cgomez

I'm looking for real street tires for my GT2. Seems that nobody does a 325 rear (not even Michelin PS2), so I will go with the closest choice which is the GT3 RS / Turbo sizes: 235F, 305R.
In those sizes there are many options, and PS2s are the most expensive by far ($553 vs. Bridgestone $336 for the rears!).

On the Bridgestone there are two options: N0 and N1 for Porsches. What's the difference? Anyone has tried the cheaper alternatives?

I will still drive PSC in the warmer months (40F+) and PSC/Hoosiers at the track, but need something that can climb up my driveway in the winter (No need for real winter tires. PS2s worked just fine in my 997S)

NJ-GT

Porsche certifies multiple versions of the same tire. N0 is the first release, N1 is the second version of the OEM tire. The higher the number, the newer the tire is.

Your car should be perfectly fine with 235/305 N-spec PS2. The PS2 is a great tire. One time while lapping Pocono North in early April, we got caught by snow. Cars were sliding all over the place, a Cayenne S started passing cars everywhere (PCA Black Group). I was running PS2, and the car held quite well, I passed the Cayenne after getting the driver to exceed the limits of safe grip on the SUV, my GT3 was rock solid.

My experience with MPSC is totally different. I ran them as my street tires for 3 years. At one time, I was lapping Watkins Glen, and we got caught in the rain, I was the slowest car in the running group. My top speed on the main straight could not exceed 85 mph, I was hydro planning. Scary stuff. On the cold dry days I took the Boxster S or 996 GT3 out on MPSC, the grip was really bad.

The Toyo RA-1 is a wonderful tire in the rain and cold weather as well. They don't make 19" sizes, but the 245/335 18" is a perfect fit for your car.

I just put 265/325 MPSC on the RS in the time being. I'm looking for a third set of wheels to run 235/305 MPS2, leaving the MPSC to drive to/on/from the track.

cgomez

Thanks Rad,

I also have great feedback on the PS2. Ran them for 3 years through several winters in my 997S (new set every year) and only got stuck once in the snow, but the premium (60%+!!) over the alternatives is hefty, but in the big scheme of things is not that it has an impact on the economics (or lack of!) of GT2 ownership ;^) .

Agree that the MPSC don't feel as good as the Toyo RA1s which I love but unfortunately they are being discontinued and the replacement R888 (from my experience in the Exige S) are a POS relatively speaking. The R888 heat cycle out and the ultimate grip is neither as good or consistent as the RA1s (I believe Toyo figured out that the repeat purchase period of RA1s from a customer was much higher than Hoosier's so they design a tire with a narrower and shorter lifespan!!)

Adil bought my 997S and figured our how to put 4 tires on the roofrack! So I might start to run V710 or Hoosiers (Do you think 315 V710 in the rears is enough for the GT2?)

NJ-GT

I figured out how to put 4 tires inside the car, and I still have space to do wider wheel tires.

Two front ones behind the driver's seat, one rear behind the passenger seat, another rear on the passenger seat. Use the high quality BlackWatch Racing tire covers. I'm waiting for BlackWatch to re-stock them, in the meantime the TireTote do the job.

I ran an autoX last week with PCA at El Toro Airport. The SCCA runs a National ProSolo tour at the same place. Huge airfield similar to Devens. Courses are always 70+ secs long.

My best time on hot MPSC 265/335 was a 76.9. My first lap on cold skinny Michelin Slicks 240/270 was 74.8. A sticky compound in small sizes is always better than a bigger size on a not so sticky compound.

Three years ago I ran Hoosier A3S05 on 275/335 against V710 on 245/285, the car was faster on V710.

245/315 V710 on 18" will have much better grip than any size MPSC you could run on the GT2. When loading the rear tire in the back, do it from the driver's side with the passenger seat reclined and moved forward. I will take pictures next time. Our cars have the same dimensions inside. Forget the roof rack.

cgomez

That tire packing strategy might work some times. Most of ocassions i will need to debate whether to strap one of my kids or the tires to the roof rack!!

BTW, congrats on the RS. I'm sure it will be a killer machine once you are done wrenching with it.
I assume you changed the whole suspension (spring rates, etc.) since you are running real slicks?

Farnbacher advised me against running slicks on the GT2 as they claim it will certainly compress to the bump stops the suspension while cornering, braking and 1st gear acceleration.

Jon70

Rad,
How did you get the 265s to fit the front?

NJ-GT

I mostly agree with Farnbacher advice, except acceleration.

Slicks have similar grip to Hoosier A6, unless we talk about soft slicks, which are not available for our cars (they're made on diameters 10" to 16"). The Michelins I have are less than 1 second faster at Lime Rock Park compared to fresh R6 driven on the same car, the same day, same driver.

On acceleration, the most weight you could transfer to the back is 1,200 lbs (assuming a full tank of fuel and both front wheels on the air, very unlikely). That's 600 lbs per corner of extra load compared to the static load. Our cars have rear spring rates on the 500-600 lbs range, that's about 1" to 1.25" of suspension travel. Hardly on the limits of suspension travel which exceed 4" on the stock rear suspension. Acceleration in 1st gear on slicks should not be a problem.

During braking, even on stock tires we can hit the bump stops. The springs are soft (225#), and the weight transfer from the back is massive, as there are 2,200+ lbs on that axle, more if you have a heavy driver, a passenger, rear seats, a couple of turbo chargers and Elmo.

I always put zip ties on the shock pistons to measure suspension travel on track days. The 450#/650# suspension on my former 996 GT3 with shorter springs (6" front 8" rear), never got within 1.5" of hitting the front bump stops.

The rear was using 1.75" of travel at Pocono North on the rear left. Consider that the entrance from the infield to the speedway is at full gas, turning right on 2nd gear and uphill, lots of loads on the rear left corner. At Pocono North that corner was just 0.5" to hit the bump stops, but it was the most travel I could see from my suspension anywhere I ran.

My 996 GT3 was at 2,800 lbs when I ran A6 tires at Pocono North. A 997 GT3/GT2 exceeds 3,200 lbs, with softer stock spring rates than 650# at the back, and slicks, it is very likely to get to hit the rear bump stops at Pocono North.

So, during braking it is easy to get to hit the bump stops, cornering will depend on the type of track (Pocono North long right, Watkins Glen Turn 2 and Toe boot, Lime Rock uphill, Laguna Seca Turn 6), acceleration no way you can reach the bump stops.

NJ-GT

Stock wheels, stock suspension, stock ride height. I wanted to run the 325 rear tires, but I already knew the 235 N-spec MPSC was too skinny, so the 265 real MPSC provides a better balance.

However, the car was still pushing, the GMG sway bars fixed the balance.

Jon70

Rad,
That is good to hear. I would have assumed the 265s would have rubbed against the fenders.