Using Deore LX Rear Der with 8 spd setup

[roller62]

Hey y'all
My OEM Shimano Alivo rear derailleur is wearing down and I picked up a Deore LX long cager (M581SGS to be exact), having read in some places that you can set up Deores to run on an 8 speed setup. I slapped the thing on and ran the chain through it (8 speed SRAM PG850 chain) and it's real snug going through the works - seems like it's rubbing. Does this mean I need to get a thinner 9 speed chain to make this work? Do the 9 speed chains shilt over the wider 8 speed cogs OK? I'm not really up for doing a whole 9 speed upgrade at this point and if the LX der is not going to work I'll probably just slap the old one back on and save up for a full change out.
Any hints on this?

Tanks Mucho.

Ron in SD

[DirtymikeTDB]

Yeah it will work fine, just run the nine speed chain.

[Winger]

This doesn't really answer your question, but my 8 speed has a plain old Deore rear derailleur. I've often wondered if I could replace it with the $19 Jenson special if it took a dump.
http://www.jensonusa.com/store/produ...leur+M510.aspx

And, DirtyMike is correct, according to Sheldon Brown...
http://www.sheldonbrown.com/speeds.html

[roller62]

Originally Posted by Winger

This doesn't really answer your question, but my 8 speed has a plain old Deore rear derailleur. I've often wondered if I could replace it with the $19 Jenson special if it took a dump.
http://www.jensonusa.com/store/product/RD703A02-Shimano+Deore+Rear+Derailleur+M510.aspx

And, DirtyMike is correct, according to Sheldon Brown...
http://www.sheldonbrown.com/speeds.html

Yeah, I don't think there's a whole lot of difference between the $19 Deore and the one I got for $45 except for materials. The SGS is an extra long cage, but that only means I can run a wider range of gears than I probably will use.

[DISCO]

I ride a deore with an eight speed and it has worked for thousands of miles on my commuter bike. I doubt it wise to run the narrower nine speed chain though, the slightly wider (and stouter) eight speed will run just fine over the narrow teeth. It's just like running a 1/8ths BMX chain over a 3/32nds chain wheel or cog. Now if it's truly the cage width as you have said I would try to mix and match with your old rear alivio dérailleur. Take them both apart and see if the bushings are wider in the old one and just swap the guts and use the newest cogs. If the issue is the cage design(?) just swap pulleys or get a new pair for around twenty bucks. Best of luck and enjoy your weekend.