i have just bought a disc for the rear of my bike, and now need to get new shifters, as i currently run an XT STI setup, and i want to know if it is worth paying the extra money and buying the XTR rapidfire shifters, or if i should just stick with the XT ones ( at the moment i run a complete XT setup)
I personally don't think XTR is worth the money anywhere, least of all the shifters. XT works as well and in some areas is even lighter. LX/Deore is functionally as good, but the use of plastics instead of alloy can make them feel cheap.
My drivetrain is mostly XT but I've just upgraded the chainset from hollowtech Deore to Hollowtech II LX. I've also got LX shifters and an old model XTR rear mech that I got cheap because the LBS had sold out of XT and let me have the XTR at a price match. It's all good and I'd defy anyone to tell the difference in functionality.
"I can't see where it could be as a full Shimano drivetrain works faultlessly"
Er bollocks, you should have been out with me on my Chameleon today, it shifted like a bag of shit, got home, cleaned, lubed only to find out that the middle cheese ring is knackered after 356 miles!!!
Why such a cracking set of cranks with such crappy rings?