Originally Posted by idodirt

How many miles on the bike/chain ? Chain wear is a normal thing, as is sprocket wear. Depending on how well it's maintained and how the bike is ridden, a set of sprockets and chain can last 15,000 miles or more. The can also wear out in less than 5,000 on a bike used at the track.

Yes, replacing the chain and sprockets will allow you to get the chain adjusted back to the proper amount of slack. You really need to replace the sprockets and chain as a set. Replacing one without the other can cause premature wear of the new parts, causing them to need replacing sooner.

Several good brands out there, DID, RK, EK are a few. Going with steel sprockets will make them last longer. Using an alloy sprocket is going to have it wear faster, and cost more. They weigh less, but unless you're racing in competition, not worth it for me. Expect to pay around $150 for a decent set.