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Rally-cross is similar to autocross in that it is a course delineated by cones and run one contestant at a time, against the clock. This makes it ideal for people looking to enter into motor sport competition without the heavy budget and risk of damage that comes from wheel-to-wheel road racing, or the trees and ditches as found in the performance rally stage. However, it differs from autocross because it’s raced on different surfaces, mainly all dirt, or a combination of dirt and paved surfaces. Rally-cross is run on an open field that often has slight elevation changes and is laid out in a way to limit speeds to approximately 40mph. The most common mishap that occurs on the rally cross course is a rolled tire. Over the course of the day a course can become rutted in tight turns and on occasion cars drifting towards these ruts will pop a tire off the rim. When this happens you can usually get the tire repaired in time to finish the day and make up for the runs that you have missed. Sometimes, however, conditions are less than optimal (such as when it’s getting late in the day and you are losing daylight, or when it’s colder than hell), and you just can’t get the tire to seal onto the rim. These are the times when you want to just call it a day and pull the rally-cross wheels and tires off and put on the street tires on which you drove to the event.

My current rally-cross setup consists of the OEM wheels and a set of Green Diamond Inari snow tires. Depending on which region is running the rally-cross, that setup will leave me in a stock class, or if they put the snow tires in with rally tires, bump me up to a modified class. In either case I am better off running snows than the RE92’s that come stock on the WRX. This is the easiest and most inexpensive way to run a rally-cross dedicated wheel and tire configuration. As I mentioned in the Green Diamond article back in February (link to story), the Green Diamond Inari’s offered a noticeable advantage to the stock RE 92’s on the WRX. It also leaves me with a winter tire setup that will be necessary, considering the street set I have chosen.

For my street setup I wanted to go with a wheel that that was a bit less common than the other WRXs that I have seen around. For that reason I decided that I would also go with an 18” wheel as well, which somewhat narrowed down the choices. After going back and forth between several different manufacturers, I decided to go with SSR and their Competition line, offered exclusively by Tire Rack. Speed Star Racing’s Competition wheels can be seen on the Realtime Acura RSX, the Trans Sport Lexus IS300 as well as several other cars competing in the Speed World Challenge Touring Car Series. One of the features that makes this a popular choice is the extremely light weight of this wheel. The 18x8 inch wheel that we chose weighs 15.2lbs, making it noticeably lighter than most other wheels in its class. With a choice of gold, silver or anthracite and a polished rim, I chose the anthracite for this project, mainly due to its contrast with the sharp looking polished silver rim. The 18” wheel diameter drastically changes the look of the WRX and is a vast improvement over the OEM wheels. The anthracite aluminum valve stems are another nice detail that adds a bit more class.

For rubber, I wanted to go with a dedicated summer tire since I would be able to use the Green Diamond/OEM wheel combo for the nasty Chicago winter driving. Using Tire Rack’s Tire Decision Guide, I was able to narrow the selection down to several options that fit well with the SSR Competitions. In the end, I went with the one that had the best satisfaction rating for the price range for which I had chosen - the 225/40WR18 Bridgestone Potenza RE 750’s. The RE 750 uses an ultra high performance tread compound that enhances dry traction, while the tread pattern is designed to improve handling in wet conditions. The tire’s ability to sweep water away and increase traction on wet roads earned it the industry’s highest “AA” UTQG Traction Rating. The RE750 also utilizes Bridgestone’s UNI-T system of technologies to improve three key factors of performance: the bead, the casing and tread compound. The steel belts are reinforced with spirally wound nylon to provide high-speed durability while keeping weight down and maximizing ride quality. Last but not least, a large ridge on the tire protects the wheel from potential damage from curbs.

After completing my research, I ordered the wheels and tires and arranged to pick them up while at the Rack 1 Rallycross, being held by Rally Cabal, Tire Rack, and the South Bend chapter of the SCCA. When I picked them up that afternoon, I did not have them mounted because I was in the middle of the aforementioned rallycross. Instead, I placed them in my pit area at the event where they were noticed and desired by my fellow rallycrossers, many of whom were amazed at how light they were. At the end of the day I mounted them, and I was pleased with the way they transitioned the entire look of the car. The initial comment from those around was “Boy… they sure make the brakes look small”. That issue will have to wait for the brake portion of this project.

The Bridgestone RE750’s provide a confident feel at high speeds and controllable breakaway characteristics while at the limit. The ride quality can be a bit on the bumpy side at times, but that is to be expected from a tire that has such a low profile. In dry conditions you are aware that the limit is approaching, and they allow the car to slowly slip into a drift without causing you to worry about an extra set of shorts. Even in the rain and on wet roads the RE750’s provide a decent amount of traction, and mixed with Subaru’s All Wheel Drive, give more than enough traction to get you onto the road and quickly up to speed with traffic.

Now that we have worked on improving our WRX’s traction, both on and off the rallycross course, it’s time to focus on the car’s reliability and protection, so that it will be able to withstand the trials through which it will undoubtedly be put.