I got a set of these in 18" and I love them: MICHELIN Pilot Sport A/S 3+ - Car Tire | MICHELIN USA (michelinman.com)
Tire dilemma
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Docman - A new Everyday Driver, Season 12 TV compares a 987.1 S vs a Toyota GR 86 trying to keep a $34k entry for a gentleman's sports car on new RE71RS. Quite a test for a 16 year old Cayman. Give it a look, shows how brakes can make a big difference.
www.gr86.org
Toyota GR86 or Porsche Cayman - Which is better at the...
Everyday Driver compared the GR86 to a 2006 Cayman S (987) to see which car is better for the same price. They were torn about which one they'd give the edge to.
www.gr86.org
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Tire Rack suggested the Conti DWS when I mentioned that there were some dry sunny colder days that I would consider taking my Cayman out, extending my driving season. I've had those tires on a FWD car that I drove year round. Surprisingly good in snow. But for as infrequent as those colder dry days are, I'd probably be better off buying summers, in the grand scheme of things.
I was just about to pull the trigger on PS4S (current deal at Costco) but I just learned about the Sport 5 that are starting to make their way to the US. I'm considering these because 1) I don't track my car 2) They are rated for long wear & 3) They have the 'Premium Touch' sidewall design (kinda cool). The car is garaged through the winter so I'm in no hurry.
One of the reasons my particular CS enticed me over the 6 others I test drove was it's sharp turn in due to it's (lower/stiffer) Cayman R springs, Tarett sta bars/drop links and likely the Yokohama Advan Neova AD08 R track/street tires (10 yr old). For as tight as the car handles, these all make for a pretty hard ride over Michigan roads, even with 40 series tires.
My question: Will I realize much of an improvement in ride at the expense of turn in by choosing Pilot Sport 5 tires over 4S, or will it be negligible? I imagine that either Michelin will probably have less stiff sidewalls than the old Yokos.
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docman, good choice of a new 981. Not sure what size wheels your new Cayman has but you certainly can go back to the Rack and ask about the gentleman's sports car RE71RS tires. For those who do not track their car but want immediate turn in and very stable braking, corning and acceleration, these are the tires for you. I have both the RE71RS and PS4s and there simply is no comparison. I have not tried the newest edition Sport 5 models. but they certainly are not Summer extreme tires.
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I love my Conti Extreme Contact DWS and feel very safe and stuck to the road in almost all conditions (not so much in snow) including AutoX. I live in VA and drive the car all year. For me a great choice and probably what I’ll replace them with.
As for PS5, I don’t think their I is a lot of info available as I don’t know anyone who has them. I do see they have a 60 day satisfaction back guarantee.
www.michelinman.com
Shawn in VA (USA)
As for PS5, I don’t think their I is a lot of info available as I don’t know anyone who has them. I do see they have a 60 day satisfaction back guarantee.
MICHELIN® Pilot Sport 5 - Performance Sport - Summer tire | MICHELIN® US
MICHELIN® Pilot Sport 5 tires - information & user reviews. See if it fits your car (browse by size or by vehicle). Get yours today at the nearest tire dealer.
www.michelinman.com
Shawn in VA (USA)
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I would like to see a competition between the RE71RS and the new PS5. "TireRack" Why not use a Cayman this time and a little longer course. We can digest the results. Mid engine and wider wheels/tires in the rear. For me, I have setup my car to utilize this running 255/35/18 f and 275/35/18 r, with a Wavetrac LSD adding more push requiring a larger tire patch in front. If TR uses a car with PVT, that would match my setup pretty closely. Both wet and dry tests as well as g loading and time trial. We will see which tire has the higher spring rate side wall giving the best turn in control, braking, acceleration and G loading.
I'll be the first to admit I'm no tire dynamics expert, but is there a reason why Porsche recommends a rear tire that's a larger diameter with a taller sidewall (235/40R18 - 25.4") f / (265/40R18 - 26.3") r for my 06CS? The difference for 911 is even greater. I leads me to think it might have to do with f/r weight bias but (for example) the front engine C6 Corvette has similar sidewall heights f/r as does the mid-engine C7.
Why not 275/35R18 - 25.6" r for the Cayman? The specs still targets a 9" wide rim.
I understand a narrower front tire (relative to the rear) for steering, but wouldn't a similar sized sidewall for handling plus a wider footprint for traction be better?
Why not 275/35R18 - 25.6" r for the Cayman? The specs still targets a 9" wide rim.
I understand a narrower front tire (relative to the rear) for steering, but wouldn't a similar sized sidewall for handling plus a wider footprint for traction be better?
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I'm no expert either, but considering that the same engineering team that designed the suspension of your Cayman chose to use 265/40R18s on the rear axle rather than 275/35R18s, and that they've used pretty much the same F/R tire size ratio on every generation of Cayman (except for the GT4; it's always 235/265 with the same aspect ratio for both axles regardless of wheel diameter), I would assume there are very good reasons why they made that choice.
Tires are only a part of the suspension equation; the sizes of the tires are chosen to complement the rest of the suspension. Changing any part of that equation would change the behavior of the whole. For one thing, mounting 275/35R18s on the rear axle of your car would introduce a speedometer error that would get more pronounced the faster you went. This is because the 275/35s have a 2.7% smaller diameter than the OEM size. And my guess is that that would be the least of the potential issues that could come from changing the rear axle geometry that much.
All in all, I'd hesitate to second-guess Porsche engineers on something so fundamental to the design of the car. But as I said, I'm no expert; this is just my two cents.
It really comes down to what you want. I mean if it is for aesthetics and just street driven it may work fine. If you are tracking them it’s really an experiment, just a different setup and the only way to tell is if the driver likes the feel of the setup, the lap time is better and tire wear is acceptable.
I’m not sure its useful to talk about the Corvette tire sizing when making a decision about a Porsche. But I believe it’s the C8 and not the C7 that is midengine. And the front and back sizing seems to have a staggered setup similar to a Porsche.
The most important thing with tire sizing is that the front to back ratio stays similar. This is important for handling balance as well as things like stability control. In particular the ratio of the front to back tire diameter should stay similar to the stock numbers. The actual sizes can change, but the ratio needs to be very close.
if you are not doing autox or track, I would stay with 40 series in stock sizing. The ride on the street will be more forgiving while the handling will be the fantastic handling that makes a Porsche what it is.
I use 40 series tires in stock sizing on my OE wheels for my street driving, and another wider set of wheels with wider and lower profile 35 series tires for track and autox. Each does it’s job best in the respective setting.
The most important thing with tire sizing is that the front to back ratio stays similar. This is important for handling balance as well as things like stability control. In particular the ratio of the front to back tire diameter should stay similar to the stock numbers. The actual sizes can change, but the ratio needs to be very close.
if you are not doing autox or track, I would stay with 40 series in stock sizing. The ride on the street will be more forgiving while the handling will be the fantastic handling that makes a Porsche what it is.
I use 40 series tires in stock sizing on my OE wheels for my street driving, and another wider set of wheels with wider and lower profile 35 series tires for track and autox. Each does it’s job best in the respective setting.
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Greg summed the tire choice up well. What I have found over the years is what to do with heat cycled tires, that are not even close to their wear bars in all three measurement places, Well I am using these tire up on the street. Yes, when its a down pour I have to be extra cautious with speed, but in my world, I would not be using my Cayman that day. So, last year, I finished off a set of Bridgestone RE71R's and put about 10k miles on them total of which less than 5% were track miles. What this usage did for me was to appreciate the unique features of these tires have for the street. I really liked their turn in and grip,
Yes they were noisy and had some vibration but they were free. I tried to switch back to my OEM setup with Michelin PS4S's, but did not like the result, so they stayed on the wall in my garage. I used up the Bridgestone's and ordered a new set of RE71RS which are on the car now, even in the winter because I find I'm not running to the store or other errands with this car. It stays in the garage until there is limited forecast for rain and the temps are above 40 degrees. So now I can have great turn in, braking, g loading and traction every day I use the Porsche.
This video is from two guys using their Porsche Cayman 987.1S vs a Toyota GR86. What this shows is the expanse of usage of the new RE71RS, which I agree with. The bridgestone created a wide range of excellent features and benefits so that they eliminated my use of the Michelin PS4S's completely.
Yes they were noisy and had some vibration but they were free. I tried to switch back to my OEM setup with Michelin PS4S's, but did not like the result, so they stayed on the wall in my garage. I used up the Bridgestone's and ordered a new set of RE71RS which are on the car now, even in the winter because I find I'm not running to the store or other errands with this car. It stays in the garage until there is limited forecast for rain and the temps are above 40 degrees. So now I can have great turn in, braking, g loading and traction every day I use the Porsche.
My bad, I obviously meant C8 when referring to the mid-engine Corvette.
When looking at tire sizes for the current Corvette, the Stingray rears are 0.5" larger diameter than the front, whereas the Z06 is 1.3". The current Mustang Mach 1 rears are 0.7" larger whereas the more pedestrian versions have the same diameter.
What confounds me is that (for example) the 1995 993 Carrera (also staggered width front / rear rims) were shod with the same diameter tires on the 16" & 17" increasing in diameter slightly (0.2") for the 18" diameter rears, all the way up in HP to the the AWD turbo. Bottom line, not a significant difference in diameter. It wasn't until the 996 (& now 986) that the rear tire diameters exceeded the fronts by roughly 1".
So, if the 993 is any example I'm guessing that it isn't just HP that has driven this trend. Newer cars either are designed for that bias, or that it is just the accepted norm for performance vehicles.
I would rather have a definitive reason why a Porsche specifies (roughly) a 1" larger diameter rear on Porsche Cayman & 911 since my car never sees
I'd rather not guess, but
I'm trying to get to the bottom of why
Sorry, just trying to wrap my head around tire sizing rationale for my Cayman S daily driver.
And don't get me started on rims - why do the GT3, McLaren, Bugatti, Lamborghini Aventador, Corvettes & even Ferrari Purosangue (as examples) have larger diameter rear rims whereas Lotus Emira, Lamborghini Huracan, & all other Ferrari & all other Porsche rear rim diameters match the front?
. Looks like the S5 will be OE only and Porsche will start seeing them soon.
Contrary to this video, I read that the the S5 are more engineered for longevity, not necessarily increased performance over the 4S & considering that 265/40R18 (let alone any sizes) aren't yet available in the US, I took advantage of a Michelin sale at Discount Tire & had a set of PS4S mounted - 235/40R18 & 265/40R18 (goodbye 10 yr old Yokos). We've had a few days in MI that broke 40° & I have to say that I'm already pleased even though my initial TPMS reading said they only reached an operating temp of 77° for that relatively short, non-aggressive drive.
I also replaced my ancient, scuffed/dull PPF & will be wiring in a Rennkit Bluetooth adapter & cell phone holder. Looking forward to a great driving season & thanks for everyone's input.
I also replaced my ancient, scuffed/dull PPF & will be wiring in a Rennkit Bluetooth adapter & cell phone holder. Looking forward to a great driving season & thanks for everyone's input.
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The PS5 looks to capture the same market that Bridgestone did with the RE71RS. That is taking an autocross tire and making a general sportsman daily driver with track abilities. They fignured out that their tire could do this multi role better and ultimately sell more tires. So that's what was behind the test between the Cayman and Toyota GR86. That test opened my eyes and confirmed what I already discovered that the new RE71RS could be used for a daily tire very very well. The only clevit was the use when the outside temps go below 40 degrees. So off my car they went and on went the Michelin PS4's for winter use. These two sets of tires is as close as I could get them. My tire shop would not mount the Michelin PS4's 255/35/18 front tire on my 8 in oem front wheel, so I had to go down one size to 245/35/18 vs the 255/35/18 for the RE71RS wheich are mounted on Signature 9 in f wheel. So, my lineup is the 18 inch OEM wheels are 8 in wide in f and 9 inch wide in the rear fitted with Michelin PS4's 245/35/18 f and 275.35/18 r. The other street tire setup is Signature 18 9 in f and 10 in r. RE71RS 18/35/255 f and 18/35/275 r. I do get a little more understeer from the Michelin tire setup, but on the street that's OK.
I do have more specific alignment requirements that work with both sets of tires. Toe out in f, 4 minutes on each side for improved turn in. I recently had my alignment changed to this spec and the camber reduced in f to -2.7 and -2.4 r. I also changed the castor to 8.4. In the rear I called for toe in of 8 minutes each side. My car sets on Tarett Cup Race LCA's without any rubber bushings, so its locked in place. That's important to keep the alignment as close to the my spec as possible to prevent inside tire wear during street operation which is about 95%.
Comparing the new Michelin PS5 to the RE71RS will show the benefits of Bridgestone's race heritage. We do need a side by side trial done though in white paper conditions with a mid engine car,
I do have more specific alignment requirements that work with both sets of tires. Toe out in f, 4 minutes on each side for improved turn in. I recently had my alignment changed to this spec and the camber reduced in f to -2.7 and -2.4 r. I also changed the castor to 8.4. In the rear I called for toe in of 8 minutes each side. My car sets on Tarett Cup Race LCA's without any rubber bushings, so its locked in place. That's important to keep the alignment as close to the my spec as possible to prevent inside tire wear during street operation which is about 95%.
Comparing the new Michelin PS5 to the RE71RS will show the benefits of Bridgestone's race heritage. We do need a side by side trial done though in white paper conditions with a mid engine car,
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