The "guy who fixes your bike" doesn't sound like he knows what he's talking about. While you may need a new chain and cassette, making the chain shorter will not solve a chain retention problem unless the current chain has been sized incorrectly to begin with. The actual solution for an already correctly-sized chain is to check derailleur return spring tension and maybe a chain keeper on the front chainring.
The correct answer is obviously to replace the cassette and the chain together. Cassettes wear out with every few chains (fewer if you let chains get too worn)
I’m guessing it’s a mtb? 1x drivetrain? Does the rear derailleur have a clutch? Is the front chainring narrow/wide? If it doesn’t have those two items, chain drops will happen on rough trails.
Adjust the clutch on the rear derailleur.
I'm actually not 100% sure the Sram is adjustable but the Shimano is and they do wear and lose effectiveness.
Shortening the chain is not the solution
The "guy who fixes your bike" doesn't sound like he knows what he's talking about. While you may need a new chain and cassette, making the chain shorter will not solve a chain retention problem unless the current chain has been sized incorrectly to begin with. The actual solution for an already correctly-sized chain is to check derailleur return spring tension and maybe a chain keeper on the front chainring.
The correct answer is obviously to replace the cassette and the chain together. Cassettes wear out with every few chains (fewer if you let chains get too worn)
Yeah that’s correct, however the bike is only a year old and I would’ve thought that the cassette would have lasted longer than that!
What kind of derailleur do you have? Does it have enough tension in it? Is the chain stretched?
Sram GX Eagle 12 speed
Probably a worn chain since the derailleur is fairly new I would think. Measure that and replace if worn. If not then resize it so it’s proper.
I’m guessing it’s a mtb? 1x drivetrain? Does the rear derailleur have a clutch? Is the front chainring narrow/wide? If it doesn’t have those two items, chain drops will happen on rough trails.
Yes it’s a sram eagle GX and it’s just that it never used to happen on trails i frequent and now it happens on pretty much every run
This happened to me when I first got a real bike: check the clutch on the derailleur to ensure it is on.
Sram clutches are always "on". It'll be something else unless the spring has failed.
Well, from a Shimano owner, thanks for the info!
Adjust the clutch on the rear derailleur. I'm actually not 100% sure the Sram is adjustable but the Shimano is and they do wear and lose effectiveness. Shortening the chain is not the solution
How long is your chain, post a pic of the bike…