Was just checking out the Martian 19x10.5 forged race wheels. They claim you can run a 305 without any fender modifications. That seems quite a bit wider than other recommendations I've seen. Can anyone confirm if this setup works?
It works - albeit barely. You may need to shave your knuckles a mm or two. It requires a lot of camber front and rear. And of course, not all tires are the same, so it could vary from one brand to another.
Well I have a different offset than the MW05's which are +40. I have 19x10.5 MW03's in +25. So, I am fairly confident you will need -3 degrees (roughly) of front Camber with 15mm spacers. In the rear, you should only need -2.5 to -3 degrees of camber. I needed almost -4 to fit the 305's.
Up front you'd need around +20 effective offset relative to OEM performance setup (so a 20mm spacer on top of +40 offset Martian sells) and about 3-3.5 degrees of camber.
In the rear, with a +40 offset you *may* get away with just lowering and around 1.7 degrees of camber. @MasterC17 posted elsewhere that with +25 rear offset (and maybe non OEM brake rotors?) he had to dial in 3.2 degrees of camber to make things clear.
A 40-offset wheel buys one ~15mm worth of clearance, which is rough equivalent to what 1.5 degrees of camber gets you. So, if you lower and get to ~1.7 degrees of camber in the rear you might be good with a 40-offset wheel and stock rear performance brakes.
If @MasterC17 is running MPP/other rear rotors that push the wheels out further, the math becomes a tad more favorable.