I recently broke a chain, and after installing a new chain (upgraded model), when in big ring, smallest 3 or 4 gears on the cassette, and high force on the right pedal, the chain skips off the front. I weigh 220lbs.

Drivetrain:

  • Crankset: Shimano FC-RX810-2, 48/31T (GRX, 2×11)
  • Front derailleur: Shimano FD-RX810
  • Rear derailleur: Shimano RD-RX810
  • Cassette: 11-speed, range 11-34
  • Shifters: GRX RX810-series
  • Bike: Canyon Grizl (gravel)

Chains:

  • Old chain (broke once, repaired, then broke again one mile from home): Shimano CN-HG601-11
  • Current/new chain: Shimano CN-HG701-11

The video shows three different things: part one is a slow mo of the chain skipping upon high force on right pedal. Part 2 is me spinning the cranks to see if there is any bend in the chain ring (I don't really know if it's in my head but maybe a slight deformation in the ring; lmk). Part 3 is what I suspect the issue to be: locking brakes and putting high force on right pedal, you can see the chainring flexing outward, into the outer part of the front derailleur cage.

I even adjusted the upper limit outward, but as you can see in part 3 of the video, it does seem to flex into the outer part of cage.

More photos in a comment. Desperately in need of help here. A test I haven't done yet is maxing out the upper limit so that even significant flex wouldn't bump into the cage, but I'm honestly sick of testing different things. Please help, lol.

EDIT: Also, I have a Sram quicklink on it. It doesn't skip on the quicklink though, it skips on group of links. Just adding for full info

Chain Comes Off Big Chainring With High Right Pedal Force
byu/UncleTito27 inbikewrench



by UncleTito27

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10 Comments

  1. Normally if you install a new chain (the correct part) and it skips it means the chainring / cassette is worn out. How many km’s do you have on the chain ring? From that photo it looks like it’s getting up there.

  2. Op you might want to look into waxing your chain. Imo maintenance is easier and less messy and the final tidbit some people report very low wear on drive train components doubling or tripping cassette and chain ring lifetimes.

  3. I have sarely seen so little chainring on a chainring. It is done for. Chanfe both chainerings, chain and cassette.

    How old / distance is your drivetrain?

  4. Did you have nspect your chainrings? How many miles on the chainrings? Do they look sharp and squared out?

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