Can someone explain different rear axle sizes please?

I’m starting to see different sizes of rear axles, never really noticed them before. Are they compatible with all frames? If not how does the axle/hub/frame compatibility work out?

Thanks in advance.

I think the ban hammer is about to smack you on the head…

Some frames have interchangable rear dropouts to make them compatible with different axle sizes. If the frame does not have these then it will only be compatible with the size it was originally designed for.

Not after a new pair of wheels are you?

I hear PeterPoddy has some going

For the record, I’m not getting banned, and the episode with Peterpoddy has been resolved, though it should never have been taken public, so that’s that, not going to mention it again.

150mm (and above, think Tomac did a 165mm) DH bikes/ long travel FR bikes.

135mm “standard” MTB, QR, 10mm, 12mm bolt through. Maxle version too.

142 Syntace 10mm QR (i think) on some bikes including newer Trek full sus. Some hubs can be converted between 135/142, DT Swiss, Hope).

157 Syntace, as per 142, just a downhill version.

might be wrong though.

The 142 is 12mm, and there’s the Syntace X12 and Shimano E-Thru variants (and maybe others?). Same wheels I think, just different axle/threads?

Doug Bradbury used to make an offset 145mm for the manitou frames once upon a time I believe. Not that its any help here.

Might be a silly question but why different lengths (widths).

I was led to believe it was the girth that counted not the length.

I see what you did there…

Might be a silly question but why different lengths (widths).

I beleive its so a stronger wheel can be built – equal dishing of the spokes.

And then there are the Fatbike axles……

Ok, so there are some big old hubs out there than need a bigger axle. Don’t they have chain line issues?

That’s why you get DH bikes with 83mm or 100mm bottom brakets