Bicycle Mechanics - Rear deraileurs, deore, xt, xtr...

I have a shimano deore rear deraileur on my mountain bike, works fine. I was wondering, how are the xt, xtr, etc., any better? Can you shift while there is a load on the chain? I believe they are lighter. Not much concern to me, though. Just wondering, thanks.

the main advantage to the XTR is weight.. not so much durability or shift performance I don't think.
I have a bike with all XTR group.

As you progress up the line through LX and XT, they are going to be lighter, made with higher quality parts -- more metal instead of plastic pieces. Bearings instead of bushings, etc. The shifting will be a bit more precise, it won't go out of adjustment as easily and can be more easily adjusted and repaired. The XT stuff is the ultimate in quality and durability. XTR is really made for racing, and so the emphasis is on weight.

The other advantage to the XT or XTR stuff is the "Shadow rear derailleurs " and "rapid rise".

"Shadow" rear derailleurs have a lower profile. They dont extend as far out from the side of the frame, so as to better protect the derailleur from getting banged up.

Rapid rise is a term that means the derailleur shifts to the lower/easier gears with less effort [ it a low normal derailleur ]. Up until rapid rise came along, all rear dearilleurs were high normal. The difference being if you broke you derailleur cable on a high normal rear derailleur, youd bike would shift to your hardest/highest gear in the rear. If the same thing happened on a rapid rise rear derailleur, you'd be riding home in your easiest/lowest gear.

Thanks for the replies. Will any of these derailleurs shift under load? Like if you were riding up a hill? My deore doesnt seem to want to, if its under heavy load.

I think you'll find that none of them likes to shift under really heavy load. After all you've got a lot of tension on the chain and then you're asking it to lift it away from the cogs and lay it onto the shift ramp of the next one up. That just is not going to go easy for any of them.

I've got mostly Deore and LX and one XTR on my hotrod commuter. The XTR does shift a shade cleaner than the others but not by much. And I tend to ease up a little, like any of us should, if I'm trying to shift on an uphill. Proper practice is to shift BEFORE you find out you're grunting anyway. For this loaded shifting I've not found that the XTR is any better than the Deore. But remember that I ease off to shift if I get caught on a hill then grunt after the shift.

By the way. Remember that shifting ease is a partnership between the derailleur AND the cassette. An XTR with a cheapie low life cassette won't shift up to XTR specs. You need to match these items to get the best and cleanest shifting. But again if you're out of the saddle and pounding a nasty uphill nothing will work.

I think that proper shifting technique really makes the most difference... no shifters really work that well under high loads and you have to know how to back off on the power input just a wee bit to allow the derailer to work at it's best.

The older Deore was very good spec and came at different levels but with newer systems coming online it has moved down the scale and XT is probably the best current system if you are looking at a good blend of price, performance, and durability.

That makes sense, trying to get the chain to lift onto another sprocket while it is tight. Thanks, that answered my main question.