Front sprocket bolt cant be moved

[GoldOxide_imp]

me too, worn at 30K miles...???

Not a lot of mileage.

[peterbaron]

Here are my sprockets after about 41K miles[/u]...and the main reason I replaced both was kinking chain at few spots, so did everything at one shot.
Sprockets and chain received average service, often 4K miles without any service intervals.

[the Ferret]

Mine at 36K miles still looked good. I replaced all the parts since I had already bought them. On my NC I replaced the 520 chain at 23,000 and used the same sprockets. My chain gets the same kind of service. Rarely adjusted between tire changes. Lubed occasionally when it looks dry or after I get caught in a lot of rain.

[GoldOxide_imp]

My chains have never stretched even halfway to replacement in the past 25 years. Sprockets have never needed changing.

I imagine if one is an aggressive rider, off-roader, or terrible at shifting gears, then yes: Chain, sprockets and tires would be often replaced.

[peterbaron]

Nothing lasts forever, well except infinity...

[misterprofessionality]

My chains have never stretched even halfway to replacement in the past 25 years. Sprockets have never needed changing.

I imagine if one is an aggressive rider, off-roader, or terrible at shifting gears, then yes: Chain, sprockets and tires would be often replaced.

Yyyep

For my part the aggressive riding managed to eventually kink up the chain a bit which made it worse, but most of the wear was already done by then. Hard acceleration. Higher revs, Lots of engine brake.