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Last Post 29 Jul 2014 09:37 AM by  hanhenze
2012 Cayman R, tire selection/size help
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djm1968
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10 Apr 2014 11:39 PM
    Hello,

    I am researching this seasons tire choice.  I take part in autox and also in a hillclimb organization that uses SCCA Solo rules; the hillclimbs are essentially a two mile, up hill, time trial.

    My current setup:

    OZ Alleggerita HLT
    8.5 x 18" - 53mm
    10 x 18" - 40mm

    Nitto NT01
    245/35/18 F
    275/35/18 R

    I have my selection narrowed down to either the Dunlop Direzza ZII or BFG g-Force Rivals. The know BFG's are supposedly the hot ticket in tw200 range, but as they are new, they are unproven. If I were to go with the BFG's I'd be limited in my size choices to:

    245/40/18 F
    275/35/18 R

    Where as with the Direzza ZII, I have a much broader size selection:
    245/35/18 F
    255/35/18 F?
    265/35/18 R
    275/35/18 R
    285/30/18 R

    The additional sizes are quite tempting as I'd like to trying running a bit more rubber up front this season to see if I can dial out a bit of understeer.  Any thoughts on fitting 255's on the fronts?

    Appreciate your input.

    Cheers,
    DJM 

    drdisque
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    Posts:317


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    12 Apr 2014 12:36 PM
    Beware that the ZII's are out of production and you may actually have trouble finding the tires you need. If you do want to get the ZII's and they're available in the sizes you want, pull the trigger sooner rather than later.
    Audii-Dudii
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    12 Apr 2014 09:46 PM
    I have an '06 Cayman S and my 18" setup used ZIIs (255/35-18 front, 275/35-18 rear) on the same wheels you have. They fit the wheels fine and clear everywhere under the fender. I have no experience with the Rivals, but as another data point, I do find my 19" setup to be slightly quicker...
    MrAWD
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    13 Apr 2014 12:40 PM
    I have 8.5" rims all around and I have 275/35/18 RS3s on them. They seem to look fine, but I have not push them in anger. If you can fit more tire inside the fender, I would use nothing less then 265s or 275s (still have to run them to know they are fine, but I do expect that to happen). Here is a picture:
    djm1968
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    Posts:31


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    17 Apr 2014 02:04 PM
    Posted By drdisque on 12 Apr 2014 12:36 PM
    Beware that the ZII's are out of production and you may actually have trouble finding the tires you need. If you do want to get the ZII's and they're available in the sizes you want, pull the trigger sooner rather than later.

    I was not aware the ZII's were out of production, thanks for the heads-up.

     

    DJM


    djm1968
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    Posts:31


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    17 Apr 2014 02:10 PM
    Posted By Audii-Dudii on 12 Apr 2014 09:46 PM
    I have an '06 Cayman S and my 18" setup used ZIIs (255/35-18 front, 275/35-18 rear) on the same wheels you have. They fit the wheels fine and clear everywhere under the fender. I have no experience with the Rivals, but as another data point, I do find my 19" setup to be slightly quicker...

    Great feedback.  Interesting that the 19" setup is a bit quicker.  When you run the 19's what tires were you running?  Sizes?

     Thanks,

    DJM


    Audii-Dudii
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    17 Apr 2014 11:12 PM
    Posted By djm1968 on 17 Apr 2014 02:10 PM
    Posted By Audii-Dudii on 12 Apr 2014 09:46 PM
    I have an '06 Cayman S and my 18" setup used ZIIs (255/35-18 front, 275/35-18 rear) on the same wheels you have. They fit the wheels fine and clear everywhere under the fender. I have no experience with the Rivals, but as another data point, I do find my 19" setup to be slightly quicker...

    Great feedback.  Interesting that the 19" setup is a bit quicker.  When you run the 19's what tires were you running?  Sizes?


    I was running Yokohama AD08s: 255/30-19 up front and 275/30-19 in back of my PASM-equipped car.  My assumption is that the shorter, stiffer sidewalls were a better match for my pitch-and-catch driving style than the 35-series sidewalls on the ZIIs, but I blew up the engine before I was able to compare a set of 18" and 19" AD08s back-to-back.  In any event, I found the 19" AD08 setup to be consistently .3-.4 seconds quicker than the ZIIs on local courses in the 40-60 second range.  The only negative I noticed is that the rear tires wore more quickly than the front tires and once the tire diameter stagger reached the .25" range (from a .4" starting point,) I started experiencing braking issues (i.e., "ice mode"), which I attribute to running too little stagger compared to the OEM ~.9" for which the ABS is calibrated.

    FWIW, I used Continental DWs in the same 19" sizes as my street tires and the one time I compared them to the AD08s, they were ~1.4 seconds slower on a dry 50-second course.  They're great for the street, though: They wear well, are good in the rain, and much quieter than the AD08s.  (I also found the AD08s to be very good in the rain, too, but not as good as the DWs during the first 15-20 minutes, when the roads are still covered with an oily film; after that, though, they might even have been a bit better.  Of course, it doesn't rain a lot here in Arizona, so this wasn't a major consideration for me...)

     

    djm1968
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    Posts:31


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    18 Apr 2014 12:37 AM

    Hey Audi-Dudii,

    Thanks again for the great info.  Sorry to hear you blew the motor -- that hurts.  I've read up a great deal about the ABS issue with the 987.1 series; this appears to have been resolved on the 987.2 cars, though I am working to keep the F-to-R diameter stagger close to OEM specs, especially considering I hillclimb too, not just autox...cliffs and all that.

    As far as the all seasons go, I am still on the factory Goodyear F1's which are fine for me.  Car only has 7k miles on her; I live in the PacNW, so much rain, but I mostly drive the 'R' for events and some nice weekends.

     Very interesting about your experience with the 19's being so much faster: 0.3 - 0.4 is a decent gap on 40-60 seconds runs.  Likely, I will still go with the 18" since I want to keep my OEM 19 wheels/tires for street usage, at least for now.

    Thanks again for all the input.  I'll follow up once I've made a decision and have something to report.

     

    Cheers,

    DJM

     

     

    hanhenze
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    Posts:73


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    01 Jun 2014 10:22 PM
    Try the RS-3 in 265 front and 295 rear on your 18" wheels. All the diameters line up with staggered fitment and you'll have a boat-load of grip. They even work well in the wet. Check or times from Spring Nationals. My co-driver and I were faster than the S2000 CR competitors when the rain hit in heat 5.
    djm1968
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    02 Jun 2014 12:14 PM
    RHS,

    Thanks for the input on the RS-3s. I ended up with 255/35/18 and 275/35/18 Direzza ZIIs, for a variety of reasons, including that they are available easily from America's Tire Co. Took the car for a drive this weekend and so far I am impressed with the Direzza's -- very stiff sidewalls with very sharp turn in, better than the 40 series Nitto NT01s I was running. It was hard to tell from just driving on the street, but the car does feel more balanced vs the 235/265 Goodyear OEM and Nitto NT01 setups I was running.

    Cheers,
    DJM
    loudes13
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    Posts:208


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    03 Jun 2014 08:27 AM
    The 245/40/18 rivals are a little tall and could rub you fender liner a tiny amount. I've run them on my 986S and 996.

    I've had bad experiences with wide RS3's on too narrow a rim, so I would be careful there. 265 & 275 seems like a lot of tire for 8.5".

    djm1968
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    Posts:31


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    07 Jul 2014 03:49 PM

    Just a quick follow-up after my first hillclimb with the new tires.  I took my Cayman to the shop and got a proper alignment done - went from roughly -0.5 to -1.35 camber up front!  Really should have paid attention to that last season.   With the wider front tires and the increased camber, front traction has improve *greatly* to the point where I was tail wagging more than I'd like.  Balance of the car changed so much that I really need to get used to it in a safer environment (autox vs mountain road!).  

    I did much better vs. last year (133 vs 121 secs for a 2 mile course), but my buddy in a 997.1 Carrera S, on street tires as well, pulled a 119; normally he trails me by a second or so.

    I was hoping someone could suggest some starting tire pressures to try with the Direzzas?  I tired 34/36 cold and car felt very loose on the rough, gravelly tarmac; 31/33 felt better, but still loose in the tail end.  Idea on where to start for pressures?

    Thanks for all the advice -- most helpful!

     

    DJM

    majormojo
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    22 Jul 2014 09:59 AM
    Han, are you running the RS3 version 2? I'm considering those for my '11 Cayman S, and looking for some input from folks who have tried the new tire.


    Sent from my iPad using Tapatalk
    hanhenze
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    25 Jul 2014 01:53 PM
    Sorry about the delay majormojo, no notification sent. I got the RS3s currently on the car at the end of Jan. this year. They have the 200 wear rating so I don't know if that qualifies them as version 2 or not. This is the first season I've campaigned that car on RS3 but we've done a lot of regional events last season (and 2013 also) in a '99 Boxster ASP. I think those tires can be almost as grippy as r-compound (maybe not fresh A6s but certainly BFG R1 S) depending on surface. My experience in Lincoln this spring supports that notion. I tried to make the car spin on the test and tune course with no success. I can definitely make it push (they're designed to do that). So over-steer is minimal but under-steer still challenging. I've been told that you can mitigate that by going closer to a square set-up (285 rear, 265 front) but that was referring to A6s. I personally like having the large traction pad on the rear. If you're thinking fresh rubber for Nationals, I'd do the RS3s. Scuff 'em good on the test and tune, then pray for rain after a really solid first run (hint - get a low number in class)
    majormojo
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    25 Jul 2014 03:35 PM
    Thanks Han. One more question, in your June 1st post you say 265/295 F/R, is that correct? TR does not show a 295 18in tire. that's why I ask.
    hanhenze
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    Posts:73


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    29 Jul 2014 09:37 AM
    My error. I checked the Tire Rack order and those were actually 245/40 front and 285/35 rear in 18". It also says those are no longer available so maybe that was the older compound.
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