Running the 325/30/19 Porsche spec Cup 2's on rear R rims

[Demonic]

In an effort to see if I get some more life out of the tires I just bought the front Porsche spec 305/30/19 Cup 2's that others have also gotten. I saw mentions of a few people also running the matching 325/30/19 Cup 2 rears on the stock rear R rims. Does anyone have any feedback on this setup? I realize it'll be a slight compromise compared to the bespoke 315/30/19 compound, but for a mostly street driven car I'm thinking it's worth trying.

Thanks

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[Sagittaria]

Dealer mistakenly put the N0 (Porsche Spec) on the fronts. 305/30/19 Cup 2 N0s.

Dunno about life but I had them immediately replace them because they did not have rim protectors. Wasn't worth the risk for me.

See pics of rim protectors of standard cup 2s vs no rim protectors of N0s.

Note: yes the rims are messed up... dealer tire tech didn't give a crap apparently.

 

[Demonic]

Dealer mistakenly put the N0 (Porsche Spec) on the fronts. 305/30/19 Cup 2 N0s.

Dunno about life but I had them immediately replace them because they did not have rim protectors. Wasn't worth the risk for me.

See pics of rim protectors of standard cup 2s vs no rim protectors of N0s.

Note: yes the rims are messed up... dealer tire tech didn't give a crap apparently.

Heh, interesting, thanks. Of course I never saw that mentioned anywhere until I bought the fronts. Not sure what to do now...

 

[madlag]

Dealer mistakenly put the N0 (Porsche Spec) on the fronts. 305/30/19 Cup 2 N0s.

Dunno about life but I had them immediately replace them because they did not have rim protectors. Wasn't worth the risk for me.

See pics of rim protectors of standard cup 2s vs no rim protectors of N0s.

Note: yes the rims are messed up... dealer tire tech didn't give a crap apparently.

Can you make the dealer replace your rim?

Heh, interesting, thanks. Of course I never saw that mentioned anywhere until I bought the fronts. Not sure what to do now...

Send them back?

 

[Demonic]

I could send them back and exchange them. I just went out to the garage and I’m wondering how much of a difference that rim protection edge really makes or how effective it is. Sorry I’m just thinking out loud at this point.

 

[Tomster]

I can't speak for cup 2's in 325, but I ran a soft R compound 325 on street and track and noticed no difference between that and 315's. The difference IMHO is minimal.

 

[madlag]

I could send them back and exchange them. I just went out to the garage and I’m wondering how much of a difference that rim protection edge really makes or how effective it is. Sorry I’m just thinking out loud at this point.

That protectective edge prob doesn’t do a very good job honestly. If you curb you curb...

 

[jlauth]

I could send them back and exchange them. I just went out to the garage and I’m wondering how much of a difference that rim protection edge really makes or how effective it is. Sorry I’m just thinking out loud at this point.

It's honestly not that effective at all. I backed in close to a curb to avoid door dings on the opposite side. Forgot just how close i was on the way out. kissed the curb and it got to the rim with what appeared to be little resistance. I am thinking if you just cut your wheel into a curb, while not moving maybe they could save you but any forward motion is going right through that curb protection.

 

[CobraO]

I could send them back and exchange them. I just went out to the garage and I’m wondering how much of a difference that rim protection edge really makes or how effective it is. Sorry I’m just thinking out loud at this point.

I bumped a curb turning right, so my RR tire. I can tell you they worked for me. No wheel damage, just a scuff on the tire. Scary couple of minutes until I could pull over and take a look.

 

[tlisotta]

I am running these tires. I am no expert but here are my thoughts. Are you tracking the car much? I only track my car and it is an R. The tires are definitely holding up more than regular CUP 2's. Not sure I would run anything higher than a 305 if you are tracking the car. My lap times have improved going with 305's all the way around. I realize it is not a true "square" set up but it works well. These cars have a tendency to understeer and this seems to help at the track. I have a buddy that has a regular 350 with a lot of "R" upgrades (he is an instructor and very fast). He has driven my car and he feels the Porsche Spec tires are a little less grippy than the regular Cup 2's. However, the regular CUP 2's do wear out quicker for sure.

Updated - I just saw your comment about mostly street driven. No question - the Porsche Cup 2' will last longer for sure.

 

[Sagittaria]

Can you make the dealer replace your rim?

Yeah I'm still going through the process. They managed to get one buffed out, two acceptably touched up/blended, and didn't even bother with the fourth one based on how the previous two turned out. So they bought me a new rim.

Took that new rim somewhere else and the new place gouged the replacement even worse than the first place. Back to these guys trying to repair them to avoid spending another $3500 on a new rim Cars are commodities these days and people just don't care.

I could send them back and exchange them. I just went out to the garage and I’m wondering how much of a difference that rim protection edge really makes or how effective it is. Sorry I’m just thinking out loud at this point.

That protectective edge prob doesn’t do a very good job honestly. If you curb you curb...

It's honestly not that effective at all. I backed in close to a curb to avoid door dings on the opposite side. Forgot just how close i was on the way out. kissed the curb and it got to the rim with what appeared to be little resistance. I am thinking if you just cut your wheel into a curb, while not moving maybe they could save you but any forward motion is going right through that curb protection.

I bumped a curb turning right, so my RR tire. I can tell you they worked for me. No wheel damage, just a scuff on the tire. Scary couple of minutes until I could pull over and take a look.

I agree with the above. If you full on curb something there's no escaping a rash. But it does help with minor taps. I had a choice though with no cost to me,

If you can't return them I'd just run them and be careful.. I've been trying to sell a full set of Cup 2s for over a month. Not enough Rs around. So I'll probably just end up running them.

 

[chedder]

I have been running the 305/325 combo in N spec on my GT350, as I did on my 5.0. Video is posted other places on the forum. Harry's Lap Timer confirms 1.3 g turns along with the cars meter. I'm an instructor here in the NW and track the car extensively. 9 days with 32 year cycles and 5 mm remaining across all 4 tires. You judge.

 

[sumfoo1]

Who do yall have install tires on these wheels ?? I think i'd lose it if someone damaged them.

 

[Stuntman]

I'd recommend 295/305 PS4S on R-width wheels over 305/325 PSC2s for street driving.

 

[Ixse]

If you don’t track, stick w ps4s. If you do use mostly for track, give a supercar 3R tire a try. Its one developed for zl1 1le, and just as fast as cup2s at much lower cost. They both seem to last about the same as well..

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