Maybe. The "10-speed" RD will work with any number of gears except pre-9-speed Dura Ace and 10-speed Dina-sys, as long as the number of gears for the cassette and shifter match.
The issue is that the road RD--regardless of cage length--isn't meant to handle more than a 27- or 28-tooth cog. If you already have the RD, then try installing the b-tension screw backwards to pull the RD further away from the cassette. If you don't have an RD already, get a 9-speed or lower long-cage Shimano MTB RD. I'd get one that's not Shadow and traditional top-normal (like the road ones).
Originally Posted by slopvehicle
Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.
The issue is that the road RD--regardless of cage length--isn't meant to handle more than a 27- or 28-tooth cog. If you already have the RD, then try installing the b-tension screw backwards to pull the RD further away from the cassette.
I have an Ultegra GS derailleur on an 11-30 cassette. It grumbles a little on the 30- tooth cog even with the b-screw most of the way in, but it shifts just fine. By grumbling I mean that the guide pulley is close enough to the cog that it makes a grumbling noise as the chain wraps first one way then the other, with the pulley nearly touching the teeth of the cog. I don't use the 30-tooth cog much, so it's not a big problem for me, but using a MTB derailleur would be a bit better in the 32-tooth case - they're built for extreme ranges of cassette.
'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Originally Posted by jimc101
Current Shimano road GS cage RD's will handle over 28t , an SS will go up to 28t,.
That's not what Shimano's product literature says. It gives a 28T maximum cog size for both the SS and GS rear derailleurs and the only difference is the total wrap capacity. If you can use a 32T cog with any Shimano road rear derailleur it's a lucky coincidence of having a derailleur hanger long enough and most frames won't permit it.
I agree with Jive Turkey's advice to the OP; if he has the rd and cassette already, try them but don't be surprised if they don't work together.