Bull

If you decide that you must use N Spec tires, RonCT is correct that you should not mix the individual specs (N2 with N3, etc.).

RonCT

One thing I wonder about is non-N tires - do they ever update them? Michelin and Porsche appear to continue to improve the tires over the years. In the 235/265 example, when introduced, you had N-0. Today, you are up to N-4, so this is the 5th version of the same tire. Are non-N still at an N-0 equivalent in compound technology? Or is it that all PS2s are now more or less N-3 to N-4 "worthy"? We'll probably never know.

Bull

If you look at several other tire brands you will see the same progression in "N" numbers. The progression usually stops when that tire model is replaced by another model and further development of the original model stops. Additionally, the discontinued model may have reached a higher "N" number, like N3 or N4, due to continuous improvement. No matter how advanced the new model of tire is, it will always begin with an "N0" designation. So, don't compare "N" designation between models of tires, as a newer tire model will frequently have a lower "N" designation than an old model.

I believe that you will find that the progression in the "N" designation numbers is driven as much, if not more, by the tire manufacturer's compound and design improvements as it is driven by anything Porsche is doing.

RonCT

What I'm trying to say is not between brands but within a brand. For example, you can buy non-N specification 235/265 PS2 tires -- or you can buy N-specification 235/265 PS2s an right now you can probably still get N2 and N3 or the latest N4. So what I'm wondering is whether the non-N PS2 (or any other tire for that matter) remains the "original" compound and design, or if the non-N improves over the years until they eliminate the tire altogether and create the PS3. At least the N-specification is a benchmark we consumers can look to to make sure we are getting the latest / newest (vs. looking at manufacture date) tires. Just as we would not mix N4 with N0 tires, I wouldn't want to mix non-N tires of different internal design and compound.

ltc

http://www.tirerack.com/tires/tirete...jsp?techid=26&

Bull

I was also referencing same brand, but different models of tire, when talking about comparing "N" numbers. Lower number doesn't mean less developed.

I would say the same thing for tires that don't carry an "N" rating in the same brand and model. They don't carry that "N" rating simply because they never submitted them to Porsche for testing. Most tires are tested by Porsche when they are submitted for consideration as original equipment tires on new Porsches. If they meet the spec, AND the price and marketing support is up to "spec", they become OE for Porsche.

As for a higher "N" number meaning something for the same brand and model of tire, who knows what it means? It could mean that Porsche was simply looking for a quieter tire for their new models, or longer tread life for rear engined models (at what cost to grip, etc.?).

ltc

It should be fairly simple to compare UTQGS ratings on 2 different N spec (homologations) for the same brand/type tire and infer any differences in compound/construction.

http://www.tirerack.com/tires/tirete...jsp?techid=48&

Bull

Absolutely...assuming the changes made to the tire effect the specs taken into the computation of the UTQGS ratings.