tell me about this? and any tips on fitting me to my bike until i get at least 130$

oh and also, i have a felt f95 60cm
175mm crank. im looking at a 177.5 or 180 mm maybe? would this help my fit? or power output? my top femur to the floor is 28in. possible 29 in.

...all the basic stuff in the article is good for bike set-up, but crank arm length is about the last thing I would worry about. It might have a little effect on fit, but unless you have short legs running 175mm cranks, or long legs running 170mm cranks, I don't think you'd notice.

do you think this article is very accurate to how to be fit on a bike? any books or website that might be more accurate?

roughly 20% of your true inseam.

varies depending on femur length and riding style.

if you go with crank arms that are too long, your knees will be pounding your chest in an aero position.

Totally agree. Just look at 5mm on a ruler, and you'll see it's a pretty small difference. Your seat height or cleat adjustment could be out that much. I've gone from 170 to 175 and don't notice any difference.

if only this were foo...

Measuring from the top of the femur may make more sense for the scientific types but its VERY hard to measure properly if your a mere mortal. I recommend measuring your inseam from hard against the pelvic bone to the floor in no more than socks. Then based on my experience of having tried MANY different crank lengths and the experience of others I recommend cranks to be in a range from 19% to 20.5% of inseam. There isn't just one length that is perfect and all the others are wrong. A 5 mm difference is nothing assuming both lengths are within the my recommended range and even a 10mm difference isn't that great as long as the bike is setup properly for the different lengths.

Anthony

Has anyone tried these:
http://home.intekom.com/murraytourdeforce/cranks.htm

They are too pricy for me, but being able to try any crank length from 160-183 really appeals to me.

Maybe I'd consider shelling out the money if I thought they'd make a difference.

I wouldn't worry too much about crank length unless you're riding a fixed gear and having problems with pedal strike.

Accurate in that its vague enough to allow for individual differences and different riding styles. I don't care for formulas and so forth except as starting points, like agreeing with the article in how it talks about KOPS, for instance, as sometimes working but sometimes not, depending on the ratio of tibia-to-femur in total leg length. I'd set a bike up at KOPS and then experiment a little with saddle fore and aft adjustments to see how they feel and so forth. Get stuff in the ballpark so you can ride comfortably and get some good miles in, and then fiddle with fine tuning over a much longer period.

Read this: http://www.nettally.com/palmk/crankset.html

This helped me a lot... I needed shorter cranks. The formula seems to be right on.