SLIPPING CHAIN

[rog 1974]

On my wifes mountain bike the chain slips when in 4th gear on the rear cogs. Ive adjusted the gears and they change smoothly up and down on all 6 rear cog,and they all run fine when the rear wheel is in the air but when you ride it, it seems to slip in 4th. anyone with any ideas?

 

[4F]

Worn chain and casette. Does she tend to cycle in the same gear all the time ?

 

[rog 1974]

The bikes only done about 100 miles, she normally uses cogs 2,3and4 on the back.

 

[4F]

Have you checked all the teeth on the offending rear cog ? It is possible it may have a broken or misaligned tooth hence causing the jump. If it has only done 100 miles then certainly the chain and cassette should be fine

 

[rog 1974]

It looks like 2 of the teeth are slightly out of line, can these be bent back straight or can i remove just the 1 cog to replace it or does the whole thing need to be repalced as a whole unit?

 

[Ademort]

It looks like 2 of the teeth are slightly out of line, can these be bent back straight or can i remove just the 1 cog to replace it or does the whole thing need to be repalced as a whole unit?

What type of cassette do you have, make, model, 8,9or10 speed and how many teeth are on the 4th gear that slips.
Ademort

 

[rog 1974]

I think its 18 teeth on the 4th cog. its got 6 cogs on the back I dont know what make they are it says shimano sis on the rear derailleur, it was only a cheap 150 pound mountain bike.

 

[PpPete]

When you say "chain slips" - do you mean pedals & chain turn, but back
cogs (& wheel) don't turn ?

If it's a old fashioned freewheel rather than a cassette (and it could be on a cheap BSO) then I'd suspect the freewheel is on it's way out (or was so badly lubricated in the first place that the pawls are not moving). Problem often appears on a single gear, then spreads to others, although usually more prevalent in cold weather.

If you can take the back wheel off, remove the Q/R skewer if there is one- and compare what you see with the four photos here

Freewheels can be a bitch to remove - although after only 100 miles it might not be too bad. Cassettes are easy, if you have the right tools.

 

[beanzontoast]

Freewheels can be a bitch to remove - although after only 100 miles it might not be too bad. Cassettes are easy, if you have the right tools.

Took two of us to get a stuck freewheel off once. That was my last ever experience with a freewheel!

 

[rog 1974]

When you say "chain slips" - do you mean pedals & chain turn, but back
cogs (& wheel) don't turn ?

 

[rog 1974]

everything works ok on the 4th gear but every 9 or 10 rotations of the pedals the chain seems to slip forward a tooth on the cog.

 

[nuovo_record]

have yo got a stiff link in the chain? maybe better to check each one and if you do find a stiff 'un, flex the chain side to side and that should help

 

[rog 1974]

its worth a look think i will try that first.

 

[4F]

have yo got a stiff link in the chain? maybe better to check each one and if you do find a stiff 'un, flex the chain side to side and that should help

I thought chain initially however if it was a stiff link then it would jump on each sprocket. I still reckon the sprockets had it.

 

[nuovo_record]

I thought chain initially however if it was a stiff link then it would jump on each sprocket. I still reckon the sprockets had it.

thats what i would have thought too, but i had a friend come round and his was jumping every now and again. went through all the links and there was 1 which was tight and he hasn't had the problem again.
can't see acouple of teeth being out of line, as it would slip more often....

oh well, theres another thing to check, keeps him busy