Have an old Gary Fisher Aquila with a rigid front fork I bought new in 98. Ride a lot. Only mods are elevated stem to reduce aggressive handlebar positioning, a new cassette and chain, and Serfas inverted tread tires for fast rolling in the urban jungle while still maintaining some off-road-ability. It is a tank! The 400 SRT FFS 3x8 speed Grip Shifters work fine coupled with the STX-RC Rear Derailleur and Shimano Alivio Front Derailleur , but the rear grip shifter is wearing out. Mainly it is the rubbery grip part. With bare hands, I can't get a grip any more if I am sweating at all, and with gloves, the rubber is so thin, it is flexing a lot and feels like it is ready to rip away. Otherwise it works fine. Is there a cheap manageable way to just replace the grip part? Or do I have to replace the whole thing? Do I just go with new Grip shifters, or consider going with index shifters? What is compatible? Should I be considering upgrading my whole drivetrain? I am handy, and enjoy adjusting, maintaining and replacing components on my and friends bikes, so expecting to do this myself.