lost about medium and long Cage Derailuers..

[.8down]

Whats the difference between a long cage and medium cage Rear D?

[el_d00der1n0]

Originally Posted by .8down

Whats the difference between a long cage and medium cage Rear D?

I believe the long cage can handle more gears up front.

[Code Blue]

Originally Posted by .8down

Whats the difference between a long cage and medium cage Rear D?

http://www.beyondbikes.com/bb/tech/?section=rdr

[genusmtbkr5]

If you're going to run 3 rings up front and say 11-34 cassette in the rear, then you will need a long cage. Some guys only that have freeride or some all-mountain bikes only run 2 rings up front, you can use a med cage then. The long cage allows for the chain to wrap around that "big" ring. The long cage also takes up the slack if you when your'e in your small rings, because the chain is much longer when running 27 speeds

[Code Blue]

Originally Posted by genusmtbkr5

If you're going to run 3 rings up front and say 11-34 cassette in the rear, then you will need a long cage. Some guys only that have freeride or some all-mountain bikes only run 2 rings up front, you can use a med cage then. The long cage allows for the chain to wrap around that "big" ring. The long cage also takes up the slack if you when your'e in your small rings, because the chain is much longer when running 27 speeds

thanks for the condensed version

[thephat]

The general guidelines stated so far will get you there.

If you want to get really geeked out, you can find out the chainwrap capacity of any rear der.

If I remember corectly, the formula to calculate chain wrap is the difference between the tooth count on the biggest cog on the cass and the smallest added to the difference between the smallest chainring and the bigest.

So if you have an 11-32 cass, and 22,32,44 rings

(32-11)+(44-22)=43

[Code Blue]

Originally Posted by thephat

The general guidelines stated so far will get you there.

If you want to get really geeked out, you can find out the chainwrap capacity of any rear der.

If I remember corectly, the formula to calculate chain wrap is the difference between the tooth count on the biggest cog on the cass and the smallest added to the difference between the smallest chainring and the bigest.

So if you have an 11-32 cass, and 22,32,44 rings

(32-11)+(44-22)=43

you need to heal-up and get back to the shop!

Call the shop and tell Brian to find me a ACS 22t freewheel

[thephat]

Originally Posted by DeeZee

you need to heal-up and get back to the shop!

Call the shop and tell Brian to find me a ACS 22t freewheel

I have never had this kind of time on my hands.

[2wheel_lee]

Originally Posted by mechmann

actually, if you are running a single ring in front and a 11-34 you can run a road bike rear der.

Road derailleurs are designed to work with a cassette having no larger than 27 teeth (12/27). It's not an issue of chain pickup, it's the angle the derailleur swings inward. Some have had good success with road derailleurs on larger cassettes, but it's not ideal.

Also, road bike derailleurs are available in short and long lengths, but the road long is the same as mtb medium (my memory is getting a little fuzzy on this).

Related, I've tried running Ultegra derailleurs on my M3 (with an Ultegra cassette), but the plate the B-tension screw threads into bends and breaks (it's aluminum vs many mtb derailleurs that are steel). The vibrations and constant chain bouncing in DH use just kills it. And yes, my chain is long enough.

[el_d00der1n0]

Originally Posted by 2wheel_lee

Road derailleurs are designed to work with a cassette having no larger than 27 teeth (12/27). It's not an issue of chain pickup, it's the angle the derailleur swings inward. Some have had good success with road derailleurs on larger cassettes, but it's not ideal.

Related, I've tried running Ultegra derailleurs on my M3 (with an Ultegra cassette), but the plate the B-tension screw threads into bends and breaks (it's aluminum vs many mtb derailleurs that are steel). The vibrations and constant chain bouncing in DH use just kills it. And yes, my chain is long enough.

Shimano makes a MTB RD that looks like it's for road, but it's for the single ring up front and it can make the jumps necessary for a MTB cassette.

[2wheel_lee]

Originally Posted by el_d00der1n0

Shimano makes a MTB RD that looks like it's for road, but it's for the single ring up front and it can make the jumps necessary for a MTB cassette.

Which model is that?
What do you mean that it looks like it's for road?

[el_d00der1n0]

Originally Posted by 2wheel_lee

Which model is that?

I was thinking of the Saint short cage.

Originally Posted by 2wheel_lee

What do you mean that it looks like it's for road?

It's real tight and compact.

[2wheel_lee]

Originally Posted by el_d00der1n0

I was thinking of the Saint short cage.


It's real tight and compact.

I've never really thought that the Saint derailleur looks like a road derailleur, but ok. The Saint derailleur is fine, if you don't mind carrying excess weight.

If you want tight and compact, look no further than the 2008 Shimano XT "Shadow" rear derailleur. You're not going to get any tighter or more compact in the Shimano lineup. It comes in medium and long cage versions (maybe short, but I haven't seen it yet).

After abandoning the Ultegra RDs, I've had great results with this new XT RD.