A drive train encompasses all the parts of your bike that chain touches – chain rings upfront and cogs in the back. Indicators that you need to replace your bike chain may be sloppy or slow shifting, mis-shifts, or grinding.
A simple test to find out if things are getting a little too worn is to pull on your chain with your fingers while it’s in the big ring. If the chain moves and wiggles around all the teeth on the chain ring, and you can see spaces between the ring and the chain, you can bet that it’s time to look at swapping everything. When your chain has been used for a long time and has stretched out, the gap between the rollers on the chain will grow larger. This will cause the chain to be misaligned with the teeth on the gears. Another visual cue is to look at the shape of the teeth. The older things get the pointier each tooth will get.
Because the chain and gears all wear in unison, if you replace just the chain, the new chain will not line up accurately with the old cogs. In addition, old cogs can wear out a new chain more quickly than it should, so it is best to change the cassette and chainrings when you replace your bike chain.
That seems a bit expensive to also change the cassette and chainrings when replacing the chain. I bought a cheap (less than $10) chain measuring tool and usually replace the chain a couple of times a year. Hopefully that will allow me to ride a bit longer before replacing the cassette and chainrings.
That is a good idea. We’ve never tried those chain measuring tools. If you can get away with swapping the chain on your old cogs and chain rings it is certainly worth looking at. The front rings aren’t soooo important, but once those rear cogs get worn you can leave yourself open to a skip or two just as you put pressure on the pedals. Not a nice situation when you’re excelerating out of a corner or trying to drop your wife on that final climb. Ahem. Hee Hee.