DONTHATEMYQ8

One of the first changes I plan on making to my Q8 is going to be a set of aftermarket wheels, most likely Vossens. I have a Prestige, Luxury Package, Adaptive Chassis, Year 1 loaded model landing soon and I plan on making my stock wheels my winter set and going up one inch in size to 23’s like the Urus. I plan on running the same Pirellis the Urus does as my summer tires: 285/35/23 front and would like to run the 335/30/23’s in the rear but I am concerned about the width. IMO the stock wheels are just way too narrow in the rear so I will for sure be running a staggered setup like the X6M and GLE AMG 63S coupe. I just don’t see much sense in going 22’s with my Vossens even though tires would be considerably cheaper and I could probably run the same wheel/tire size and the AMG 63S Coupe which also comes on factory 22’s. Can anyone who already has taken delivery give me any ideas on clearance? Thanks in advance!

DONTHATEMYQ8

markcincinnati

A rear-engined Porsche pretty much NEEDS wider tires in the rear to mitigate oversteer . . . on the other hand . . .

I have carefully read what it is you want to do regarding your Q8's wheels. What the staggered tread widths and aspect ratios you suggest you plan (or hope) to do are confusing to me unless your sole purpose (beyond spending money) is cosmetic.

First what I think I know about the Q8: It, like many Audis, tends to be biased to understeer due to the front-rear weight distribution. It is not "engineered" for neutral steering bias and certainly not for oversteering. Typically, if you want to negate some of a vehicle's tendencies to understeer, you can apply the brake on the inside front wheel (meaning if you're making a sharp left turn and understeer is detected, braking the left front wheel will help the vehicle "pivot" on the left front tire). Another form of understeer mitigation is to employ a torque-vectoring rear differential that routes the torque (in the above example) to the outside rear wheel. The brake method has some critics who don't like a "trick" that applies a brake since it slows the car somewhat. They argue you can't improve the handling if you "take away" power by braking the inside front wheel. Although this argument can go on and on, both systems do help combat an understeering vehicle's tendencies to plow when entering a turn at high (relative) speeds.

Putting wider ties on the REAR of your Q8 will not help the understeering proclivities of the car (quite the contrary). The wider tires -- IF the goal is to improve the handling -- should go on the front. Wider front tires tend to INCREASE oversteer. In a car such as the Q8, putting the wider shoes on the front should be considered unless the sole purpose is to "look cool" which is not a bad goal, unless it detracts from the performance (and wider rear tires are certainly capable of having that effect, FWIW.)

I suspect this is why Audi improves the handling of its fine RS3 by putting the wider tires on the front and also uses brake-based understeer management (which is also used by the Q8).

"By increasing the size of the contact patch up front, the car has excellent turn-in and there’s more grip in the front than the rear, allowing the car to slide a bit [oversteer-like]. This makes the car feel more playful and gives it some personality that other Audis might be lacking." - Autoguide.com

BTW, the so-called "rolling diameter" must remain the same, no matter what you do.

DONTHATEMYQ8

Thanks for the detailed response. I’m solely buying larger wheels for looks and cosmetic purposes. The stock setup looks a little underwhelming to me. I’ve traditionally always upsized my wheels on my cars and kept the stock setups for winter use and long road trips only.