After searching a bit, I couldn't find a direct answer...

I'm looking at a set of new wheels. The tech at (one of) the manufacturers I'm interested in isn't 100% sure of fitment, so i thought i'd pose this here.

Front: 20 X 8.5" 5X114.3 +40
Rear: 20 X 10" 5X114.3 +40

The tech claims these particular wheels will have no problem at all clearing the front calipers - but he's not sure about fender clearance for the 10" rears. Says that other wheel manufacturers seem to run +47 offsets on most/all 20 X 10" wheels.

So what's up. Will +40 on the rear axle work? Dropped on Eibachs. Planning on going F: 245 35-20 // R: 275 (or 285) 30-20

In general: is there a universally "safe" offset range for staggered 20 X 8.5/10" aftermarket wheels I can go by? This is my daily driver - love the idea of a more flush/aggressive look, but maintaining optimum performance is most important to me.