REAR SPROCKET CARRIER PROBLEMS

[Trigger]

Had a little time to look into the problem of the wear on the rear sprocket carrier as I have a few with loads of play and every rear wheel I have bought had the same problem. What I did find is that the sprocket carrier had worn the hub at the contact surface. Nearly all the hubs I measured up had gone egg shaped and there would be no point whatsoever buying a new sprocket carrier and putting on to a non matching surface, as this would just wear the bush on the new carrier, that would be a complete waste of time and money.
The only way I could do this job was to machine down the hub surface until it was completely circular and true. Then I set about removing the old bush out of the sprocket carrier, and making a new bush.
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[K2-K6]

I don't know their arrangement on that one,  is the sprocket carrier not supported on a bearing to centre it then?

I'd like a lathe that would take wheels complete.

[Trigger]

I don't know their arrangement on that one,  is the sprocket carrier not supported on a bearing to centre it then?

I'd like a lathe that would take wheels complete.

The carrier is supported on a bearing on the 750 but, not on the 500 or 550. I have seen minimum wear on the 750 but, not requiring this type of work.

[K2-K6]

Ah,  no wonder they wear then. 

I guess if it gets too bad you may feel that under load when riding it as it must put oscillation into the chain run.

[Seabeowner]

Agreed, it's an awful design. Surely it should be dismantled and regreased at regular intervals. Isn't that what the grooves are for in the original carrier?
But of course that's near impossible as the retainer is often nigh impossible to remove.

[Trigger]

Agreed, it's an awful design. Surely it should be dismantled and regreased at regular intervals. Isn't that what the grooves are for in the original carrier?
But of course that's near impossible as the retainer is often nigh impossible to remove.

yes, better to remove it every 10,000 miles, clean it up and apply new grease, tell the PO that one  . I was trying to work out the grooves on the original bush but, the movement on the carrier when riding is small and the grooves don't really do there job, in fact any grease would just collect in them and leave the surface dry. I was toying with the idea of drilling a pattern of counter sunk dimples to hold the grease more evenly.
A lot of wear starts when the cush rubbers start to fail, which increases the movement on the bush to hub surface.
Easy to remove the retaining ring with the right tool     

[K2-K6]

I don't know what the grease spec is but would something like the molly filled stuff they use inside car cv joints be appropriate?

It runs at road wheel speed,  generally has a low surface movement when running straight ahead but move when the joint is steered. Presume the joint is just shuffling back and forth with any backlash in the drive rubbers.

Or further along those lines,  something like "Cal Guard Chain Kote" the black one with molly compound for similar lubricating properties but with really high stickiness to keep it where you left it.

[Moorey]

The grooves look to be a simple labyrinth seal, and as such should be cleaned out and not filled with grease. The idea been as dirt or grease slowly travels between the carrier and spindle spacer the centrifugal force or the rotating wheel flings the debris into the grooves to be trapped. But not having seen the particular arrangement close up its my best guess as to the reasons for the grooves.

[Trigger]

No the grooves were placed there to allow grease to collect in them, it's not the best arrangement but it works to some degree. Trig is spot on, as the damper rubbers wear the sprocket carrier moves more and more and the allows the lack of grease to really become a problem. I've seen them really eccentric and the grooves missing on one side but fine on the other. A liberal application of grease on assembly and periodic replenishing and it works fine, problem is, if you don't know about it you find out too late.

I agree Oddjob, the grooves do not do the job unless you remember to strip and re grease at every major service or tyre change. As I over engineer everything I do and I only like to do the job once and get it right, any ideas on improving the way to hold grease on the bush ?
I have a few to do and one for a customer who only wanted his wheels re rimmed with new spokes. As the wheel arrived whole, I found the sprocket carrier worn, the cush rubbers as hard as metal and the brake hub cracked. I did advice that it would be cheaper to find another rear wheel or hub unit. Everyone he has bought has been worse, so not cheaper in the long run.

[Trigger]

Had thought about grease nipples but, if the grease squeeze out past the 0 ring then it would be all over the cush rubbers.