Cycling UK Forum

Despite many years cycling I have never had a rear derailleur problem before beyond the normal adjustment - they always look fragile to me so I treat them carefully. However today I broke my chain - putting out lots of power in a highish gear on a hill. That was a first to me. When I replaced the chain the new one rubbed on the derailleur cage at the upper jockey wheel. There is no visible damage but obviously it's not straight if the chain rubs. I haven't dropped it or fallen off. So, what's my next move? I'm inclined to brute force but thought I'd ask experts here first. It's a Dawes Galaxy about ten years old with a mixed deore/tiagra drive gear from new.

ensure you have put the chain in correctly.

there is a little metal tab between the 2 jockey wheels.

If you've put the chain in the wrong side of that tab it will rub.

this link may help ( i don't agree with some of his technique when it comes to putting the chain on but the part you need is at 1.03 mins which is what i'm talking about )

https://www.youtube.com/watch?v=bYGCpdJorT4

hope it helps !

bikerwaser

Besides the above you may have bent the hanger.

Look from behind the cassette and the hanger should be parallel with the sprockets.
https://www.parktool.com/blog/repair-he ... -alignment

I also look from above the cassette with the chain in small sprocket/small ring.
Again the dérailleur cage should still be parallel with the sprockets.

Check the cage plates and mech' are not bent or twisted.

Thanks very much for your replies. Of course I had gone round the wrong side of the tab and I am grateful for the diagnosis - I thought I'd somehow bent the cage. Despite cycling for many years and changing many chains this is the first time I'd managed to go round the wrong side of the tab. Apparently in my mid 60's I'm hell bent on finding new ways to get things wrong.

nez dans le guidon wrote:Thanks very much for your replies. Of course I had gone round the wrong side of the tab and I am grateful for the diagnosis - I thought I'd somehow bent the cage. Despite cycling for many years and changing many chains this is the first time I'd managed to go round the wrong side of the tab. Apparently in my mid 60's I'm hell bent on finding new ways to get things wrong.

Don't feel bad about doing that, I think everyone on here has at some time hence the speedy diagnosis. If it makes you feel any better, old mechs don't have the tab, you could remove it without any detriment to gear operation.

it's another bit of idiot proofness as the American market couldn't work out how to fit rear wheels and often mangled stuff.

Thanks Foxyrider!

nez dans le guidon wrote:Thanks very much for your replies. Of course I had gone round the wrong side of the tab and I am grateful for the diagnosis - I thought I'd somehow bent the cage.

I've done that as well, but not ridden with it like it. I'm not sure why that tab is even there. Consider the simplicity of an old Suntour ARX derailleur.

That's what's on my Major Nichols. But fair dos - I got it wrong.

don't beat yourself up about it; it is easily done. I have seen the tab nearly worn through because someone rode that far with it wrongly arranged.

Last year I went MTBing with one of my chums (who is a bright lad in the normal run of things) and his transmission seemed rougher and noisier than normal. Turned out he'd got the chain the wrong side of the tab, so I set to by the trailside and put it right. In truth I was glad of a break; he was going at an unusually high rate of knots and I was finding hard work. I arguably shot myself in the foot; he was distinctly quicker once we'd fixed it....

cheers