[Jared]

The 7-spd Mountain LX rear derailleur snapped and we lost the cover to the rear shifter. I'm not really "up" on what is compatable. Can I install a 8 or 9 spd new deore derailleur and shifter on a 7 spd sprocket? I'm not really worried about "retro-correctness," just want to get it back up as a spare or turn it into a roadie. Thanks.

And what is the diff between a long/short cage rear d?

 

[Rumpfy]

The 7-spd Mountain LX rear derailleur snapped and we lost the cover to the rear shifter. I'm not really "up" on what is compatable. Can I install a 8 or 9 spd new deore derailleur and shifter on a 7 spd sprocket? I'm not really worried about "retro-correctness," just want to get it back up as a spare or turn it into a roadie. Thanks.

And what is the diff between a long/short cage rear d?

Well...if you're not in any hurry, you should be able to find an LX rear derailleur of that vintage for free. At the very least they can be had on eBay for under $10 I would think. A bike swap meet would also have what you need for cheap.

If it's a 7 speed, 9 speed won't work with the shifters, chain, and chain rings you've got...8spd is iffy too and doesn't jive well IMO. The most clean, simple, and economic solution is to keep it as 7 spd and spair yourself the headaches.

Just my $.02!
Good luck!

 

[Brandon]

The 7-spd Mountain LX rear derailleur snapped and we lost the cover to the rear shifter. I'm not really "up" on what is compatable. Can I install a 8 or 9 spd new deore derailleur and shifter on a 7 spd sprocket? I'm not really worried about "retro-correctness," just want to get it back up as a spare or turn it into a roadie. Thanks.

And what is the diff between a long/short cage rear d?

The new deraileur will work fine but the shifter won't, you'll have to locate a 7sp shifter if your's is really broken. The important parts of deraileurs haven't changed anytime recently. I have a 7sp XT shifting a 9sp cassette using friction suntour bar-end shifters on my road bike (built around 5sp era). For true bomb-proofness pick up a set of friction thumbshifters and you'll be able to shift any combination you can imagine and never worry about indexing getting messed up again.