worker1

Someone on one of the forums changed from the sport contact 6 to MPS4s and had a hard time so bought a pyrometer to measure the temperature of different parts of the tire. His conclusion was that while 38/32 worked well for the continentals, the MPS4S have a stiffer sidewall that bears more weight and the center of the tire was not heating up, indicating under inflation. He ended with 41 front, 35 rear on the Michelins and says they now outperform the Contis. I copy pasted his information in case I need it later but didn't save his username.

DCB1951

It may have been @Dan99 . Those are his tire pressures.

Dan99

Regarding tire pressures, that was my post, but it was specific to an RS5 Sportback. OP has an S5 Coupe.

The best tire pressures will vary with the car, wheels and tires, load, and how it's driven. All things being equal, an S5 Coupe will need different pressures than an RS5 Sportback. Even the RS5 Coupe and Sportback have different recommended pressures. In addition, OP went to the stock tire size for an RS5, but placed them on 10" wheels instead of the stock width of 9.5". So, there are differences in wheel size, wheelbase, and suspension components. It's just necessary to fine-tune pressures when any of these components are changed. While I used a pyrometer to fine tune pressures on my car, the markers on the sidewall can also be used to help find the best pressures for a given situation. My previous posts (both audiworld.com and audizine.com) go into this in detail.

Regarding tramlining, I experienced this just by moving from an S4 (with Michelin PS4S) to an RS5 (with Continental SportContact6 tires). The added tire width just made the RS5 more sensitive to the road surface. I've gotten used to it, but it bothered me at first. However, it might be worth getting an alignment if the tramlining is excessive. My car was a bit squirrelly from the factory and an alignment fixed that.

Regarding wheels, they come in essentially 3 flavors, cast, flow-formed, forged. Flow-formed are sometimes called flow-forged, or the product name contains the word forged even though the wheels are not. While you can spend $2000 or more on a single forged wheel, I purchased a second set of oem forged wheels from the Audi dealer when I got my car, and paid under $4000 for all 4. I was considering BBS-FIR wheels at the time, despite their higher price (~$2600 each), but found some weight ratings that indicated they are probably too light weight for the hazards encountered in daily driving. So, lighter is only better to a point. If you are looking for a competition wheel and have the money to repair or replace ultra light weight wheels as needed, get the lightest wheel possible. But, if you want to minimize repair or replacement costs, don't go to ultra light wheels for the street unless they have a weight rating that is appropriate for the car.