kmckmc

I was told that for AWD, front tires and rear tires should be the same brand/model so that their coefficient numbers are the same.


But for RWD, it is not so crucial that all 4 tires be the same brand/model.

Currently, my 996tt has PS2 at front and new Advan Sports V103 at rear.

Should I be concerned?

Landshark87

i don't know about the Porsche AWD system, but mismatched tires on Subarus will destroy the differential.

i was curious about this also, because the 996tt i'm looking at has "new rear tires".

adam_

No.

They should be the same SIZE- in terms of rolling diameter. within 0.1 inch is ideal, 0.3 inch is OK.

Are you running on a track?

As long as the tire compound rating (ie 220AA, etc) is close, between front and rear, you should be fine.

You will hear little old ladies citing PCNA documents or blather from experts warning all sorts of stuff (like I've heard it is dangerous to have PS2s that are N2 rated mixed with PS2s that are N3 rated on another axle...right) But for most use, not sliding around a track, just get the compounds close.

A

kmckmc

No, I do not do track.
I still have stock wheels/rims and use stock spec dimension tires.

So, I suppose most forum members have matched tires on all 4.

Michael-Dallas

I've got Nittos in the front and Hankooks in the rear right now. My Turbo hasn't turned into a pumpkin, not even when it's raining...

/m

adam_

That is not at all what i said.

Match the ACTUAL diameter. Get close on the rubber compound rating...

kmckmc

Thanks for all your input.
Basically, I was just wondering if I should install new V103 at front as well. Currently, it has PS2 at front.
Cheers,

LVDell

If you have different tires you need to make sure they are same grip level, etc. It's a combination of diameter and grip that the diff and abs rely on. Personally, I would only run with the same tire and wear. I wouldn't want 50% life on one axle and 100% life on the other.

Macster

Not concerned in the strictest sense.

There is disagreement on this subject but I have always adhered to running N-rated tires of the same brand and N-rating on my Porsches.

While some owners opt to mx N-numbered of the same brand of tires or mix different brands of N-numbered tires or run N-rated and non N-rated tires or even going so far as to mix brands of tires, I have not

Many or most who do the above claim -- and I believe them -- no untoward behavior occurs. But some have reported the opposite.

These tires are too expensive to experiment with so I just stick to what Porsche recommends regarding brands, sizes, and N numbers.

I can tell you this: When I took my 03 Turbo in and it was found to need new rear tires the parts manager at the dealer told me he didn't think he could find the same tires: Continentals, N2 (or maybe N3 I forget now). He said that if he couldn't the front tires would have to be replaced to match the new rear tires.

Thinking I was being taken advantage of I started to protest and the service manager stopped me and said that if this were the case Porsche would pay for the front tires. The car was under a CPO warranty and the front tires would be covered if the proper matching rear tires could not be located.

Apparently Porsche feels so strongly about not even mixing N-numbers that it will cough up the money to avoid this.

It is your car. You can run whatever tires you feel safe running. My advice though to you would be to as soon as you can get the tires sorted out by installing whatever Porsche recommends/supports for that car.

I have no desire to risk my car's drivetrain, my safety, my peace of mind, by running tires not recognized and supported by Porsche on my Porsches.

Also, some authorities on these cars and Porsches in general advise that in checking out a used Porsche and finding it equipped with incorrect tires is at least a reason to lower one's estimated value of the car and even reason to call into question how good of treatment/care the car has received from the current owner. If he has skimped on tires what other services and fluids has he skimped on?

Sincerely,

Macster.

TT Gasman

Non N rated tires are"ok" for street use as long as the sizes, esp diameters, are same as stock. I have non N rated Re11s on the car.....in a word crap, gonna order some N rated sport cups.

LVDell

I have always run n rated tires for the simple fact that porsche and the tire manufacturers go through a rigorous process to match he tires to our cars. More specifically, the load ratings on the N tires are different than their non N tire also offered. Our cars have different balance requirements than a 50/50 split car.

For the track, obviously there is no way to go N if you run dot-r tires or slicks. BUt no biggie since they have higher load ratings and stiffer sidewalls anyway.

raineycd

I think the N rating has more to do with the tire manufacturer not changing the specification for that model after they make it. Porsche ran into some issues with OEM brand tires and then the tire company changed the formulation and the performance of the tire changed. I think Porsche puts tires on more for financial reasons (how good a deal they get) than performance. The N rated Pirelli's that came on my car were horrible compared to the half price Sumitomo tires I have on it now.

As for the mismatch, I ran Sumi's on the front and Pirelli's on the rear one track weekend. All the death wishes that were prescribed were highly over exaggerated. The car performed fine and I probably got better performance due to the lousy traction of the rears for less understeer!

Obviously, for consistency, you will want to get experience with how the tires will react and I would suggest that with ANY tire change. Tires are one of the most important factors in the car gripping the road and like any hardware changes, should be tried out before going around a corner at full tilt!

Michael-Dallas

That sounds a wee bit dramatic, but, as you say, whatever floats yer boat. I have all the confidence in driving my Turbo in the confines of the street and the laws. I don't have confidence in the hundreds of other drivers around me that think of their automobile as a utlilty and are driving SUV's on bald tires that are improperly inflated. That poses a greater danger than us enthusiasts that have common sense and logic.

I'd certainly hate to think that Porsche manufactures faberge eggs that require special oil, tires, brakes, etc., otherwise the car will break. I'd wonder how they completed and won so many races.

And it is because of this perception that when it comes time for me to move on, I will replace the tires with matching N-rated tires.

/m

Macster

Well, that's the problem I guess. If one choses a non N rated tire how does he know it still falls within the envelop of acceptabilty of all its metrics?

How does one know its diameter, its actual diameter, is the same as the "stock" or N rated tires?

Sincerely,

Macster.

Macster

It will be interesting to hear you explain to a prospective buyer the absence of any tire receipts over the course of your time with the car save just one that covers the recent replacement of tires with N rated ones.

One likes to see a car has been loved its whole time with the current owner, not just prior to putting the car up for sale.

Sincerely,

Macster.