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Discussion Starter #1 (Edited)
Anyone run different model of tires front and rear so eg.. Michelin PSS front and Michelin PS2 rear?

Apart from why would you, what are the why won't you considerations?

In addition, the PS2 235/40/18 for front are 25.4 overall diameter and the PSS 225/40/18 are 25.1 overall diameter. So I guess the front will be slightly lower if the rears are on ps2S?

I note also that the PSS have a lower max load of 1389 lbs against the PS2s 1521 lbs.

Any negative effects of going PSS front and PS2 rears?

Thanks
 

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I wouldn't because the "experts" say not to. That's good enough for me. While not specific to your configuration, I've read many times how different manufacturers/tread designs on the same Porsche have resulted in irregular/difficult handling issues. Perhaps your config is "close enough", don't know. But I wouldn't do it.
 

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Discussion Starter #3
I wouldn't because the "experts" say not to. That's good enough for me. While not specific to your configuration, I've read many times how different manufacturers/tread designs on the same Porsche have resulted in irregular/difficult handling issues. Perhaps your config is "close enough", don't know. But I wouldn't do it.
Thanks for chiming in Bud. I've read that quite a few Cayman owners here on 18s have run the PSS in the past albeit 987.1 owners. I'm not sure if 987.1 18s had 225/40 or 235/40 prescribed though. I don't think its too much of an issue. I don;t know.

I'm wondering more about running PS2s on the rears with 225/40 PSS on the front which have a slightly smaller overall diameter than the 235/40 PS2s. I visualize it will be an ever so slight a dip in the front due to the slightly small tire diameter (am I even making sense?)? If so, what effect on normal driving and at speed?

Any downsides, not so much of the PSS as its supposed to be a superior tire to the PS2, but due to going to 225 from 235 for the front and the slightly smaller over diameter of the PSS over the PS2.
 

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Discussion Starter #5
Thanks. WIll read up.. But in this case, not different brands but models of the same brand.
 

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Discussion Starter #6
Just read this.. had some funny moments that brought a chuckle.

Ideal is all the same but based on how i read it, I think same axle same tires and 2 different brands on 2 axles while not ideal, is workable. The PS2 and PSS are obviously different tires but both being max performance tires and really PSS being a successor to the PS2 (maybe one generation more?), are they really such nigh and day different performing tires to cause such a huge concern. Chow's comment and Porsche manual disclaimers all noted and understandable.

Asking to learn and not suggesting.
 

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It depends. I went from PS2 to PSS on all 4 wheels. Around 20k miles later, one of the rears got a puncture that couldn’t be fixed. Discount Tire did not have PSS, which was on back order.

They ended up ordering PS2 for the rears. They said as long as it is not a 4WD car, mixing high-performance tires front-to-rear is OK (as long as there is no track driving). ~12k miles later, I am perfectly fine. In terms of my driving experience, I have done PEC and COTA multiple times (not mine though). On streets, I try to be reasonable and my g meter max is around 1.03.
 

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Discussion Starter #8
It depends. I went from PS2 to PSS on all 4 wheels. Around 20k miles later, one of the rears got a puncture that couldn’t be fixed. Discount Tire did not have PSS, which was on back order.

They ended up ordering PS2 for the rears. They said as long as it is not a 4WD car, mixing high-performance tires front-to-rear (not side by side) is OK (as long as there is no track driving). ~12k miles later, I am perfectly fine. In terms of my driving experience, I have done PEC and COTA multiple times (not mine though). On streets, I try to be reasonable and my g meter max is around 1.03.
Thanks for chiming in Dave. I think you do a lot more aggressive driving than I do. I've got zero track and 90% city driving.

Although I'm a real rookie when it comes to stuff like that, I find myself leaning towards the "its not ideal but its ok" route.

Do you find the ride height a tad different when on PSS and on PS2 due to the difference in overall diameter for your front?
 

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I would look at the ratio of rear tire diameter vs. front tire diameter for the stock tire sizes and compare it to what you plan to use. You don’t want to deviate too far from the stock ratio, as you will negatively affect the operation of PSM. With 90% city driving, I wouldn’t be too concerned with running PSS on one axle and PS2 on the other.

I would also look at the date codes on the older tires to make sure they’re not more than about 5 years old. If they are, check for dry rot / checking and realize they have hardened and will not provide the same level of grip as a new tire.
 

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Thanks for chiming in Dave. I think you do a lot more aggressive driving than I do. I've got zero track and 90% city driving.

Although I'm a real rookie when it comes to stuff like that, I find myself leaning towards the "its not ideal but its ok" route.

Do you find the ride height a tad different when on PSS and on PS2 due to the difference in overall diameter for your front?
I have not really noticed a difference in ride height. Just to be clear, my fronts = PSS, rears = PS2, all the same sizes as the original PS2's that came with the car.

I pick my spot when I drive a bit aggressively. That g-force number happened when I was following a 991.2 GT3RS on a PCA outing:) Good luck.
 

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Discussion Starter #11
I have not really noticed a difference in ride height. Just to be clear, my fronts = PSS, rears = PS2, all the same sizes as the original PS2's that came with the car.

I pick my spot when I drive a bit aggressively. That g-force number happened when I was following a 991.2 GT3RS on a PCA outing:) Good luck.
I'm thinking front pss and rear PS2 as well.

Curious, are you on 19s as you say you're on all the same sizes as the original PS2's that came with the car. For 18s, the prescribed PS2 is 235/40/18 and the PSS only comes in 225/40/18 (which I'm thinking of). Not sure about 19s.
 

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Discussion Starter #12
I would look at the ratio of rear tire diameter vs. front tire diameter for the stock tire sizes and compare it to what you plan to use. You don’t want to deviate too far from the stock ratio, as you will negatively affect the operation of PSM. With 90% city driving, I wouldn’t be too concerned with running PSS on one axle and PS2 on the other.

I would also look at the date codes on the older tires to make sure they’re not more than about 5 years old. If they are, check for dry rot / checking and realize they have hardened and will not provide the same level of grip as a new tire.
Yeah.. I;m aware of the age issue and hardening of the compound.

I think the ratios are similar. When you say don;t deviate too far, your definition of too far?

I found this on tire rack

PS2
266352


PSS

266353
 

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I'm thinking front pss and rear PS2 as well.

Curious, are you on 19s as you say you're on all the same sizes as the original PS2's that came with the car. For 18s, the prescribed PS2 is 235/40/18 and the PSS only comes in 225/40/18 (which I'm thinking of). Not sure about 19s.
Mine is 987.2 BS, 18s. Discount Tire found the exact same size for the rears. There was no height difference AFAIK. They even matched the PSS price because PS2's were $20-30 more expensive per tire. This was a couple of years ago.
 

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Discussion Starter #14
Mine is 987.2 BS, 18s. Discount Tire found the exact same size for the rears. There was no height difference AFAIK. They even matched the PSS price because PS2's were $20-30 more expensive per tire. This was a couple of years ago.

OK.. So you're on PSS front 225/40/18 and rear PS2 265/40/18 and all good?
 

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This is what I have on my car according to Discount Tire. I didn't drive the Boxster today. I will check the sizes when I get home and if different, I will post here.
266354

@wmclarenf1, this is from my original MPSS order and the front size is 235/40/18, not 225.

Product Information:
2 (35523) Michelin
235/40ZR18XL 95Y B
Pilot Super Sport

2 (35526) Michelin
265/40ZR18XL 101Y B
Pilot Super Sport
 

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Discussion Starter #16
Thanks Dave . The order sheet is for PS2 on both front and rears so 235 for PS2 front is per prescription.

I was just curious if you are on PSS and 235/40/18 because my understanding is for PSS, it only comes in 225/40/18 per my reply in post #12 above.
 

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First I'm not sure where you are coming from. Do you have these different tires now or are you having to replace one set and the matching set isn't available where you live ??

Your posted TireRack listing shows besides different model and size tires but also regular Michelins vs Porsche rated N4 how mixed up do you want to get ?

None of this all means a hill of beans. The tires will be fine for 90% city driving. You and the car will never know anything's different.
But you never answered the question of tire age. That can be a concern and if so why not just replace 2 tires and match the other set.? It's $500-600 different from doing nothing.
 

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Discussion Starter #18
First I'm not sure where you are coming from. Do you have these different tires now or are you having to replace one set and the matching set isn't available where you live ??

Your posted TireRack listing shows besides different model and size tires but also regular Michelins vs Porsche rated N4 how mixed up do you want to get ?

None of this all means a hill of beans. The tires will be fine for 90% city driving. You and the car will never know anything's different.
But you never answered the question of tire age. That can be a concern and if so why not just replace 2 tires and match the other set.? It's $500-600 different from doing nothing.
Yeah.. looking to replace my front PS2s which are 4 years old and close to approx 20% thread wear left. My rears are new PS2s changed last month. I would go PS2s front as well but there's an opportunity to go PSS fronts now hence the questions. Seeing that PSS is supposed to be a much better tire and PS2s are long in the tooth model wise, I'm thinking of PSS fronts and then hopefully go PSS rears later as well as rears wear faster. PSS does come in the prescribed 265/40/18.
 

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Since you just replaced the rears last month I would go with PS2 for the fronts even PSS's are better. If you wanted the most current and best it should PS4s not PSS much as I love them.
 

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You asked about ratio of rear tire diameter to front tire diameter.

My street wheels are 19", track wheels are 18". Here's the ratios that I have run that are ok:


[TR]
[TD][/TD]

[TD]Wheel
Diameter
(in)[/TD]
[TD]Width
(mm)[/TD]
[TD]Aspect
Ratio[/TD]
[TD]Sidewall
Height
(in)[/TD]
[TD]Tire
Diameter
(in)[/TD]
[TD]Ratio[/TD]
[/TR]
[TR]
[TD]stock[/TD]
[TD]19[/TD]
[TD]235[/TD]
[TD]35[/TD]
[TD]3.24[/TD]
[TD]25.48[/TD]
[TD][/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]19[/TD]
[TD]265[/TD]
[TD]35[/TD]
[TD]3.65[/TD]
[TD]26.30[/TD]
[TD]
1.032​
[/TD]
[/TR]
[TR]
[TD]RE-71R[/TD]
[TD]18[/TD]
[TD]235[/TD]
[TD]40[/TD]
[TD]3.70[/TD]
[TD]25.40[/TD]
[TD][/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]18[/TD]
[TD]275[/TD]
[TD]35[/TD]
[TD]3.79[/TD]
[TD]25.58[/TD]
[TD]
1.007​
[/TD]
[/TR]


As long as the front diameters are a little smaller than the rear diameters (which is true for either front tire you are considering) you are ok.
 
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