For those that don't track or thrash

MLJ said:

This probably applies to your former sports cars since tire manufactures may not have caught up yet. I'm interested to know whether anyone has gone to a harder compound tire and/or lower speed rating? I can't imagine I'll get anywhere close to the Y rating criteria or need all the grip that come with factory-provided tires. Mostly thinking about increasing longevity of the tires for a DD.

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I'm sure there are some who have switched out the Max Summers for All-Seasons, particularly in middle-of-the-road climates where below-freezing temps happen regularly but snow and other inclement weather don't. It's probably less common on Porsches than having a set of winter tires/wheels on hand (or storing the car for the winter), but it likely does happen.

For comparison, I switched from Bridgestone Potenza RFTs (run-flat Max Summers) to Michelin Pilot Sport A/S 3+ (All-Seasons) on my most recent car, a BMW 2 Series. It's also RWD. They don't grip as well, but they will last considerably longer than any Max Summer tire because the compound is generally harder, as well as affected by ambient temperature changes far less.

Basically, when you switch to an A/S tire, this is what you gain and lose:
- Gain: Tire life
- Gain: Viability in more types of conditions (i.e., below 40F, light snow, etc.)
- Gain: Quietness (A/S are generally not as loud)
- Gain: Less risk of punctures (An A/S tire's harder compound sheds sharp objects more readily)
- Lose: Rolling resistance (can increase fuel economy negligibly)
- Lose: Absolute grip, in both dry and wet conditions
- Lose: Comfort (generally, A/S tires have a stiffer sidewall)

I'd ask around the 981 forums on P9 and Rennlist for folks who did the switch on 981s. I doubt very many, if any, have done it on a 718 yet.

As for speed rating: Anything that fits the rims on our cars is going to have a fairly high rating. Frankly, I wouldn't even pay attention to it unless you're overly concerned about the engineering and choosing between two or three (or more) tire types/brands.

krehm1990 said:

- Lose: Comfort (generally, A/S tires have a stiffer sidewall)

Mike, are you sure about this "A/S tires have stiffer sidewalls". In my auto-crossing experience, max summer tires tend to have much stiffer sidewalls than any A/S tire. You get a lot less roll over creating a bigger "tire patch" on the road surface with summer tires. A/S tend to have softer sidewalls for the comfy ride.

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Gaaah! You're right (that's what I get for not proofreading my post). Apologies, folks ... Though there's a caveat:

A/S tires generally have a significantly less stiff sidewall regarding compression flex, which is how much a tire flattens out under load (heavy weight, a sharp bump, etc.). This increases comfort under most circumstances (though it's also part of the reason A/S tires generally should be run with 1-2 psi higher air pressure). However, A/S tires generally have only a marginally less stiff sidewall regarding torsion flex, which is how much the sidewall bends under hard cornering and other inertial Y-axis forces.

autobahn said:

Honestly, you can pick up a set of Michelin Pilot Super Sport or Pilot Sport 4S and get a ton of miles out of them. You don't really need to step down into some hard as a rock A/S tire to get longevity while sacrificing handling.

On square setups, Michelin actually guarantees 30k miles out of them and many people see 40k+. Of course, 718s don't have a square setup.

The thing is, unless you are daily driving the 718 over 10k miles a year, you're probably going to want to replace the tires before you get to that point anyway.

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Please define 'a ton'. It's fact that non-square, RWD setups promote tire wear, as you say. And not all A/S tires are 'hard as a rock.' It's all about the compound.

We had this discussion in another thread. Max Summers wear faster, and frequently do not reach their guaranteed mileage because the cars they tend to be on aren't driven lightly by their owners. Furthermore, Max Summers should not be used regularly in temperatures below about 40F. The compound gets harder than an A/S tire's at those temps. You can be careful and get around, but it's basically like driving on hockey pucks -- and if it snows or ices, traction is pretty much like a hockey puck on a rink.