Thread: Need some help with a 08 GXP

Just bought an 08 GXP from Carmax with 24K. The front tires have been replaced with Kuhmo Ecsta ASX in 255/45R18. The rears are OEM Potenzas and in need of replacement soon. The ASX tires are rated as Ultra High Performance All-Season by Tire Rack and get pretty good reviews. Unfortunately, they are not available in 225/50R18. I have several choices that do not include spending big coin. First, I can put on Kuhmo Ecsta LX Platinum in the proper size. Second, I can put on a pair of ASX in a size very close to the original such as 235/40R18. I'd appreciate your input.
Keith

Originally Posted by Bio248

get the 235s in the back so your car doesnt look so funny. i actually hate the staggered offsets they put on that car.

believe it or not it actually helps that car handle. that car is everything the 97-03 should have been, brakes are great, ride is nice, it actually handles well too. too bad i find them hideous

This is the third car I've bought from Carmax so on a hunch I them about the tire situation. I explained I was not happy with the tires and asked what they could do to help me out. Today I was told they ordered a new set of Kumho LX Platinum tires in the correct sizes and are charging me only what the tires cost them. They are even mounting them for free. I'm saving over $250 on a new set of tires. Now that's customer service I can be happy with.
Keith

you learn something noew everyday, did not realize the gxp had two diff offsets. what are the offsets just out of curiosity

Originally Posted by echarleswhyte

you learn something noew everyday, did not realize the gxp had two diff offsets. what are the offsets just out of curiosity

255/45-18 front, 225/50-18 rear

The GXP model is 64/36 percent nose heavy. As a result the front tires can't transmit steering inputs as well, on top of that they also have to transmit power to the pavement and end up being overwhelmed with the multiple assignments. The final result is ridiculous understeer. Pontiac's solution was to put more rubber up front then in the rear. With all this said if you want to lose handling performance for a better look, put the same size in the rear, if not go with the recommended size.

kewl interesting to know. i guess i will abandon the idea of getting gxp wheels for my reg gp. ooooo well

Yesterday, I had Carmax install a set of Kumho LX Platinum tires on my '08 GXP. They ordered them for me at their cost and installed them for free. My total cost was $643 for a set of four installed and balanced. Prior to Carmax agreeing to my request the best price I had found was TireRack at $706 delivered but not installed.

The difference in how the car drives is significant. When I bought the car it wore Kuhmo Ecsta ASX in 255/45R18 on the front and OEM Potenzas on the rear. While the front ASXs were new the rears were in need of replacement. Frankly, the car drove like crap. In particular it had an odd reaction when it went over sharp bumps...the rear would sidestep to the right. Now, it has none of that. The suspension feels more compliant and planted and the handling is crisp and sure footed.

The only issue I have now with the car is a slight loose feel through the steering wheel as if a engine cradle mount is loose or a dogbone is worn. With only 25K on the car I doubt either is the cause but I'm going to have it diagnosed in any case. I'd like to hear from anyone with similar issues with their '04-'08 Grand Prix, especially GTPs and GXPs

By the way, thanks for your comments and input. I found the discussion helpful.

Keith