Thrown Chains

I’m constantly having my chain come off to the outside of the big ring when doing full sprints in the big ring 11t combination.

As it’s happening when I’m not changing gear I don’t think it’s anything to do with derailleur set up. The only thing I can think of is that the chain rings are quite possibly a bit worn and maybe that’s causing it?! Well, obviously it’s actually my Sufferlandrian watt bombs that are causing it…… :rofl:

Does anyone have any ideas/suggestions? Don’t worry about risking stating anything that might sound obvious as I’m not the world’s best home wrench!!

I will be getting the rings replaced and at that point I will get it serviced. But the LBS I trust are booked up for the next month or so and the rings I want are actually not due back in stock until Sept/Oct!! So just want to see if there’s anything I might be able to do to try and fix it.

Cheers!!

I’m gonna guess your front derailleur height is set a tad too high. There should be no more than 1-2 mm clearance. I had a similar issue but I’m not getting much use out of the 11 tooth cog when I’m sprinting :stuck_out_tongue_winking_eye:

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I will double check. I’m just not sure how that would cause the issue though as it’s fine during shifting. But I’ll definitely check it out! Cheers :slight_smile:

Also double check the limits and alignment on the FD. It should barely clear the chain in the big ring, (1mm or less) and the cage should be parallel to the ring.

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I did have to bend the front mech cage back into shape the first time it happened as the chain jammed against it as it came off!

I’ll check the clearance and alignment when I check the height. I know there are two marks on the SRAM mechs which should line up with the ring

How long has it been since you replaced your chain and chainrings? I had a similar problem last year. Started with just dropping off my big ring when sprinting. Eventually progressed to where if I put even just a firm amount of pressure on the pedals my chain would drop off my big ring. I replaced my big ring and chain which solved the issue. I also changed my cassette at the same time to upgrade it and it was best to change them all at the same time, anyway. That solved my issue and it’s been fine since.

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Chain is quite new but rings are definitely quite old. Not 100% sure on the cassette, but will likely just get it all done!

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Yeah. I hadn’t changed my big ring in the 4 years I had it. lol. So that was definitely a big part of my issue.

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Mine is possibly 5 years as I think they’re the original SRAM ones fro me hen I upgraded the cranks. Although my mileage hasn’t been mega high. I think the cassette may actually be ok wear wise as my mileage has been way down and a lot of what I have done the last few years has been indoors so on the KICKR cassette.

I am so sorry, I don’t know why I didn’t suggest this as a first course of action…NEW BIKE!!!

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:rofl: i mooted that idea with the gaffer but got a very swift and stern negative response ::joy:

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Very common for a new chain to jump and have problems on worn cogs/rings, which no longer mesh properly with an unworn/elongated chain. One thing that might fix it is putting an old worn chain back on until you get new cogs/rings.

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