Yes, I finally did it, I swapped my Potenza RFTs (OEM) for Michelin Pilot Sport PS2 non-RFTs. The result? Its a lot smoother and quiet now. It really does change the character of my sports package car. You still have some of the stiffness from the suspension but its not nearly has harsh over less than perfect roads.

I definitely noticed some changes in the handling as well. There is more dead center feel than before. I remember with the RFT's it was razor sharp steering (sometimes resulting in twitchiness on the freeways).

Also at the cornering limit, the car is not as sharp as before either (at least thats my initial impression). I have a section of road close to my house with a 180 degree freeway ramp that I tried a few times before swapping tires. With the PS2 tires on, there seems to be more body roll on that corner and the back end seems to step out a little. Keep in mind this is going very fast around that corner, anything less than extreme and the reflexes are still sharp.

When I installed the new tires I did not get any low tire pressure warnings, so I didn't reset the tire pressure monitor system. Should I still reset it? Also what about tire pressure? The tire shop inflated it to the door jam spec, which I think is like 29psi in front and 36psi in rear.

I noticed that the car feels like its going a lot slower than the speedometer is indicating! I thought maybe it was inaccurate because of some tire size issue but when I was driving by one of those 'Your Speed Is:" signs it was accurate, I might check the speed with an after market GPS just to make sure The new tires are 245/40 18 inch all around so I'm assuming its the right size. The Load factor is 93Y.

 

If your tire size is as replaced the only difference would be the slight increase in rolling radius for new tires. Maybe it's the quieter and smoother ride that makes you think you're going slower ?? Check it with GPS or a timed run through a marked mile to be sure.

As for reset of your TPMS - definitely check the inflation pressures of your new tires and do a quick reset. Just to be sure!

 

Great tire choice. Put about 35-36 psi all the way around and then see what you think. Then play around with the psi as you see fit. 29 psi in front will make turning sluggish. Also, keep in mind that new tread is deep and soft, thus has a tendancy to fold or "wiggle" a bit when new. Some guys go so far as to have their tires shaved to avoid this. Believe me, over time you will love these tires compared with RFTs.

 

Don't forget that new tires need some break in miles on them before they have full traction. The non-RF's are superior especially PS2's. It's my next tire. I'd have them now but I'm probably upsizing to 19's. Slumming with the RF's for now.

 

Yes I definitely do feel the "wiggle". Interesting point about the front tire pressure, I'll give it try! Maybe that will stiffen up the steering feel.

 

Congrats, I actually would try running 42 in the rear and 36-38 in the fronts. Since you lost the run-flats with ultra stiff side-walls, you will want to increase the tire pressure from that recomended on OEM since that takes into account the run flats. A higher pressure will stiffen the side-walls up and increase performance on corners/turning. Run-flats are heavy and have downsides but their stiff side-walls are a great performance feature, hence them being placed as OEM on sports packages

 

+1 .. the PS2 (prob. the best performance tire out there) does need some break in (esp. the tire edges) ... approx. 50-100 miles (if I'm right) AND they need to reach optimum temperature before they bring out their true performance potential. Give it a little time and go easy on the maneuvers ... you don't want to be slipping out. Gradually break 'em in and THEN .. give it a whirl. You should be amazed.

Also NOTE that Bridgestone did make a few revisions to the run-flat tires over the years since they were first introduced. The Turanzas were the ones that REALLY SUCKED. The Potenzas were deemed OK by a lot of magazine reviews (of course PS2 is still the king ... but may not be by too much as once thought).

 

The 35-36 psi you are suggesting, is that ok for a staggerd set-up?

Thanks.

 

Yes, that's (36psi) what I'm running on my 245/275 staggered 124s. These cars are pretty close to a 50/50 balance, so not much need to soften the front. Again, tastes vary, some go a little higher, some lower depending on comfort/cornering needs or preferences. Some guys run 40 psi (usually on 19s or 20s) citing that the higher pressure will blow out the low aspect ratio sidewall and save the wheel. My tires are more expensive than my wheels probably, plus 40 psi feels like I'm riding on rocks. But again, it's a personal choice.

 

I am riding 35 to 36 psi on all 167m wheels (19 inch).