Originally Posted by
maddog34
either SRAM or Shimano Cassettes will work fine.. they are interchangeable...
make sure the chain you get is 6-7-8 speed compatible. a KMC Z51 or Z72 will work fine, but you WILL need to correctly size it once you have the new parts... easiest way is to shift to the SMALL cog in the back, then make the chain short enough to put the derailleur tension arm to a position that is below horizontal by 15 or so degrees. If the old chain was so cut, it can be used as a guide by counting the number of links, then making the new chain the same count... not LENGTH.... COUNT.... the old chain has worn pins/bushings that will make it appear longer.
contrary to popular belief... Chains DO NOT STRETCH, they WEAR.
avoid getting a chain at a big box store... they are sometimes beyond "worn out" spec, directly from the package!
count the number of teeth on the cassette's big and little cogs, then order that range cassette... done!
Chains absolutely stretch. Measure the new chain say to 100 links and then measure the chain when you take it off to the same pin at 100 links. You'll measureably see the stretch.
In fact anyone who knows anything about working on a bike knows how to measure chain wear with a ruler. If you truly live in a reality where you think chains don't stretch, and don't know how to quantify the stretch/wear you probably shouldn't be in an Internet forum giving advice on bike mechanics!