DiD ZVM2. X-Ring chain designed for heavy, long lasting street use. I have it on my 749 track bike. How many miles? As a general rule, yes. Replacing sprockets is rather cheap insurance to prevent early chain wear. But if it's fairly low mileage and there's no damage you may be OK. I've installed a chain on old sprocket before with great results. Last time I did it, still got 12,000 miles out of the chain. If it's fairly low mileage or the sprokets look great, you're most likely going to be OK. I would be hesitant of putting a new chain on old sprockets that were carrying a bad chain however.