When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It is time for me to get new rear tires on my 2014 Cayman S. I have 20" rims. The rear tire size on my car is 285/30ZR20. After doing some research, it looks like the standard 20" tire size is 265/35-20. My door sticker says 265/35 ZR20 so the last owner must have changed it. Am I better going back to 365/35s? Are there advantages to staying with the wider size? I don't track it, but I would like to sometime (once or twice). I don't live by any fun roads, but I am taking a guys road trip next month (4 sports cars) to Beartooth Highway in Montana/ Wyoming, and Needles Highway/Iron Mountain Road in the Black Hills SD. But generally, my car just gets used in town and a few highway trips to see our sons if I can talk my wife into taking the car. It has Michelin PS4S and since I am not changing the fronts this time, I will probably stay with them, unless somebody has a good reason for me to change. Their new PS4 A/S have me intrigued. I drive from spring till fall in northern SD, and park it for the winter. If I drive it when it is down to 40 degrees, I take care, but generally that is when I put it in storage.
Are you running an OEM 20" wheel or if not do you know what width the rim is?
I think you could probably squeeze 285s on the Sport Techno wheels (which were the widest available from the factory) but the 265s on mine already have a bulgy sidewall.
That being said, I'm running OEM sized 265s on my 20" wheels.
Surprised they fit with how much 265s bulge on my wider wheels. I'm sure others will chime in though - 285 is a common size just not sure about it on the OEM wheels.
If you don’t track much, or at all, 285 seems fine. I have the cayman turbo style wheels on my 981 GTS (same width as sport technos), with 285 PS4S (2019) and it’s great for comfort (w/x73) and grip. I chose oversize for comfort because I was intending to get a track wheel/tire setup; I still haven’t so I’ve been on the 285s for the last 4 years as DD and weekend mountain drives. Not as fun as the 265 pzeros that came with the car, because with the 285 PS4S I really have to try to lose traction even in PNW rain, but great for street and road trips. Maybe someone with your wheels and suspension will chime in.
Love the Black Hills. Some great roads out there!
In your situation I think I'd get whichever tire size was available and priced more competitively. If the 265s are less expensive, I'd go that route. I don't think you'll gain any advantages going to 285.
It is time for me to get new rear tires on my 2014 Cayman S. I have 20" rims. The rear tire size on my car is 285/30ZR20. After doing some research, it looks like the standard 20" tire size is 265/35-20. My door sticker says 265/35 ZR20 so the last owner must have changed it. Am I better going back to 365/35s? Are there advantages to staying with the wider size? I don't track it, but I would like to sometime (once or twice). I don't live by any fun roads, but I am taking a guys road trip next month (4 sports cars) to Beartooth Highway in Montana/ Wyoming, and Needles Highway/Iron Mountain Road in the Black Hills SD. But generally, my car just gets used in town and a few highway trips to see our sons if I can talk my wife into taking the car. It has Michelin PS4S and since I am not changing the fronts this time, I will probably stay with them, unless somebody has a good reason for me to change. Their new PS4 A/S have me intrigued. I drive from spring till fall in northern SD, and park it for the winter. If I drive it when it is down to 40 degrees, I take care, but generally that is when I put it in storage.
The engineers speced 235 front and 265 rear for a reason. Just go back to OE sizes for street and occasional track. Fresh PS4S in stock sizes will be optimal for your use case. The A/Ss will give you year-round capability with not much loss in the summer (but don't track the A/Ss).
Just got the new rears installed yesterday. I decided to go with the stock size of 265/35/20. I didn't realize just how bad the inside edge of the old ones were until they were off the car. The wear looks fairly even until that last 1" of the inside edge. The right side was by far the worst, but you could see it on the left side also. The last owner put about 9,000 miles on the tires and then Carfax shows it had new front tires installed and was aligned right before I purchased it. I put about 5,500 miles on the tires for a total of about 15,000 which sounds about normal for rears on the 981. I'm not sure if the last alignment took care of the wear issue, but I'm not taking a chance with the new tires. I have an alignment set up for this afternoon.
Left Rear Right rear Right rear size difference (not mounted)