Rattling noise from front derailler under load

chronyx

Just a quicky, it's fine on the workstand but my Hardrock makes a sort of chain rubbing noise under load.

Just wondered if anyone knew off the top of their head what it is, before I get the books out

It's now got a rack and 'normal' size SPD pedals...just need some panniers for it to be a proper commuter

whyamihere

Is the chain rubbing on the front mech?

chronyx

Yeah, I think that might be it - is that just a case of tinkering the L/H screws?

Does this mean the chain is over stretched now?

whyamihere

The rubbing doesn't say anything about how much the chain is stretched. Could mean the cable is stretched though.
If the limits were ok when you got the bike, I would leave them alone. Not worth risking screwing up the shifting. If the mech struggles to shift to a larger chainring, then add some cable tension using the barrel adjuster on the shifter.
Having said that, I'd guess that you're spinning the cranks when the chain is on the small ring and the small sprocket opn the back or large/large. In this case, the chain will always rub, and there's nothing that can be done about it, other than not doing it.

chronyx

Good point, thanks, I'll try the cable tension, although I have fitted new bottom bracket, deraillers all round, etc so the only thing original is the frame! It's the first time I've ever attempted anything like that so I just got it to a stage where it all worked, half winging it and half following Robert Zinns MTB book.

Not guilty of dodgy gear combos though, understand just enough about chainline!

whyamihere

If you've changed the BB, then the limits might have to be changed, depending on if the axle is a different length. Zinn's book will tell you how to set the limits properly.

chronyx

Just to finish this thread, a quick twick of the cable tension adjuster at the handlebars pretty much sorted this. Cheers!