Bike not changing gear?

jimbob 2705

Hi Guys,

I have just picked up an secondhand GT Chucker 2.0 cheap but it won't change gear.

On the actual gear changer on the Handle bars it will hardly move. It is on gear 8 at the moment but it takes a lot of pressure to get it to gear 7 and it is impossible to get it down to gear 6 then.

When you change down to gear 7 it doesn't move on the deraileur.

I think it has Shimano SX4's (Something like that) but I will double check today.

Does anybody have any suggestions on what the problem could be?

Cheers

bennett_346

Are they gripshifts?

jimbob 2705

bennett_346 wrote:

Are they gripshifts?

No

bennett_346

Sorry misread your post, SX4 are trigger arent they. My mistake.

Check the length of cable to see if theres anywhere it could be sticking, if its frayed mid cable it could be sticking going into an outer. Also try backing the tension right off and trying it with full tension to see if anything happens. Try moving the mech by hand to see if its jammed and spray i with lubricant whether it is or not.

alexj2233

I had something similar the other day, somehow the cable had moved inside the shifter so wasn't where it is suppossed to be. This meant it was jamming the ratchet system inside the shifter.
I just took the shifter apart and put the cable back where it should be, be careful of the springs though

jimbob 2705

bennett_346 wrote:

Sorry misread your post, SX4 are trigger arent they. My mistake.

Check the length of cable to see if theres anywhere it could be sticking, if its frayed mid cable it could be sticking going into an outer. Also try backing the tension right off and trying it with full tension to see if anything happens. Try moving the mech by hand to see if its jammed and spray i with lubricant whether it is or not.

I will try and have a look at it today. Thanks for that.

The only problem is that I am not very experienced with bike parts so I don't really know much about parts and stripping them.

Cheers

jimbob 2705

alexj2233 wrote:

I had something similar the other day, somehow the cable had moved inside the shifter so wasn't where it is suppossed to be. This meant it was jamming the ratchet system inside the shifter.
I just took the shifter apart and put the cable back where it should be, be careful of the springs though

I don't really know how to strip a shifter. Is there a guide or something?

Cheers

bennett_346

Theres hundreds of video guides on youtube about adjusting gears, probably not as many, if any about how to service your particular shifters. They may use the same internals as more popular shifters but i couldn't say for certain.

Salsa

Before pulling shifters apart (which are a pain at best to reassemble) do the obvious stuff. Undo the cable on the mech, push the mech towards the large gear to see if it moves freely.Now the cables released try clicking the shifter whilst holding the cable tight too see if the shifter works.Look at the state of the cable, is it all rusty/dirty. Grab the cable outers & see if they slide on the cable, or are they so worn/dirty they are restricting the cable.
Put the shifter in the highest gear, undo the little screw inbetween the paddles & see if the cable end is visible in the shifter, pull it out too see if it's frayed inside.
One of those steps should tell you if the mechs broke, the shiters bust or the cables at fault.

richg1979

cables are fubbard, replace and all will be fine.

jimbob 2705

richg1979 wrote:

cables are fubbard, replace and all will be fine.

Do you know where to get some?

Cheers

cooldad

jimbob 2705 wrote:

richg1979 wrote:

cables are fubbard, replace and all will be fine.

Do you know where to get some?

Cheers

A bike shop.

jimbob 2705

cooldad wrote:

jimbob 2705 wrote:

richg1979 wrote:

cables are fubbard, replace and all will be fine.

Do you know where to get some?

Cheers

A bike shop.

I know but do I need a particular cable for a GT Chucker or do all bikes use the same cable>

bennett_346

Gear cables are generic, just get any.

The Rookie

Halfords do some nice PTFE ones (Clarkes in a bikehut package) for £8 a pair, or go to Wilkinsons supermarket if you just need inners, reasonable quality for just 79p each (they don't do outers for some reason!)

Simon