[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

[sr71bb]

UPDATE

The TOYO 315 30 18 tires WILL NOT work with the EC7 18 x 11 ET25 wheels. We clearanced the shock tower enough for the INSIDE of the wheel to clear BUT the TOYO TIRE HAS A SECTION WIDTH of 12.6 inches and the TIRE itself was an issue with an inside RUB.

So we will be trying some 305 660 18 pirelli slicks on those same EC7 18 x 11 ET25 wheels. The section width of THIS tire is 12.1 inches so we should be good to go.

Since it looks like we cant run wider than a 305 30 18 setup, we might go back to SM10 18 x 10.5 ET22 wheels. We know that will work of course because our street setup NOW is 19 x 10.5 SM-10's ET22 and 305 30 19 MS tires.

The PIC below is where your need to grind back on the strut brace as indicated by the blue circled area.

[sr71bb]

UPDATED 6-10

OK just got thru test fitting a 305 660 18 Pirelli Slick on an APEX EC7 18 x 11 ET25 wheel on the FRONT and THAT combo will work.

So my basic conclusion here is that this is the WIDEST combo that can be run on a NON-ZL1 fender using SG3 suspension and a MIN of 2.2 degrees negative camber is THIS ONE. I DO NOT have any tire poke at the top of the tire and I AM NOT using spacers.

Technically you COULD run a 10.5 width wheel since tire is 305 width but you have to account for the fact that the PIRELLI slick and TOYO RR tire is WIDER than the street 305 size tire like the MS 4S 305 .

The 11inch wheel will provide a little more stiffness to the sidewall compared to a 10.5 inch wheel so that's what I am going with.

My Thanks to Cory at APEX for getting the wheel to me so quickly so that I could test fit it.

[kropscamaro16]

yea im still trying to figure out if i want to go 19x11 square or 19x10 19x11 probably going to be ordering up a mcs 1 way kit here from vorshlag soon so gonna wait until i get the coils first

[RUQWIKR]

Of my multiple wheel / tire combos I have, I run 18x11 +25 EC7's with a 15mm spacer up front (extended studs) with the struts ground with -3.1/-3.2 front camber. I've run 315/30/18's (Hoosiers, A052's, etc.) along with 300&305/660/18 slicks up front. I do have ZL1 front fenders as far as not poking. That combo (+10mm effective offset) is outboard 1mm more than the ZL1 1LE 19x11 +11's I run also.

With aggressive negative camber, even on SS stock front fenders, the ZL1 1LE or this type of combo isn't too bad for poke knowing it's a tracked car. FYI - Pirelli slicks seem to run narrower than Hankook, Michelin, and Yokohama slicks in the 300/305 range.

[carguy55]

I have a SS 1LE so I have the MRC suspension. I've been running 19x10.5 ET22 square for almost 2 years. I don't have camber plates installed but have the strut mod and 5mm spacers with longer studs in front. I'm looking at also getting 18x11 wheels to be able to run other tires including slicks and figure this will take the plates + spacer. I've been told the 18x11 ET25 will work so its interesting to see your results.

[RUQWIKR]

Originally Posted by carguy55

I have a SS 1LE so I have the MRC suspension. I've been running 19x10.5 ET22 square for almost 2 years. I don't have camber plates installed but have the strut mod and 5mm spacers with longer studs in front. I'm looking at also getting 18x11 wheels to be able to run other tires including slicks and figure this will take the plates + spacer. I've been told the 18x11 ET25 will work so its interesting to see your results.

Mike - Your setup with the spacer would poke 13.4mm less than my 18x11 +25 with 15mm spacer. Yours would be 0.7mm closer to the strut. You are running around the front negative camber I'm running, and I have ground the crap out of the struts to give me ~5mm clearance to the wheel inner barrel and wide flavor 315's like Hoosiers and A052's, & various 300mm slicks. Even with any runout and tire deformation, I have never rubbed on the strut upright body nor the bottom of the spring perch.

sr71bb - I'm a member out at Cresson. I typically have some scrub 18" Hoosiers, Pirelli / Hankook slicks, etc. laying around if you ever want to test fit and run a Member Day while there. Just IM me. Dave