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View Full Version : Bontrager/fore-aft/pruitt/serotta fit gurus!


CarlosContreros
01-03-2009, 11:25 PM
Well...
In my ever ending search to find my optimum position(max power but
safety for my wimpy..chondromallacia afflicted knees!) with mostly focus
on saddle height and fore/aft(aka pedal position) it seems many people
don't really put much credence into the ole "plumb line" solution!

Bontrager's article was quite a discertation to wade through....but maybe I'm just not that "literate"....but what I did get from the article is the fore/aft
on the bike is not to positon yourself for max power from your legs..but to
really be in the best position to accomodate your upper body comfort and also the amount of weight you place on your hands.

I find it very interesting that someone like Dr. Andy Pruitt would stick by his plumb line from the front of the kneecap to align with the front of the crankarms. Seems to me to be a very far position forward...but I don't know 'cause I've never been fit by him so maybe after your computer analysis he makes adjustments to fore and aft after seeing how your body "grades" out.
So what I'm asking?...is fore and aft not so much positioning for power...but for getting the upper torso into the most comfortable position (be it hands..
back..and also aerodynamics)?

David Kirk
01-04-2009, 08:14 AM
I think Bontrager nailed it.

Dave

thrasher
01-04-2009, 06:41 PM
Well...
Bontrager's article was quite a discertation to wade through....

Where can I find this article?

I just read Pruitt's book a few days ago. I need time to digest and read it again.

David Kirk
01-04-2009, 07:13 PM
I just gooooogled "bontrager kops" and got this -

http://www.sheldonbrown.com/kops.html

There are a few different version of the article floating around and most have been edited a good bit for space. It's worth reading the longer original version.

dave

thrasher
01-04-2009, 07:19 PM
I don't mind reading the original.

bhungerford
01-05-2009, 07:44 AM
seems to make sense to me, and more of a scientific method of locating the contact points. But also, KOPS is just a starting point, i think that's where most people get confused, its not the end all perfect spot, well maybe it is for some, but not others. I think as long as a fitter realizes that it is just a starting point, it should be fine to use, because as Bontrager said it gets you in the range of correct fit. "Still, it is easy to see how the KOPS method can get by. It usually puts the rider in the range of correct fit, although in my experience, the more anatomical proportions vary from the norm, the more off the mark the KOPS method is."

And we're rather adaptable, dynamic engines on our bikes, we do spend most of the time seated, but our CG changes everytime the road changes incline, which is all the time.

interesting article, good to read and learn a bit more, thanks for the link DK

Peter P.
01-05-2009, 05:34 PM
Fore/aft positioning is strictly used for locating the knees somewhere with regard to the pedals. It has nothing to do with positioning the upper body.

Z3c
01-09-2009, 04:57 PM
I think Bontrager nailed it.

Dave

Ditto. KOPS=what I call "Fit by Guido".. Old School when there was little/no technology applied to fitting.

Scott

Z3c
01-09-2009, 04:59 PM
Fore/aft positioning is strictly used for locating the knees somewhere with regard to the pedals. It has nothing to do with positioning the upper body.

Nothing in fit is independent; move one contact point and you affect the body.

Scott