TopSpeed Motorsports

With the amount of GT-R owners switch over to the Michelin PSS after the stock run flats we decided it was time to get you guys some hard data. We teamed up with Michelin USA and they were kind enough to supply us with several sets of tires for back to back testing. Prior to the stock sizing being released for the GT-R it was very popular to run the 285 square setup for may GT-R owners. Whether the car was full street or street/track many people were seeing great results from this setup.

The purpose of this test was to really see the difference between the stock tire and the PSS. Michelin was very clear with me that the exact results were to be totally public whether good or bad…they wanted the community to have back to back, real world data.

So I went to work, I needed to find a completely stock GT-R (harder than I thought it would be) to use for testing and employ professional driver Leh Keen to give us the back to back driving precision we would need for an accurate test. With all that gathered up we headed for Roebling Road in Savanna to start testing.

The test was performed using three different setups, on the same car, back to back, with the same driver.

Track: Roebling Road Raceway
Car: 2010 GT-R BONE STOCK
Driver: Leh Keen

Setups

#1
Stock Bridgestone Potenza RE70

Sizes:
255/40/20 (F)
285/35/20 ®

#2
Michelin Pilot Super Sport (PSS)

Sizes:

255/40/20 (F)
285/35/20 ®

#3
Michelin Pilot Super Sport (PSS)

285/35/20 (F)

285/35/20 ®

Here is the feedback from driver Leh Keen concerning the three different setups.

Stock Potenza staggered – This obviously is a great tire for dry conditions. It works very well on the GT-R as it was designed specifically for the GT-R. This is a proven setup that the factory has chosen. It is a runflat and has a very stiff sidewall. I know this tire does not last long with normal road use. It is also horrible in the wet and noisy on the road. Compared to the factory sized PSS setup the Potenza was 0.1 seconds slower in lap time. The Potenza did not quite have the overall grip of the staggered PSS but did show more response from the front and better balance although still had a bit of push. The threshold of lateral grip held a bit longer than the PSS but then had a quicker release rate. The sharpness of the front helped with understeer and this gave the car better balance then the staggered PSS. The front would simply respond to inputs better resulting in a better balance in the car. Although the time was 0.1 slower on the PSS, the car was nicer to drive and “felt” better on the factory setup.

PSS Square – This was awesome. This setup “fixed” the understeer that the stock and staggered PSS setups had. The front responded well to steering inputs and had the overall front grip to make the car turn. Although not as sharp as the Potenza the general front grip made up for that. Overall grip increased but only marginal the big difference was the balance. The time was a full 1.0 second quicker using this setup! 80% of that time increase was thanks to the better balance in the car. Actually I would say the car was almost perfectly balanced (for a completely stock car). Slight understeer in lower speed corners with slight oversteer in entry to med and lower speed corners, which is simply a GT-R character trait. It was easier to find the limit of the tire and that resulted in a great overal feeling and confidence. I was very impressed with this setup and was surprised to see how much quicker it was.

Overall we are we were very happy with the performance of the PSS. The tire lasts longer, rides better, and is just as fast or faster than the factory setup. I want to personally thank Michelin for the opportunity to doing this testing for them and look forward to more real world/track research in the future. The new combination that Michelin just released (285/295) will be tested hopefully in the coming weeks. While it may add a little more push to the car we are hoping the increased rear grip will compensate for that and translate into lap times. If for no other reason the 295 simply looks better on the car

Please feel free to ask any questions you may have. I am sure that all of the information you guys need isn’t totally covered in this writeup, but we are here for that. Leh and myself will be answering questions that come up so don’t hesitate. I had the guys put together a little video for the community as well as some pictures….see those below.

We also have a huge stock of all the tested tires. Everything is in the building and ready to ship. So if anyone is looking for a PSS setup please shoot us a PM, email, or just call the shop.

Thanks for the continued support, we hope this writeup aids some of you in your decision making process.

~Team TSM