After 30,000 Km I had to replace tires, after much research, decided to go with BF Goodrich G Force. Realy nice looking tires, I even went 235/40 front and 255/40 rear on 18 inch rims. Recently I have noticed that in tight turns at agressive speed the front end doesn't seem to stick or track as well as the stock tires (pilots), now the rubber doesn't brake grip or anything, but the front end just seems to "float" around the corner as opposed to the stock tires that gived me a feeling of control and grip. Is this because the sizes are off and the car has been lowered due to the 40 vs 45, and does this interfere with the traction and VDC stability of the original computer settings??.

 

I just replaced my worn-out Pilot Sports with a set of Avon Tech's (same size as originals). The reviews on tirerack.com for the Avons is very positive. I was especially interested in getting some quieter tires. The lower price was attractive too.

Anyway, the new tires are a lot quieter than the Pilot Sports, but they sure don't handle as well. Going around corners, the car seems to float a bit, just as you describe. I believe this is due to a softer sidewall, or the fact they're an all-season tire, rather than high-perf summer. Since I don't usually drive my G too hard, the lower-perf tires don't bother me too much, but I'll probably try another brand next time.

So, there could be reasons for the change in "feel" other than the tire's size.

-Brian

 

I can see significant change in your "all-season" tires, but my G-Force is a High End performance tire.

 

The size change could be causing the change in feeling. The larger rears are going to increase understeer, which will give the feeling that the fronts are "giving up" before the rears. That might be the "floating" you describe, although I would call it more of a "pushing front end". This feeling can happen as early as 7/10's, since you have changed the balance of your car in cornering. It will also make it harder to induce power oversteer by applying the throttle.

 

If one put the same size tire on the front "255" would that fix the problem and bring back steer/road feel?

 

Xthecat how many miles do you have on your tires?? Do you like them beside the sterrring problem you are having. The reason I ask is my car is getting the same tires you have tonight and I can't wait to get them on. I will give yo an update on how my car feels with them on. I also got the 40 series tires.

 

It's hard to beat the pilot sports. How many miles do you have on them? For the first few hundred miles the tires won't have maximum traction.

 

Do you realize that you are decreasing the diameter of you tires by over a 1/2".

 

I don't really think it will be that much of a difference in size. I would understand if I would be bring my car to a road course but this is for the street. I don't thing 5mm in size is going to make that big of a difference. Am I missing something?

 

The G-Force tires are really nice (I'm not a company rep), they look great and also "lower" the car. As mentioned in other threads going up that one size is perfectly OK with the stock rims, but also the downside is that the car doesn't track as well taking corners agressively (floats), also mentioned and explained in this tread. I have had my car since Oct 02, and only have 32K Kilometers on it, not much driving, and about 2K on the new tires. Overall I guess its stock tire Performance vs replacement estetics. I'm sure that ALL the custom body upgrades that people put on their G's also have an effect on overall dynamics and performance of the car as well.

 

Actually the front is 14.5mm smaller dia. and the rear is 16.5mm smaller dia. It will throw the speedo off some and the VDC is sensitive so you may have problems there.

 

Which model of gForce tires did you get? There are several different tires of varying performance. Only the KD and KDW come close to the Pilot Sports' performance, but still not as good, I've heard.

A lot of people put 245/40-18's on the fronts and keep the stock rear size. This helps to reduce understeer.

 

Just talked to my cousin who owns the shop that is putting on the tires. He said they exact same thing you did. He just measured them and he said I will possibly have problems with the VDC. I can hold off on putting the G-forces on but once I mount them I have bought them no test drives.

 

BFGoodrich g-Force T/AŽ KDW NT Tires. (Cool thread design). What do you mean "problems with the VDC?" does it not engage as soon or missreads?. Only about 1,5K.