For wheels (see the Centerlock Wheel Buyers Guide, ec September 2010, for a range of choices), I selected a set of custom Forgeline wheels for three main reasons: the many available style and color choices, strength, and price-point. All Forgeline three-piece wheels are custom made to order, utilize forged 6061 T6 centers, forged 6061 T6 spun rim halves, and stainless steel aircraft-grade fasteners.
Forgeline's strength and durability testing begins at the design stage using advanced computer stress analysis to test each new design under a simulated load and optimize it before machining ever begins. The test wheels are physically tested beyond SAE standards, and real-life racing variables are used for such test criteria. The finished 19-inch wheel set for Project T-Rex weigh in at about 23.5 pounds (8.5x19) and 26.5 pounds (12x19), for the front and rear wheels, respectively. This saves about 3.5 pounds per corner in the rear, but gains about 0.4-pound per wheel up front. I selected the 10-spoke Performance Series ZX3S with matte titanium centers, the hidden wheel fastener option (note that this adds about a pound to each wheel over the standard exposed fasteners), and a brushed aluminum rim for an very understated, high-tech look.
8.5x19 and 23.5 pounds in front, 12x19 and 26.5 pounds in the rear.
With the new wheels and tires mounted up, the 2010 GT3 looks spectacular; much less "blingy" than the OEM setup, yet plenty purposeful and mean. I was able to scrub and sufficiently heat cycle the R888s on two separate occasions before lap testing began. Fortunately, the weather for the test day was sunny and dry, and I was able to collect some new data with the Traqmate GPS. The car felt surefooted and fast, and I also perceived less understeer in the slower corners thanks to the tight tread blocks and sticky rubber of the R888s.
These were paired with Toyo Proxes R888 R-compound rubber.
However, I did notice that I was having trouble with grip in Turn 6, a very fast left-hand sweeper. Had it gotten more slippery since initial testing earlier in the season? Was I not driving it the same way or was I now lacking in guts or confidence? I couldn't say; all I did know was that my lap times, still in the 1:24s, were still not what I was hoping or looking for. After a week of analyzing the data and thinking about the results, I ruled out my initial thoughts regarding worn tires, as the new Toyos should work better on dry pavement than the OEM Pirellis, and I also ruled out "driver issues" (i.e., me) by having my racecar driver buddy, Steven "The Bloke" Tory, drive the car with similar results. The conclusion, then, was simple: Something had to be wrong.
Next time, we'll solve the problem and get back on the track to fully demonstrate the quality of the upgrades for this project car. Look out-this GT3 is gonna fly.