|Project Audi S4: Wheels & Tires
As covered in the introductory article, the stock tires on our Audi S4 were identified early-on as a glaring deficiency in what has otherwise proven to be a very capable performance vehicle. While clearly intended as reasonable all-weather solution, we found the Bridgestone RE040 tires to be merely adequate when the car was pushed during high acceleration cornering or quick lane changes.
Of greater concern was the inability of these tires to provide comfortable road handling and feedback in wet-weather conditions. More than once we experienced what could only be described as a relatively "slick" feeling on wet surfaces. Whether simply psychological or result of the tire design, the tires had to be upgraded.
Buying new tires meant the opportunity to also upgrade the wheels. In Vancouver, as is generally the case in most areas, S4's are most prevalent in Light Silver Metallic. While we are big fans of the stock 6-spoke Avus wheels, we wanted to explore a more unique look for this car that would help it stand out from the crowd.
18 x 8 Mille Miglia Action Sport Wheels
With the underlying intent of maintaining "everyday driver" feel in this car, going with an 18-inch wheel was not a forgone conclusion. For one thing, larger wheels utilize a smaller tire sidewall width in order to maintain (at least closely) stock rolling diameter. Unfortunately, because of the small amount of sidewall flex available, it is much easier to damage low profile tires when driving over road hazards and curbs. Ride quality can also diminish.
Additionally, larger wheels generally weigh more, which in turn affects acceleration and handling. We calculated the weight of the Mille Miglia Action Sport Wheels to be 26.5 lbs., which is definitely on the high end of the range we hoped to stay within. [Editor's Note (7/9/01): Our weighing methodology involved an old digital scale. We are now hearing the wheel is actually 22.5-23 lbs.]
However, already feeling quite comfortable with our S4's performance ability, and knowing full well that the car would not be spending time at the track, we decided to focus on form over function. The cosmetic upgrade was judged to outweigh, almost literally, any minor giveaways in ride comfort or performance.
With that decision made, the overriding factors for selecting a wheel were design and price. We were concerned that a wheel with an 8.5" width (many 18" wheels are 18 x 8.5) would not only look slightly too wide for the wheel wells, but would end up throwing debris onto the side of the car. For this reason, the search was refined to include only 18 x 8 wheels. We also set an upper price limit of $349 per wheel.
The sizing and pricing requirements immediately excluded high-end offerings from Fikse, BBS, SSR and HRE. We considered the BBS-looking AT Italia Flash wheel, but opted instead for the Mille Miglia Action design with its considerably more "open" look.
This choice was further solidified by the Sport version of the wheel painted in what Mille Miglia calls Bright Satin Silver paint. Truth be told, the color is actually closer to a metallic titanium/gray. Perfectly suited to camouflage ever-present Audi brake dust, the wheels are simply stunning on the silver S4, be it parked or on the move.
225/40ZR18 Bridgestone Potenza S-03 Pole Position Tires
Larger wheels certainly modify the look of the car, but, as described above, do little to improve the way the car actually handles. Considering the lackluster performance of the stock tires, there was little doubt that we could improve handling through upgraded rubber. Anything, it seemed, would be better.
The final tire selection turned out to exceed our expectations by leaps and bounds. For months AudiWorld readers have used the discussion forums to sing the praises of Bridgestone's Potenza S-02 Pole Position tires. Widely regarded as the best price/performance tire in a group that includes the Pirelli P-Zero Rosso and Michelin Pilot Sport, we were excited to have the opportunity to test Bridgestone's latest technological marvel.
The Potenza S-03 Pole Position is a max performance "summer" tire utilizing Bridgestone's F1 tire technology. We use the word summer in quotes because the tire has been designed to maximize both dry and wet traction without abandoning comfort and wear. High performance sticky rubber normally suffers greatly on wet roads, while lasting, at best, one summer season. These typical qualities were undesirable for the car since rain is a semi-permanent fixture in Vancouver, where Project S4 calls home, and our budget would not allow for new tires every 6-9 months.
Further technical information regarding the S-03's, including the UNI-TAQ II Technology, is available through Tirerack's website.
The mandate for this Project Car was to maintain drivability. Our intent was to modify the look and performance of the car only to the extent that it did not begin to feel like a track car. The wheel and tire upgrade - the very first upgrade on the car to be covered - has perhaps pushed these guidelines already. On the bumpy city streets of Vancouver there is a slight to moderate deterioration in ride quality (attributed to the low profile tires), although there is no perceptible deterioration in ride quality on the highway.
The sacrificed ride quality is more than compensated for by the performance of the S-03's. Although we have no empirical data to present regarding the tires, the "seat of the pants" test results in very favorable feedback in both high speed cornering and stopping distances. Sweeping ramps onto or off of the highway become thrill-inducing high-speed maneuvers; twisty roads are greedily sought after.
Further behind-the-wheel feedback on the wheel/tire combo came to us one afternoon during a spirited drive up the canyon from Vancouver to Whistler while following a friend's Porsche 911 Carrera 4 Coupe. Just two months earlier, the same drive made us feel tentative on the corners. With the new wheels and tires on the car we suddenly felt a whole lot more competitive, although we still tip our hats to the Porsche.
From a cosmetic perspective Project S4 has clearly adopted a more aggressive look. Since many newer cars now utilize 17-inch wheels, the 18-inch wheel makes a clear statement that the car is not like every other S4 on the road. The alluring color contrast between the Action Sport wheels and Light Silver Metallic exterior is also good for many double takes in parking lots and from other drivers in traffic.
The wheel/tire upgrade for Project S4 represents just one of many possible paths we could have chosen. Wheel designs and preferences are clearly unique among individual owners and, to a large extent, make a statement (be it refined, understated, aggressive or outrageous) about the owner.
We accepted the higher cost of 18" wheels and tires and a slight performance hindrance because the "look" was important to us. Each owner has to make that decision for him/herself.
Up Next . . .
Savvy readers will note from the pictures that additional modifications have already been made to Project Audi S4. Stay tuned for future installments covering exhaust, suspension and interior upgrades.