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The GT Radial Champiro SX2 (left) offers a quite different asymmetrical design similar to that of the Bridgestone RE-11A (right) except the larger contact block is on the inside vs the outside. (Both wheel are face up in this photo)Loading up the GT Radials in the CRV we went to visit my good friend and last years codriver of Project Autocross BRZ, Lance Keeley. He has recently become my go to local tire mounting guy (kinda what happens when he is super close and is willing to take extra care during the mounting /balancing process). Mounting went smooth we did not notice anything abnormal during the process. We did however notice that once the Champiro SX2 was mounted on the 17×9 Enkei RPF1’s and aired up they appear to be slightly wider (roughly ¼ on an inch) than the Bridgestone RE-11A’s in the same 245-40-17 size they replaced. Will wider be better?
After loading up the tires and wheels back into the CRV it was time to head home to bolt them on for initial impressions. Bolting on the Enkeis clad in the new GT Radial Champiro SX2 was a short 15 minute cakewalk of course. Prior to leaving the garage we set the pressures to 28 psi on all four, which has become my go to tire pressure on the BRZ. leaving the garage in the BRZ for the 1st street scrub in though was what I was really looking forward to. Warming the car up on the way to some twisty backroads my initial impressions of the Champiro SX2 had been very good. Tire noise was almost non existent, grip leaving the light once the mold release came off was excellent and the cornering proved to be on par with other top tier tires on the market (Hankook RS3 v2, Dunlop ZII, Bridgestone RE-11A). The spirited country road drive did the job to wear off the the mold release and also allowed me to get some seat time and impressions of the Champiro SX2 which I looked forward to actually getting it on course.
The first actual on course experience with the Champiro SX2 took place at our local event site Miller Park in Milwaukee WI. I was able to get some time on a Saturday to use a standard course setup that we use every year for our local Solo drivers school. Here is where the rubber meets the asphalt, this is where we can see how the SX2 will do. The first few runs on the tires putting in a hard scrub felt really good. I decided it was time to inspect the tires and let the tires cool down a bit for a more solid baseline. Upon that inspection I found that the tire had very little wear to them, while that is great for a street tire it does not always bode well for an autocross tire. Deciding to get them back on course and really start to push them was not even a question in my mind. I ran the SX2 pushing it to its limits and beyond. While the times weren’t really showing me what I wanted to see the tires still felt great, they really did well beyond the adhesion level in full drift mode form. The times were consistent of the previous generation tires such as Hankook RS3 v2, Dunlop ZII, Bridgestone RE-11A. With that said though they were no match for the current generation Bridgestone RE-71R, which was roughly .7 of a second faster on a short 26 second course.
Putting the Champiro SX2 tires to the highway test through our least favorite city, Chicago, on the way to Toledo OH.
As an autocross tire the SX2 may have come just a year too late to be at the top. I have not given up on the SX2 though as they have been a great street tire. I have since initial testing put roughly 4k miles on them with a kinda aggressive alignment (-3.4 camber up front). The tire tread noise is still barely audible, no odd wear patterns or aggressive wear characteristics either.
The next long haul for the SX2’s on the BRZ was going to be a 5hr drive to Toledo Ohio for the SCCA ProSolo being held at the Toledo Express Airport. It did also just so happen to look as if the weather was going to be wet for the weekend too. (For those of you not familiar with the ProSolo Format think of it as a drag race into mirror imaged autocross courses and each heat you will take 4 runs back to back, 2 runs per side alternating sides). Honestly in all the miles I have put on the SX2’s none have really been in the wet. That said GT Radial does say that this tire is designed to perform above average in the wet weather department.
Can we say really wet?
