rear wheel/ sprocket runout. BAD. wtf?

[ian miller]

So I installed new chain and sprockets on my 13k mi '06.  I bought it used at 11k  and the old chain was kinda kinky and jumped around a bit, so I figured it hadn't been looked after very carefully.  Well, I put all the new stuff on and the chain has the same catch in it that the old one did.  I sit down behind the bike as it's running in gear and see that the entire hub assembly has what looks like a quarter inch of vertical runout and also seems warped horizontally so that the brand new rear sprocket is wobbling back and forth causing the chain to catch.

Obviously, I did something wrong when I reassembled the wheel, right?  So I take it all apart again, make sure the cush drive is seated properly, clean everything (again), put it back together, and it's exactly the same. I did notice that the bearing in the cush drive hub is less than perfect, but certainly not out of round or facing imminent failure.  The other bearings were smooth. The rim and rotor don't seem to have any wobble, yet hub looks like its running on a cam at an angle.

I've found on this site that people have had problems with front wheels but only one mention of a rear problem, and if I remember correctly, that was a rotor/brake issue.

Anybody else seen or dealt with this?  Any ideas?

Thanks,

Ian

[Stretch]

There is a collared spacer between the hub bearing and the left side axle bearing.  I had a bit of trouble getting that spacer aligned properly the last time I was changing the rear tire... the spacer would slip out of place before I could get the hub seated on the wheel.

I fixed it by "gluing" the spacer in place with grease, holding it in place long enough for me to assemble the wheel.

Click on "Wheels / Tires / Final Drive" at the bottom of the blue list on the left, and then look at Part # 17 in the "Rear Wheel" diagram...  http://www.bikebandit.com/houseofmotorc ... er/o/m6914

So, maybe this spacer is out of alignment?

[ian miller]

Thanks Stretch.  I don't see how that spacer would get out of alignment, so maybe that's my problem...one side of it fits into the bearing and the axle slides through it.  Please let me know if I'm missing something.  I spent a bit of time staring at this assembly trying to find the problem but i just don't see it.  It seems that the hub is drilled off center.

There is a collared spacer between the hub bearing and the left side axle bearing.  I had a bit of trouble getting that spacer aligned properly the last time I was changing the rear tire... the spacer would slip out of place before I could get the hub seated on the wheel.

I fixed it by "gluing" the spacer in place with grease, holding it in place long enough for me to assemble the wheel.

Click on "Wheels / Tires / Final Drive" at the bottom of the blue list on the left, and then look at Part # 17 in the "Rear Wheel" diagram...  http://www.bikebandit.com/houseofmotorc ... er/o/m6914

So, maybe this spacer is out of alignment?

         

[clayrat]

You had the same problem i did on my 06 tiger from new  ,wheel hub center was machined offset from axle at factory .Sprocket had 6mm runout  .factory replaced wheel and sprocket carrier ,now has .020 runout on vertical and chain now runs cold  obiviously now in tolerance.

[Stretch]

Oh, wow.  The machinist fell asleep at the wheel, huh?

Ian, if that's the case with yours, there's little that can be done except to replace the wheel and hub.  Looks like a trip to the dealer is in your near future.  I do hope the warranty hasn't expired yet.

[ian miller]

Oh, ya.  Stopped by the local triumph dealer today...got the complete blow off.  Out of warranty, and the guy I talked to was a bmw wrench.  "I don't know how those assemblies work."  "Well, do you think the Triumph guy could take a quick look and let me know if he's seen this before?"  "Well if he's out here looking at bikes, he's not back there making money.  He works on flat rate, you know."  Yes, I  know. I know he won't be working on any more of my bikes, either. Especially after the questionable job they did on my (EXPENSIVE) 12k "major" service.  I hoped to develop a relationship with them and have this machine serviced there so that I could spend my wrenching time on my old and truly unreliable bikes, but I won't be going back.  I'm on the verge of a real rant, so I better stop here.  

I can buy a new cush drive assembly from bikebandit (thanks again, stretch) for $276. I'm pretty sure that's the culprit, but I think I'll take it apart again and get the cush drive hub measured for runout.  Anybody out there have one laying around thats straight and that I might buy for less?  


Thanks,

Ian

[Stretch]

That's a shame about your dealer.  Please do us all a favor and post its name and location so the rest of us can avoid it like the plague.


For used parts...

Try Ma's Cycles...  http://www.mascycles.com/

or Baxter Cycles...  http://www.baxtercycle.com/

They sometimes have used parts on hand from wrecked bikes.




To avoid buying the cush rubbers unnecessarily, try assembling the hub and wheel on the bike (with the axle tight) without the cush drive rubbers in place.  If you have runout even without the rubbers installed, it would sound more like an improperly-machined hub.  Or maybe a misaligned bearing...

Make sure the sprocket carrier hub bearing is fully seated and sits squarely, and that the snap ring is in place.  (You'll have to lift out the seal to do this.)  If the hub bearing was loose inside the hub, the hub would wobble on the (tight) bearing, as the axle merely centers the hub bearing with the axle (wheel) bearings.  When the axle is tightened, the wheel and hub bearings are essentially joined at the inner races, and aligned with each other on the axle.  No lateral or vertical movement is possible, except by way of the bearing itself (defective), or its fit inside the hub (loose and slightly tilted).  Or the hub was machined improperly.

Be sure to let us know how it turns out, so we can refer this thread to others with a similar problem.

[clayrat]

IAN if the dealer wouldnt fix rear wheel and hub i was going to weld up the wheel hub and machine back to factory spec as steel insert insprocket carrier was hardly marked but bearing was had it   .The wheel hub was worn on one side like yours .i checked mine by leaving the sprocket carrier off the axle but used bearing and spacer to re mount wheel in swingarm and tightened axle to torque figure. I then set up a dial gauge  on worn section of hub to see if that was the problem .it was totaly out of true .diffrence between axle andworn area shouldnt be more than a couple of thousandth of an inch .im a fitter welder by trade it is not a complicated job .good luck to you