Rear Mech compatability?

BMKN

I need a new rear mech, I am running ultegra 53/39 chainset with rear cassette 11/25? I need to know the difference in short and medium cages, I am looking at 105 rear mech. My last one snapped on me with that not many mileage on her.
Will this be compatible

Top Features of the Shimano 105 5700 10 Speed Rear Derailleur
10-speed 105 wide link rear derailleur medium cage - GS
Advanced Wide Link design increases rigidity and shifting performance
Super stiff for fast and accurate changes across the cassette
Large 11 tooth pulleys increase service life and reduce noise
Super light shift action
Compatible with 8, 9, and 10-speed drivetrains
Maximum low sprocket 32T with double chainset
Maximum front difference 22T, total capacity 40T
Average weight 232 grams [/b][/b][/b]

ic.

Yes

arlowood

The one you list (medium cage GS) will be compatible but with your set-up you should be using the short cage (SS) rear mech.

The GS is really only needed to accommodate the extra scope/chain tension needed when running a triple chainset.

BMKN

The GS is really only needed to accommodate the extra scope/chain tension needed when running a triple chainset.[/quote]

Clears things up a little bit. I seem to be very unlucky with rear mechs, my second one since the summer time

richiebones

have you had the mech hanger alignment checked?

southdownswolf

richiebones wrote:

have you had the mech hanger alignment checked?

More to the point, is this the same bike where the rear hanger has snapped off?

Essex Rouleur

arlowood wrote:

The one you list (medium cage GS) will be compatible but with your set-up you should be using the short cage (SS) rear mech.

The GS is really only needed to accommodate the extra scope/chain tension needed when running a triple chainset.

Or a larger cassette such as a 11-32.