little help with a rear derailleur

[angellonewolf]

i have a back gear derailleur that does not want to change gear it goes up one push at a time but does not drop when the lever is pushed the once it will drop when the lever is pushed the 2nd time

any help please

thanks angel

 

[Deleted member 4366]

It sounds like the cable is trapped somewhere. You didn't put a cable-tie or a tool bag or whatever around it, did you? If not, you can get a new cable in Wilkos for next to nothing.

 

[Alan Quay]

This will happen if the cable is gritty/rusty/Manky. As Dave says, change the cable.

You could also just take it apart and clean it off. A squirt of GT85 might help to free it up....

 

[D C]

It certainly sounds like the cable has got miss-aligned or kinked somewhere or the rear derailleur has had a knock which has moved it out of line very slightly.
If that isn't the case, check that the rear derailleur mechanism is clean and moving freely, dirt and grit can sometimes defeat the ability of the spring to pull back for the smaller cogs.
If that's all OK then maybe a slight adjustment of cable tension is needed.
There should be an adjusting screw where the cable goes into the gear lever, screw it inwards to slacken the cable which should help the chain to drop onto the smaller cogs, if you go too far and the chain doesn't want to go up onto the larger cogs then screw it back a notch at a time. You need to feel for slight steps in the adjustment screw and do one step at a time, don't leave it between steps.
There is an adjustment screw at the rear of the cable as well but that normally doesn't need touching once set up from new.
If all this fails to help and the derailleur mechanism is old or worn the spring may be tired and you may need to replace the whole thing.
Dave.

 

[angellonewolf]

thanks for your replys was hopping that it not replacement as got the bike only for the tires but my son likes the bike and theres not much wrong with it was playing with it for 3 hours last night putting on new grips straightening the wheels adjusting the brakes greasing the bottem bracket and the last bit was the gears and found it would not ajust right had a sleep on it and feel better this morning will remove the back bit and clean and get a new cable i might have on as i do keep a few spares will post back a bit later hope with good news

thanks guys

 

[neptune]

I have slight derailleur problems myself at preset. I recently fitted new chains and sprockets, and a new rear mechanism. I also fitted a new inner cable. It was OK for a while, but now gear changes have become sluggish and unpredictable, especially when changing to a higher gear. Sometimes, to get it to change up, I have to change up two gears, and then change down one.

It gives the impression of a sticky cable, but I fitted a new inner, and greased it before fitting. I am beginning to wonder if I should have replaced the outer cables as well. Any ideas/theories please?

 

[D C]

The problem may well be the grease on the inner cable, try cleaning it all completely off both inner and outer or better still replace inner and outer cable and definately don't use grease

 

[Deleted member 4366]

There's three main adjustments to get right. First the end-stops. Two little screws fix the end position to stop running off the ends of the cassette. Then you adjust the cable length so that the derailleur will pull the derailleur from top to the next gear in one click. Then chech that all the gears engage correctly. You might have to make fine adjustments to the cable length to get all the gears. The final adjustment is the derailleur tension with a little screw on the back. Higher tension gives more precise changing at the expense of slightly more friction in the system. It can also compensate a bit when your chain wears and the tension drops off a bit.

 

[Aushiker]

I find this video handy to follow when adjusting my rear derailleur

Andrew

 

[mountainsport]

I find this video handy to follow when adjusting my rear derailleur

Andrew

Good video Andrew, This had been added to my favourites about two years ago which also saved me money and time too.

MS.