So I have these new tires. I warmed them up and then took them on my favorite set of twisties to test them out.

First thing I notice is that under highspeed turning they tend to feel a little "hairy". Like the tread blocks are twisting. The car doesn't break loose and I am not getting any noticable tire growl or squeel. It just requires a lot more finesse in the handling in the high speed turns.

The bigger issue is the braking.

What is happening is when pulling down hard from 70mph+ the rear end tends to shift out towards the drivers side. Not serverly, might not even notice it from the outside, but the feeling in the car-you totally feel it. The ABS/VDC never really trips either and the car stops rather quickly. It just does it sloppy from high speed.

So what would cause that? Any tire pros out there know?

My other question would be that my old stock Potenza's when inflated and warmed up in the summer heat, their PSI was around 42-44. These new ones are 35 max. I am wondering if maybe they are under inflated and this is my entire issue?

Thanks.

 

Underinflated could be an issue, check them when they are cold they should be 35 then. Also what kind of tire did you go with and did you change the sizes? Some tires have softer sidewalls and will flex more under load giving you that floaty feeling.

 

I went with a firmer sidewall actually and the stock sizes, the BFG KDW2's. Now I know it's not the first choice for an all weather high performance tire. But for the price and limited selection my stock wheels give me, it was the best thing.

As for straight line grip and medium speed turn-ins they are darn sticky. I will check the tire PSI tonight. They should be under 35psi, cold, since they were 35psi hot. I'm right in thinking, hot, they should be around 40psi?

 

They were brand new ? Not broken in yet ?

It takes between 100 and 200 miles to get rid of the demolding agent. Before that, you're basicaly driving on Armor All

Heat cycling will also improve the tires performance.

How much fuel did you have aboard ?

Grippier tires will allow you to get a lot more front weight transfer. Lightening the rear and increasing the tendencie to oversteer.

 

Okay cool, was wondering about that as well, any factory coatings and crap.

With my sway bars the car already tends to oversteer more than stock (which is good) so if the tires contribute to this even more, cool. Take some more getting used to, but of course it's always more fun!

Also, I had a little under half a tank.

 

To add to the possibilities stated above, if it always swirls to the drivers side I would check your left front brake.

 

But would a tire change reveal bad brakes? All that changed was the tires. That's when this started happening.

Thanks for the tip though.

 

I'm running the same tires, I think the same sizes. I also have a SmarTire monitoring system. At 70F, the KDW2 will heat up to about 120F. Oddly enough, if the road it crowning badly, the high side tires hit about 128F or more. They also spike a good 10F with a long sweeper. They heat up and cool down quickly. Not sure if thats good or not, but I've heard they arent a good AutoX tire because they will overheat and wear prematurely. I havent seen this, even with some hard driving in the mountains.

As for braking, I cant say I've seen that but if conditions permit, I'll scrub some brake pad and see what a hard stop does. At 1200 miles, I think I've done a few and dont recall any pulling.

I do know one thing, they didnt mount up right the first time. The bead didnt sit right on the rim. The tire shop had to try twice. I could see the slight wobble This was only the 245s. The 225 bead fine. Anyway, the Hunter machine saw there was a problem and we got it beaded right. No problems after that.

Will let you know if I can duplicate your issue.

 

You are right, normally it shouldn't make any difference but maybe something happened when they put on the wheel

 

What was the pavements conditions when you experience the car becoming loose?

Where there slight ripples? I hadn’t noticed your mods on my previous post. What stiffness setting are you using on your rear sway-bar? Can you go softer? If the pavement was uneven and the rear sway-bars was pretty stiff, the rear wheels might have been literally skipping on the pavement (live axle effect from to much wheel travel transmitted to the opposing wheel via the sway bar).

Try running a bit softer rear sway bar setting and reproduce the same condition. It might help to stabilize the car.

 

I have the exact problem with the KDW2. My thread is down a couple spots in this section.

I have heard about the bad mount several times with these tires. Can you see it by looking at the tire? How would you know if they are correct?

THANKS,

Dan

 

well, the first time the tire shop sent me out with the wobble and I could see it and hear it..

You can see it here
http://www.timware.org/g/freakinBFG.wmv

I came back in and they remounted.. no good. Then they used *alittle* wd40 on the bead and it settled in properly when they aired it up. Again, this was only the 245's.

 

The fronts are set to the soft setting (still firmer than stock) and the rear is in the middle or medium position. The rear has three levels. (remember I love oversteer)

I set the tires to 35psi today when they were cold (they were at 29!). Warmed them up and they got to 37psi, rears hit 38psi for a bit. It was only 70 degrees today and I didn't get to run as hard. However I already noticed an improvement.

I am going to check the mount of the tire tonight. I will look around the rim closely to see if I can see any deviations.

Thanks again.

 

you know, I totally forgot I had asked my AutoX friends about the rear getting loose last month. Its not in straight line stopping, but when taking an off ramp and moderate brake, I was getting some squirm too. It was a bit unsettling the first time I felt it. Once you feel it, you tend to drive around it, outside that range.. I had forgotten about it.. But I may be also experiencing some odd behavior. I guess that makes 3. I've been running up to 38 psi and more recently 36.