Originally Posted by
Slaninar
I would not judge the level of expertise of LBS mechanics by a post made by an, obviously, no offence meant, unexperienced cyclist, who writes as he understood, interpreted. Just my experience from dealing with different people - always hear both sides.
SRAM is a bit picky - they want particular distance of der from the cogs - probably 4 mm from the cogs - that is correct.
Chain can get worn from 1000 km (700 miles). Poor quality one, or lots of cross chaining, or using the smallest sporcket at the rear most of the time etc. There is a simple way to test that - just measure the chain for wear.
Edit: it is 6 mm for SRAM, or 3 chain rivets for older SRAM models of rear derailleurs.
There is a lot to be said for actually reading the documents that come with your components. Although it looks like you can just slap on an FD and adjust it, there are very specific difference between the way Shimano, SRAM and Campy are supposed to be set up. And different generations have variations too.
For FD, most specifically is how high above the big chainring the cage should sit and the exact angle of the cage with respect to the chainring.
For RD, they will tell you exactly which cog to adjust on and when the chain should start to touch the next cog when shifting. They will also give specific info for the tension screw.
Getting this correct makes on the road shifting pretty much perfect from the get go.
Getting it "kinda close" means you will drop chains inexplicably and have shifting problems under load.