Chain slipping

[Charlieboy28]

cheers dave and drystone, see i have ridden far worse rings with no slippage, but on a set up that aged together if you know what i mean. I have accepted that the granny and middle need to go

Being the optimist that i am im hoping the cassette will be ok, but im having a feck of a time finding compact middle rings,

anyone

 

[drystonepaul]

Spa Cycles in Harrogate normally carry a good range of chainrings.

TA: --> http://www.spacycles.co.uk/products.php ... b0s113p910

Stronglight: --> http://www.spacycles.co.uk/products.php ... b0s149p291

 

[tinkerer]

I have found that chain slippage can be caused by the spring on the derailleur losing its tension. I mean the spiral one that is fitted into the place where the attachment bolt goes!

Cheers

 

[PhilStone]

Really? Is there anyway to check the tension is as much as it should be?

I've got jumping chain as well at the moment, absolutely fine when ridden normally but tends to jump when in the middle of the cassette - cassette is second hand but not thought to be particularly old, chain is 150 miles at most as is the chain set..

Obviously cassette is the weak link but the rear mech is also fairly old...

Any suggestions as to which first?

 

[Anthony]

Re: my pics

pics

I wouldn't be surprised if your problem was the very short cage rear mech.

Also your chain looks if anything too long as the rm is in quite a normal shape even though it's in the big ring and the penultimate sprocket - you would see the rm pointing almost forwards if the chain was shorter/correct length. With a combination of short-cage rm and too long a chain, you must have very little spring tension in the middle and granny rings, and that could be destabilising the system.

I suggest you make sure that your rm has sufficient capacity (should be marked on it somewhere) to deal with your gear range (big ring minus granny plus biggest sprocket minus smallest). Short-cage rms are for road cassettes really.

Also the correct length of chain is found by laying the chain over the biggest sprocket and the biggest ring (not through the rm) and cutting it to two links longer than that.

 

[tinkerer]

I had a nice Dura Ace 9 speed mech owned from new that always caused chain slippage after about 3 years of use, whether on a road bike or mountain bike. After much huffing and puffing and putting new chains/cassettes nothing worked. I looked closely at the mech and found the spiral spring that presses the upper jockey wheel towards the cassette was lazy. On my other mechs, if you pull down the mech snaps back up vigorously. On this Dura Ace it didn't. I think it causes chain slip by reducing chain wrap.

 

[PhilStone]

Cheked my indexing etc today and its spot on, however on a couple of rings, namely the 2 next to the smallest on the cassette, I can make the chain slip with heavy cranking... I'm guessing this will be cassette wear rather than the derailleur issue mentioned above?

Cheers

 

[Gonzalez]

That outer also looks pretty well worn out. The middle looks okay but the inner looks a bit ropey too.

How wide is the chain you are using? That TAYA one almost looks like a 1/8th inch BMX chain rather than a 3/32th MTB one.

middle ring is new, not sure on the chain width, I thought I bought the correct one at the time but bike has been sat idle for over a year now so can't remember. I'll check.

 

[Gonzalez]

Re: my pics

pics

I wouldn't be surprised if your problem was the very short cage rear mech.

Also your chain looks if anything too long as the rm is in quite a normal shape even though it's in the big ring and the penultimate sprocket - you would see the rm pointing almost forwards if the chain was shorter/correct length. With a combination of short-cage rm and too long a chain, you must have very little spring tension in the middle and granny rings, and that could be destabilising the system.

I suggest you make sure that your rm has sufficient capacity (should be marked on it somewhere) to deal with your gear range (big ring minus granny plus biggest sprocket minus smallest). Short-cage rms are for road cassettes really.

Also the correct length of chain is found by laying the chain over the biggest sprocket and the biggest ring (not through the rm) and cutting it to two links longer than that.

I think the RM is original, but not sure. I've ran it for a long time with no problems but you amy be right. I'll check the spring tension and maybe swap it out. I'll check the chain length but remember taking loads os links out when I fitted it

 

[PhilStone]

Just a quick aside question, if the cassette is worn and the chain is about 150 miles old, should I replace the chain at the same time as a new cassette or is 150 miles still bedding in?

Cheers