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997.2 targa 4S winter tire question

 
Old 03-10-2019, 02:19 PM
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hippak
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Default 997.2 targa 4S winter tire question

Hi all.

I have winter tires and rims off a 987.1 Cayman and wondering if the tires would work on a 997.2.

They are winter tires (using stock tire size for summers)

Fronts: 225/40/18
Rears: 265/35/18

Would these be suitable for a 997.2 4S or should i
just sell them?

Thansk.
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Old 03-10-2019, 04:17 PM
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ogun228
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Manual says 225x40 R18 Front
265x40R18 Rears
Offsets are 57 F 60 R

You could try them. When I first got my 2009 C2S, I used
18 winter wheels and tires from my previous 996 C4S for 2
winters b4 switching to 19. Kind of regret doing that.
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Old 03-10-2019, 06:11 PM
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rap
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I have 225/35/18 fronts and 275/30/18 rear
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Old 03-10-2019, 06:18 PM
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jbaker136
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Originally Posted by hippak View Post
Hi all.

I have winter tires and rims off a 987.1 Cayman and wondering if the tires would work on a 997.2.

They are winter tires (using stock tire size for summers)

Fronts: 225/40/18
Rears: 265/35/18

Would these be suitable for a 997.2 4S or should i
just sell them?

Thansk.
Those will not fit your Targa. Here are your correct tire and wheel options:


Good luck.

Jeff
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Old 03-11-2019, 09:37 AM
  #5  
Petza914
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Look up the rolling circumference of those two tires from the manufacturer's website. If they're within 1% of each other you should be fine. Beyond that and you may cause issues with the 4wd system . There's no reason to run a 295 width rear snow tire - just makes it float on top of the snow when it's deep. The narrower tire will get down through the snow better and to the road surface for grip.

Make sure the load rating of the rear tires is high enough to support the load on the 911. Should be a label on your car that gives front / rear GVWR info. The rear tire needs to have a load index that equates to 1/2 that rear number or above.
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Old 03-11-2019, 01:01 PM
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rap
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My mistake. Mine are 19.
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Old 03-13-2019, 07:43 PM
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hippak
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Originally Posted by jbaker136 View Post
Those will not fit your Targa. Here are your correct tire and wheel options:


Good luck.

Jeff
Thanks Jeff. Running 295 rears per the manual suggestion seems crazy... Do people on this board actually run that size in deep snow?

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Old 03-13-2019, 07:45 PM
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hippak
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Originally Posted by Petza914 View Post
Look up the rolling circumference of those two tires from the manufacturer's website. If they're within 1% of each other you should be fine. Beyond that and you may cause issues with the 4wd system . There's no reason to run a 295 width rear snow tire - just makes it float on top of the snow when it's deep. The narrower tire will get down through the snow better and to the road surface for grip.

Make sure the load rating of the rear tires is high enough to support the load on the 911. Should be a label on your car that gives front / rear GVWR info. The rear tire needs to have a load index that equates to 1/2 that rear number or above.

Do you mean the rolling circumference difference between the front and rear? I looked up the rolling circumference between the stock fronts vs rears and its around 2.7% so unclear about the 1% rule creating an issue for the AWD system?

The difference between rolling circumference of the tires i'm looking to run is 0.8%...does this mean that I should be good?

Thanks for the help guys.

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Old 03-13-2019, 11:27 PM
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Originally Posted by hippak View Post
Thanks Jeff. Running 295 rears per the manual suggestion seems crazy... Do people on this board actually run that size in deep snow?
Run the recommended tire size (Pirelli Sottozerois the only option and is a great winter tire) and have fun. If the 295 width is impacting the performance, there is too much snow for the car! Look at the fun you can have!


Jeff
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Old 03-14-2019, 12:14 AM
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C4SDayton
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Originally Posted by hippak View Post
Do you mean the rolling circumference difference between the front and rear? I looked up the rolling circumference between the stock fronts vs rears and its around 2.7% so unclear about the 1% rule creating an issue for the AWD system?

The difference between rolling circumference of the tires i'm looking to run is 0.8%...does this mean that I should be good?

Thanks for the help guys.
It is the tire height. Rear should be about .7 inch taller than front. Winter setup is about .5 inch difference. Others have used tires with .3-.4 difference successfully. There is more choice with non N rated tires. Don't be afraid.
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Old 03-14-2019, 02:06 PM
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Originally Posted by hippak View Post
Thanks Jeff. Running 295 rears per the manual suggestion seems crazy... Do people on this board actually run that size in deep snow?
No. I run the pirelli sottozero in 265/40R18 rear 235/40R18 in front with the BBS SR in the correct offsets on my 997.2 C4S. I would think that your wheels should fit, but probably need a rear spacer to correct for the offset difference with the Cayman rear wheel.

Deep snow is relative. The car only has a few inches of clearance before the skid plates turn it from car to sled. But my experience has always been on thin snow that a narrower tire will cut down to asphalt a little better and a wider tire will float. The new thinking on winter tires is that they aim for a bit more snow adhesion to the tire and use the snow for traction. In that sense, the wider may have similar grip on ice, but I'd rather get down to asphalt if possible.
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Old 03-14-2019, 02:17 PM
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Originally Posted by GoldenGorilla View Post
No. I run the pirelli sottozero in 265/40R18 rear 235/40R18 in front with the BBS SR in the correct offsets on my 997.2 C4S. I would think that your wheels should fit, but probably need a rear spacer to correct for the offset difference with the Cayman rear wheel.

Deep snow is relative. The car only has a few inches of clearance before the skid plates turn it from car to sled. But my experience has always been on thin snow that a narrower tire will cut down to asphalt a little better and a wider tire will float. The new thinking on winter tires is that they aim for a bit more snow adhesion to the tire and use the snow for traction. In that sense, the wider may have similar grip on ice, but I'd rather get down to asphalt if possible.

thanks. So what Iĺm hearing is that the wheels plus tires may potentially work (with a spacer)? I checked
the tire height and I looks like the difference between front and rear is 0.2 inches. Will this create an issue with the AWD system?
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Old 03-14-2019, 02:27 PM
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^The default tires have a height difference as well. I asked about it and was told that it's to keep some load on the diff for NVH reasons.
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Old 03-15-2019, 12:52 AM
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The 235/40R18 265/40R18 is an approved combination for the 997.1 but the 997.2 only lists a 295/35R18 rear spec option which is 2.75mm smaller in radius in theory. The awd system is designed for offset whrel sizes so there has to be some tolerance. I have put about 4k on the car this winter and haven't seen any issues. However with a 225/40R18 front, you will be adding 4mm additional offset. I'm not really sure.
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Old 03-15-2019, 08:02 AM
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I'm running 235/35-19 and 295/30-19 Nokian Hakkapeliitta7s for two reasons: (i) availability and (ii) these are the registered sizes - if I wanted to run 18s I'd need to try and register the new tyre size (to stay legal) and the authorities might not agree. Especially since they can read tables.

Anyway, all this being said, I've not had any issues with snow, or even deepish soft snow. The constrant is the ride height, not the width of the tyres.
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