Thinking of getting 20" straggered on my cayenne
Need help on tire size

Someone told me I need
275/40/20
315/35/20

Is this right?

Some website selling rims package with
245/30/20
285/25/20

Please help !!

 

Need to know the width of the rims to pick the tires.

 

20×8.5 ( front )
20×10 ( rear )

Or

20x10 all around

 

On my 20x10s, I’m running a 275/40 ZR20 106 Y XL all around. It is in the middle range of its 9.0 - 11.0 fitment range and is within 1.31% of the OE 18s.

 

Could you tell us the "Offset" (front and rear, or "all" for the 10") ?

 

Thank you

 

You may want to try tire rack as they have all three original equipment wheels and sizes on their site. Then you can go from there but I would personally stay with the 20 that Porsche lists as original euipment sizes. Otherwise you will run into alignment and balancing problems.

 

My 2016 manual tells 275/45R20 110Y XL
9jx20,ro57 without wheel arch extentions
9,5jx20, Ro47 with wheel arch extentions

Personally i would go for the 45 profile over the 40 for the 275/20" wheel.
Because this will give a more accurate speedometer.
I have 275/45/20 for winter tires.
(My 295/35/21 wheels, that have a few percent smaller diameter, give 4 km/h to high speed reading at the speedometer.)

 

A 275/45 on a 9 or 9.5 x 20 will have a 2.41% error coming from the OE 18s.

 

My 2004 Turbo has a tire correction program buried in the PCM somewhere. You hit start, drive around for a while, and I guess it corrects the speedo for non-standard tires. At least that's how I understand it's purpose.