Mountain Biking - Rear Derailleur: Long or Short Cage

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adaze
04-22-02, 02:20 PM
ok if im gonna get a new rear mech, before i get new cranks, (no cranks as yet so compatability isnt a factor till i get the cranks) whats the difference between the XTR Long cage and short cage, also it specifies Rapid Rise or Standard for each cage length, whats the difference between these, i have no real idea what they mean?

bikerider
04-22-02, 02:59 PM
The difference between the short cage (GS) and the long cage (SGS) is in the chain capacity. The GS can handle a total 33 tooth capacity versus 42 for the SGS. This assumes a 22 tooth max difference on the front. Shimano's numbers are conservative in practice, by the way. All the XTR rear derailleurs will accomodate 11-34 cassettes and, of course, anything in between.

Take (largest chainring-smallest chainring) + (largest sprocket-smallest sprocket) to determine your needs. If it exceeds 42 teeth then Shimano wants you to use the long cage. If you run only two rings up front or a highly geared cassette (or both) then the short cage would probably work. In practice, if you are careful with your shifting you can put a short cage on most anything, but I won't recommend it across the board.

The Non-Rapid Rise (conventional) XTR derailleurs are numbered M952. The Rapid Rise are numbered M953. Rapid Rise uses the same shifters, but the action in the derailleur is reversed. This means that with rapid-fire you use the trigger to down shift instead of up shift (and vice-versa). The 'rest position' for the derailleur is on the largest sprocket instead of the smallest one. Most people who try it seem to prefer it but it has never really caught on and I heard that Shimano was going to abandon it. If you have more than one bike it will be a pain to keep adjusting back and forth.

If you are looking at Shimano's website use:

http://www.shimano-europe.com
toolfreak
04-23-02, 10:14 AM
If you ever have enough money to buy the XTR rear, i`d say go for the rapid rise.
Its such a good feeling to shift uphill! , this is possible because the spring action is reversed and faster then the cable action.

I like it a lot, and its shifts so quiet and smooth, SUPERB :D

adaze
05-07-02, 06:57 AM
OK, ive finally chosen my crank + chainrings, and am probably settled on a shimano XT cassette. If the chainrings are 22/32/44 and the cassette is either 11-32, 11-34 or 12-34, which derailleur would be best? Plus i kinda wanted to get compact cranks and chainrings so how do i choose an equivalent cassette that will accomodate this?

thx