Rear Mech Problems

JC987654321

Hi Everyone,
Whilst transporting my bike with the rear wheel off i have done something the the rear mech.
It keeps jumping in/out of the rear cogs (particulary the smaller ones) so i am unable to put any power through as its jumping.
I guess i have knocked/bent something but i can see anything obvious....
should i wizz it back to the shop (i bought it Sat) or can i re adjust?
Thanks in advance!
Jay

submityournentries

you should be able to see if its bent, just pop the wheel in, put the mech in a middle gear, and see if its straight.

if you only bought the bike saturday, it could just be cable stretch meaning the gears need re indexing (setting up again), which isnt massively trickey, but the shop will do that for you if you dont fancy it.

JC987654321

i cant see anything obvious, but must have banged it the car whilst wheel was off.
I will give Evans a call and get them to look at it.
cheers

mak3m

could be cables all mine seem to have given up

two new brake cables last week and now front and rear mech have gone. if they have stretched might be worth getting them to stick on a decent cable, mine came with cheap steels and im currently upgrading them to teflon coated, so hopefully will last a bit longer.

gl

JC987654321

they are going to look at it this afternoon for me.

its a Scott Scale 35 so the cables should be ok you would expect....

hopefully it'll be sorted this avo as if the weather stays like this i need to be out on it!!

Herbie The Dog

I'd be surprised if the cables have stretched to the point of skipping after less than a week.

If cables are looked after and were installed properly there's no reason why they won't last at least a year before stretching to the point of needing replacing.

Obviously they will stretch over time but this can be sorted through indexing and ensuring they are still fitted correctly.

It's the main reason why any reputable dealer will offer you a free check up around the six week mark. Unfortunately far too many people ignore this offer (or just can't be arsed). My advice is use it. And, as above, if this is done correctly then you shouldn't have any problems for months.

Thewaylander

Herbie The Dog wrote:

I'd be surprised if the cables have stretched to the point of skipping after less than a week.

If cables are looked after and were installed properly there's no reason why they won't last at least a year before stretching to the point of needing replacing.

Obviously they will stretch over time but this can be sorted through indexing and ensuring they are still fitted correctly.

It's the main reason why any reputable dealer will offer you a free check up around the six week mark. Unfortunately far too many people ignore this offer (or just can't be arsed). My advice is use it. And, as above, if this is done correctly then you shouldn't have any problems for months.

LOL what planet are you on? First ride out on a set of cables i can stretch them enough to be out nearly an entire gear, its only a few Mil on a metre or so of cable

Check your mech positioning mate, Onces its in gear just look at the line of the mech in comparison to the gear its in, if the mech has moved slightly down your cassette its a good cahnce its cable stretch. and its a simple barely adjustment to fix

Herbie The Dog

Thewaylander wrote:

Herbie The Dog wrote:

I'd be surprised if the cables have stretched to the point of skipping after less than a week.

If cables are looked after and were installed properly there's no reason why they won't last at least a year before stretching to the point of needing replacing.

Obviously they will stretch over time but this can be sorted through indexing and ensuring they are still fitted correctly.

It's the main reason why any reputable dealer will offer you a free check up around the six week mark. Unfortunately far too many people ignore this offer (or just can't be arsed). My advice is use it. And, as above, if this is done correctly then you shouldn't have any problems for months.

LOL what planet are you on? First ride out on a set of cables i can stretch them enough to be out nearly an entire gear, its only a few Mil on a metre or so of cable

Check your mech positioning mate, Onces its in gear just look at the line of the mech in comparison to the gear its in, if the mech has moved slightly down your cassette its a good cahnce its cable stretch. and its a simple barely adjustment to fix

Planet Cytech.

If you are stretching a set of cables on a first ride then they weren't correct in the first place, your shifting was gash, they were very very cheap cables that weren't pre-stretched or you rode for hours and hours and made hundreds of gear changes.

Every time I've come across indexing being out after one or two rides it's for one of the above reasons.

Hitby

Is the wheel definitely seated properly in the dropouts

Thewaylander

Meh I run with Sram ferrites pretty much all the time, These are good cables, But most people do ride for hours an hours.. I means aa ride below 3 hours.. short..

And yes i live in wales with varying hills short burts climbs moving to long steady climbs back and so on so yes hundreds of shifts are required.

So yes its easy to get cables to stretch in a ride, especialy if you ride in all weather mud and grit helping to gum things up.


So yes my gears were set up well thank you, and yes they are decent cables. And yes its a decent ride not just a little 1 hour and 10 minutes round 1 trail center track lol


To the open, check the alliment of the mech with your cassette you will soon see if

A) The mech isn't straight
The mech isn't alligned

Also check how far the mech is sitting from the cassette, it shouldn't be very far from the cassette in first if its hanging a mile away you will ahve to adjust that.

x-isle

I had a Scott Scale a few years back, great bike, but the rear mech hanger did seem a little brittle. They did an an upgrade for it to make it stronger, but not sure if these are fitted as standard to a new bike.

Possibly all changed now, but back in 2006/2007 the hangers were painted black and the stronger ones where polished.

Hope you get it sorted soon.

submityournentries

i just put 2 new clarkes gear cables on my bike, with sram X.9 gearings, i worked as a cycle technician for 2 years, so know how to set up gears properly.
they have been on the bike 2 weeks, and needed a tweak of barrel adjustment to make them right again. cable strech happens over a short period of time, simple as

Chunkers1980

Some people talk such rubbish.

Cables don't stretch that much if there's not too much friction in the cable. Discount the cable friction and the cable is being stretched by the force of the spring and pivot system of the rear mech. That alone will not stretch a new cable more than a couple of click in the barrell adjuster.

Stretch will mostly come from cable outer settlement and the friction and excess force applied through the lever for a normal gear change due to the mech not moving for some reason.

Herbie The Dog

As I said...set up correctly and you shouldn't have any issues.

OP - I hope you get the problem sorted.

borntobemild

I've got through two rear mechs in six months. SRAMs. Not impressed. In both cases cases the chain had jumped off and jammed the mechanism.