Not quite right if you're off 4 mph at 55 mph or more. It's more like 8 miles per 100 miles, if it matters to you.
If you have to your bars just to FIT the tires, then they will rub at extreme flex, especially when turning. Getting a tire ON, and getting it to not rub throughout it's entire range of motion, are two different things. Having run 35's for a bit, I can attest to that, as can anyone else who's put on big tires with less than perfect clearance.
The word "fit", therefore is misleading. Lot's of tires "fit" and don't rub in normal driving. Go thrash it a bit and see what happens, lol.
I don't mean this to be unduly critical, but this post doesn't really answer the question of fit because you haven't really tested them yet.