RS4208250

So I was at the track this weekend for 2 day event. Had 4 new Pilot Sport Cups on the car. Cold pressures initially 34 front and rear. Hot about 41 front and 39 rear. At VIR there are many high speed hard right turns and the left front always gets loaded significantly more than the right. After first two sessions one could see some wear pattern at sidewall (my P zeros did this also). Constantly checked pressures immediately after run and befor going back out. The grip was MUCH better than the P's, however improved after lowering psi to about 37 hot front and rear. Apparently ideal grip for the Cups is between 32-36 hot. Times and feel improved, and I thought that with the 'sidewall' wear pattern and the weight of the car, putting more air in (to 37) was a good idea. At the end of the last run on Sunday, the cords were showing at the junction of the sidewall and footprint. This with new tires! Naturally my Porshce buddies suggested I need a different car. It is a great tire, but with this car who knows? The only solution I can think of is better suspension, and adding some negative camber. Can this be done on the stock suspension--anybody know? I think the pressures were about right; this car with the Quattro pulls so hard with the fronts as you are coming out of a corner, that I could feel the fronts spinning a bit past the limit of grip--and I think the tread wore down. Any thoughts?

Bob W.

if you want a DOT competition tire that is appropriately rated for the RS4 (in stock tire size), there's only one choice: Pirelli Corsa. I wouldn't expect cups to last long on a tracked RS4.

RS4208250

On Tirerack I didn't find a stock size for the P Corsa or P Corsa System. The load rating for RS4 is 1565 for each tire, and unless you get up to much wider non-stock size tires, every tire has a lower load rating (Bridgestone REO1R included). Most guys here think the lower load rating should not be much of an issue. Maybe the answere is adding more negative camber?

Ubercar

I use mine only at the track. I have 10 track days on my Sport Cups and they still have some usable life remaining. Before I got the suspension right and was careful about rotating them from event to event, I did abuse one of them. I have the Stasis Motorsport suspension and H-Sport sway bars, however, with some negative camber.

The Porsche boys run them extensively and I learned as well that the tires run on lower pressure.

As to load rating, I do not think that should be a major factor.

KarlBlomquist

I've used Pilot Sport Cups (PSC) on my M Coupe (essentially a track car) for many years.

A few points about the tires and the RS4...

First as you noticed later on in your day, the PSC's ideal hot temp is in the mid 30's. Any higher and you overheat the tire, slowly turn it to grease and the rubber happily starts to melt away under the stresses of a heavy car like the RS4.

Next, esp on AWD cars..., rotate the tires frequently to get max life out of them. You should rotate front to back and also left to right. Most tracks are hardest on the front driver's tire so you want to rotate such that you're putting even wear/stress on all tires over the course of a day. On an AWD car I'll typically rotate my tires back/front side/side 2x over each day. You'll want to invest in a lightweight alum hyd. jack and a decent cordless impact drive to speed this process up.

The two steps above will help you get the most out of any tire, not just the PSC. You could add other enhancements like front camber plates, etc., and this would be a small increment in your tire life (and turn-in perf.), but depending on how often you plan to track the car it may not be worth it.

Finally, and this is just my opinion, others may differ, the RS4 is not a very good track car. It's far too heavy and even though Audi has done a tremendous job balancing the car with its engine hanging over the nose, you're still fighting the car's desire to go straight every time you hit a turn... it is the phenomenal traction system and decent suspension that help this car to be turned into a turn as well as it does, but the weight of this car coupled with the front end imbalance makes turn-in and maintaining traction awfully hard on tires... it's hard on brakes too once you start getting up serious speed and start braking hard and deep into corners.

I took my RS4 out a couple of times for kicks to see what it's like on the track, it was fun, but I certainly felt heavy out there. :-) If you have no desire to own a 2nd lighter car more suitable for track, then it's still a blast to take the RS4 out for sure, but no matter what, it's going to cost you in tires and brakes.

Unfortunately, after flogging my '01 M Coupe around tracks for 7 years, this Sept I put it into a wall and trashed it... :-( so sad. But... I had purchased an '07 Sti Limited back in May, so I put a bunch of upgrades on that car so I could have a decent setup for track for the remainder of the year. THAT car, with the AWD and approx 3100lbs weight, with an experienced driver, kicks some serious a$$ around the track!! What a blast! The only problem is the AWD is starting to make me a lazy driver because it's just so forgiving... I could not get away with 1/2 the stuff in my M Coupe as I can with this Sti.

Have fun on the track... and stay away from the walls! :-)

Cheers, Karl

Bob W.

Pirelli definitely makes them in stock size....it's an OEM tire for the RS4 in Europe. evidently they can be difficult to find, however.

<a href="http://www.pirellityre.com/web/catalog/car-suv-van/catalogo_sizerange.page?categoria=/catalog/car-suv-van/car/summer&uri=/pirellityre/en_IT/browser/xml/catalog/car-suv-van/CAR_FITM_PzeroCorsaSystem_SUM.xml&prodotto=1558&ve hicleType=CAR-SUV-VAN">here</a> is Pirelli's website, which clearly shows the Corsa available in 255/35ZR-19.

All Wheel Driver

Driving style can make the tirewear worse also.
If you are carrying a little too much speed into turns, you may be scrubbing the tires due to understeer. This will give you wear in the place you described.

mkaenel

what about the "Corsa System".

Also, how would you go about fixing the front camber on these cars?

Thanks

RS4208250

All good points. Yes there is always some understeer given the weight and balance of the car, but I was tossing the car around a bit and some wear could also be seen on the rears by the end of the weekend. Trail braking helps a bit to rotate the car. Only the left front was corded. Good idea about rotating the tires (guess you try to wait about an hour before changing and re-torquing so that things can cool down?).

Very true about the car being hard on brakes; I've done 6-7 events with the RS4 and am on the third set of front pads, with the originals on the back--

One of my guys suggested (via Stasis) lowering the car which adds a little negative camber. Apparently no one makes camber plates for the car?? Anyone know anything different??

So, my plan might be the following; a. lower the car via the shocks, b. rotate the tires during the event, c. try the Pirelli Corsa as suggested by Bob below (or the Corsa System, Bob?), d. beef up the suspension/sway bars, or e. buy a 30K, 2500lb track car?????

RS4208250

Is it from the Motorsport suspension or the H-Sport sway bars, or the combination of both? Is there any other way to get some camber adjustment for this car?