Squeaky Semcycle cranks

Unicycles and Equipment
1

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 that.

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. :slight_smile: Is hammering the crank into the axel the right solution?

Thanks in advance,

Matt Macauley http://www.tou.com/host/matt

2

Re: Squeaky Semcycle cranks

Opps…

I just realised that I got my own partners url wrong! :-]

John’s Url should be www.unicyclesource.com

I think I am going to have one of those days today, will post about it later but
we (Paul Selwood, Sarah Miller and my self) did the coast to coast this last
weekend in 2 days. Basically my body doesn’t know whether it is coming or going!

Roger

 The UK's Unicycle Source <a href="http://www.unicycle.uk.com/">http://www.unicycle.uk.com/</a>
3

Re: Squeaky Semcycle cranks

Wow you’ve gone hard-core using epoxy to keep the cranks on.

You should be careful when using a press to put the cranks on. I’ve heard tales
in one of the bicycling FAQs about people splitting cranks by putting oil on the
taper and then over tightening the crank bolt. You can also end up deforming the
taper and forcing the crank further on the axle than it was intended.

I’ve been using sleeve retainer to hold my cranks on. Sleeve retainer is like
thread lock but is designed to fill larger gaps than thread lock. Sleeve
retainer is generally used to secure press fit (metal to metal) parts. The grade
designed for removable bearings (rather than a permanent grade) is handy for
securing your bearings to the axle and also for securing your tapered cranks to
the axle. Loctite is one brand that makes a sleeve retainer but there are
others. However, the stuff is hard to find in a regular consumer store. You
might be able to find it at a store that specializes in fasteners. Industrial
supply stores also carry it, but they usually only do business to business sales
(no sales to the regular public). Might be able to have your favorite local bike
shop order some sleeve retainer from one of their suppliers.

My muni (using Black Widow Lite cranks), my Coker and a few of my other unis
have had their cranks secured with sleeve retainer. A little thread lock on the
nut too for good measure to keep that darn nut from vibrating loose. Haven’t had
a crank come loose on me since using the sleeve retainer. And when using the
sleeve retainer you don’t have to force the crank on as forcefully. A few light
wacks with a rubber mallet is good and then tighten the nut on (but not too
tight). When using the sleeve retainer make sure the axle and crank tapers are
clean and free of oil and other crud before applying the sleeve retainer.

I haven’t had to remove a crank after it has been secured with sleeve retainer
(knock on wood) so I don’t know how easy it will be to remove. The sleeve
retainer and thread lock get weaker when you heat it past some magic temperature
mentioned on the packaging so a little heating with a torch might be necessary
to remove it if it won’t come loose using the regular hand tools. Hopefully the
regular hand tools will be enough.

john_childs

From: (Unicycle17)
>everything in the previous message is true, but I would like to offer the
>following.
>
>I have made a crank press out of a couple thick peices of maple wood and some
>3/4 inch all thread or threaded rod. I put the all thread through the spokes
> and the maple spans across the end of the crank arm and by tightening the
> nuts on the allthread I am able to get a great deal of force to bear on the
> cranks, pushing them farther onto the hub.
>
>I bought some black widow cranks from the Unicycle Source which were in fact
>better than any others I have used. They lasted three times as long, and I am a
>hard and heavy rider. But just recently they did wear until the press and
>tightening the nuts no longer worked. Now they are epoxied on. I put a
>punctured piece of visqueen plastic sheeting over the end of the hub to protect
>the bearing from the epoxy. The plastic was tight enough around the hub that
>the epoxy could not leak through, and I tore it off after the epoxy cured. I
>cleaned the morse taper with alchohol and covered it with epoxy before
>installing the crank. I also put some epoxy on the bottom of the nut. Care must
>be taken to keep the epoxy from touching the removal threads of the crank. The
>advantage of epoxy over welding is that epoxy can be heated with a propane
>torch and softened for removal. I used system three epoxy because it has a
>lower softening point than some of the others even though it is designed for
>wood. It seems to be working fine but I have not actually tried to remove any
>cranks that were installed in this way yet. Heating the cranks to soften the
>epoxy may wreck the bearing seals so it may be necessary to replace the
>bearings at that point. This epoxy should be soft enough for removal at 200
>degrees faranheit. My cranks have stayed firm for a week of abuse.
>
>This is a very common problem. I suppose one remedy would be to buy the British
>unicycle with the splined hubs. DN I think.
>
>Idaho Joe

Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

4

Re: Squeaky Semcycle cranks

Matthew,

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.

Roger

 The UK's Unicycle Source <a href="http://www.unicycle.uk.com/">http://www.unicycle.uk.com/</a>

----- Original Message ----- From: “Matthew Macauley” <mmacauley@nospam.hmc.edu>
To: <unicycling@winternet.com> 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 that.
>
> 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. :slight_smile: Is hammering the crank into the axel the right solution?
>
> Thanks in advance,
>
>
> Matt Macauley http://www.tou.com/host/matt

5

Re: Squeaky Semcycle cranks

everything in the previous message is true, but I would like to offer the
following.

I have made a crank press out of a couple thick peices of maple wood and some
3/4 inch all thread or threaded rod. I put the all thread through the spokes and
the maple spans across the end of the crank arm and by tightening the nuts on
the allthread I am able to get a great deal of force to bear on the cranks,
pushing them farther onto the hub.

I bought some black widow cranks from the Unicycle Source which were in fact
better than any others I have used. They lasted three times as long, and I am a
hard and heavy rider. But just recently they did wear until the press and
tightening the nuts no longer worked. Now they are epoxied on. I put a punctured
piece of visqueen plastic sheeting over the end of the hub to protect the
bearing from the epoxy. The plastic was tight enough around the hub that the
epoxy could not leak through, and I tore it off after the epoxy cured. I cleaned
the morse taper with alchohol and covered it with epoxy before installing the
crank. I also put some epoxy on the bottom of the nut. Care must be taken to
keep the epoxy from touching the removal threads of the crank. The advantage of
epoxy over welding is that epoxy can be heated with a propane torch and softened
for removal. I used system three epoxy because it has a lower softening point
than some of the others even though it is designed for wood. It seems to be
working fine but I have not actually tried to remove any cranks that were
installed in this way yet. Heating the cranks to soften the epoxy may wreck the
bearing seals so it may be necessary to replace the bearings at that point. This
epoxy should be soft enough for removal at 200 degrees faranheit. My cranks have
stayed firm for a week of abuse.

This is a very common problem. I suppose one remedy would be to buy the British
unicycle with the splined hubs. DN I think.

Idaho Joe