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"Don't know what you're basing this opinion on because the chain on my new T800XC is an RK525GWX with "JAPAN" stamped on it so as far as I'm concerned is equal quality to the DID X-ring fitted OE to my 2002 Tiger955i."

Somewhere between 2004 and now Triumph switched from DID to RK which in my opinion was a business decision which had no impact on quality.

"As for rust on your chain. That just proves that you're not lubricating it enough."
I think you have a point there.

"Anyway, I've always believed that the sprockets should always be changed along with a new chain because even the slightest amount of wear on the sprockets will accelerate the wear of the new chain because the teeth will not mate exactly."
Don't buy your rationale on this point. If the teeth have good shape, yes there may be a bit more wear but not enough to offset the cost of buying a sprocket with every chain. I can see getting a new countershaft sprocket if it is significantly getting pointy.

"Life? I got 33000 miles out the OE chain on the 955 and the second one (also a DID X-ring) has now covered 32000 miles and I'm just about to renew that with another DID X-ring. I've run a Scottoiler from new and also a 19t front sprocket which I replace after 15000 miles from fitting the new chain. I always have the scottoiler turned up enough to get the chain nice and wet. IMO you either have a clean bike or a long lasting chain." I changed my last two chains at about 23K and probably could have gotten to 30K, but for sure my rear sprockets where in excellent shape. It looks like a have a free replacement for a Scottoiler, my output shaft seal is leaking a bit of oil :D
 

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"Anyway, I've always believed that the sprockets should always be changed along with a new chain because even the slightest amount of wear on the sprockets will accelerate the wear of the new chain because the teeth will not mate exactly."
Don't buy your rationale on this point. If the teeth have good shape, yes there may be a bit more wear but not enough to offset the cost of buying a sprocket with every chain. I can see getting a new countershaft sprocket if it is significantly getting pointy.
My reasoning is that if your chain is knackered, it is longer between pin centres than a new one and will have transferred that extra length into wear on the sprockets. So when you mount your new chain it will try to match the shape of the worn sprockets instead of being nicely cradled by the correct length of a new sprocket. All that puts extra strain on the pins and they will wear quicker.
By all means try it but I'm convinced that your new chain on old sprockets will only last maybe 2/3rds the life of the previous one. This has been well proven and demonstrated over many, many years. That's how these rules of thumb come about in the first place.
 

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My reasoning is that if your chain is knackered, it is longer between pin centres than a new one and will have transferred that extra length into wear on the sprockets. So when you mount your new chain it will try to match the shape of the worn sprockets instead of being nicely cradled by the correct length of a new sprocket. All that puts extra strain on the pins and they will wear quicker.
By all means try it but I'm convinced that your new chain on old sprockets will only last maybe 2/3rds the life of the previous one. This has been well proven and demonstrated over many, many years. That's how these rules of thumb come about in the first place.
I fully understand your rationale on wear. Where I do disagree is just how much wear and the "well proven." I have a background of getting numbers to prove things. Considering, IMO, the majority of riders change their chain and sprockets just by numbers in a book or intuition, I have yet to see hard numbers to support the chain and sprocket rule of thumb. Far too many "rules of thumb" fall into the category of "old wives tale." To restate my point of view, I'm pretty sure that the new chain will wear somewhat more with the old sprocket, but I'm not that sure it will wear to the degree that it is cost effective.
 

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I fully understand your rationale on wear. Where I do disagree is just how much wear and the "well proven." I have a background of getting numbers to prove things. Considering, IMO, the majority of riders change their chain and sprockets just by numbers in a book or intuition, I have yet to see hard numbers to support the chain and sprocket rule of thumb. Far too many "rules of thumb" fall into the category of "old wives tale." To restate my point of view, I'm pretty sure that the new chain will wear somewhat more with the old sprocket, but I'm not that sure it will wear to the degree that it is cost effective.
I fully understand your point of view but I'm coming from an engineering point of view. When new the sprocket is machined to match the pitch of the new chain exactly. When either are worn, any new part put into that system will not match and will, therefore, wear abnormally fast.
Let us know how you get on with the new chain on old sprockets. What I do know is that my second chain has lasted as long as the first by renewing it all at the same time.
 

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This thread has been interesting to me, coming from years of shaft driven bikes.
Devildog and blacktiger have a difference of opinion, but I've gained knowledge from both points of view.

When it's time for a chain, if my sprockets don't show visible wear, I won't replace them.
I don't usually put more than 10-15K on a bike before replacing with another machine.
And I never buy a new bike, there are too many good used low mileage machines out there, for sale by owners who decided they didn't really won't to ride after all.
 

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This thread has been interesting to me, coming from years of shaft driven bikes.
Devildog and blacktiger have a difference of opinion, but I've gained knowledge from both points of view.

When it's time for a chain, if my sprockets don't show visible wear, I won't replace them.
I don't usually put more than 10-15K on a bike before replacing with another machine.
And I never buy a new bike, there are too many good used low mileage machines out there, for sale by owners who decided they didn't really won't to ride after all.
My previous bike to the Tiger was shaft, BM R1100S, and I do miss the relatively maintenance free aspect, my bevel box went at 80k, I got a S/H unit for £100, so still way cheaper than say 3 C&S sets, though I also like the fact that when you do replace a C&S youve got a brand new final drive again, swings and roundabouts, oiling is a pain though, and I wont go near scotoilers, just me.
 

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From a mechanical point of view the moment the chain and sprockets move after fitting they begin to wear and "seat in" together. If you have to replace your chain in under 10,000 miles and the sprockets look good, don't be fooled. They will look good but they will have some wear. This will affect how the new chain seats in when fitted, just need to be aware you are unlikely to get the full life of the sprocket or chain if fitted in this way.

However, if you are going 12,000 -15,000 miles or more then you should fit new sprockets when fitting a new chain. You don't have to it's your choice, but there is an increased likelihood of premature chain failure if fitting a new chain to old sprockets.
 

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From a mechanical point of view the moment the chain and sprockets move after fitting they begin to wear and "seat in" together. If you have to replace your chain in under 10,000 miles and the sprockets look good, don't be fooled. They will look good but they will have some wear. This will affect how the new chain seats in when fitted, just need to be aware you are unlikely to get the full life of the sprocket or chain if fitted in this way.

However, if you are going 12,000 -15,000 miles or more then you should fit new sprockets when fitting a new chain. You don't have to it's your choice, but there is an increased likelihood of premature chain failure if fitting a new chain to old sprockets.
All true, sounds good. I will readily admit that probably you will get fewer miles on that second chain. My question is "how much fewer" and will the cost per mile on those extra miles offset the cost of the new sprocket? I'm not talking 12-15K either, mine were 20-23K hard braking, hard shifty twisty road miles AND even though I replace both chain and sprocket NEITHER had to be changed for a lot more miles. Only the countershaft sprocket was getting close to a point of concern. This is not a true apples to apples comparison, because most of us yanks don't ride in the nasty weather that Europeans do.

I'll repeat myself from a previous post, how many of you have had a chain fail??? IMO, if you have had a chain fail, I bet you 10 to 1 the reason was NOT sprockets but that component that fits right above the saddle. You should experience tight spots or frozen links well before a chain fails, plenty of time for you to get it replaced. Additionally, your chain won't hold proper adjustment when stretched. I check my chain all the time before I go on a ride. The ONLY time it has needed adjusting is after I change my tire. Soooo if you see your chain getting loose and you are constantly adjusting it, it's time for a new chain. Still plenty of time before it falls to the ground or less likely shoots through an engine case.
 

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DevilDog - chains usually fail due to poor maintenance of the chain, usually caused by not enough lubricant and the chain gets tight spots. This will happen whether or not the sprocket is good. If the sprocket wears then the chain will eventually jump and teeth on the sprocket break. I have to say that you can spot the wear well and truly before it gets to the chain jumping stage.

So in a way I agree with you, you can choose to replace the chain without changing the sprocket but my advice is if you are replacing the chain at over 15,000 miles I would replace the sprocket at the same time. It's a choice thing rather than a tight rule.
 
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