Campag Centaur BB compatiblity

[Seca Blue]

Afternoon all.

Is there any definitive answer on what BB I can use for a Centaur crank apart from the obvious Campag one?
I need to put a 121-125max bb in a frame and I really want to use my Campy crank but can't find an ISO(I believe that's the closest to Campy) bb in that length.

It's been on a Mavic sealed job for 30 years and working fine, but for various reasons I'm not reusuing that BB.

Someone I spoke to today said just use a JIS it'll be fine, but if anyone knows for sure be good to know.

Any help gratefully received.

 

[27motorhead]

Some info on Seldon Brown:
https://www.sheldonbrown.com/bbtaper.html

 

[Seca Blue]

Some info on Seldon Brown:
https://www.sheldonbrown.com/bbtaper.html

I had been on there but not seen that page thanks. Will have a good read.

 

[gfk_velo]

Afternoon all.

Is there any definitive answer on what BB I can use for a Centaur crank apart from the obvious Campag one?
I need to put a 121-125max bb in a frame and I really want to use my Campy crank but can't find an ISO(I believe that's the closest to Campy) bb in that length.

It's been on a Mavic sealed job for 30 years and working fine, but for various reasons I'm not reusuing that BB.

Someone I spoke to today said just use a JIS it'll be fine, but if anyone knows for sure be good to know.

Any help gratefully received.

Centaur was made for either a symmetrical 111mm (28.6mm seat tube) or 115.5mm (32 or 35mm seat tube) ISO taper.
121-125 seems on the long side and might impact on good chainline (generally recommeded at 43.5mm +/- 0.5mm) with a 130mm rear end spacing in a "double" system, 45.5 +/-0.5 mm in a triple system.
Even is you are looking at a 135mm rear drop-out spacing and a 35mm dia seat tube, the longest BB axle you'd normally need to acheive that, would be a 120 (115 + 5mm).
Or ... is the application a tandem or similar, with a greater than 135mm back end?

 

[Seca Blue]

Centaur was made for either a symmetrical 111mm (28.6mm seat tube) or 115.5mm (32 or 35mm seat tube) ISO taper.
121-125 seems on the long side and might impact on good chainline (generally recommeded at 43.5mm +/- 0.5mm) with a 130mm rear end spacing in a "double" system, 45.5 +/-0.5 mm in a triple system.
Even is you are looking at a 135mm rear drop-out spacing and a 35mm dia seat tube, the longest BB axle you'd normally need to acheive that, would be a 120 (115 + 5mm).
Or ... is the application a tandem or similar, with a greater than 135mm back end?

Hi, thanks for that.
The frame is a Roberts, see my build thread, and the one issue is that the stays are a little wider than they should be at the bottom bracket, hence running a slightly wider than normal axle.
The chain line on the 125mm Mavic bb worked fine but meant the chain did run on seat stay when in smallest cog at the rear.

So I can defo take a shorter axle, and I ‘think’ 120 ish would probably be fine as it’s only 2.5mm per side shorter right.

Problem is unless I stump up for a Phil Wood I can’t see an option for an ISO BB anywhere in the length I need.

 

[hamster]

Careful! @gfk_velo 's answer is for the ROAD Centaur chainset, the MTB one takes a longer BB

 

[Seca Blue]

Careful! @gfk_velo 's answer is for the ROAD Centaur chainset, the MTB one takes a longer BB

Ha FFS. Those Italians have ALOT to answer for.
If only it wasn’t so pretty…