Know the rules The Paceline Forum Builder's Spotlight


Go Back   The Paceline Forum > Bike Fit

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old 06-16-2020, 06:48 PM
owly owly is offline
Senior Member
 
Join Date: Oct 2015
Location: australia
Posts: 420
Will going to a 5mm longer crank upset weight at bars?

Been using 172.5mm arms for a few years. A couple of years ago when hunting around for a suitable gravel frameset, the Competitive Cyclist fit calculator suggested in its numbers that I use a 177.5mm arm.

When I fit anything larger than a 700x33 tyre, I find the ride height too tall and haven't been able to get used to it / like it. So rather than shell out quite a bit of money for a new frame with a lower bb, I am thinking that longer crank arm will pull me down about 5mm into the bike, which should offset running a 35mm. (I'm hoping to be able to try a 38mm ideally; achieve a good ride feel/height).

I think I'm correct in thinking that longer arm length will pull me a bit forward in the saddle when the arm is pointing forward (parallel with ground), and thus at the bars my balance in the bike would now be too far forward. I would need to move my saddle back a bit to compensate, however I can't really move my position back as my cleat fore/aft position is locked into place in the shoe.

I have experimented with moving my cleats forward a mm at a time in the past. When they get to a little over 2mm forward, I start getting some numb toes.

So in summary is there any way to run a longer crank arm and still find the right fore/aft weight/balance feel when riding, by tweaking component position? or am I going to run into trouble?

Edit: Geometry/maths speaking, is a lower bb position the only correct (fit) solution here?

Last edited by owly; 06-16-2020 at 06:54 PM. Reason: txt
Reply With Quote
 

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:06 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.