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The clearance issue we were talking about was the ability to clear a slightly bigger than stock tire. That is an issue that I don't think would be affected by a longer or shorter travel suspension, so long as they both end travel at the same point.
If a tire rubs it's when turning the wheel far or deep in the suspension stroke.
 

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The clearance issue we were talking about was the ability to clear a slightly bigger than stock tire.
I'm curious why you are considering a bigger than stock tire. Back in the old days manufacturers chose tire sizes for various reasons such as cost and availability. Intermediate price cars could usually handle larger tires but to keep the diameter more or less the same you'd reduce the aspect ratio when selecting greater width. In contrast, Porsche already installs tires about as big as the fenders can handle, price notwithstanding. On my Cayman w/20" wheels the tires come right out the the very edge of the fenders. Another quarter of an inch on the outside and they'd be throwing up rooster tails of water and debris. I don't know how much clearance they have on the inside.

Were you tracking you'd want whatever was legal for the class. For street use Porsche's choice doesn't need much improvement. These cars come from the factory with unbelievable performance.
 

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I'm curious why you are considering a bigger than stock tire. Back in the old days manufacturers chose tire sizes for various reasons such as cost and availability. Intermediate price cars could usually handle larger tires but to keep the diameter more or less the same you'd reduce the aspect ratio when selecting greater width. In contrast, Porsche already installs tires about as big as the fenders can handle, price notwithstanding. On my Cayman w/20" wheels the tires come right out the the very edge of the fenders. Another quarter of an inch on the outside and they'd be throwing up rooster tails of water and debris. I don't know how much clearance they have on the inside.

Were you tracking you'd want whatever was legal for the class. For street use Porsche's choice doesn't need much improvement. These cars come from the factory with unbelievable performance.
Go back and read the last page. I want 18" wheels and I'd stick with stock tire size but probably put all-seasons on right away (I live in the high alpine). I was commenting on a guy saying it would be nice if owners who have installed all-seasons on their 20s could comment on clearance and mention which suspension they have.
 

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Weight, ride quality, damage prone on bad roads. I prefer the look of 19" over 18" but all the other factors have me leaning 18. 20s just look odd to me, too big. Correct me if I'm wrong but they're worse in every performance metric, right?
Aesthetics: That's a personal decision. My wife & I had decided early on that we liked the looks of the 20" wheel in Platinum enough to spend the extra money on them.
Ride quality: Ride quality in my CGTS is amazingly good with the 20" wheels & Michelin tires. It is definitely stiffer and somewhat painful on rough roads when in Sport+. However, in normal/sport modes I'm amazed by how comfortable it is. I also run the non-comfort setting for tire pressures (33lbs). With that said, I will do 19" wheels if I go with a winter set as I want the extra side-wall because of winter road damage. My wife trashed 2 tires/wheels on her Legacy GT in one sitting by hitting a hidden chuckhole during the winter.
Damage prone: We've hit some big pavement transitions unfortunately but so far no issues.
Performance: No real experience with 19s or 18s but this car with 20s shines in ways I could only imagine in the twisties of NH/VT.

MOO
 

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Reviving a dormant thread, not zombie yet but definitely dormant.

My original Porsche wheels are 20" w/PS4S. This winter I've been running 19" aftermarket wheels with Alpins, a nice combination. I discovered yesterday that the extra inch of curb clearance does not grant immunity from scraping a rim against a normal city curb. Fortunately it was not one of the original Porsche wheels. It's not a big dent, just a little scratch.

This has been a public service announcement for those of you wondering about the advantages of one size over another.

And I got tired reading the same threads about whether you could power-shift the MT or whether the GT4 w/GPF sounds like a turbo.
 

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I was going to smirk, "Well, another inch would have saved you!" but, with my stock 18"ers I did the same or similar thing too. A rough little 2-3 inch scar on the wheel. Didn't cost me anything to have the wheel repaired as good a new, except for the cost of the wheel/tire insurance. Now, if I do the same thing another 10 times or so, that puppy's paid for!
 

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And I got tired reading the same threads about whether you could power-shift the MT or whether the GT4 w/GPF sounds like a turbo.
LOL... but can you powerglide noLiftShift the GPF turbo PDK on the GT4.0S 2.5L without using heel toe?


I have the Turbo Wheels and I believe they are one of the few wheels from Porsche that are Forged. I love them, but the cost of replacement scares the poo outta me. Benefit of forged is lighter and stronger, and they are definitely lighter, but I'd rather not test the stronger aspect.

I do like the look of the 18" and would consider running them. Finding the wheel that can clear the brakes is the issue for us S & GTS owners. I thought I seen somewhere that there was a company working on making an 18" to fit, but I'm sure it will come with a hefty Porsche Tax.
 

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I just bought a set of 18" Apex wheels for track day use on my CGTS. Apex confirms fit with both the stock steel brakes and the Essex / AP Racing 355mm brakes with six-pot calipers I'm dreaming of upgrading to.

There's a group buy that ends in just a few hours that'll save you some money:

Apex SM-10 for Porsche Applications
 

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I just bought a set of 18" Apex wheels for track day use on my CGTS. Apex confirms fit with both the stock steel brakes and the Essex / AP Racing 355mm brakes with six-pot calipers I'm dreaming of upgrading to.

There's a group buy that ends in just a few hours that'll save you some money:

Apex SM-10 for Porsche Applications
EDIT: I'm stupid, but I figured it out!
 

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I was on a tight budget so my Cayman has the 18" wheels because that's what comes on a base car like mine. I didn't really consider any other size wheels.
That said, the outer diameter of all these tires is almost identical. That's because the sidewall height on the 19" and 20" wheels in less than the 18" wheels. (i.e.- the aspect ratio of my 18" tires is 45 versus the 35 aspect ratio of the optional 20" tires).
So tires on the larger size wheels don't really fill out the fenders any more than the smaller size wheels. The only thing that really might make the tires seem to fill out the fenders more is the visual effect created by lowering the car.
One other point: the taller sidewalls of the 18" tires means there is more rubber between the wheel and the road. So the 18" tires tend to be able to deal with rougher roads with less wheel damage. This may be more of an issue to me than other folks since I live in New Jersey, where our state symbol may as well be the pothole. :rolleyes:
 

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This may be more of an issue to me than other folks since I live in New Jersey, where our state symbol may as well be the pothole.
:ROFLMAO:🤣:ROFLMAO:🤣:ROFLMAO:
Yes, amen! Live in Philly, work in NJ--I second the statement above!
 

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My 19" Alpins fill out the fender wells exactly like the 20" PS4S's. The 1" higher sidewall would seem to offer more protection against deep potholes but it isn't enough against curbs.

I have aleady had my 20" turbo wheels repaired twice, charged to the wheel protection instead of to me. (The incidents were the unavoidable sort so I don't feel too guilty.) But the real eason I purchased the protection was to cover the tires or replacement of a wheel. One bed of nails dropped from a sloppy utility truck and bam bam bam bam I'm looking at a big bill. I had a rear tire replaced once already, so little wear on it that they said I didn't need two.

Two years ago while commuting by bicycle I saw what looked like a nail gun cartridge dropped in a busy intersection, nails scattered about. I called the state highway department office for that area. The regional amanger didn't even believe that was state jurisdiction even the posted signs and the road design clearly said so. I went on vacation, came back and rode that route several weeks later, saw they were still there. I called the state office, mentioned it. A week later they were cleaned up. Then I got a call from the regional office manager asking that if I saw something like that again that I call him directly. I figure he got a reaming oujt from the state office. That's okay by me if he didn't even know what roads he was responsible for. For all I know a dozen cars might have picked up flat tires there during the previous month.
 

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Yeah, if you ride a bike or walk near public roads near me, the trash on the roads can be stunning.
I've had one flat (rear tire) so far in just under 10,000 miles. Luckily it was a slow leak and I was local when it happened. I have the Goodyears and I plugged it myself. That was about 3000 miles ago and no issues.
The wide tires on these cars are probably a higher risk since they have such a big footprint (two of my classic cars have 165 width tires).
By the way, I typically just run the car on shorter, local trips so the lack of a spare tire isn't much of an issue. But I also bought the car for some longer trips so soon after the car was delivered, I picked up an appropriate spare tire, which I occasionally bring along on certain longer rides. I realize most people here are not that worried about this issue, but just in case you're curious, here's the story of my spare tire:

Spare Tire - 718 Cayman
 

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I was on a tight budget so my Cayman has the 18" wheels because that's what comes on a base car like mine. I didn't really consider any other size wheels.
That said, the outer diameter of all these tires is almost identical. That's because the sidewall height on the 19" and 20" wheels in less than the 18" wheels. (i.e.- the aspect ratio of my 18" tires is 45 versus the 35 aspect ratio of the optional 20" tires).
So tires on the larger size wheels don't really fill out the fenders any more than the smaller size wheels. The only thing that really might make the tires seem to fill out the fenders more is the visual effect created by lowering the car.
One other point: the taller sidewalls of the 18" tires means there is more rubber between the wheel and the road. So the 18" tires tend to be able to deal with rougher roads with less wheel damage. This may be more of an issue to me than other folks since I live in New Jersey, where our state symbol may as well be the pothole. :rolleyes:
Exactly. The outside diameter of the tires for these 18", 19", or 20" wheels is about the same, only the inside diameter and therefore the sidewall height changes. The most obvious difference other than aesthetics is the more compliant ride from 18s compared to 20s, the additional sidewall height offering additional shock absorption between the road and the wheel.
 

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Exactly. The outside diameter of the tires for these 18", 19", or 20" wheels is about the same, only the inside diameter and therefore the sidewall height changes. The most obvious difference other than aesthetics is the more compliant ride from 18s compared to 20s, the additional sidewall height offering additional shock absorption between the road and the wheel.
Yes, and the ride height doesn't change.
I do remember a Top Gear program where they tested the same car with different profile tyres/wheels and the low profile tyres were slower!
 

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Yes, and the ride height doesn't change.
I do remember a Top Gear program where they tested the same car with different profile tyres/wheels and the low profile tyres were slower!
This has been the result of every test I've seen, with 17 or 18" wheels being fastest. That's why I was so surprised to see all the new Porsches coming with 19 and even 20" wheels. I get that people think they look cooler but this is a brand that has always put performance first and at least makes an effort at "light weight".
 

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Slower how? And where? I'm not sure I'd trust Top Gear to do it in a way that is meaningful to me.
 

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This has been the result of every test I've seen, with 17 or 18" wheels being fastest.
...
This may well be the case from a standing start, though I'm not so sure there would be measurable difference in this case. If the weight of the 20" wheel with a low profile tire is greater than that of an 18" wheel with higher sidewall tire, then I believe the car with 18s will be faster in theory. But again, I'm not so sure it would be measurable over just a handful of measurements.
 

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The first test I saw like this was around 2000 by Sport Compact Car magazine. Timed acceleration and laps using the same car and same wheel/tire models in different sizes. Since then I've seen similar tests. The larger sizes are always heavier which hurts acceleration in reverse proportion to a car's torque and at some point the sidewall gets too short and stiff which hurts grip in all but the smoothest corners. The consensus was always that depending on the car (power, weight, & overall tire height) 16, 17, or 18" was the fastest size and going bigger was just for looks.

It could be that overall heights have increased enough that the 19s are now coming with a tall enough sidewall, the 20s I'm still suspicious of. Also, cars like the 911 have gained enough torque in recent years that the weight difference is easier to overcome. I suspect on the 300ish horsepower cars weight still matters though and the 20s (if not the 19s) must be heavy.
 
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