Sorry, another tire combo question for this Panamera newbie. Anyone see any issue with the 255/40/20 (28" tall) or 275/40/20 (28.7") front and 315/35/20 (28.7" tall) rear tire combo for a 2016 Panamera Turbo S? I have the classic rims that are 20"x 9.5" for the fronts and 20"x 11" for the rears. I know the Panameras are AWD and have the same height tires at all four corners. My factory tire and rim size is 255/40/20 (28" tall) and 295/35/20 (28.1" tall). Will that .6" difference in height on the rears cause an issue? Anyone running this combo? I am needing new tires and now would be the time to change if this will not cause any problems. Also, if anyone is running this combo and has some pictures, it would be greatly appreciated. Thank you.

 

what did you end up doing? I am in the same boat.

 

Generally speaking keep the height consistent between front in rear is more important than keeping the height the same from the factory. The AWD system expects the rotation to be the same distance per turn in all 4 corners, and if not, it sees it as slip and adjusts power accordingly. It can create some unexpected effects, including premature wear of the AWD system. Bottom line, if you stay with the same height front and year you should be fine. I wouldn't recommend running 255/315 combo - I'd go 275/315 to keep it closer and reduce the chance of a problem.

However, if you stay with the rear stock rims they are likely too narrow for those size tires. If the shop will even put them in they will be tucked. Here is a chart that lists the ideal/max tire size for each size wheel. 11" max is 305 (285 or 295 recommended), 9.5 is 275 (255/265 recommended). It may not be recommended but if you weren't going to track or do a lot of aggressive handling it would probably work ok since it's only 1 size over the maximum and only in the rears.

https://www.tyresizecalculator.com/c...rim-size-chart

I actually want to run the same width setup, but likely going to buy wider rims.

 

The tyresizecalculator.com website seems to be slightly off from manufacturer specs it seems. I checked www.tirerack.com for several of 275/40R20 and 315/35R20 to find:

275/40R20 9.0" - 11.0" *
315/35R20 10.5" - 12.5"

* ContiSportContact 5 SSR shows 9.0" - 10.5" on www.tirerack.com but Continental website says 9.0" - 11.0". The remaining on TireRack match the latter.

I wish I knew exactly which wheel combo ours has, the manual notes 9.5J x 20 front but either 11J x 20 or 11.5J x 20 rear. It doesn't matter in this specific tire size but it would be nice to know. Also, if this size rubs because it is larger than stock...

 

ok back to the OP's orignal question - has anyone used 275/40/20 (28.7") front and 315/35/20 (28.7" tall) rear tire combo for a 2016 Panamera Turbo S or GTS?

 

yes it has been done with out any issue! Usually within .3” will work, the back should be equal or larger than the front.

 

Mike - got any pictures of your car with this set up? 275 & 315?

 

I’m still on stock sizes, look up mod2fame on YouTube he runs the 265/315 set up ona. PTT with some R888’s.

 

Went on YouTube to look mod2fame up. He ran 275/40R20 up front with stock setup and 305/35R20 with spacer on the rear.

 

I thought he was on a 315? It would be a better option seeing they are closer to the same OD.

see the chart as to compatible sizes, it is important to keep the same OD because of the AWD system! Rule of thumb is within 1% is ok, personally I’m not sure how Tolerant the Porsche differential is.

 

I found then watched the entire video on him switching out his 22s for stock 20 wheels with slightly larger tires than stock. He pretty clearly states 305. I rewound and replayed it to make sure. I also saw his really shiny wheel spacer on the rear that made the rears stick out some vs the front that looked somewhat recessed in comparison.

I completely agree the tire size calculator on www.tires.com shows 275/40R20 and 315/35R20 match up perfectly in height/circumference. Just don't want to possibly misinform the one asking that it fits. I'm also interested in this size as Atturo AZ850s come as runflats in this exact size combo. (Won't need tires for a while with the tread left on ours though)....

 

I didn’t review the video that closely. But I think with the AWD system the closest to oem OD is the best

 

It's a nice size combo as you point out. Thank you.


@ 5:29

(Wonder how much faster it would be if he got the 315/35R20 vs 305/35R20)!

 

I use 275 40 20 front and 315 35 20 rear Continental DWS06 tires. Here is the thread from ages ago: https://www.6speedonline.com/forums/...5-20-rear.html

 

Do you use spacers, any rubbing issue?

Thanks