Bicycle Tutor

I've had an old huffy aluminum shock hard tail mountain bike for a long time (9 years) and the thing is practically bullet proof. The only problem is I need to replace my rear derailleur for the second time and I can' find one with the right mounting brackets. I either get the "just get a new bike" or they try and sell me one with an extension arm on it which always screws up my shifting because it hangs too low and rubs against the chain in low gear. It originally had a shimano sis shifter on it without an extension arm, do they not make that style without the extension arm on it anymore or am I not looking in the right place?

Have you tried adjust the B screw to prevent it from rear derailer from touching? I used to have the same prob w/ my used schwinn until I tightened the B screw which brought the pulleys up so it wouldn't touch any gears. The last gear it seems like it touch but it doesn't make that "friction noise" before i adjusted it.

trail-rider, are you able to upload a photo of your derailleur? I think Sleepy is right, it sounds like a 'B' screw adjustment... check out this video at about 1:10 and see if that helps.

Thanks for the tips, I have tried adjusting the b screw and it didn't work, the extension arm on the derailleur is is making the tension pulley and the guide pulley too close to each other and the chain is contacting the guide pulley. I have to find a derailleur the fits the mounts without that pesky extension arm, I 'll try and get a picture of it up in the next few days while I search for the correct derailleur to fit like the original. And again thank you for the help and I'll check that video out when I get home from work.

Are you looking for a derialleur that attaches like this one?

That's exactly what the extension arm looks like Alex , do you know if the make a derailleur that can use that kind of a mount without that pesky extension arm?

Or perhaps what that kind of mount is called?

I think it's called a derailleur mount. Some derailleurs mount like the one shown above, by sliding up into the rear dropout, and then fastened by the tightening of your rear wheel. The other more modern style screws into a derailleur hanger that is built into the frame.