What tires fit - 640i GC

[8one6]

I ordered new wheels and need help with tires

I've been searching the forum for weeks now trying to get some tires spec'd for my new wheels and can't find the answers I'm looking for...

Car Info
-2013 640i GC M-Sport
-not x-drive
-stock ride height

New Wheel Specs
Vossen HF-5's
Front: 20x9, +33, Poke: 79.3mm, Inset: 149.3mm
Rear: 20x10.5, +42, Poke: 91.4, Inset: 175.4mm

Tire Options
Stock sizes have such little sidewall that I fear driving this thing on the roads of Kansas City. While upgrading wheels, I feel like I owe them a little more protection.

Front
The front carriers leave little room for additional sidewall. Has anyone been successful with anything with a sidewall larger than a 255/40r20? What about a wider tire? Any recommendations?

Rear
What's my max width and sidewall back here? I know 285 & 295/30r20 are common. Is anyone running one of the following? Any concerns about a rear sidewall being an inch larger than the front for ascetics or functionality?
-295/35r20
-305/30r20
-305/35r20

Thanks in advance. Feel free to drop some pictures to help me visualize the your setup or recommendation!

[shine775]

I bought a 2013 640i with aftermarket 20" rims that I don't like. So I'm going to buy some stock rims. I'm going to get 19" or maybe even 18" rims specifically or the same reasons. The more sidewall, the better the ride, and better protection for the rims.