Creaky Coker

Unicycles and Equipment
1

Two weeks ago, on my weekly Coker commute, I notice an irritating creak. It
wasn’t regular and it only happened when I was riding. I eventually
concluded that it was probably the saddle, so when I got home I tightened
all the seat bolts, a couple of which had come loose.

Last Friday morning the creak was worse, but this time it was regular,
occurring on every downstroke of the left pedal. When I got to work I found
that it was happening when I pushed the unicycle, pretty much ruling out the
cranks, but I was still unable to definitely identify the cause. The ride
home was much the same, except that the location progressed around the
wheel. By the end of the ride, the creak was starting at the bottom of the
left downstroke.

It occurred to me that it could be spokes rubbing together. The wheel was
badly in need of truing anyway, so I trued it. Then I put the tyre back on,
screwed the wheel back into the frame and spun the wheel (before putting the
cranks back on). It still creaked (although once I started listening
closely trying to work out what was creaking, I couldn’t get a sound out of
it).

This morning the creak was still happening once every revolution, but the
location of the creak progressed round the wheel faster than last week. The
duration also got longer - after a couple of miles I noticed that the creak
was continuing most of the way round. By the time I got to work, I only had
a short creak-free gap on each revolution. That has now all but
disappeared.

If I stop for a while, I can sometimes ride a hundred yards or so
creak-free, but then it starts again and gets progressively worse as I ride.

Any ideas? It could still be that the spokes are too tight or too loose,
but how can I tell? Roger has mentioned before that the spokes on the Coker
shouldn’t be anywhere near as tight as the spokes on a smaller wheel, but
just how tight should they be? What tone should they make when I ping them?

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

2

The reason the Coker spokes can’t be as tight is not because the wheel is larger, but because the rim can’t take the stress, especially with the stock hub. With a GB wide hub and the Aero rim, I have my spokes at a very, very high tension - at least 6x what the stock setup will take, if not more. The tension has to be so low on the stock setup that my tensiometer won’t measure it within calibration limits.

With the stock setup you’re lucky to get a ping at all. If that’s what you have, just do your best. I doubt that’s the source of your creak anyway.

You might try pulling your cranks, then greasing the spindles, and reinstalling the cranks with a torque of about 35 ft-lbs.

The idea that it’s the cranks is supported by the idea that the back pressure you put on them to stop reseats them a bit.

My two cents.

3

Re: Creaky Coker

U-Turn suggested:
> The idea that it’s the cranks is supported by the idea that the back
> pressure you put on them to stop reseats them a bit.

But not by the fact that the creak was still present when I had the cranks
off :-/

I wouldn’t rule out the possibility of there being more than one creak,
though. Thanks.

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

4

Check that the bearings are still snug on the hub. A bearing sliding inwards and outwards on the hub might cause a squeak.

I had to LocTite the bearings on my Coker because the bearings got loose on the hub. It caused the tire to start rubbing the frame. If you haven’t noticed the tire rubbing the frame then your bearings are probably still snug. If you use LocTite the LocTite Sleeve Retainer (high strength) will work. You can get it at many auto parts stores.

5

Re: Creaky Coker

“john_childs” <john_childs.fzf1z@timelimit.unicyclist.com> wrote in message
news:john_childs.fzf1z@timelimit.unicyclist.com…
>
> Check that the bearings are still snug on the hub. A bearing sliding
> inwards and outwards on the hub might cause a squeak.
>
> I had to LocTite the bearings on my Coker because the bearings got loose
> on the hub. It caused the tire to start rubbing the frame. If you
> haven’t noticed the tire rubbing the frame then your bearings are
> probably still snug. If you use LocTite the LocTite Sleeve Retainer
> (high strength) will work. You can get it at many auto parts stores.

Even before doing that perhaps check the spokes where they cross over each
other (X). They could be rubbing together and generating some noise there.
You could quickly lubricate each crossing point with some vaseline or
silicone spray and see if that helps.

Good Luck,

David Winston

6

I wonder if there’s a chance that a bearing is either going bad or has some contamination. Does the creak sound anything like a bad bearing?

B

7

Sounds like your knees need oiling if you ask me. ;0)

8

Re: Creaky Coker

john_childs suggested:
> Check that the bearings are still snug on the hub. A bearing sliding
> inwards and outwards on the hub might cause a squeak.

As near as I can tell with the wheel still in the frame, the bearings are
snug. I’ll have to take the wheel off again to check properly, but it’s
certainly worth looking into.

I’ll try U-Turn’s suggestion of greasing the spindles while I’m at it (OK, I
know it’s not good for the cranks, but it’s not as if I’ve got aluminium
cranks on there).

> I had to LocTite the bearings on my Coker because the bearings got loose
> on the hub. It caused the tire to start rubbing the frame. If you
> haven’t noticed the tire rubbing the frame then your bearings are
> probably still snug.

I have noticed the tyre rubbing the frame very occasionally, but that was
when the wheel needed truing. Even so, the rubbing wasn’t consistent, so it
could well indicate loose bearings. Thanks for the suggestion.

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

9

Re: Creaky Coker

David Winston wrote:
> Even before doing that perhaps check the spokes where they cross over each
> other (X). They could be rubbing together and generating some noise
there.
> You could quickly lubricate each crossing point with some vaseline or
> silicone spray and see if that helps.

I’m pretty sure they were rubbing together before I trued the wheel, I
wouldn’t be too surprised if they’re still rubbing a little. The Vaseline
seems like a good idea (or maybe gaffer tape actually, it’ll last longer).
Thanks, I’ll try that.

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

10

Re: Creaky Coker

yoopers suggested:
> I wonder if there’s a chance that a bearing is either going bad or has
> some contamination. Does the creak sound anything like a bad bearing?

It doesn’t feel or sound like a bad bearing, IME, although John’s suggestion
of loose bearings seems fairly likely.

It’s possible, of course, that transporting that enormous, weak Coker wheel
like this put’s too much strain on them:
http://www.speedy5.freeserve.co.uk/danny/unicycling/gallery/02081129unicar.j
pg

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

11

Hmmm. Why would greasing the spindles be bad for the cranks? That’s my standard procedure and it works very very well. I use grease on the spindle, blue loctite on the retaining bolt/nut and torque it to 35 foot-lbs.

Take a look at this article on Crank Installation from Scott Bridgeman’s Muniac Manor:

http://www.muniac.com/emuni.htm

As far as the squeak goes, perhaps it’s time to go back to the frame and saddle; you could try removing every bolt/nut and greasing them and reinstalling. Doing your seatpost too might help.

Rebuilding the pedals is easy too and might be worth it. After ten months or so of riding my freestyle with Miyata pedals they became dry and loose and would clatter when it hit the ground (it often hits the ground!). After a quick rebuild they are nice and tight and quiet.

12

Try turning the bearings by hand with the wheel out of the frame.
If they are wearing out you can’t tell by just spinning the wheel since it has so much angular momentum.

My bearings starting going with a little “chirpy” squeak 25 miles later I had ground through the races on one.

see

http://www.unicyclist.com/gallery/album56/aac

Leo White

13

Re: Creaky Coker

“Danny Colyer” <danny@jugglersafety.net> wrote:

>I have noticed the tyre rubbing the frame very occasionally, but that was
>when the wheel needed truing. Even so, the rubbing wasn’t consistent, so it
>could well indicate loose bearings. Thanks for the suggestion.

Is the tire rubbing associated with going up (or down hills), especially
steep ones? If so, the tire rubbing may be due entirely to frame flex.

I have brakes on my Deluxe Coker and when going up hills that are close
to my limit the frame flexes so much that at least one brake pad engages
at least slightly making the assent even more difficult. If I didn’t
have brakes on, I’m not sure the tire would rub the frame though. If
someone wants to comment on the tire-brake rubbing problem, a new thread
would probably be appropriate.

Sincerely,

Ken Fuchs <kfuchs@winternet.com>

14

Re: Creaky Coker

I set the brakes so when they are fully on they stil do not lock the wheel.
The advantage of this is 2 fold, one you don’t lock the wheel by accident
and two they are well clear of the rim when riding up hills.

Roger

----- Original Message -----
From: “Ken Fuchs” <kfuchs@winternet.com>
To: <rsu@unicycling.org>
Sent: Sunday, December 22, 2002 5:25 PM
Subject: Re: Creaky Coker

> “Danny Colyer” <danny@jugglersafety.net> wrote:
>
> >I have noticed the tyre rubbing the frame very occasionally, but that
was
> >when the wheel needed truing. Even so, the rubbing wasn’t consistent, so
it
> >could well indicate loose bearings. Thanks for the suggestion.
>
> Is the tire rubbing associated with going up (or down hills), especially
> steep ones? If so, the tire rubbing may be due entirely to frame flex.
>
> I have brakes on my Deluxe Coker and when going up hills that are close
> to my limit the frame flexes so much that at least one brake pad engages
> at least slightly making the assent even more difficult. If I didn’t
> have brakes on, I’m not sure the tire would rub the frame though. If
> someone wants to comment on the tire-brake rubbing problem, a new thread
> would probably be appropriate.
>
> Sincerely,
>
> Ken Fuchs <kfuchs@winternet.com>
>
>

> rec.sport.unicycling mailing list -
www.unicycling.org/mailman/listinfo/rsu
>
>

15

Re: Creaky Coker

U-Turn wondered:
> Hmmm. Why would greasing the spindles be bad for the cranks?

If you manage to push the crank too far onto the spindle (i.e. to the point
where the tapered spindle is wider than the hole in the crank) it’s
supposedly possible to damage the crank, causing cracks to spread from the
corners of the holes. Lubrication makes it that much easier to go too far.
Received wisdom is that BB spindles should never be greased for this reason.

> Take a look at this article on Crank Installation from Scott Brdgeman’s
> Muniac Manor:
> http://www.muniac.com/emuni.htm

Thanks, that’s an interesting article. It actually explains the received
wisdom, before disagreeing with it:
'The admonition to not lubricate the tapers of the crank spindle seems to
find life only on bicycle cranks, of all the machines I have seen. I have
pursued the “dry assembly” instruction by talking to crank manufacturers and
discovered that they apparently had warranty claims from customers who split
their cranks open. It is easy to prove that cranks cannot split by
over-tightening simply by attempting to do so. It is not possible to split a
major brand crank this way, the bolt will fail first. ’

IIRC I’ve only ever heard of it being a problem with aluminium cranks
anyway. I think it’s worth a go on my Coker. I’ve got no way to measure
the torque, though. I’ll just go as tight as my 6" monkey wrench will take
me, that’s worked for the last 10 years.

–
Danny Colyer (remove safety to reply) ( http://www.juggler.net/danny )
Recumbent cycle page: http://www.speedy5.freeserve.co.uk/recumbents/
“He who dares not offend cannot be honest.” - Thomas Paine

16

Here’s a little more on the “to grease or not to grease” debate for cranks.

It is my opinion that unicycle cranks with the standard square taper should always be greased. Before I started greasing the taper I would regularly get loose cranks during a ride. Since I started greasing the taper, pressing the cranks on, and using red LocTite on the retaining nut, I have not had a crank come loose on me yet. Splined cranks also get greased.

The article on Muniac.com about crank installation is straight from the rec.bicycles newsgroup FAQ.
<http://draco.acs.uci.edu/rbfaq/FAQ/index.html>
<http://draco.acs.uci.edu/rbfaq/FAQ/8f.11.html>
It’s a very informative FAQ and well worth the read.

If you get a mechanic or a friend who claims you should not grease the taper, refer them to the FAQ. If they are still not convinced then call them pig headed and old school and don’t let them install your cranks.

The quickest way to ruin a unicycle crank is to have the crank get loose and then ride with it loose. Riding with a loose crank just once can cause permanent damage to the crank. The risk of spitting the crank or enlarging the taper by pressing it too far on the spindle (hub) is nil compared to the risk of damaging the taper because the crank came loose.

When tightening the retaining nut on just a 6-8" wrench (spanner). There is no need to use a longer wrench. It is very easy to get the nut on tight enough with a 6" wrench. Don’t tighten it on like it is some sort of strong man contest. If you have to really reef on the wrench to get the cranks tight then you are not greasing the taper or the taper has already been damaged.

Race Face has also joined the “grease the tapers” side of the debate. Quote from the installation instructions for Race Face cranks with a square taper:

Race Face’s explanation for greasing the taper is different from the reasons given in the rec.bicycling FAQ. The Race Face cranks are made from 7075 aluminum alloy which has poor resistance to corrosion. It is corrosion that Race Face seems to be most concerned about. Race Face anodizes the cranks to help protect them from corrosion.