Bridgestone Tires - trouble with negative camber?

[rpavlicek]

Does anyone have experience with these tires on the Model S?

Bridgestone Potenza RE970AS Pole Position

Overall the reviews indicate the tire is excellent except I found this:

The Audi dealer regional rep and both tire companies that were authorized Bridgestone dealers indicated that they would not have recommended these tires for the Audi or any other negative-camber aligned car (principally VW and Audi).

...since the model S has negative camber in the rear, this had me worrying.

 

[simplesolar]

no tire can be recommended from manufacturer with negative camber aligned cars. They will all wear unevenly due to the setup. What you can do is get non-assmetrical tires so you can swap the directions and balance the wear.

 

[gtimbers]

Your energy usage will go up with the Bridgestone RE970's. Look at the TireRack test data on that tire. It may cost you as much as 5% over the stock Goodyear tires. You now have an option of the Michelin Pilot A/S3. There is a brand new comparison test on Tirerack indicating that this tire is really good also. It is several percent more efficient than the RE970. I have about 1200 miles on a set and they perform incredibly well. I am showing about a 1%- 2% range loss so far, although the weather got hot at about the same time as I got the new tires.

 

[mgemmell]

Interesting negative camber comments... I put Bridgestones on my Roadster on Monday and had them replaced today with Mitchelins as I was finding the car impossible to control properly. It just wouldn't go in a straight line. It would rock one side and then the other... rocking to the left made it turn to the right and vice-versa.

The sidewall of the Bridgestones is very stiff... may have something to do with it, but either way, I cannot recommend them for the Roadster. The model S has 2k kms on the clock so no new tyres yet

 

[jerry33]

Interesting negative camber comments... I put Bridgestones on my Roadster on Monday and had them replaced today with Mitchelins as I was finding the car impossible to control properly. It just wouldn't go in a straight line. It would rock one side and then the other... rocking to the left made it turn to the right and vice-versa.

I wonder if the loaded radius is lower on the Bridgestones? Reducing the loaded radius (distance between the center of the hub and the ground) reduces the trailing distance of caster* and can cause that kind of behaviour.

* Although caster is measured and set as an angle, the angle doesn't really mean a whole lot. What caster really is, is the distance from a vertical line through the center of the hub (at ground level) to the spot where a line drawn through the ball joints intersects with the ground. Because the distance is measured along the ground, loaded radius has a lot to do with caster's trailing distance. Too little caster makes the car unstable, too much causes the wheels to shimmy back and forth (like a bad shopping cart's wheel).