I bought a Coker big a year ago, and everytime I mount it, the wheel
begins to bend and finishes hitting the frame. I weigh 240 pounds. I
know, this contributes to the problem. But i think it must be strong
enough to support this. Examinig the uni, I found two possible causes:
The hub seems to be too narrow for the huge size of the wheel and the
bearings aren`t completely centered on the hub.
Re: Wheel problems with the Coker big one unicycle
> I bought a Coker big a year ago, and everytime I mount it, the wheel
> begins to bend and finishes hitting the frame. I weigh 240 pounds. I
> know, this contributes to the problem. But i think it must be strong
> enough to support this. Examining the uni, I found two possible causes:
> The hub seems to be too narrow for the huge size of the wheel and the
> bearings aren`t completely centered on the hub.
>
> Anyone has the same problem? any solution?
I have the 240#+ problem, though not the wheel bending problem.
Re: Wheel problems with the Coker big one unicycle
Make sure the bearings are not slipping on the hub. When you are on the uni check if the bearings are sliding towards the cranks.
Bearings are pressed on the hub. If the press fit isn’t tight enough the bearing will be able to slide around on the hub when you pedal hard which can cause the wheel to rub on one side of the frame.
I hope you can get Loctite in Spain. The fix is to pull off the bearings and put them back on using Loctite bearing or sleeve retainter.
Loctite <http://www.loctite.com/> and Permatex <http://www.permatex.com/> and probably a few other companies make sleeve retainer. The stuff you want is known as retaining compound, bearing mount, and/or sleeve retainer.
Over here in the USA I can get the Loctite sleeve retainer (part number 640) at automotive supply shops. It may be available in similar shops in Spain.
I have had to use the sleeve retainer on the bearings of my Coker and my Pashely MUni. It’s not a problem specific to the Coker.
Re: Wheel problems with the Coker big one unicycle
skurland@juggler.net writes:
>> I bought a Coker big a year ago, and everytime I mount it, the wheel
>> begins to bend and finishes hitting the frame. I weigh 240 pounds. I
>> know, this contributes to the problem. But i think it must be strong
>> enough to support this. Examining the uni, I found two possible causes:
>> The hub seems to be too narrow for the huge size of the wheel and the
>> bearings aren`t completely centered on the hub.
>>
>> Anyone has the same problem? any solution?
>
>I have the 240#+ problem, though not the wheel bending problem.
>
>Get the wheel trued and it may go away.
It’s worth mentioning that Cokers of old (not the newer ones) can only get
SO trued – there is apparently a defect that prohibits true truing. That
make sense?
And I’ll add that I have had no trouble on my old Coker wheel despite my
190# – and it’s given me 3,500 good miles without problems.
David
Co-founder, Unatics of NY
1st Sunday / 3rd Saturday
@ Central Park Bandshell
1:30 start time after 11/1/01
There does seem to be a limit, though, to the Coker wheel’s resistance. I weigh in at 285 and have folded a standard Coker wheel by just planting myself on the seat. As I indicated in a previous post, the speculation for that incident seemed to be that the spokes were overtightened…much like my head during the workday.
I’ve not had a hint of problem with my Coker Deluxe, the Airfoil rim is fabulous. I had to replace the hub on my CD and while the wheel was disassembled, the rim lay true and flat. Wonderful.
Ben and Brad have the standard Coker rims and the spokes seem to be as tensioned as they were when the Cokers arrived a couple weeks ago. But the rims are now quite a bit out of true. I haven’t tried truing them yet but will soon. David, I sure didn’t want to hear about the alleged limit to truing. Both boys are less than 100 lbs. and so far, the non-trueness doesn’t seem to affect them.
Is there such thing as an inexpensive spoke tensiometer? How other than gut feel can I know how much to tension the spokes?
The rim is made of mild steel which is rather crudely shaped and joined, and the hub is very narrow in relation to the radius of the wheel. Add to that that the spokes are unlikely to be accurately tensioned when the wheel leaves the factory and you have a recipe for pretzels.
You can’t easily change the rim or the hub, but you can get the spokes tensioned. As the spokes are tightened, they pull the rim back into line. It’s a skilled job, requiring experience and a ‘knack’. No way would I try it myself on a Coker.
But help is at hand! My wheel went the same way and I took it to the local bike shop and the bloke there took it as a challenge and did an excellent job for about 17 quid.
Show willing though: remove the wheel from the frame and remove the tyre and rim tape before replacing the wheel in the frame. If you have a crank tool, remove the cranks. Leave the seat on, or put a cheap one on. The Coker wheel won’t fit in the standard wheel trueing jig, so the technician will need to use the forks as a jig. If the seat’s in place, she can stand the uni upside down on that to work on it. Money well spent.
I may be incorrect on this, but I’m pretty sure John Drummond told me that he has all Coker wheels that come through Unicycle.com trued by Mr. Kovachi. When the boy’s Cokers arrived, they were indeed true. But in the short time they’ve ridden and done tricks on their Cokers (see http://www.unicyclist.com/gallery/cokertricksters), the wheel has gone out of true. I sincerely do not believe this has any reflection on Mr. Kovachi’s input into the wheel or on Unicycle.com as a company. After our so far short relationship with the Coker unicycles, I believe it is completely characteristic of the quality of product coming out of Taiwan.
Re: Wheel problems with the Coker big one unicycle
I only weigh 165, but have had the wheel taco on me briefly when hopping.
I’ve since upgraded to the Airfoil rim and it feels much more solid.
—Nathan
“Little Jon” <timetab@telefonica.net> wrote in message news:68786e13.0210020643.48b65baa@posting.google.com…
> I bought a Coker big a year ago, and everytime I mount it, the wheel
> begins to bend and finishes hitting the frame. I weigh 240 pounds. I
> know, this contributes to the problem. But i think it must be strong
> enough to support this. Examinig the uni, I found two possible causes:
> The hub seems to be too narrow for the huge size of the wheel and the
> bearings aren`t completely centered on the hub.
>
> Anyone has the same problem? any solution?
>
> Thank you in advance for your answers.
>
> Little Jon, from Madrid, Spain.
----- Original Message -----
From: “john_childs” <john_childs.bwpkn@timelimit.unicyclist.com>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Wednesday, October 02, 2002 6:25 PM
Subject: Re: Wheel problems with the Coker big one unicycle
>
> Little Jon wrote:
> > *I bought a Coker big a year ago, and everytime I mount it, the wheel
> > begins to bend and finishes hitting the frame. I weigh 240 pounds. I
> > know, this contributes to the problem. But i think it must be strong
> > enough to support this. Examinig the uni, I found two possible causes:
> > The hub seems to be too narrow for the huge size of the wheel and the
> > bearings aren`t completely centered on the hub.
> >
> > Anyone has the same problem? any solution?
> >
> > Thank you in advance for your answers.
> >
> > Little Jon, from Madrid, Spain.
> > *
>
>
> Make sure the bearings are not slipping on the hub. When you are on the
> uni check if the bearings are sliding towards the cranks.
>
> Bearings are pressed on the hub. If the press fit isn’t tight enough
> the bearing will be able to slide around on the hub when you pedal hard
> which can cause the wheel to rub on one side of the frame.
>
> I hope you can get Loctite in Spain. The fix is to pull off the
> bearings and put them back on using Loctite bearing or sleeve
> retainter.
>
> Loctite <http://www.loctite.com/> and Permatex
> <http://www.permatex.com/> and probably a few other companies make
> sleeve retainer. The stuff you want is known as retaining compound,
> bearing mount, and/or sleeve retainer.
>
> Permatex stuff
> <http://tinyurl.com/1en8>
>
> Loctite stuff
> <http://tinyurl.com/1r25>
>
> Don’t worry that the stuff may claim to be “high strength”. Even with
> the high strength stuff you’ll still be able to pull the bearings off
> using a bearing puller like this one at unicycle.com
> <http://www.unicycle.com/shopping/shopexd.asp?id=419>
>
> Over here in the USA I can get the Loctite sleeve retainer (part number
> 640) at automotive supply shops. It may be available in similar shops
> in Spain.
>
> I have had to use the sleeve retainer on the bearings of my Coker and my
> Pashely MUni. It’s not a problem specific to the Coker.
>
>
> –
> john_childs
>
> john_childs (at) hotmail (dot) com
> ------------------------------------------------------------------------
> john_childs’s Profile: http://www.unicyclist.com/profile/449
> View this thread: http://www.unicyclist.com/thread/20802
>
>
This seems like a good time to mention a project I’m working on for Unicycle.com.
I purchased one of my two Cokers from Chris Reeder about a year ago. He had modified the hub, adding distance between the flanges to create a stronger wheel.
I’ve ridden this wheel over a 1000 miles in the last year, and I have never had to true it. I use a rim brake and the rim is true between the pads, though the rim (chromed steel) width varies so much that I rarely use it. I haven’t been on a scale in ages, but I’d guess I weigh somewhere between 170-180 lbs. I’ve ridden the Coker pretty aggressively, off curbs, up curbs, mild off road and again have never had to true it.
I’m currently modifying some Suzue hubs in a manner similar to the hub I own. They’re going to be available from Unicycle.com in the very near future (possibly 2 weeks at most) and should be pretty reasonable priced.
To see pictures of said hubs, go to my website and follow the “Wide Coker Hubs” link under R&D.
I’m expecting someone to mention Q factors with regard to the wider hubs. I’ve got a lot of miles on both narrow and wide hubs, and I like the wider hub better on my Coker. I feel like I free mount and corner better with the wider hub.
>I bought a Coker big a year ago, and every time I mount it, the wheel
>begins to bend and finishes hitting the frame. I weigh 240 pounds. I
>know, this contributes to the problem. But i think it must be strong
>enough to support this. Examining the uni, I found two possible causes:
>The hub seems to be too narrow for the huge size of the wheel and the
>bearings aren`t completely centered on the hub.
A well maintained Coker is easily strong enough. Warning: Always lean
sideways in line with the frame or you can taco the wheel;
Forward/backward leaning can be done anyway you want without harm.
Very tight spokes will reduce the chances of a wheel taco.
Solution: True the wheel so it stays centered in the frame as it is spun
around by hand. Be sure the spokes are all about equally very tight.
The hub should be wider, but it may be difficult to get a significantly
wider hub.
The bearings put on by Coker are not very good and could be wearing out.
Spacers could be added to center the hub in the frame.
An untrue wheel is probably the only problem though.
Not seeing the Coker does make it hard to diagnose the problem, so I’ve
mentioned a lot of problems, but can’t be sure they exist on your Coker.
