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I'm currently using a 50-34 FSA crankset (9-speed) with an 11-23 Sram cassette. I've seen on IRD's website that they have an 11-28 cassette which they claim is a good match with compact cranks. I'm considering switching over to it for a couple of extra lower gears for climbling. They also have an 11-25 which is a possibility. Does anyone have any experience with the 11-28? Would I have to use a triple rear derailleur with it?
 

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I'll tag along here, as I'm considering the 11-28 9sp for Michigan mt. biking. My curiosity is whether or not the cassette shifts as well as XTR or Dura Ace.
 

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Yatesie said:
I'm currently using a 50-34 FSA crankset (9-speed) with an 11-23 Sram cassette. I've seen on IRD's website that they have an 11-28 cassette which they claim is a good match with compact cranks. I'm considering switching over to it for a couple of extra lower gears for climbling. They also have an 11-25 which is a possibility. Does anyone have any experience with the 11-28? Would I have to use a triple rear derailleur with it?
Shimano road rear derailleurs are rated to handle up to 27t cogs, but can generally go larger (Sheldon Brown says they'll shift 30t cogs, I have run 28s). A road triple derailleur has the same cog size rating but the cage can take up more chain slack ("chain wrap") to handle the front granny ring. Shimano racing rear derailleurs are rated for 29t of chain wrap. With a 50-34 compact and an 11-28 cluster you would have 33t of wrap, or 29t if you avoid the cross-chain combinations as you should.
 

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too much wrap...

Yatesie said:
I'm currently using a 50-34 FSA crankset (9-speed) with an 11-23 Sram cassette. I've seen on IRD's website that they have an 11-28 cassette which they claim is a good match with compact cranks. I'm considering switching over to it for a couple of extra lower gears for climbling. They also have an 11-25 which is a possibility. Does anyone have any experience with the 11-28? Would I have to use a triple rear derailleur with it?
The 33T wrap of a 50/34 with an 11-28 is too much for a short cage RD. The only safe way to use it would be to set the chain length long enough that the chain would hang loose in any of the smallest 3-4 cogs. The idea of avoiding the largest combo (with a s1 inch shorter chain) sounds great until you accidentally shift into it and reek havoc on the drivetrain. The 11-28 would be nasty in 10 speed with no 14 or 16T cogs and even worse in 9 speed.

If you really want a large range of gearing and no big jumps between cogs, a triple is the answer. My Campy drivetrain with an FSA 53/39/28 crank, and 12-25 10 speed cassette has it all. No loss of top gear, no big jumps and a low gear that's like a 39/35 or 34/30. I get by with a medium cage RD.
 
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