[DVBC] Bike Fit Riddle?!

[david c bennett]

I think Gina's accessment of the situation is the most logical:  That its 
not the distance that is critical (the distances measure too close to 
matter) its the position of the bottom bracket/crank.  That is that if the 
bottom bracket is more forward, on the Fuji, than on the Litespeed or the 
Cannondale, that would cause a more pronounced angle in David's lower back 
and hence cause more back pain.  Try measuring the distance from the bottom 
bracket center to the handlebar/stem on the Litespeed and compare that to 
the Fuji.
Sorry to hear about your beloved Cannondale.

David B.   Friend of IROCK, Andy Knox. Rob LaDrew, etc.....
----- Original Message ----- 
From: <Drew.Knox at bentley.com>
To: <dvbc-list at dvbc.org>
Sent: Monday, May 01, 2006 7:30 AM
Subject: RE: [DVBC] Bike Fit Riddle?!


Yes, riddlers everywhere want to know the solution.

I'm guessing you're on the right track, Ira, in that we got one absolute
value (the handlebar height) and, likely, one relative value (seat
height). That is, David wanted to match his leg extension, so he
probably measured from the bottom of the crank, or from the crank bolt
if he knew the cranks were the same length to set the seat height.

I can believe as much as a half inch difference in bb heights and maybe
a half inch difference in seat tube angles (even though he looks like a
74 degree angle type of guy). If the latter were true though, the reach
would differ.

The second part of the riddle is more important: how to set up the new
bike to get rid of the back pain?

-----Original Message-----
From: dvbc-list-bounces at list.dvbc.org
[mailto:dvbc-list-bounces at list.dvbc.org] On Behalf Of Ira Josephs
Sent: Sunday, April 30, 2006 7:58 PM
To: dvbc-list at dvbc.org
Subject: Re: [DVBC] Bike Fit Riddle?!

Do they have different bottom bracket heights? Also manufacturers use
different reference points for the frame size, especially with sloping
top tubes. Top of bottom bracket or center. Top of seat tube or center
of lug.
Ira (You know who)
----- Original Message -----
From: "David" <dcunicelli at rcn.com>
To: "bike club" <dvbc-list at list.dvbc.org>
Sent: Saturday, April 29, 2006 8:41 PM
Subject: [DVBC] Bike Fit Riddle?!


> Hello all,
>    I've been trying like crazy to fit my bike in as close a manner as
> possible.  I've got all of my measurements and have laid the bikes out

> accordingly.  however one bike has defied logic and math to give me
> trouble.
>
> here it is.  on both bike the following measurements are near
> exact-seat height, bar height as measured to ground, distance from
> nose of seat to bar.
> but the drop from my seat to the top of my bars comes out quite
> different-2
> inches.  the 2 inch difference is telling on my back.  can anyone
> figure out what i'm missing and how to fix it without radically
> altering any other measurements?
>
> any help would be greatly appreciated.
>
> david c
>
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