Shimano GS vs. SGS rear derailleur

[El Chupacabra]

I'm building a bike, and need to order a Shimano 10-speed rear derailleur (already have Shimano 10-spd shifters). Front is a triple 24/32/42; rear is an 11-36 cassette.

Can I use a GS mid-length rear derailleur on this? Or do I absolutely have to use the SGS long-cage?

I like the crisper shifting of shorter-cage rear derailleurs, and don't cross-chain.

[mntlion]

I'm sure someone will come on and work out the math on this.

if you are carful, and dont cross shift big to big. (and only use the outer ring, in the bottem/smallest parts of the cassette) odds are you can.

if you screw this up, odds are the derailer will snap, chain break, and you are on a single speed to get out.

I'd go with the SGS to be sure.

[marshalolson]

long cage (sgs), especially if its full suspension bike.

[El Chupacabra]

It's a full suspension bike.

Googling says that GS = max of 33T difference, SGS = 45T. And there's a little wiggle room with Shimano.

With the gearing I have, it adds up to 43T, which is way outside the range for GS. Oh well.

[robnow]

Whatever happened to the days when everyone was rocking the shorter cages, just making sure they were staying out of the big/big combo? I think many people who have been biking for a while have learned to ride this way, no???

[stuckathuntermtn]

Even without cross chaining, which you should never do anyway, the deraileur still has to pick up the extra slack in the chain.

Don't worry, xt shifts fine. I have an older 9-speed shadow and you can see all the rock hits on it. Shifts crisp and quickly with some slx shifters.
This is a 5" Kona from 08.

Sent from my cell phone. no, a cell phone.

[beaterdit]

What do you need a big ring for? Take it off in favor of a bash ring and run a medium cage. You can even swap your 32 for a 36 for more top end.

[Finstah]

Whatever happened to the days when everyone was rocking the shorter cages, just making sure they were staying out of the big/big combo? I think many people who have been biking for a while have learned to ride this way, no???

People used to run 3.0 Gazzalodi's on their 50lb. freeride bikes with 70* headtube angles too. In retrospect none of that was a good idea either.

The general rule of thumb these days really is : 1 chainring = ss derailleur cage, 2 chainrings = gs cage, 3 chainrings = sgs cage.

[lph]

What do you need a big ring for? Take it off in favor of a bash ring and run a medium cage. You can even swap your 32 for a 36 for more top end.

agreed. I always go 36 up front and I have never spun out of that on singletrack. hit high 30's today on a singletrack while pedaling on 36/11. very, very fun and a little scary. didn't need a bigger ring.

[Finstah]

agreed. I hit high 30's today on a singletrack while pedaling on 36/11. very, very fun and a little scary.

Dude, that's scorching fast!

You sure your computer isn't programmed for like a 900cc wheel?

[lph]

GPS. (not that that makes it accurate. )It is almost a dead straightaway and smooth. slight downhill. but I was up out of the saddle and hammering as hard as i could.