Not my department, but I think I remember reading somewhere that dot5 is better for bikes. The reasoning being the reservoir being small, the dot5 is less likely to boil than dot 4. If a small amount of fluid is doing a lot of stopping this seems logical? None of my brakes have ever been disc though.
I use DOT5 for the simple reason that if you get a leak, a burst or damaged hose, or simply are hamfisted and slightly drunk whilst working on your brakes, it won't damage the paint on your bike like DOT 4 will if not removed quickly.
Yeah you are right on that one buddy.
I was working with dot 4 the other day and i ended up feeling sick and had a sore throat.
So i threw what little i had left in the bin , as all my stuff is stored in
my apartment and not a good idea really.