Gear changes under pressure

AndyMark

Hi. I have a Raleigh MTB - about 15 years old, but generally looked after despite my shortage of skills ! However, now I have a problem.

My back gear (Shimano) changes into a higher gear when I put it under pressure (i.e going uphill) - thus making the damn hill even harder (and there's lots of them around here!)

I'm sorry I have a lack of techo skills. I have just changed the gear cable and it's still doing it. (Perhaps still 'bedding in' ?). The teeth are maybe getting a bit worn - could that be it?.
I have checked fittings and all same ok - nothing wobbly as such.

Hmmm....any ideas or what to check out please ?

supersonic

Check Park Tools for a guide on setting up the gears,. Could be a number of causes - poor chainline, cables, adjustment, frame flex.

Larok

My first thought would be the teeth on the cassette are worn, along with the chain and the chain rings. Have you changed any of those at all/ever?

Its advised to change them all at the same time and then change the chain on its own when it stretches over a certain amount.

It could be that the derailleur is not set up right but it sounds as though you've tried adjusting it?

Got any pics of the cassette/chain rings. Might be worth measuring your chain as well.

Marjory Stewart BAxtor

buy a new bike!!!!!!!!!!!!!!!!!!!!!!!!!!!!!