loose cranks

Help! I can’t seem to keep square taper cranks from coming loose. I
have to tighten (45 ft-lbs) the bolts every time I ride. I’m on my
fourth set of cranks (two aluminum, two steel). Some have been
pressed on with a bar clamp. I even heated one set of cranks and
cooled the hub before installation for a very tight fit. I’ve used
loctite on the threads, and when that didn’t work one one unicycle, I
switched to anti-sieze on the next one I built.

I’m tempted to blame the hubs (both the same brand), but Unicycle.com
says they haven’t heard any complaints. They offered to replace both
hubs, but I’d like to figure out what’s wrong before rebuilding the

I don’t think I ride these unicycles hard enough to need splined
cranks: They are used for freestyle, transportation, hopping up curbs,
riding down stairs, and drops of 18" or less; I weight 178 lbs.
Besides which, splined hubs don’t seem to have short (125mm, 110mm)
cranks available.

Any ideas or recommendations?



What’s the hub? Suzue? Unicycle.com Chromoly? Semcycle XL?

Re: loose cranks

If you’ve gone through three sets of square tapered cranks, you are riding hard enough to need splined cranks!

There’s no way around it. The square taper on your hub is an unfortunate by-product of the bicycle industry. This design is not suitable for the lateral strains induced by unicycle riders.

Re: loose cranks

“john_childs” <john_childs@NoEmail.Message.Poster.at.Unicyclist.com> writes:

> What’s the hub? Suzue? Unicycle.com Chromoly? Semcycle XL?

Both hubs are both Unicycle.com Chromoly. The aluminum cranks were
really cheap (one came from a Sun and was suspect from the start), but
the steel cranks are Bicycle Euro and Semcycle.


Re: Re: loose cranks

Had all of the cranks been used before on other hubs?

If the cranks had been used on a different brand of hub, it is possible that the tapers on the cranks got formed to fit the old hub and now don’t agree with the UDC hub. Not all hubs and cranks have exactly the same taper. The tapers can be slightly off or slightly different.

I don’t have any experience with the Unicycle.com hub. Perhaps someone who has used the UDC hub can comment on how well different cranks fit on it.

Re: loose cranks

Only one pair of cranks had been used on a different hub, the rest
were brand new.

If there is a particular brand of crank that works best with the UDC
hub, I’d be happy to switch. Unfortunately, there don’t seem to be
many choices in the 110m length.