tFUnK

Not a question, just sharing my experiences of being pleasantly surprised that I was able to clear a 32t cassette using short cage rear derailleurs. This was on two different frames (Trek XO2, Guru Photon) with different drive trains (Ultegra 6700, Sram Red). The Ultegra on the Trek seemed a little strained but adding links to the chain and playing with the B screw got it working fine, though I've since added an extender to pair with a 36t cassette. The Red on the Guru looks like it could handle a 34t, even.

I realize that this will be a case of trial and error for each frame/drivetrain setup, so YMMV.

cny-bikeman

The ability of a short cage to clear a larger cog is a function of the distance from the cassette center to the top of the upper pivot, which may be the same or close to that of a long cage. The function of the long cage itself is to wrap more chain. Although you can reach that cog with your short cage you are limited as to the difference in chainwheel size in order to still wrap the chain in all usable gears.

tFUnK

Good point. I am running 46/34 on the Trek, and chain wrap was fine.

I did test the entire gear range on the Guru (50/34-12/32) and all gears work fine, but again, YMMV.

MikeWMass

I run a 50-39-30 triple with a 12-27 cassette with a short cage 105 (5600) derailleur. Works fine as long as I stay near the top of the cassette on the small ring. I think if you clear the large rear sprocket and size your chain big-big, you won't get into serious trouble, you just may have to shift to the large (or larger) ring sooner.

fietsbob

And minimized difference between the 2 chainrings., to be within the smaller t capacity total..

I could run a short cage & 14~ 34 freewheel with a single chainring..

as it climbs the cluster.. needing more chain, to the bigger cog the bottom pulley rotates the top one downward..

B ccrew shown by the mountng bolt can be turned over to get it longer to wind the derailleur further away from the low gear, for more clearance..





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