Let's get serious about track tires for GT350

[petstang]

That settles it then. I've had four people from two different forums tell me to jump on it, so I did! $368 each less the rebate. They send a rebate form with the tires. I forgot to ask if it's $70 or $100 though...

https://www.discountedwheelwarehous...ort+Cup+2+305/30R19+XL+102Y&partno=Mich-24727

I ordered from them 2 new Michelin SC 2's 305/30/19 ( 98Y) back in September for 720$ and all went more or less fine. After having received some confusing e-mails about delivery dates and availability, 5 days after ordering, I called them and the next day I got the tires. They offer the lowest prices for SC2's - wonder how long it will last though.

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[MikeR397]

That settles it then. I've had four people from two different forums tell me to jump on it, so I did! $368 each less the rebate. They send a rebate form with the tires. I forgot to ask if it's $70 or $100 though...

https://www.discountedwheelwarehous...ort+Cup+2+305/30R19+XL+102Y&partno=Mich-24727

So the only distinguishable difference on paper is the load rating of 102y vs 98y right, and that is somehow why they are lasting Longer? What Porsche are these stock on?

Like honey badger i got an eBay deal on the 315/30/19 oem cup 2 rears for my R (3 years old but $215 cost each) and now have 6 extra rear tires but zero fronts as I can’t find a screaming deal yet....

Is there a reason I can’t run these 102y Porsche spec fronts with my oem spec 315 rears I grabbed on eBay? That might actually be a perfect combo as the fronts wear out easily 30-40% faster than my rears when the car gets mostly track use (my fronts both corded last time and rears looked like they had some life left). Otherwise it’s a pita to change 2 tires at a time and have to do it 2x as much, so this approach of longer lasting fronts with oem rears might be perfect? Thoughts on this approach?

ETA: damn I’m kicking myself for not buying more oem 305 spec cup 2 at last year Walmart deal for $190 each. Should have bought 3-4 years supply!

 

[honeybadger]

So the only distinguishable difference on paper is the load rating of 102y vs 98y right, and that is somehow why they are lasting Longer? What Porsche are these stock on?

Like honey badger i got an eBay deal on the 315/30/19 oem cup 2 rears for my R (3 years old but $215 cost each) and now have 6 extra rear tires but zero fronts as I can’t find a screaming deal yet....

Is there a reason I can’t run these 102y Porsche spec fronts with my oem spec 315 rears I grabbed on eBay? That might actually be a perfect combo as the fronts wear out easily 30-40% faster than my rears when the car gets mostly track use (my fronts both corded last time and rears looked like they had some life left). Otherwise it’s a pita to change 2 tires at a time and have to do it 2x as much, so this approach of longer lasting fronts with oem rears might be perfect? Thoughts on this approach?

ETA: damn I’m kicking myself for not buying more oem 305 spec cup 2 at last year Walmart deal for $190 each. Should have bought 3-4 years supply!

My understanding is that the Porsche spec is a slightly harder compound with additional tread depth. If I were you, I would run 315s all around. With 6 tires, you'll wear the fronts out before the back anyways!

 

[MikeR397]

My understanding is that the Porsche spec is a slightly harder compound with additional tread depth. If I were you, I would run 315s all around. With 6 tires, you'll wear the fronts out before the back anyways!

Has anyone tried this? I had a bad experience with rubbing (no issue on street, but big problems on a track) with my old 996tt with wider 997tt wheels on it.

Regardless, as you say, the fronts wear out faster than the rears, so it'd seem to me to make perfect sense to use the 102y porsche spec (harder/extra tread) fronts with the oem rears and possibly both will be 100% gone simultaneously. I'm doubtful I'd actually notice a handling difference from this setup (same tires but maybe slightly harder compound up front). Otherwise, you have the annoying problem of replacing rears before they are really worn out or have to replace 2 tires at a time and spend 2x the time/trips to a touchless tire mounting facility.

 

[The Chairman]

So the only distinguishable difference on paper is the load rating of 102y vs 98y right, and that is somehow why they are lasting Longer?

According to the Michelin website: the 102Y tires have 7.2 32nds tread depth while the 98Y tires have 5.5 32nds.
- So a 30% increase in tread depth.
The 102Y also weigh 28.35 lbs vice 26.52 lbs. 1.8 lbs more rubber per tire (7% weight penalty).
Good trade-off.

 

[CSL]

The Porsche spec tires are a different design with a much more squared sidewall. They are clearly a more robust tire overall, hence the increased load rating.

 

[MikeR397]

The Porsche spec tires are a different design with a much more squared sidewall. They are clearly a more robust tire overall, hence the increased load rating.

So what do you think about running the Porsche spec on the front and 350r spec cup 2 on the rear for the reasons I listed above?

 

[CSL]

So what do you think about running the Porsche spec on the front and 350r spec cup 2 on the rear for the reasons I listed above?

I think it would be a better setup than the OEM R spec setup. One of my buds did the reverse and ran the R spec 315 up front and Porsche spec 325 on the rear, just because that’s what he had. The tires worked fine together, just not as neutral as he would like. I think the Porsche 305f and R spec 315r is the much better option if combining the two. You will notice the tire/sidewall design is slightly different between the two.

Bottom line is our heavy front when pushed hard quickly overwhelms the less robust 98Y tire.

 

[MikeR397]

I think it would be a better setup than the OEM R spec setup. One of my buds did the reverse and ran the R spec 315 up front and Porsche spec 325 on the rear, just because that’s what he had. The tires worked fine together, just not as neutral as he would like. I think the Porsche 305f and R spec 315r is the much better option if combining the two. You will notice the tire/sidewall design is slightly different between the two.

Bottom line is our heavy front when pushed hard quickly overwhelms the less robust 98Y tire.

Thank you, very helpful feedback! I’m going to give this a shot and will report back. Have 2 track days on the Walmart deal R spec tires now, so will be late spring (in Michigan) until I’ll be able to share initial results once these are dead and will try Porsche spec cup 2 fronts with my supply of 6 R spec rears.

I’m going to do camber plates (probably m&m since I’m not convinced yet I need the extra camber afforded by the Vorshlag at 2x the price — ie m&m allows for ford suggested track camber) as well. If I can get 7-8 full track day instead of barely over 4, it’ll be a big win in my book.

The next issue is brake pads, as I killed my oem pads after 5 track days. I’m happy with them, zero issues (ran srf fluid all season for 7 events no flush needed), but looking into track pads. This is mostly a track car but I don’t want constant squeal or to eat up the pricey rotors. I did have my buddy resurface my front rotors at pad change as I got bad vibration after the fifth day — probably just material build up and not warped though. they dropped from 36mm to 35.4mm after one resurface (min spec is 34mm). Not sure about pad/rotor/$/noise trade off yet.

Btw, does Michelin still offer that $70 or whatever on 4 tires rebate on the Porsche spec fronts?

 

[NvrFinished]

Found these on the front porch this morning!

 

[MikeR397]

Holy crap, there is actually an outside groove to those cup 2s! It’s 1/32 on the oem r cups lol

 

[jedirocker]

Took advantage of Black Fri specials and ordered some Apex wheels and Cup 2s for square setup. Finally made it by DT to pick them up tonight. Here are a few shots. Will take more when I get them on the car.

ETA: These are 102Y 305/30 19...I purchased from DT for Black Fri $200 rebate

 

[honeybadger]

Took advantage of Black Fri specials and ordered some Apex wheels and Cup 2s for square setup. Finally made it by DT to pick them up tonight. Here are a few shots. Will take more when I get them on the car.

Your going to love the square feel on track!

 

[Ryan P]

Man the sidewalls on those is substantially meatier than the 98Y Cup 2's. My 305 cup 2's almost look stretched on a 19x11 wheel. Those will look great and perform even better! car.

 

[The Chairman]

That settles it then. I've had four people from two different forums tell me to jump on it, so I did! $368 each less the rebate. They send a rebate form with the tires. I forgot to ask if it's $70 or $100 though...

https://www.discountedwheelwarehous...ort+Cup+2+305/30R19+XL+102Y&partno=Mich-24727

I went to the Discount Tire website, looked for the same tire, and there is a link where you can request a price match. They came back to me and said they would match the price except adding the shipping. Essentially, would sell me the same tires at the same price as delivered. Their price also includes mounting and balancing. So its actually cheaper to buy through Discount Tire as you won’t have to pay someone to mount/balance....

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