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Chain slipping under pressure.
Had this problem for a while but seems to have gotten worse recently. Culminating in it causing me to smash my knee into the handlebars and nearly come off in front of a bus last night! So it now has my full attention.
99% of the time it happens when I set off. At lights for example. So a lot of pressure from my right foot bearing down. There's usually a 'CLANK' and the resistance is suddenly gone causing my foot to fly 'through' the pedal if that makes sense. The chain never actually comes off, and once I've composed myself and set off 'gingerly' the chain seems to bite ok.
Gonna get it up on the stand and have a look, but any ideas where to start?
Thanks!
EDIT:
It's basically a bit of a 'Trigger's Broom' pub bike. So quite possible that there's mismatched parts on it etc. Old Spesh frame with slicks. Can't remember the other parts but can update later when I've got it out.
Pawls in rear hub slipping sounds like
Yeah what DB says.
Or maybe the cassette is slipping around the freehub under the added pressure.
Ah interesting. So the chain is a red herring.
Thanks, I'll start at the hub/cassette.
It's probably the hub pawls and a cheap fix, if the springs have gone, is to replace them with cut down ones from a ballpoint pen (my bodge is still going years later).
😀
Love it.
Now that I'm thinking about it I seem to remember attempting to check the freehub ages ago but gave up when I needed a massive allen key which seemed to be impossible to find.
ROUND TWO. FIGHT!
Usually à 10mm allen key.
Forgot to mention, if you need to replace the springs, hold them in place with a little bit of grease while putting the freehub body back on. Invaluable for avoiding the little buggers inevitably pinging off across the garage.
Usually à 10mm allen key.
*hollow laugh*
...UPDATE...
So, after trying all my allen keys, it turned out to be a 12mm. Which I had to order in as it's against the law to stock allen keys bigger than 10mm in major UK city's it would appear...
Big ass allen-key arrives: nothing happening... try whacking it with lump hammer, scaff pole as leverage... nothing. Take it to LBS who put it in a vice... nothing. So, whole wheel in the bin. New wheel/hub bought.
Put it all back together yesterday. Lovely weather today so looking forward to a good ride out. Get it about ten yards down the road and CLANK. The problem is still there.
So now I'm looking at chain/chainrings/BB as possible culprits. Could anything here cause these symptoms? Borked BB? Worn chainring teeth? Stretched chain?
Here's a photo of my middle chainring. The teeth look pretty worn to me? Opinions?
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Those things on your middle chainring aren't teeth, they're bumps. Chain and cassette will need replacing too.
Yes, middle looks pretty worn. Just use the big ring only, you'll be fine. 🙂
That does look a bit spikey! Of course you must have tried it in the big ring too??
I've had similar to what you describe when the cassette lock ring wasn't done up tight enough.
New cassette, chain and chainring time.
Get a chain checker so you know when to replace it before it knackers the cassette.
I think the mystery has been solved. Big 14st lump putting about 100k miles on the middle ring. Little ring is for going up vertical things, big ring is for hurtling down long straight downhill roads. 😀
The middle ring is very worn. The teeth are pointy like shark fins compared to the rounder profile of the small and big rings.