Tire dilemma

I bought my 06CS with Yokohama Advan Neova AD08r tires. The car also came with Tarrett drop links, sway bars, HR springs and sump extender (The car had some track history). Unfortunately, I couldn't get up my driveway without scraping so I replaced the front springs with Cayman R while adding wheel spacers (7/15 mm F/R). Scraping issue solved & it now has a purposeful stance, but I'm going to need new tires soon. The car is now basically a daily driver with the occasional back road tour. I've been impressed with the Yokohama's grip, appearance, even the tread is marginally wider, but was considering Pilot Sport 4S which seem to be the go-to tire & may provide a better ride. Now I see Tire Rack has my Yokohamas on closeout, nearly half of what I would spend on the Michelins. Any thoughts?

How much grip do you want on your sports drive? Your car seems to be equipped to handle spirited drives though the corners where grip is king. What is the wear pattern of the tires? Outside shoulder nearly to the cord or inside showing signs of wear. The reason I ask is what suspension alignment details look like. Did the previous owner put camber into the car to prevent front outside tire shoulder roll. Can you get this info as it will provide some starting point for tire replacement. Many brands allow tire fipping. Others do not. If the shoulders are only for one corner, not a good choice if you want to maximize the tire tread. Many track guys know this and extend their wear by using the inside shoulder on their outside wear use. The other variable is do you drive your car in the rain? As a case in point here is Bridgestone older Summer tire model RE71R when driven on the street and the tires were flipped, The rain gutters are running against evacuation so almost causing hydroplaning. Currently, my tire choice is RE71RS, but will be changing to my OEM rims with Michelin PS4S for the winter. The new Bridgestone RE71RS are not flippable due to their asymmetric tread pattern. Never the less, as they wear, I may flip them during their final wear days. My camber is -2.9 f and -2.5 r with a little toe out in front and some toe in in the rear. I do not skimp on my tire selection as they are the final part of rubber meets the road.

If you're even a little impressed at the old Yoko's you can be confident in a new set exceeding the current bar. Apex is right, never go cheap on tires but IMO, Yoko isn't a cheap choice. I would rather run Yoko than Firestone or Sumatomo but having said that I'm putting nothing but Michelins on from here on out.

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As purchased, (35k miles, now 37.5 k miles after 2 years) the car had pronounced negative camber due to the lowering springs. Surprisingly, the tires (2013 date codes) showed even wear. Camber was adjusted front & rear as best as possible, still -1 degree greater than spec. Caster & Toe are now to spec. New bump stops, bellows, strut mounts & bearings went in with the "R" springs, new tie rods were also installed. (I'm now at 37.5k miles) True, AD008R are typically expensive & I'm a big proponent of buying the best tire possible, but for as infrequently as I drive the car and as impressed as I am with the Yokos, plus decent Tire Rack reviews, it's tempting.

docman- Read carefully the comparison of the Yoko A052 and Bridgestone RE71RS. Summer tires for the street, the Stones would last longer than the A052. With little milage each year, as long as you can afford the initial Tirerack and your Tirerack local install shop, then you would need to be able to use them up in say 5 years. You maybe able to get 10-12000 miles our of the RE71RS, but maybe only 6000 out of A052's. The Advan A052's are softer than the RE71RS. The other tires are not rated as Summer extreme tires by the TireRack, but certainly can give longer performance but not the grip. The question is are you going to drive your car enough to get more than 10,000 before you sell it in the future. Not likely, so spend money now, go drive it hard. Have some camber put back in to the alignment. Say -1.5f and -1.5r. camber and 0 toe f and 12 minutes of toe in in the rear. The outside front tire shoulder wear is the badge of courage as it measure how much front tire roll over you are extracting. Rippled front tire wear almost to the wear stars between the crown of the tire and the shoulder of the sidewall shows good play activity at the right tire pressure.

My current camber is -2.3f & -2.1r, that's adjusted as positive as possible without further modification. I looked up RE71RS, & with MI potholes I'm glad I have 18" rims. RE71RS makes 235/40R18 for the front, but I'm not sure what would be a suitable size tire for the rear. One thing I realized when buying closeout tires is that I'm screwed if I blow out a sidewall (MI potholes) so I should probably pass on the AD08R even though they're affordable.

docman - My size suggestion is 255/35/18 f and 275/35/18 r. Thats exactly what I am running. I am pretty sure your local shop that has a connection to the tirerack can mount this size on your 8 inch wide front rim and 9 inch wide rear. The RE71RS is a new model for the older RE71R that was discontinued a couple of years ago. Bridgestone just started importing this model in April of 2022. My size became available in August. The Tirerack can pre scrub the tires as a breakin. They will be ready to fly as soon as mounted. I did not know about this service, mine only took a couple of drives to get the rubber soft and sticky. Read the TireRack white paper on their test with the BRZ. I was especially interested in the wet application as this tire came out ahead of the softer A052. The TireRack has these in stock now. One mod you might be interested in is the WaveTrac ATB LSD. Take a look at their web site and read about how the wave slider transfer torque from the slipping slide to the gripping side. It actually works without causing a lot of understeer. I'm talking about the application of throttle at the apex to the exit of the corner. This LSD is excellent in that it does not totallly lock up as some clutch models do. Instead it allows some rotation deviation between rear tires. so you get maximum torque without mandating wheel slip as the clutch type does on lockup. I've had mine for 3 years now without any issues. It allows me to have a pretty consistant slip angle of 8 degrees without triggering the PSM.

255 on an 8” is too wide. I agree with the sizes, that’s what I have. 245/275 would work as good given your rim widths

Can’t go wrong with Michelins or Contis in most cases, I have had both, but I think the 4S and 4SA//S are the best combo for summer/winter. My 981 came with p-zero tires, but the next set will be 4S. Currently running 4S A/S for the winter months.

docman - The limiting factor in the front tires selection is that OEM front wheel is 8 inch wide. So the 245/35/18 will be a better match. It works very well with the 275 rear. Especially with a Wavetrac LSD that does add some understeer in front. So the contact patch is larger in front and with the better traction in the rear, makes for a great combo. If you have both the Michelin PS4S as a winter tire and the Bridgestone RE71RS summer tire, there is no comparison. I have both so in dry and wet conditions, the Stone works best. Only when the rain is enough to create a hydroplane condition, then the Michelin is better, but not until.

docman - Send us a picture of your new HRE wheels/tires. Hopefully you chose the RE71RS to pair with the new wheels.

My car is currently in hibernation, so upgrades are on the back burner until Spring. The only reason I was looking into new shoes for my Cayman at this time is because I stumbled onto Yokohama Advan's closeout pricing - the identical tires that hooked me, even with 8 years on them. Since I'll probably not go that route, I've got another 5 months to put something together. Regarding the HRE wheels, I've been in contact with Dave Nussbaum at Wheels Boutique in Miami - HRE's largest dealer in the world. Apparently I need R101 for 18" fitment. Again, lots of time to decide (thankfully) since the holidays, property & income taxes are due soon.

I get it. Lets talk next year.

If you don't intend to track it or drive it really hard, being in Michigan I'd think you'd want a performance all-season tire. On my previous 2 987s I had Conti ExtremeContact DWS 06. I have a 981 now w/ Michelin PS4S but will switch to the Contis when I need to. I do my hard driving on the track on track tires.

I have considered all seasons to extend my driving season. Tire Rack doesn't even recommend storing Summer tires below 40F, let alone driving (my car starts hibernation early). It's just that the suspension setup almost begs for Summer tires. I bought my car after test driving 6 others & was blown away with my car's handling & grip & that was when my Extreme Summer tires were already 8 years old. I'll be the first to admit that the sidewall stiffness telegraphs absolutely everything. Exactly what you want for the track, not so much for the street?!?

That's what autocross taught me in that you can run these stiff walled tires with substantially less tire pressure. There were many runs with 26 PSI in my old RE71R. I always pumped them back up before leaving the track though. The instrument panel was constantly on telling me I had a flat tire. I tried to turn off the msg, but just had to deal with it. At any rate, my usual pressure was around 30 PSI on the street (just enough psi to keep the flat tire msg off). This gave me a little cushion when hitting ruts or chip seal dips in the road. The outside temp is really what keeps the car in the garage though. Now with better wet traction from the RE71RS tires, there is less need for another tire, like the Michelin PS4S which does not have stiff side walls.

bldn10 - Do you use your Conti DWS year round, switching to PS4S for the track? Granted, TN has milder winters than MI. Still, I can't fathom driving the Cayman through snow, although there are probably those that do. Years back I built up a highly modified Focus ST (daily driver) with dedicated Summer wheels/tires, using ing the factory alloys/all seasons for Winter until I slid into a curb destroying 2 rims. I ran dedicated Winter tires after that. My eventual buyer benefitted by having 3 sets of wheel/tires.

docman- I would use a front offset of 47 for a 9 inch front wheel and a 36 offset for a 10.5 wide rear wheel. Hope that helps

Yes, I ran the Contis year round. But I have separate track wheels and tires. The MPS4s came on my “new” 981 .

I got a set of these in 18" and I love them: MICHELIN Pilot Sport A/S 3+ - Car Tire | MICHELIN USA (michelinman.com)

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. 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

Docman- the above side by side testimonial with change over drivers. I would add at least your -2.3 f camber f and -2.1 r using your Cayman R springs and swaybars. R brakes to stop the action, steel shifter cables and a GT3 short shifter, you should be all set.

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.

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.

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. Pilot Sport 5 Learn about the MICHELIN car tires, its benefits, customer reviews, current offers, and available sizes in the USA. Explore all the features and advantages of the PILOT SPORT 5 tire. www.michelinman.com Shawn in VA (USA)

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 tractio n be better?

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.

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.

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