[sr71bb]

On Standard 2019 SS2 I was running Michelin Sport 4S 285 35 20 tires on the stock SS rim 20 x 9.5 on the rears (total weight 55.8 pounds with TPS installed) and 245 40 20 MS 4S tires on the stock SS rim 20 x 8.5 on the front 55 pounds with TPS installed.

THEN after SG3 suspension, 1LE sway bars and ZL1 brakes I switched to a SQUARE setup APEX SM-10 ET22 19 x 10.5 wheels wrapped in MS 4S 305 30 19 tires weighing in at 53.4 pounds each. Overall diameter dropped to 26.2 inches effectively lowering the car .85 inches to the ground (compared to 285 35 20). I have used this setup for BOTH track and street use. I desired NEUTRAL handling and that's what I got. I have run this SAME set of tires and wheels for about 20K miles with 15 or so track days and I am JUST NOW replacing the tires on the rear which are at 2/32nds from a starting point of 9.5/32. The fronts are still around 5/32nds. I DO rotate the tires but i would suggest a rotation every 2000 miles or so because I rotated them every 5K miles or so.

For BOTH track use and street use, I ran -2.0 degrees camber on the rear. I ran -3.6 degrees camber using VORSHLAG Camber Plates on the FRONT at the track and then I would adjust to -2.2 degrees camber for my street setting. THIS change would only take about 10 minutes at the track.

The tire wear is completely EVEN across the face of the thread so I was pleased with that. For a 300TW tire this tire handled EXTREMELY well at 30 pounds cold pressure. There is NO BETTTER tire in the rain as I had the chance to do a track event while it was raining and of course on the street occasionally. i will say that the ONLY time I have noticed a tire adhesion issue was on the last track day I did. The MS 4S tires that had just 2/32nds treadwear (REARS) were becoming pretty slippery in the last two sessions. The fronts were just fine. I also noticed that in the rain I was getting some uncharacteristic hyroplaining on the rear tires just the last week or so,.

Now wanting to have a track dedicated set up I am test fitting some APEX EC7 18 x 11 ET25 wheels with TOYO RR 315 30 18 tires 40TW. We will be making any modifications necessary to make these work as a SQUARE setup for track use. i will be taking some pics on how to make this work. The overall diameter of the tire / wheel combo is 25.4 inches again dropping the car another .4 of an inch LOWER to the ground.

The plan is to haul a small customized trailer around to hold my track tires , jack , tools etc. when I do the track days.

I will be putting on another pair of MS 4S 305 30 19 tires on for street use. I considered using a TOYO R888 tire as a combo track/street tire but they sound like a dump truck when you are using them for the street. The GY 3R's are DEADLY in the rain and will hyroplane if you even spit on them The NON R rated GY I have run and they are OK but NOT as good a street tire as the MS