FSA Omega crank (Topstone) chainline?

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

Moderator: Moderator Team

Post Reply
tomh79
Posts: 170
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

I just measured the front chainline of my stock crank (FSA Omega 46/30) on my Topstone 105. Did measure multiple times...constantly getting around 46/47mm chainline - several (German) websites list a 43.5mm or 44mm chainline for this crank?!?! no info on the FSA website...does anybody know more? If the 46mm are correct - I could easily switch to GRX 46.9mm without noticing...

by Weenie


Marin
Posts: 3691
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

In the middle between the rings?

tomh79
Posts: 170
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

yes - middle frame to middle of small and large chainring.

fourfa
Posts: 76
Joined: Mon Sep 26, 2011 3:04 am

by fourfa

If your FSA crank is like mine, it's possible to have a longer spindle than is strictly necessary, and some spacers and a wave spring taking up the extra space. Move those around, and you can make dramatic changes to chainline. Perhaps Cannondale has done this? So the midline of the spindle is not exactly midline of the frame, to make more clearance for the rings around the chainstay?

But yeah, probably a good indicator for a GRX switch

tomh79
Posts: 170
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

Good point. Will check.

tomh79
Posts: 170
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

No spacers.

by Weenie


EricBayArea
Posts: 1
Joined: Thu May 14, 2020 3:18 am

by EricBayArea

Can you provide an update on what you ended up doing? Did you swap out for a GRX crank, if so which one (single, double, 600, 800) and how was the fit?

Did you also change the BB thread-in bearings to?

Thanks in advance-

Post Reply