So I got an old MTB I’m restoring and am using a ton of different parts from the co-op. The chain is new, the cassette is not. The chain is smoothly shifting through all the gears on the stand thanks to friction shifting, but under heavy load when riding (i.e. just pedaling quickly) I notice that the chain jumps forward. It does however _not_ shift into a new gear or drop a cog. The RD hanger looks fine. I’ve only noticed it in the middle cogs but am not 100% sure it doesn’t happen in the other ones, hard to cycle through all the gears.
From googling it seems like a common issue is a worn cassette with new chain. I had some tight chain links but massaged those out and it’s running smoothly on the stand as I’ve said. As it mostly seems to happen in the middle cogs which probably saw most use, I’m suspecting it’s just worn down but I don’t have much experience. Would love to hear some thoughts.
Could it be anything else? Chain too long/short?
HeckinYouOut on
Stuck links and cassette wear are the typical biggest culprits. Is your RD and hanger lined up or is it bent inwards?
nowhere3 on
Your red circles on those teeth are a perfect example of a really worn out cassette. While most of the time you’ll get skipping on the smaller cogs of the cassette due to the fewer number of teeth connected to the chain when the teeth are that worn out they will skip with a new chain.
mtranda on
Had those exact symptoms just the other week after changing my chain and derailleur. My cassette was very old and worn out, looking just like yours, but since I had also neglecter the chain and it was also in bad shape, it still meshed. As soon as the new chain went on the bike became unusable.
Popped a new cassette on and it now shifts like a dream.
4 Comments
So I got an old MTB I’m restoring and am using a ton of different parts from the co-op. The chain is new, the cassette is not. The chain is smoothly shifting through all the gears on the stand thanks to friction shifting, but under heavy load when riding (i.e. just pedaling quickly) I notice that the chain jumps forward. It does however _not_ shift into a new gear or drop a cog. The RD hanger looks fine. I’ve only noticed it in the middle cogs but am not 100% sure it doesn’t happen in the other ones, hard to cycle through all the gears.
From googling it seems like a common issue is a worn cassette with new chain. I had some tight chain links but massaged those out and it’s running smoothly on the stand as I’ve said. As it mostly seems to happen in the middle cogs which probably saw most use, I’m suspecting it’s just worn down but I don’t have much experience. Would love to hear some thoughts.
Could it be anything else? Chain too long/short?
Stuck links and cassette wear are the typical biggest culprits. Is your RD and hanger lined up or is it bent inwards?
Your red circles on those teeth are a perfect example of a really worn out cassette. While most of the time you’ll get skipping on the smaller cogs of the cassette due to the fewer number of teeth connected to the chain when the teeth are that worn out they will skip with a new chain.
Had those exact symptoms just the other week after changing my chain and derailleur. My cassette was very old and worn out, looking just like yours, but since I had also neglecter the chain and it was also in bad shape, it still meshed. As soon as the new chain went on the bike became unusable.
Popped a new cassette on and it now shifts like a dream.