Floppy rear changer

[Danny]

The rear Sora changer on one of my bikes seems to have gone "floppy". By this I mean that it while it holds the chain tension when the chain is on the large front chainwheel, it has suddenly stopped doing so when the chain is on the middle or small chainwheel.

As far as I can tell the gear cable is not snagging,

The bike was second hand so the rear dérailleur is of uncertain age. Could the spring in it have gone and if so is this replaceable?

 

[Gerry Attrick]

I would first remove it from the bike entirely, then clean it thoroughly with a toothbrush and chain cleaner before re-lubricating it. I suspect that crud has infiltrated the pivot and partially seized it.

 

[swee'pea99]

You say "As far as I can tell the gear cable is not snagging"...how sure are you? That would be the first thing I'd check out. Just detach the cable from the mech and maniuplate both the mech and cable - does the mech feel 'springy'? Is the cable running freely? (Use the changer to pull it 'that way', then pull it back manually, by grabbing the end and pulling.) Not having looked at it, I'd suspect cable problems rather than mech. But like I say, easy enough to check, simply by disconnecting the two and having a fiddle.