I think from your description that you have actually had loose cranks and
they have worn the crank/hub. They have what is called a Morse taper on
them and this should be identical, it is about 1 degree.
As a general rule you should tighten your cranks as soon as you hear them
creak. This is a sign that they are moving and any movement in this area
will create wear.
As you have realised kick up mounts do put consider and this is probably the
reason for the loosening.
I would take your cranks off, but mark where you had them on. Then inspect
the cranks and the hubs. With luck it is your cranks that have worn, the
Sem hub is one of the better ones about so this hopefully will be the case.
If there is no sign of wear... clean up the surfaces up, oil with a very
light oil or kerosene, then put the cranks back on 90 degrees off from where
they were previously. Use a hammer and a block to put the cranks on tight.
If there is wear on the cranks, don't put them back on, buy new ones, it is
worth it as they will damage the hub in the end! You can get replacement
cranks relatively cheaply from John Drummond in the USA at
www.Unicycle.Source.Com If it is your hub and cranks that have worn... you
really need to replace both... or just pop down to your local welder and
weld them up. You have nothing to loose because if you put new cranks on a
worn hub it will ruin them and visa versa.
I hope this has been helpful.
The UK's Unicycle Source
----- Original Message -----
Sent: Monday, July 03, 2000 5:50 AM
Subject: Squeaky Semcycle cranks
> Hey all,
> I got a new Semcycle (not the XL) last November which I've already
> ridden a lot on (several hundred miles). Recently, the place where the
> crank is joined to the axel has been squeaking quite loudly (both
> cranks). Has anyone else notice this with Sems? I done a fair amount of
> kick-up mounts and other abusive tricks, so I'd imagine that puts extra
> stress on that part of the uni, but it still should hold up better than
> I've tried oiling it, and this hasn't worked. But the problem seems to
> be that the axel itself has been over time been worn down and "shaved
> down," so the end of it is slightly smaller in diameter than the base.
> So I tried hammering the crank further into the axel. This worked for a
> few weeks or so, but the squeaking is back. Maybe it just came loose, or
> maybe the axel has worn down further.
> Is this problem fairly common? I'm a little disappointed in the quality
> of this uni (though it was much better than my old Zephyrs!). I'm sure
> many of you hotshot riders put a lot more abuse into your Sems than I
> do. :-) Is hammering the crank into the axel the right solution?
> Thanks in advance,
> Matt Macauley