Slipping chain

[Trevor Holloway]

Monday night I treated my bike to a new drive chain (18 speed front hub drive) but now the chain "jumps" on the sprockets.
Have tried taking out a couple of links to increase the tension but it still jumps, would not be so bad but the electrics are off at the moment so had to use the car.
Any suggestions as to what I may have done wrong ?

The chain is an anti-rust one from Halfords (standard size I thought) and it was fed through using the old one so is routed correctly.

 

[Pedalo]

Your sprockets are probably worn and need replacing.

Happens to me every time! I don't even bother trying new chain on old sprockets any more, I just replace them together.

 

[tillson]

I don't want to insult you, but are you sure that the chain is the correct one? Does it sit nicely on the sprockets both at the front chain ring and on the rear cassette? By nicely, I mean all teeth engaged and the chain fully seated to the full depth of of the sprocket teeth.

 

[HarryB]

You allowed your chain to stretch and now the rear sprockets or cassette is worn out and will have to be replaced - you may notice the jumping is worse with the smaller sprockets. Please don't remove chain links as a short chain can be dangerous - pop them back with a new cassette.

There are two school of thoughts here. One is to change your chain before the stretch wrecks the sprockets or keep the chain running until it wears out all the sprockets and then replace everything (you might get away without replacing large chain wheels). Both have economic advantages so the choice is yours (you appear to have taken the later route this time). You can get a nice tool that check for chain stretch.

 

[Trevor Holloway]

Guilty as charged

The old (probably original) chain was so worn I felt bad keeping it on, would I need to change the derailer tensioner too ?

 

[HarryB]

I doubt it - those little wheels are fairly forgiving and they don't have any real pressure applied to them. Make sure you get that chain length right though.

 

[Trevor Holloway]

Will pop out at lunch time and spend more money then.

Actually the bike (Peugoet Hybrid) was bought second hand a good 12 years ago and only really started getting used properly last year when the electric kit was fitted - so has done more miles in the lat eight months than the rest of its life !
Not surprising that it needs the work but was still a good base for conversion.

 

[Streethawk]

As a rule of thumb, if the chain is worn out, the rear sprockets and chainring will be too, so replace all three parts.

If you fit one new part of the three then it will wear much more quickly.

Derailleur jockey wheels dont *need* changing each time, but for a couple of quid each i do tend to swap them. Also, its worth putting a new shift cable on too (unless you have sealed ones already), as they'll probably be past their best too.

 

[Trevor Holloway]

OK - I'll probably end up getting new V brakes and cables too !

It will probably end up like Triggers broom !

 

[Streethawk]

Also, make sure you get the right chain for your number of sprocket gears. 7/8 speed are the same.

 

[Scottyf]

On motorbikes a rule of thum was always - replace sprockets and chain as a set - never on their own - as doing so would wear them out much much more quickly.

Surely the same logic applies here.

 

[HarryB]

On motorbikes a rule of thum was always - replace sprockets and chain as a set - never on their own - as doing so would wear them out much much more quickly.

Surely the same logic applies here.

There are two school of thoughts here. One is to change your chain before the stretch wrecks the sprockets or keep the chain running until it wears out all the sprockets and then replace everything (you might get away without replacing large chain wheels). Both have economic advantages so the choice is yours (you appear to have taken the later route this time). You can get a nice tool that check for chain stretch.

I have changed plenty of chains before they have stretched without having to change the sprockets. There is a specific wear indicator tool to allow you to do this. If the chain isn't stretched it will take a lot of use to wear out the sprockets. Motorcycle chains take the second route and you change all three items - however sprockets are cheaper than cassettes. There are different grades of cassette too - some will wear more slowly than others. Take your choice about the methods - I prefer the first method (but that said I didn't get away with it last time).

 

[Trevor Holloway]

Dis-appointed

Changed the rear sprocket set at the week-end for a new one and it still jumped this morning making it impossible to ride safely so back in the car
Still open to suggestions.

 

[tillson]

That seems very odd. I don't know a great deal about chains, but I am wondering if they come in varying pitches, and if they do, do you have the correct pitch.

I am at well over 7000 miles on the original chain and sprockets on my Pro Connect, but that is a hub gear system, so probably experiences less chain wear.

 

[Trevor Holloway]

Must admit I thought the same ie a mismatch between chain and sprockets but got them both from Halfords where you do not get a choice !
The chain fits correctly over the front rings.

 

[Streethawk]

In that case its probably the derailleur setup causing it, i'd suggest you let a bike shop setup your gear shifting.

If yu fancy having a crack yourself there's plenty of info here.

 

[tillson]

Must admit I thought the same ie a mismatch between chain and sprockets but got them both from Halfords where you do not get a choice !
The chain fits correctly over the front rings.

Again a bit of a guess. I think chain is supplied in varying widths, if you have one which is too wide, it might not be seating properly on the rear sprockets (making contact with adjacent sprockets on the cassette and lifting the chain enough to cause it to slip) Can you measure the width of your new chain and compare that measurement with the oruginal chain?

 

[z0mb13e]

Did you change the (front) chain ring as well?

 

[Trevor Holloway]

Nope not the front one but thats not slipping.
Could be that the chain is not running central on the gears - will check that out tonight.

 

[z0mb13e]

Nope not the front one but thats not slipping.
Could be that the chain is not running central on the gears - will check that out tonight.

I had the same problem with the Whisper around xmas. What I thought was the chain slipping on the rear was actually jumping on the chain ring. It looked like it was slipping on the rear as you could see the dérailleur jumping and causing noise at the rear as the chain slipped and expanded round the chain ring. Took me a while to track that one down. I could see the chain wandering on the chain ring but couldn't see it slipping. I changed all 3 components and everything works a treat now.

If possible, try flipping the chain ring over so the teeth face the opposite direction. I found this cured the problem for a few days, but then the wear set in again very quickly - I should post some photos of the state of the chain ring, chain and free-wheel. I've never seen so much wear on a bike I owned before - mind you my previous bikes rarely did more than a few hundred miles a year!