Is there a OEM Porsche Wheel Fitment Cross Reference Chart/Guide?

[jonbek]

Simply put, I'm watching ebay and rennlist etc for a second set of wheels for winter, and maybe track use. I'm just curious what other Porsche models I could consider as perfect or even close fitments for this idle pursuit of mine.

Is there any simple chart or explainer across p-models?

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[TaycanCook]

your best bet is likely to just focus on the offsets. If you want a set of winter wheels, no better than just getting the base stock wheels. plenty abound.

 

[whan]

I've spent a lot of time looking into wheels, so I guess I'll write a primer on it by steps:

1. Make sure you're first picking wheels that have a Porsche bolt pattern, which is 5x130. This is the actual spacing and number of bolts. If you don't have this, the wheel will not bolt onto the hub and will be guaranteed to not work
2. Ideally, make sure your center bore is the same size as the Porsche 71.6mm. This is the size of the hole in the center of the wheel. You can get a wheel with a larger center bore, but you'll need to use centering rings to fill the gap. I'm not going to debate any other possible downsides of doing this here, but know it's not as ideal as getting one with the correct center bore from the start
3. Look at what the OEM wheel specs for width and offset. A good source is here https://www.wheel-size.com/size/porsche/taycan/2021/.
   • Width is self explanatory, it's how wide the wheel is. The wider a wheel is, the more it will poke out of your fenders as well as the inside lip being closer to your wheel lining since it increases width in both directions.
   • Offset refers to where the mounting point of the wheel is, relative to the middle of the wheel by width. So +10 offset means that the mounting point of the wheel is 10mm closer to the front/display face of the wheel, vs. the middle of the wheel. -10 offset means it's 10mm further from the front, or 10mm closer to the back of the wheel. The more positive offset a wheel has, the closer it sits to your car's suspension parts and brakes. The more negative, the further away from these components
4. Once you have wheel width and offset for your aftermarket wheel, you need to use these items in combination to figure out if it will fit. There are 3 things to be careful about:
   • First is making sure the wheel clears your brake caliper. Note that this is a bit dependent on wheel design, but you ideally want the front face of your wheel to at least be the same distance away from the mounting point as the OEM wheel. Any closer, and the front face of the wheel could hit the brake caliper. In practical terms, this means that if the wheel is the same width as OEM, you can do lower offset as the front will sit further away from the caliper. If you change the wheel width, the change in width vs. OEM will extend 50% in each direction. So if you go from a 9 inch to a 10 inch wheel, each side of the wheel will extend 0.5" more on both sides vs. OEM. These two items can have opposing effects though, so if you went from a 10 inch wheel to a 9 inch, the front face would sit 0.5" (12.7mm) closer. This can be counteracted by lowering the offset by 13mm, which pushes the front face back out by the same amount, since the mounting point is 13mm closer to the rear of the wheel.
   • The second is making sure the front of the wheel isn't extended too far out, IE not too wide / not too low offset. This will result in your wheel being past your fender, which most people don't like the look of. Additionally, it may cause rubbing on your fender liner when turning, but this depends on a car's suspension geometry and fender dimensions
   • The third is making sure the inside of the wheel doesn't touch any suspension arms. This mostly is caused by having a wheel that's too wide
   • There is a website that can visualize how two wheels of different specs will sit, including front and rear face, and mounting point.
5. A good way to see how various offsets might fit is searching for people who have installed spacers. Spacers effectively lower the offset of the wheel by however thick they are. So 10mm spacers decrease offset by 10mm and push the entire wheel 10mm further out. People on this forum have done up to 15mm front and rear with no issues, although this is a relatively aggressive fitment on a lowered car (increases negative camber which helps the top of the wheel tuck into the wheelwell). 15mm/12mm and 12mm/10mm are somewhat more conservative setups that have been done with less lowered cars

As a TLDR, I'd recommend finding wheels with the same width as stock, and up to 15mm less offset in front, and 12mm less offset in rear, but at most the same offset as stock (do not allow it to be more positive offset than oem or it might not clear brakes). You can have some variance in width as well, but make sure they fit your tires (OEM tires are pretty stretched, so likely won't work with wider wheels), and you compensate so that the front of the wheel isn't closer to the brake caliper or pushed out too far. So if you did 8.5" front wheel instead of 9", make sure the offset is at least 7mm less than OEM, since the front face is now 0.25" (0.5"/2 for each side), or 6.4mm closer because of decreased width

 

[whan]

Other points / considerations

• If you're going with a non-OEM tire size there are three things to consider.
  • First is that the tire will fit on the wheel you are thinking about. Tirerack has manufacturer specs on appropriate wheel widths for any given tire in a specific size. For example, the 285/40/20 on the rear of the Taycan works on 9.5-11" wheels. So you can't do an 11.5" rear wheel and still use the same tire
  • Second is overall tire diameter. This website can help you calculate how tall the tire you're thinking about will be. In general, there aren't any issues with the tire being smaller in diameter vs OEM, but if too big, it might rub your fender liner and not fit. Note that smaller than OEM tire diameters will increase your speedometer reading (since smaller tire rotates faster), and vice versa.
  • Interestingly, the OEM tire diameters actually differ meaningfully. The 21 inch tires are smaller in overall diameter by the 20s by close to an inch in the rear
  • Third is the ratio of diameter (or circumference) between the front and rear tires. You need to maintain this within factory OEM specs. The car monitors rotation of the front and rear tires for traction control purposes. If the rear tire is rotating faster than the car expects, it thinks it is losing traction. But if for example, you get a too small rear tire vs. front, it will rotate faster than the computer expects for the front tire rotation, and will think you're losing traction even if you're not.
  • Again, there's actually significant variance here in the OEM differences. 21" has the rear smaller than front by 0.4% and 20" has rear bigger by 1%
• From a max tire / wheel width perspective, this is a lot more trial and error / unknown. Someone on this forum was able to fit 275 front and 325 rear on 20x10 and 20x12s which is wider than even the factory 305 setup https://forgeline.com/customer-gallery/glaswerks-customer

 

[whan]

Finally, make sure to consider wheel load rating. Taycan is a heavy car, and GVWR can be up to 6350lbs. I'd be looking for something with a weight rating per wheel of at least 1550lbs if you have a RWD/4S Sedan and 1600lbs if for a Turbo or CT

Sorry OP, also realized you asked about OEM wheels on other porsche models. I think given the weight rating considerations, Panamera wheels are probably your best bet. I know someone on this forum bought aftermarket Avante-garde wheels for a panamera that fit on his Taycan

 

[Rik_CT4s]

Other points / considerations

• If you're going with a non-OEM tire size there are three things to consider.
  • First is that the tire will fit on the wheel you are thinking about. Tirerack has manufacturer specs on appropriate wheel widths for any given tire in a specific size. For example, the 285/40/20 on the rear of the Taycan works on 9.5-11" wheels. So you can't do an 11.5" rear wheel and still use the same tire
  • Second is overall tire diameter. This website can help you calculate how tall the tire you're thinking about will be. In general, there aren't any issues with the tire being smaller in diameter vs OEM, but if too big, it might rub your fender liner and not fit. Note that smaller than OEM tire diameters will increase your speedometer reading (since smaller tire rotates faster), and vice versa.
  • Interestingly, the OEM tire diameters actually differ meaningfully. The 21 inch tires are smaller in overall diameter by the 20s by close to an inch in the rear
  • Third is the ratio of diameter (or circumference) between the front and rear tires. You need to maintain this within factory OEM specs. The car monitors rotation of the front and rear tires for traction control purposes. If the rear tire is rotating faster than the car expects, it thinks it is losing traction. But if for example, you get a too small rear tire vs. front, it will rotate faster than the computer expects for the front tire rotation, and will think you're losing traction even if you're not.
  • Again, there's actually significant variance here in the OEM differences. 21" has the rear smaller than front by 0.4% and 20" has rear bigger by 1%
• From a max tire / wheel width perspective, this is a lot more trial and error / unknown. Someone on this forum was able to fit 275 front and 325 rear on 20x10 and 20x12s which is wider than even the factory 305 setup https://forgeline.com/customer-gallery/glaswerks-customer

I believe 285 width is still fitting on a 11.5J rim...

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