[ducsingle]

I sold my '98 M900 almost 2 years ago to an acquaintance. Just before the sale, I installed a slightly larger rear aluminum sprocket. The bike has been ridden less than 1200 miles since then. Total mileage is about 5500.

The new owner recently called me and said that a shop had told him the aftermarket aluminum sprocket "had not been installed correctly" and that he needed to replace the chain and front and rear sprockets at a cost of $300. I asked him what was wrong, and he said he didn't know. Apparently he didn't feel like getting more details from the shop, but since I installed the sprocket myself, I felt obligated to see what was going on.

I took a look at the bike, and there is definitely some strange wear as the chain has basically worn a shelf into the left side of the sprocket and the teeth are already showing a fair amount of wear. Chain tension and rear wheel alignment are fine, and the rear wheel spacer is installed correctly. The front sprocket looks great, and the chain actually looks okay too.

Has anybody seen anything like this? I didn't see anything wrong with the installation, so I'm guessing the sprocket was either the wrong size (too narrow?) or maybe the aluminum alloy was too soft.

 

[Norm]

I don't know what caused that wear, but why not tell your friend to just buy a new rear sprocket for $30-40 & forget the rest?

 

[Andrew_Cornett]

This is why you should never sell a bike or anything for that matter to a friend. They will come back to you as if it was your fault. If the shop would have installed the sprocket for you, would you still fill the obligation to your friend? No offense, but sh*t happens and the bike is no longer yours. If it was your bike still you would need to replace the parts and such. Your friend should replace the sprocket on his own dime. Heck for all you know the sprocket itself could have been defective and its really the manufactures fault for the wear. Just my .02s worth.

 

[ducsingle]

Yeah, I would have second thoughts about selling a bike to a good friend for the same reasons. I would categorize this as more of an acquaintance sale, but I still felt obligated to take a look - - - plus I was curious to see what was really going on. At this point my conscience is clear unless somebody can point to something I screwed up.

I told him that if it were my bike, I would clean the chain, install the original steel sprocket (that looks perfectly fine) and go for a ride. I think the shop freaked him out by telling him that it would be incredibly dangerous to replace just the rear sprocket.

 

[ducman851]

Unless the wheel was installed slightly out of alignment. This might cause a wear pattern more on the sides of the sprocket. ???

 

[chris]

I sold my '98 M900 almost 2 years ago to an acquaintance.