Square taper BB sizing

[Jimbo.]

The town bike needs a new bottom bracket. It’s a singlespeed/fixiett affair. The old BB is, as believe, a 68x110.5 JIS square taper. Other than cheap Chinese ste of eBay I can’t find anything to match. Would I be right in thinking that a 68x110mm will work? 0.5mm difference (or even 0.25mm if symmetric) wouldn’t shaft the chain line up too much, would it?

[smifffymoto]

Try SJS cycles or another touring specialist for stbb.

[Get Karter]

Jimbo. said:

The town bike needs a new bottom bracket. It’s a singlespeed/fixiett affair. The old BB is, as believe, a 68x110.5 JIS square taper. Other than cheap Chinese ste of eBay I can’t find anything to match. Would I be right in thinking that a 68x110mm will work? 0.5mm difference (or even 0.25mm if symmetric) wouldn’t shaft the chain line up too much, would it?

The only possible problem would be if the left crank (or chainset) clearance from the frame’s BB shell was so close that 0.25mm less would make it tighten up to foul on that part of the frame. Unlikely.
If it wasn’t scarily close, go for the 110; if it was try the next a available size, 112mm I think.

[Jimbo.]

Cheers. Have taken a punt on the 110 as you could get a bus between BB shell and the inner face of the crank arms.