Mountain Biking - I need a new rear derailleur for a 21 spd

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glazer1972
12-11-10, 07:15 PM
Somehow a stick jumped up this morning on the woods trail I was on and I broke the Shimano Altus rear derailleur on my 2010 Giant Boulder.

It has Shimano EF-50 7 speed shifters, Crank: 28/38/48, Cassette: 14/16/18/20/22/24/34.

I found a good price on a Shimano LX M581 and was considering it. Any reason why it wouldn't work for me?

JonnyV
12-11-10, 07:24 PM
That'll work just fine. Get it. Go ride. Break more stuff. Repeat.
DirtPedalerB
12-18-10, 01:47 AM
The number of gears(speeds) don't matter on the derailleur, the shifters control that.

fuji86
12-18-10, 04:58 AM
Here's a guaranteed match ? If you were satisfied with OEM ?

http://cgi.ebay.com/SHIMANO-ALTUS-MTB-ATB-7-8-SPEED-REAR-DERAILLEUR-/120659357737?pt=Cycling_Parts_Accessories&hash=item1c17dbb029
Deshi
12-18-10, 08:21 AM
Almost any modern derailleur will work for you. The LX is a good robust derailleur and will serve you well. That was my derailleur of choice whenI was racing downhill.

Id say go with the LX, ride the crap out of it and enjoy.
glazer1972
12-20-10, 08:11 PM
I ended up getting the same Altus shifter, a new chain and retruing of the rear wheel. Should last me a while longer.