JWBLue

I notice the 20 inch wheels come standard with summer performance tires.

Would 19 inch wheels give better traction in snow and mud?

I thought the bigger the wheel, the better the traction.

Then again, the 20 inch wheels come with summer tires which makes me believe otherwise.

BigGrasshopper

In this case, a 1" difference will not make a substantial difference, assuming the same tires on each. However, for all practical purposes, the tires will be the most important aspect.

You are correct, the summer tires will not be ideal in snow, but neither will the stock all-season tires.

For best performance, you will want snow tires, which will be easier to find in 19" than in 20".

Huey52

Many folks go with smaller diameter/width rims and narrower dedicated snow tires in Winter. This facilitates a taller sidewall profile that helps absorb more impact (potholes and the like). It also presents a narrower head-on tread width to reduce "snowplow effect." Of course the dedicated snow tires are made of a compound that remains flexible in colder temps and also has a more aggressive tread pattern. Winter traction is relative to a number of factors and wider is therefore not necessarily better.

Victoryroad

On a D3 sport the 20" wheels with summer (performance) tires provide excellent traction in warm, dry conditions. I use 19" wheels with winter compound tires from Nov to April in Boston and they provide exceptional traction and a somewhat smoother ride, but not the same cornering capabilities of the 20" wheels with summer tires. Do not even think about using summer performance tires when temp goes below 40 degrees. I will use 19" wheels and winter compound tires on a D4 as well. (Just waiting for the final 2013 engine options and the D4 S8 specs. before making a decision on a D4.)

DRCHA6

I have the 20 inch with summer tires, bought the car in January and to my surprise, had absolutely no problems during several winter snows. Other than slight noise, the GoodYear asymmetrics have been excellent.

JWBLue

Which would be better:

> All season tires on 19 inch rims.

>> Identical all season tires on 20 inch rims.

hupark

The problem is you are not explaining how you want to use the car. 20 inch on the track for better cornering etc. However, you do not want 20 inch rims in the winter if you get any snow/slush. You want a wheel to be able to take "hits" from the road and the 20 inch wheels will get banged up quickly. Also, many people like to under-inflate the tires to get more traction in the snow which is hard to do with 20 inch wheels. For the reasons above, it is hard to find snow tires (the good kind like Nokian) in 20 inch for the A8.

Getting back to my original question. What car do you have and what are you using it for? You don't but an A8/A8L to drive it like a Porsche (not a new one anyways). Most people would also use an SUV if the weather got really tough and leave the A8 at home.