Bicycle Mechanics - Chain shows no wear, replacing cassette, replace chain anyway?

I'm going to be trying out a new drivetrain on my bike, replacing the cassette and my smallest chainring. I used a park chain wear tool to look at the chain last week and it shows no sign of wear after 2,500 miles, and the cassette seems fine too.

Should I replace the chain anyway?


I will keep the old cassette and switch it back on whenever I'm going to do really hilly rides, as it has a lower gear on it (11-34 vs 12-30). So if I do change the chain, should I keep the old chain and use that when switching to the old gearing or would it be ok to use the new chain? There's only a 4 tooth difference so I think I can get away with using the same length of chain as long as I'm careful to avoid severe cross-chaining.

What change are you making for the chainring?

You'll probably be fine, but it wouldn't hurt to get a new chain for the new cassette, and then swap both when you use the old one.

EDIT: No wear after 2500 miles? Not bad -- you should check it with a ruler, too. ;)

Measure a second time with a ruler.

+1 to check it again, with a ruler too. that's a lot of miles if a 9-10 speed. Maybe not so many if 8-speed or less.

I've got a Park CC-3.2 and I always check the chain in at least 2 different spots too sometimes.

The problem with such a short chain checker is that it is only looking (feeling atually) at a very small chunk of the chain as a sample. I'm not 100% convinced that chains wear evenly all around the length -so I want to check a little more of the chain than just a tiny 4" chunk of it. Doing the ruler check also gets more links involved into the measurement over a longer distance.

Having a chain "check good" on a chain-checker isn't always a true positive of good -but if you have one check "bad" it is almost certainly bad.

I'd package the chain and cassette together , in a bag.. if I were you.

+1 to check it again, with a ruler too. that's a lot of miles if a 9-10 speed. Maybe not so many if 8-speed or less.

I've got a Park CC-3.2 and I always check the chain in at least 2 different spots too sometimes.

The problem with such a short chain checker is that it is only looking (feeling atually) at a very small chunk of the chain as a sample. I'm not 100% convinced that chains wear evenly all around the length -so I want to check a little more of the chain than just a tiny 4" chunk of it. Doing the ruler check also gets more links involved into the measurement over a longer distance.

Having a chain "check good" on a chain-checker isn't always a true positive of good -but if you have one check "bad" it is almost certainly bad.

The chain checkers always show a chain as worn out before it is. The only accurate to gauge chain wear is with a ruller.

The chain checkers always show a chain as worn out before it is. The only accurate to gauge chain wear is with a ruller.

Not quite true.
The Shimano TL-CN40/TL-CN41 is the one checker that measures correctly.
http://pardo.net/bike/pic/fail-004/000.html

It's a 10 speed. I checked in 3 places using the park tool chain checker.

Got a tape measure I suppose I could use. Ordered a new chain anyway though. Was hoping to go the whole season with just 1 but I'm not sure I'll risk it.

The crank is 26-36-48. I'm replacing the 26 with either a 22 or 24. Ideally a 22 but if that doesn't work right (concerned about the 14t drop) I'll try 24.

I'm using the heaviest SRAM chain if that matters, the 1030 one.

Mithrandir, If the chain has trouble with the new cassette and skips, then install the new chain. I've swapped cassettes around without any problems to suit the terrain I'm expecting on a ride. You may want to consider a chain minder, or something similar to keep the chain off of the frame.

Brad