Hello everyone,
I have owned my 08 Grand Prix GXP for several months now (I love it)...Recently it became necessary to buy new tires. Generally the tire buying experience is related to what a person can afford and what kind of performance, tread life, and environmental use a person could expect from their purchase. However, as most of us know, the parameters are somewhat different for the Grand Prix GXP.
First one needs to consider that there is NO spare tire. I looked in my local bone yards for a doughnut type and met with disappointment because I could only find the 17" spare and this WILL NOT clear the front brake calipers on this model vehicle. Bummer, so much for my $5.00 solution. The expense involved for buying a regular wheel and tire varies, avg- $300 as I would not expect to put a piece of garbage on my car(no matter how temporary)...
The other two issues with the regular tire solution are weight and space. 18" tire= around 38 pounds and prepare to lose your trunk. This combo WILL NOT fit the factory wheel well. If this solution is chosen, then the rim width should be 7" and not the 8" width on FRONT ONLY.
So, now I am faced with the fact that this model car rocks two different tire sizes from front to rear. The meaty 255/45-18-55mm offset for the front and the225/50-18-40mm offset for the rear. Most would be tempted to replace the tires with one size, however, this not recommended for a daily driver or an import shredder. These widths and sizes where carefully designed by GM, on a computer in order to make right the inherent torque steer, and inherent under-steer related with this model Pontiac. Unless you have driven a Grand Prix GXP you may or may not fully understand what this would mean. The car is literally a handful under full throttle response and wants to pull left, right, left, right, yea, a straight line is difficult. The tires on the rear need to be the narrower set because the car is nose heavy, under extreme cornering the rear end needs to let go in order to keep your steering, enough said.
Now we are faced with NO SPARE, massive torque steer, heavy under steer, and two different size tires. I purchased the Bridgestone Drive guard, run-flat and added road service to my insurance. The expense was about $180- $300 more than I would have spent on another brand and model. This tire has an A-symmetrical design, this means it can be rotated side to side. Very good traction, quiet, fuel efficient, 50,000 mile tread life, all season, and I can drive 50 mph for 50 miles with no air in any of them.
I can hear the snickering from all the extreme performance junkies, yea it's a freakin Brigestone commercial. No, just a solution to a very real problem. I drive this car 30 miles back and forth to work every day. My goal is to run a high 10, low 11 quarter mile at Bandamere speedway (with of course the appropriate tires on the front),. drive home and retain the overall reliability and economy of this vehicles capabilities. To me, that's how a real car should perform. However, race cars are indeed real cars too!
