Cycling UK Forum

With Brucey, all of the axle bends/breaks I had back in the day were always inboard of the RH cone.

Thankfully i've not had a breakage for a good few years, the last was on the freehub, snapped mid axle, didn't notice for a while as it was clamped up, fell out when took the wheel out!

foxyrider wrote: Thankfully i've not had a breakage for a good few years, the last was on the freehub, snapped mid axle, didn't notice for a while as it was clamped up, fell out when took the wheel out!

what kind of freehub/axle was that?

Stradageek wrote:... I've never had any trouble removing the cones from said bent axles; if the axle had been bent beyond the cone this would have been nigh on impossible....

exactly; I was going to mention the same thing.

I suppose that the RH end of the axle might perhaps bend after it has broken, provided the frame is strong/stiff enough around the dropout. But in practice broken QR axles most usually lead to broken frames, if the bike is ridden with a broken axle.

cheers

I have also bent axles, specifically on a cheap 135mm-spaced MTB with a 6 speed freewheel. The overhang is extreme and the axle is unsupported. This is, of course, why we have freehubs now.

I wasn't clear on the bending mode: the unsupported flexing is between the cone and the dropout but the damage does indeed occur at the cone, being effectively the root of a cantilever. I should draw a sketch.

You'd be surprised how tight I can get a "cheesy locknut" on a good quality hub. I've never stripped one as they are very hard.

Anyway, if you have an MTB with a freewheel, get the locknut just finger-tight and go and do a few jumps to see what happens.

rogerzilla wrote:...You'd be surprised how tight I can get a "cheesy locknut" on a good quality hub....

its either less tight or more tight than the track nut/QR. If the latter, you have not secured the wheel properly. If the former, the locknut torque is irrelevant.

cheers

Brucey wrote:

foxyrider wrote: Thankfully i've not had a breakage for a good few years, the last was on the freehub, snapped mid axle, didn't notice for a while as it was clamped up, fell out when took the wheel out!

what kind of freehub/axle was that?
cheers

If i remember rightly it was an XT circa 1989 which broke in about '95 - at the time my mtb was a rigid steel (half 531 after an accident repair!) Falcon, the rear triangle was built of girders i think, you couldn't spring the dropouts at all. Oh slotted not vertical dropouts too.

well that would br a very rare thing, a broken steel shimano freehub axle then....

cheers

Brucey wrote:well that would br a very rare thing, a broken steel shimano freehub axle then....

cheers

No that rare Brucey, admittedly I do tend to see a lot of much abused MTBs but I've seen at least three hollow freehub axles snapped. IIRC they tended to break just after the drive side threaded section.

which type of axle have you seen break? IIRC there are at least three patterns of 10mm dia. shimano freehub axle;

a) CrMo, threaded much as an axle for a threaded hub for a freewheel would be (which effectively means more than sufficient threads on the RHS)
b) all threaded
c) all threaded, with a relief which coincides with the position of the hollow bolt

cheers

All type a) as far as I can recall

OK, so am I right in thinking that this is away from the RH cone, and away from the highest (gross i.e. associated with the parts fitted to the axle) geometric stress concentrations? If so perhaps some local stress concentration which is associated with the manufacturing process used to make the threads is responsible?

cheers