I'm in that minority of folks whose sweat corrodes the finish on Shimano (6600,5600, 4500) brifters and cranks. These little cracks start in the finish and I think the salt from my sweat collects in the cracks, grows crystals, and spiders across the brifter until the finish is all but gone.
I've talked to a few other people that have the same problem. They all recommended going to SRAM, since they didn't have the same problem. But I'm thinking it might have something to do with the clear finish. Has anyone had trouble with this with the Ultegra SL or 105 black finish? What about 6700 Ultegra? I hear the finish is different.
Never noticed any parts that are totally immune to this. Had one guy almost have to replace a fork because his sweat was collecting around the o-ring on the top cap of his king headset, ate right through the steerer tube in a ring right above the o-ring.