[Closed] Slipping chain - road bike - thoughts ?

freehub

Yeah, maybe the pawls are sticking open. Give them a clean out.

Don't see why it should be climbing the teeth though - are you certain nothing's worn?
(bent hanger is my other bet)

... it's not a narrow-wide ring and you've got the links on "wrong"??

How do you know your cassette is in good order? Have you got another one you can try?

It might just be not shifting properly due to winter filth on the cables and the chain skipping between sprockets under load.

Or it's the freehub slipping. They often start failing in winter when the grease (or watery gunk thats replaced it) freezes to a wax and the pawls won't engage. Feels like the chain skating over the sprocket, and sometimes even looks like it to anyone following as the jerk throws the chain off.

Both solved by a bit of tlc.

Sounds very like worn chainrings. Being worn isn’t always easy to spot

If they are very worn it is easy to spot as they look like sharks teeth.

The chain, chain rings and sprockets are all in good order – nothing needs replacing and I keep my bikes regularly cleaned.

lets see a pic of this then

I have ridden very worn rings, the larger ines on road bikes seem to last ages, at least 2 or 3 chains and cassettes so doubt they are the issue, worn chain, cassette or freehubs as said above are first thought, I'd also check for a stiff link in chain, the bent mech hanger is also a good shout.

I also thought all worn teeth are easy to spot ie shark toothing. Not always the case

When I had this issue it turned out to be a worn Ultegra chainring. Wasn't obviously visible and I replaced the freehub with a spare one first.

How many miles do you estimate the chainrings have done?

If it's slipping by riding over the teeth then it's definitely badly worn rings, or similar for the cassette at the other end. Can't be anything else really. A stiff link is a clunk every time it goes around.

This usually happens when you change a chain on old worn cassette or rings, if you leave the worn chain on too long.

My stepdads bike had this problem last week, I fitted a new chain and cassette for him and problem solved. It’s either going to be chain and cassette or chain and chainrings.

I also thought all worn teeth are easy to spot ie shark toothing. Not always the case

That may be true. Was picking up on the VERY in your very worn comment. If VERY worn they will be shark tooth. If worn enough to cause issues they may not be.
Anyway, going to be hard to do this over the internet unless a close up picture of each tooth can be posted!

Worn chain/cassette combination. Swap both. It won’t be the chainrings. You can run some seriously warm shark teeth or even just points on the front and not get skipping, but the rear can be very sensitive.

Is the chain new? If the chain rings are worn, the new chain will slip over them.

Need pics, but sounds very much like wear.

Sounds like a worn chain to me. Have you measured the length over a number of links to compare? Each link should be 1/2". Park tools recommends replacing at 0.5% elongation. At ten links this would mean 133mm instead of 127mm.

Thanks everyone.

To answer a few points: The running gear was all fitted (new) about 500 miles ago and it's been predominantly dry miles since then, all without issue. Had also checked to make sure there were no sticking links prior to asking.

Will look at the pawls though - thanks. The timing of this would fit with the recent cleans after winter / cruddy rides.

Thanks again everyone.

plus one

Member
Sounds very like worn chainrings. Being worn isn’t always easy to spot

This^^ Especially if its whilst climbing.