I wanted to ask if any of the mechanics here could recommend a good replacement 7-speed mountain rear derailleur. The rest of my drivetrain is Shimano Deore DX with SIS thumbshifters (yes, we're talking circa 1992) and I do not ride off-road at all...this bike is solely for commuting to/from work. That said, I do ride pretty hard and have a huge hill every day coming home...so I simply want to find a replacement derailleur that works well and won't fall apart.

Thanks for your help.

Deore and Deore DX are all over ebay if you have to have an original. You can actually use any non SGS type current Shimano offerings also. Nashbar has regular Deore on sale for under $20. Good luck

Tim

As cs1 mentioned above, Nashbar has Shimano Deore rear derailleurs on sale. They're very good derailleurs.

Regarding your "7 speed" derailleur, the number of "speeds" are in the shifters and the number of cogs on the cassette or freewheel, the derailleur just moves the chain from cog to cog and keeps it properly tensioned.

https://www.nashbar.com/profile.cfm?c...%20Derailleurs

Any long cage Shimano derailer will work. I have a long cage Ultegra on my 7 speed mountain bike.

I really like my old and virtually NOS Deore DX group... the shifting is extremely crisp.

You can get a super cheap shimano "tourney" RD for $15-$20.

DX was a very underrated group in it's day. I think it was a mistake to drop it from the lineup.

Tim

Why do you want/need to replace the dérailleur?

Care to give us a clue what your gearing is, and what dérailleur you want/need to replace?

I have the RD-M510 Deore from Nashbar ($18 closeout) on my 7-speed Rockhopper. It's a fantastic part. Ignore the 9-speed sticker.

Thanks for everyone's help so far. In response to some of the questions:
- Gearing is 24/36/46 up front, 12-28 in back.
- I'm looking to replace my derailleur as, quite frankly, it's not sounding very healthy. Lots of strange noises (not just when shifting), and it's literally 15 years old...so maybe it's just time.

If I'm understanding things correctly, it sounds like any 7, 8, or 9-speed derailleur will work fine. My original concern was that I didn't know if the cogs on a 9-speed were spaced differently than a 7-speed.

I know two of you recommended the RD-510 Deore, and it's certainly a great deal at Nashbar right now. That said, the reviews on MTBR weren't very positive for this model. Who knows. The SRAM x.7 got good reviews, or actually...maybe a good choice since I'm not doing any off-road would be a 9-speed Shimano 105??

Thanks again for all your help.

I would ignore the reviews on MTBR, there's nothing wrong with the Deore derailleur at all and it's on sale for a great price. My teenaged son has one on his bike, it shifts as smooth as silk. And if it can survive the abuse he puts it through, I'm confident in saying it's a very durable derailleur. Sure, you can go for a more expensive derailleur, with the gearing you have you could probably even get away with using a long cage "road" derailleur. But in terms of performance and durability, you won't do any better than the Deore, and it's $17.99-

Yes, 7, 8 and 9-speed is spaced differently, BUT the rear derailleur does not care. The indents are set in the shifter; the RD just goes where the shifter sets it for each gear.

You can't use the SRAM x.7 with your current shifters because SRAM went to an alternative cable pull (1:1 vs 2:1) ratio for most of its MTB rear derailleurs (I believe anything with a number in its model name) and is only compatible with SRAM shifters.

Shimano Deore is an excellent choice, and should have no problems on a 12-28 cassette as far as wrapping chain or clearing the big cog.

I ran a Tourney with built in hangar for over 2000 miles on my commuter bike with absolutely no problems, before replacing it with a Deore and a generic R/D hangar that Harris Cyclery sells. Shimano makes a Tourney "rapid-rise" R/D that I have thought about putting back on the commuter bike, which has bar shifters, just to see how I like it.

BTW, 7 & 8 speed have the same spacing, but the 8 speed is by nature one cog wider. A 7 speed cassette will work on a 8 or 9 freehub, but will require a spacer on the inside of the cassette. I think its a 5mm spacer. There were some early 7 speed hubs, such as the Deore LX "Parallax" freehubs that would take only 7 speed, but nothing bigger.

https://www.bikemannetwork.com/biking/p/ATCOMPRD/ATRDSDX


https://www.bikemannetwork.com/biking...MPRD/ATRDSXTSC

Why are you pointing him at a short cage with his gearing?

The deore one from Nashbar for $17 works well. Have it on a 7 speed 12-28.