adjusting rear derailer, how often?

xchudy_1325

reason i ask is ive had to adjust mine twice in the last 10days, because of the gears slipping

Wirral_paul

New bike - so you well be getting some cable stretch there mate. Once the cable settles then you shouldnt have to keep adjusting it.

When i fit new cables - i try to stretch them as much as possible at time of fitment. Clamp the cable and pull down where the bare cable runs along the down tube. Do this 2 or 3 times and then re-clamp after pulling the resultant slack out. This seems to minimise adjustments required.

ThatBikeGuy

Adjusted mine when i originally indexed it last october, haven't had no problems since. *touch wood*

This is also a Shimano Sora derailleur so by all accounts i am very pleased with how long its been running for!

declan1

Wirral_Paul wrote:

New bike - so you well be getting some cable stretch there mate. Once the cable settles then you shouldnt have to keep adjusting it.

When i fit new cables - i try to stretch them as much as possible at time of fitment. Clamp the cable and pull down where the bare cable runs along the down tube. Do this 2 or 3 times and then re-clamp after pulling the resultant slack out. This seems to minimise adjustments required.

This ^ The latest Shimano gear cables are already pre-stretched though, and I haven't experienced any problems with them. I re-index my gears every week or so anyway just because I like them to be perfect

majormantra

The real problem isn't 'stretch' per se, it's everything settling into place. After the bikes been used a bit the outers will have been pressed into their ferrules a little, creating a tiny bit of slack.

ilovegrace

Funny you should post this.
I have had my Giant CX bike for 6 months now (of it with an elbow injury for 8 weeks, but that is another story) it seems as though every 4 weeks or so I need to adjust the mech because of the gears slipping.
This has happened more or less since I bought it .
Took it back to the Bike shop on the first couple of occasions but I have found out how to do it myself
Is this normal to have to adjest this frequently ?
The rear cassette has been changed from (I think ) from new ,26 to 30 so don t know if this has anything to do with it ?

zx6man

2300 setup on mine, not adjusted it since intial setup 2 years ago, 6000 miles.

changing from 26 to 30 should be ok if thats in the rear mech range, or it could have troubles I suppose

MattC59

As mentioned above, if its a new bike, then it's probably due to everything bedding in. It should settle down.

That said, I've got Gore cables and they've not needed adjusting since being installed last July.

team47b

Never had to do it.

I'm just not trying hard enough, am I :roll:

goonz

Never adjusted mine after first check after purchase.

Out of interest how do you index the gears?

crankycrank

Also check the cable for fraying. Worst spots are at the shift lever, where cable routes under the bottom bracket, where the cable exits the chainstay housing and at the rear mech clamp bolt.

wheelie-bin

Something small, but when you store your bike, if you leave it in a gear with high cable tension it could stretch the cable if you catch my drift

binsted

goonz wrote:

Never adjusted mine after first check after purchase.

Out of interest how do you index the gears?

You type the question into Youtube and pay attention

Mikey41

Mine needed adjustment a couple of times in the first 2 months, but I barely have to touch it now.

Monty Dog

wheelie-bin wrote:

Something small, but when you store your bike, if you leave it in a gear with high cable tension it could stretch the cable if you catch my drift

Cables don't stretch - the outers and ferrules settle into the frame cable stops. I've never experienced any problems with a bike left 'in gear'.

wheelie-bin

Monty Dog wrote:

wheelie-bin wrote:

Something small, but when you store your bike, if you leave it in a gear with high cable tension it could stretch the cable if you catch my drift

Cables don't stretch.

Well that's me out of a job Are you actually being serious? Can't tell...

NewTTer

Well they do stretch, but you will need a damn site more pressure than can be generated by a rear derailleur return spring to do it! So in normal use they wont stretch, and as Monty quite rightly says, it is a "settling" process that takes places, this creates the illusion of stretching

wheelie-bin

NewTTer wrote:

Well they do stretch, but you will need a damn site more pressure than can be generated by a rear derailleur return spring to do it! So in normal use they wont stretch, and as Monty quite rightly says, it is a "settling" process that takes places, this creates the illusion of stretching

You might want to get on the dog & bone to some cable manufactures about their pre-stretched cables & fraudulent advertising

Sprool

What really bugged me about my Scott S30 when I got it new last year was the time taken for the cables to 'stretch in' - it turned out to be the barrel adjusters which would keep creeping back with the vibrations of a ride. I kept tweaking the cables tight again, then after 2 or three miles it seemed like the cable was slack. I replaced the barrel adjusters with some more positive Jag ones and its been sweet ever since.

desweller

Not another semantic debate on the definition of 'stretch'!

They don't plastically deform but there is definitely a wearing-in process throughout the system.

I rarely adjust mine after the 'installation lap'.

If you're getting a lot of drift then check that your cable clamps are tight enough. If you're using PTFE coated cables then you will want to sand the coating off at the clamp point.

NewTTer

wheelie-bin wrote:

NewTTer wrote:

Well they do stretch, but you will need a damn site more pressure than can be generated by a rear derailleur return spring to do it! So in normal use they wont stretch, and as Monty quite rightly says, it is a "settling" process that takes places, this creates the illusion of stretching

You might want to get on the dog & bone to some cable manufactures about their pre-stretched cables & fraudulent advertising

Oh dear, just how much pressure do you think a derailleur spring generates? and how much do you think is needed to "stretch" a steel cable?

MattC59

NewTTer wrote:

wheelie-bin wrote:

NewTTer wrote:

Well they do stretch, but you will need a damn site more pressure than can be generated by a rear derailleur return spring to do it! So in normal use they wont stretch, and as Monty quite rightly says, it is a "settling" process that takes places, this creates the illusion of stretching

You might want to get on the dog & bone to some cable manufactures about their pre-stretched cables & fraudulent advertising

Oh dear, just how much pressure do you think a derailleur spring generates? and how much do you think is needed to "stretch" a steel cable?

It produces absolutely zero pressure.

NewTTer

MattC59 wrote:

NewTTer wrote:

wheelie-bin wrote:

NewTTer wrote:

Well they do stretch, but you will need a damn site more pressure than can be generated by a rear derailleur return spring to do it! So in normal use they wont stretch, and as Monty quite rightly says, it is a "settling" process that takes places, this creates the illusion of stretching

You might want to get on the dog & bone to some cable manufactures about their pre-stretched cables & fraudulent advertising

Oh dear, just how much pressure do you think a derailleur spring generates? and how much do you think is needed to "stretch" a steel cable?

It produces absolutely zero pressure.

Another pedant, it is quite common for spring rates to be quoted as pressure. It exerts pressure on a system either in tension or compression. So if the derailleur return spring on your bike produces no pressure you need a new rear derailleur Matt as yours is broken!