Hollowgram cranks/mtb bb spindle/road spider on cx bike?

Especially for light weight issues concerning cyclocross / touring bikes & parts.

Moderator: Moderator Team

Post Reply
Posts: 1485
Joined: Mon Oct 15, 2007 9:28 pm

by boots2000

I am trying to figure out how I can increase Q-factor (pedal width) on my cross bike.
The width of my hollowgram MTB crank with MTB BB spindle is perfect- wondering if I could run the same setup only with a compact road spider (for 36/52) on the cross bike?
My cross bike is a Specialized Crux with bb30.
I am pretty sure it will work- more concerned if chainline would be funky or anything like that.

Shop Owner
Posts: 1980
Joined: Sat Jun 13, 2009 4:02 am
Location: NoVA/DC

by thisisatest

i havent worked out the math or anything, but here's one solution for the F'd up chainline:
get extra-long chainring bolts and nuts, and some bolt spacers the same width as the chainring tabs of the spider. mount the outer ring in the INNER ring position, followed by the spacers, and then the inner ring, and chainring nut. off the top of my head, it'll be close to ok.

by Weenie

Posts: 1485
Joined: Mon Oct 15, 2007 9:28 pm

by boots2000

Your idea does not sound so good.
I may try to get my hands on the bb spindle to try it

Posts: 87
Joined: Wed Dec 14, 2011 4:37 pm

by Dustin

I forget how long the mtn spindle is...134mm? Road spindle is 104mm...so, seems like basically you'd just have to divide the difference and add that amount of spacers to each side of the shell. Though, I don't think I'd actually do it like that, simply because of chainline.

Posts: 1152
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Road spindle is 104mm. MTB spindle has been made in 122mm 128mm, 131mm, 132mm. 132mm is the current length. Using a mtb spindle your chainline will move out half the difference between the mtb and road spindle. 122mm-9mm, 128mm-12mm, 131mm-13.5mm, 132mm-14mm. So it'll pretty much suck!

If you want to get a q-factor like the mtb hollowgram on a frame designed for the road hollowgram get longer pedal axles or pedal axle extenders. I'm guessing you've got current model spindles on each bikes so you're looking to widen your q-factor by 28mm. Longer axles are readily available for Crank Bros and Speedplay. There are various companies offering pedal axle extenders as part of their 'fit kits'.

Post Reply
  • Similar Topics
    Last post