Let's get serious about track tires for GT350

[MikeR397]

Anyone tried the new FP spec 19 cup 2 base 350 tires on an R? The higher 104y rating (vs Porsche 102y vs r original 98y) load might indicate better construction and durability? Are the smaller sizes ok on an R? https://m.tirerack.com/tires/tires....&frontTire=935YR9PSC2XL&rearTire=035YR9PSC2XL

I’m getting 4 days on 98y r fronts before chording (7 or 8 on rear) and it’s annoying, looking for alternatives.

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[CSL]

Anyone tried the new FP spec 19 cup 2 base 350 tires on an R? The higher 104y rating (vs Porsche 102y vs r original 98y) load might indicate better construction and durability? Are the smaller sizes ok on an R? https://m.tirerack.com/tires/tires....&frontTire=935YR9PSC2XL&rearTire=035YR9PSC2XL

I’m getting 4 days on 98y r fronts before chording (7 or 8 on rear) and it’s annoying, looking for alternatives.

35 v 30 aspect ratio is primary reason for different load rating. It will be interesting to see if these last any longwr and how much of a performance difference there will be with a taller tire.

 

[JAJ]

Anyone tried the new FP spec 19 cup 2 base 350 tires on an R? The higher 104y rating (vs Porsche 102y vs r original 98y) load might indicate better construction and durability? Are the smaller sizes ok on an R? https://m.tirerack.com/tires/tires....&frontTire=935YR9PSC2XL&rearTire=035YR9PSC2XL

I’m getting 4 days on 98y r fronts before chording (7 or 8 on rear) and it’s annoying, looking for alternatives.

The most long-lasting track tires I've come across are Trofeo R's, BUT it's important to note that my tires tend to heat cycle out (lose grip) before the tread is gone, so they might not solve your problem. The Trofeo's on my car now have 29 track sessions on them and they still grip just fine. My last set of MPSC2's were done when they had fewer than 25 heat cycles.

 

[CSL]

The Porsche spec 305/30s are wearing real well for me and I have uniform wear across the tread width with -2.5ish neg camber.

From strictly a performance perspective, I think the Bridgestone RE71R is better. My comparison is on my SN95 3klb race car in a 255/40/17 size, but nonetheless, the Bridgestones were much more crisp and less prone to lock up on a non-abs car. They definitely don’t wear as well as the French version of the Cup2, ie. Porsche spec design. @honeybadger can confirm these findings.

Everything is give and take. There is no magic pill with tires.

 

[TDC]

It’s still a little early for me on the MPSC2’s but so far I agree with you that the RE71R is much more responsive and communicative through the sidewall than the SC2’s. Plus when new the SC2’s tram line like a motherf$&@er, I couldn’t believe it. I haven’t run a track I know well yet with the PSC2 so maybe I’ll be wrong in the long run. Super light tire though.

 

[nastang87xx]

71R is a wonderful tire but that 200 tread rating is the biggest joke since the term "nawz" was coined. Keeps SCCA happy for classing.

 

[CSL]

71R is a wonderful tire but that 200 tread rating is the biggest joke since the term "nawz" was coined. Keeps SCCA happy for classing.

And all the other “street tire” endurance series.

 

[svttim]

71R is a wonderful tire but that 200 tread rating is the biggest joke since the term "nawz" was coined. Keeps SCCA happy for classing.

That's why you sold them to me

 

[honeybadger]

The most long-lasting track tires I've come across are Trofeo R's, BUT it's important to note that my tires tend to heat cycle out (lose grip) before the tread is gone, so they might not solve your problem. The Trofeo's on my car now have 29 track sessions on them and they still grip just fine. My last set of MPSC2's were done when they had fewer than 25 heat cycles.

Thoughts on Trofeo R's vs RE-71Rs? Working on picking a class for Gridlife and am either limited to 285 RE-71Rs all around in Street Mod or unlimited width Trofeo Rs (or anything else 40 treadwear and higher) in Track Mod.

Competition will obviously be higher in Track Mod, so I'm torn.

 

[MikeR397]

I’m inclined to try the Porsche spec cup 2 before the 19 base gt350 spec at the same price point. Have two sets of 15 production year 98y R spec to kill first, hopefully -3 degrees of front camber now will get me to 5 days at least now.

 

[JAJ]

Thoughts on Trofeo R's vs RE-71Rs? Working on picking a class for Gridlife and am either limited to 285 RE-71Rs all around in Street Mod or unlimited width Trofeo Rs (or anything else 40 treadwear and higher) in Track Mod.

Competition will obviously be higher in Track Mod, so I'm torn.

There's some weird things happening in tires these days. I'm running 285/35x19 Trofeo R's on the front of my GT350 matched up with Trofeo R 325/30's on the back because they're the same diameter. The weird thing is that the 285's are the widest 285's I've ever seen. If you measure the contact face of the tire tread (measure the full width and subtract the voids), they actually put more rubber on the ground across the face of the tread than 305/30 MPSC2's. The 285<=>325 match-up isn't as unbalanced as the numbers would suggest - the tread face measurement of the 325's is only 20mm wider than the 285's, even though the carcass is 40mm wider..

So what does this all mean? Well, it means there are specs and then there's the stuff tire manufacturers do to bend performance without bending the rules. It's too bad you can't run Trofeo R's in Street Mod. The 60 TW rating kills it though, and once the sizes are unlimited, it's a whole new ballgame. By the way, the widest 305's I've ever seen are the Goodyear 3R's. I have a new set waiting for the Trofeo's to wear out. The GY 305's are almost as wide as the Trofeo 325's. And they're dramatically less expensive...

So, I reread this post and realized that I was basically assuming that you, having spent all that time and money on HB, simply wouldn't be satisfied to buzz around on 285's. I just don't see it happening

 

[honeybadger]

There's some weird things happening in tires these days. I'm running 285/35x19 Trofeo R's on the front of my GT350 matched up with Trofeo R 325/30's on the back because they're the same diameter. The weird thing is that the 285's are the widest 285's I've ever seen. If you measure the contact face of the tire tread (measure the full width and subtract the voids), they actually put more rubber on the ground across the face of the tread than 305/30 MPSC2's. The 285<=>325 match-up isn't as unbalanced as the numbers would suggest - the tread face measurement of the 325's is only 20mm wider than the 285's, even though the carcass is 40mm wider..

So what does this all mean? Well, it means there are specs and then there's the stuff tire manufacturers do to bend performance without bending the rules. It's too bad you can't run Trofeo R's in Street Mod. The 60 TW rating kills it though, and once the sizes are unlimited, it's a whole new ballgame. By the way, the widest 305's I've ever seen are the Goodyear 3R's. I have a new set waiting for the Trofeo's to wear out. The GY 305's are almost as wide as the Trofeo 325's. And they're dramatically less expensive...

So, I reread this post and realized that I was basically assuming that you, having spent all that time and money on HB, simply wouldn't be satisfied to buzz around on 285's. I just don't see it happening

Haha. You hit the nail on the head. With all the aero and other performance upgrades, not sure the 285 RE71Rs would be fun. How do you feel about grip levels between the RE-71Rs, Goodyear 3Rs and Trofeo RS assuming relatively the same size tire and in a time attack setting?

All assumes that the set of tires would be shot by end of weekend. HB + my driving kills tires

 

[JAJ]

Haha. You hit the nail on the head. With all the aero and other performance upgrades, not sure the 285 RE71Rs would be fun. How do you feel about grip levels between the RE-71Rs, Goodyear 3Rs and Trofeo RS assuming relatively the same size tire and in a time attack setting?

All assumes that the set of tires would be shot by end of weekend. HB + my driving kills tires

I've never driven the RE71R's and I haven't driven the GY3R's yet either. The Trofeo R's have been great to drive on, and they handle the weight of the GT350 just fine. Oh, AND THEY DON'T TRAMLINE!!!!

The difference as I see it from just reading about the various tires is that the RE71R's are great street tires you can track. The GY3R's, the Trofeo R's and MPSC2's are all track tires you can street. More grip, shorter life.

Just to indicate the scale of the GY3R's, here's a picture:

The one on the left is a 315/30x19 MPSC2 and the one on the right is a 305/30x19 GY3R. Both are on 11" rims.

 

[nastang87xx]

That's why you sold them to me

Ha, actually some of the guys I autocrossed with were able to get a full season of DD'ing, a full season of Milwaukee autocross, SCCA Spring Nationals, and SCCA Solo Nationals. Interestingly enough it SEEMS like RE71R's actually last longer the bigger the size you go despite them having to support bigger cars too (GTR's, Mustangs, etc etc)

 

[Spacebird]

Question for you all.

I ended up with Porsche-spec 102Y on the front of my R (blew one tire and that's what the local Discount Tire had). I like the additional tread depth as I've been sawing through my 98Ys in no time. Frankly, I'm not a good enough driver to enjoy and perks that the 98Ys might have.

I'm looking at the standard 315/30R19 100Y or 325/30/R19 105Y N0(Porsche) for the rear. It is my understanding that the latter will fit R spec wheels without issue. Are the rear 105Y's "Porsche-spec" with deeper tread like the front 102Ys?

Or should I be looking at a different rear tire to last me a little longer?

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