SRAM cassette/Shinano shifter and RD incompatibility?

I recently picked up another Bike Friday on eBay. It came with a SRAM
cassette 11-32, SRAM chain and a SRAM rear derailleur and gripshifts.
All with less than 100 miles on it. I swapped for Dura Ace index
barcons and an XTR rear derailleur I had on another bike. Now the
chain doesn't want to stay in the 4th cog from the smallest - it skips
and shifts down cluster on either front chainring (56-46). All the
other cogs work OK. I've fiddled extensively with the cable tension
and always at least one cog doesn't work well. I put on a Shimano
cassette 12-27 and the bike shifts perfectly. Hubs are 105.

Is the SRAM cassette incompatible with the Shimano shifters or rear
derailleur? If not, what suggestions to get the SRAM cassette working
properly?

Thanks in advance for assistance.

Marc Rosenbaum

"Marc Rosenbaum" wrote in message
om...
I recently picked up another Bike Friday on eBay. It came with a SRAM
cassette 11-32, SRAM chain and a SRAM rear derailleur and gripshifts.
All with less than 100 miles on it. I swapped for Dura Ace index
barcons and an XTR rear derailleur I had on another bike. Now the
chain doesn't want to stay in the 4th cog from the smallest - it skips
and shifts down cluster on either front chainring (56-46). All the
other cogs work OK. I've fiddled extensively with the cable tension
and always at least one cog doesn't work well. I put on a Shimano
cassette 12-27 and the bike shifts perfectly. Hubs are 105.

Is the SRAM cassette incompatible with the Shimano shifters or rear
derailleur? If not, what suggestions to get the SRAM cassette working
properly?

Thanks in advance for assistance.

Marc Rosenbaum

I can't offer much advice, but I don't think it's a derailleur problem. I use
SRAM 7 and 9 speed cassettes with Shimano derailleurs and they work well. In
both cases I'm using SRAM shifters, though. Can you switch the barcons to
friction mode and see if all the gears can be made to work?