Winter tire sizes fitting / do you need to fit in all numbers?

[MyA]

For the 2025 Macan Turbo Electric, the standard 20-inch tire dimensions are:
• Front: 235/55 R20 
• Rear: 285/45 R20

It is not my intention to downsize and would like to keep my original rims. Do the winter tires have to exactly match the numbers above?

Looking into Nokians Hakkapeliita R5 EV
Available sizes:

235/35 R 20 92T XL SILENTDRIVE
235/45 R 20 100T XL SILENTDRIVE
235/50 R 20 104T XL SILENTDRIVE
245/45 R 20 103R XL SILENTDRIVE
255/40 R 20 101T XL SILENTDRIVE
255/45 R 20 105T XL SILENTDRIVE
255/50 R 20 109R XL SILENTDRIVE
265/45 R 20 108T XL SILENTDRIVE
275/30 R 20 97T XL SILENTDRIVE
275/45 R 20 110T XL SILENTDRIVE
285/40 R 20 108R XL SILENTDRIVE

Thank you for your input!

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[jwatte]

The first number is how wide the tire is; if it's not the same, then the tire won't attach tightly to the rim -- either be too wide, or too narrow.
The last R number is the diameter of the rims; if it's not the same, then the tire either won't fit onto the rims, or the tire will have a big gap and not attach at all.

The second number is the profile percentage -- what percentage of the width is the depth. If this number is slightly bigger than standard, then the total diameter of your tire will be slightly too big, which might have clearance issues to the wheelhouse. If this number is slightly smaller than standard, then the tire will be slightly lower profile than standard, and your outer tire diameter will be slightly smaller, so the speedometer will indicate slightly faster than actual speed, the ride and road bump feel will be slightly harsher, and there will visually be a slightly bigger gap to the wheelhouse. The difference "45" vs "40" should IMO be possible to deal with, but not ideal. Larger differences, like "45" to "30," are not recommended.

Also, make sure you get the appropriate speed/load rating. EVs are heavy, and Porsches are fast.

 

[sor]

You can double check these but this combo looks to work and is within 1% of the original size. These are all XL, T or R should work and probably exceeds the OEM spec.

• Front: 255/50 R20
• Rear: 275/45 R20

 

[ColdCase]

All the tires need to have near the same diameter spec, regardless of tire width. The diameter can vary from OEM a bit, but the set of four must match. The OEM wheel width needs to be in the range specified by the tire manufacture. The tires have to have OEM load rating or better. Otherwise it is suspension and body clearance if you go too big. .

 

[Petzi]

don't you think that this will cause all sorts of (software) problems to play around with tire size?

 

[ColdCase]

Only if you change the tire diameter too much. The RWD is probably not as picky except perhaps the stability control.

 

[sor]

don't you think that this will cause all sorts of (software) problems to play around with tire size?

No. You lose more than 1% diameter just driving and wearing out your OEM tires, and often front and rear at a different rate. They must be able to handle variation within a reasonable amount. The OEM tires themselves come in minor variations of width and diameter as well.

 

[ADS]

I bought the non EV version:

Nokian Hakkapeliitta R5 SUV 235/55R20XL 105R BSW Nokian Hakkapeliitta R5 SUV 285/45R20XL 112T BSW

 

[MyA]

Yeah this is what my dealer is offering me.
Debating if the R5 EV is really worth the hassle…..

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