Hello experienced ones.....

Have a chain and sprockets questions or two. Hope that someone can give me some advice.

Fitted a OTR drive kit set eatlier this year. 525 size and X-ring and sprockets size 15/48. And have after that done a long overlanding tour and are going to continue soon....

Now after around + 30 k km the rear sprocket is almost done but the front sprocket looks as new, as good as no sign of wear. Isnt that a little strange?
The chain has only been adjusted 3 times during this 30 k km as it havent been neccesary to do it more often. And not much at a time either. Could the chain just be too hard on the rear sprocket? Harder material or something like that?

So its soon time to change, well at least the rear sprocket. But I suppose I should I change the chain as well. What do you guys think?
Front sprocket looks fine so I guess I dont need to change that....or?

Have got a hold of a gold O-ring 525 chain here I am now but I also carry a spare X-ring chain with me. Is there any big difference in these ones? What would you guys fit?

Thaks in advance!

__________________
Suzuki AC 50 -78 owned from 83 to 84
Kawasaki Kh 100 Es 81 owned from 84 to 86
Honda Transalp Xlv 600 -97 owned from 01 to 05
Honda Nx 650 Dominator -98 owned from 07 to 10
Triumph Tiger 955 i -01 owned from 10 to 13
Yamaha XT660Z Tenere ABS -11 owned from 2013 and present bike.
Honda Crf250L -12 my bike in Thailand.

That doesn't sound normal!

Each individual tooth on the front sprocket comes into contact with a chain roller three times as often as a tooth does on the rear. Theoretically you'd expect the rear to last three times as long as the front. In reality, it's more like two fronts to one rear in my experience.

Either the rear sprocket was poorly manufactured, or was exposed to sand or abrasive particles, or maybe silty water for long periods? Exposure, I'd suggest, is the most likely cause, as the front sprocket is covered and better protected and the rear hangs low and closer to the ground; a problem particularly in deep ruts. Were you riding in ruts, sand, or sandy conditions a lot of the time?

I've never, in all my years of biking, had to change a chain and sprocket set because the rear sprocket wore first. It has always been the chain or front the fails first. Your issue is a weird one!

As for x-ring versus o-ring, they're both good and perfectly up to the task, it's just the x-ring design of seal acts as a wiper as well as a seal and keeps things cleaner.

__________________

Thanks for the answer Pleiades.

Yeas thats what I thought too, its a little strange indeed. I have been driving through Kazakhstan, Kyrgizstan, China etc and can definetively say that there has been some sandy stretches, gravel roads, dusty sections etc. And I havent cleaned the chain and sprockets along the road either. Which I am suposed to do I guess....have been spraying the chain quite often though.
So maybe some of the answer lies there.

Anyhow - 30-35 k km, is that a normal lifespan on a sprocket?

Would you have changed only the rear sprocket or would you have changed the chain as well?

__________________
Suzuki AC 50 -78 owned from 83 to 84
Kawasaki Kh 100 Es 81 owned from 84 to 86
Honda Transalp Xlv 600 -97 owned from 01 to 05
Honda Nx 650 Dominator -98 owned from 07 to 10
Triumph Tiger 955 i -01 owned from 10 to 13
Yamaha XT660Z Tenere ABS -11 owned from 2013 and present bike.
Honda Crf250L -12 my bike in Thailand.

30-35,000Km (20,000+ miles) is pretty good going for any sprocket and the chain. The only thing that's odd about your story is that the back one has worn worst. Other than that, I'd be reasonably satisfied if got that distance out of C&S set, especially if you never cleaned it and only used spray lube.

If the chain and front sprocket are still good (and money is tight), you could feasibly just change the rear. Up to you really. All I'd say is, if the chain and front sprocket have got less than 10,000Km left in them, it would probably be less hassle to do the whole lot - at least then you'd know you had a definite 30,000Km of life in the drive train.

__________________