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I picked up a screw in one of the front 245/45 tires and decided to go with 275/40 up front and 285/40 in the rear. Although some weight was added, the setup is a great middle ground for a balance of looks and performance.
Steering feel, precision and overall turn in is truly amazing with the wider front tire and lower profile than the OE 20" sidewall size, while still retaining the visual treat of wide tires. It feels similar to my 21" set but somehow better.
The perfect 29" diameter match to the 285/40 rear is a 255/45 but the rear tires have some wear to 8/32 and I measured the circumference of each within 6mm of each other, leading to an overall diameter variance that is closer than the OE paired setup. I am using Michelin PS4 NF0 from a Taycan in the rear and PS4S generic up front. I have a feeling that the NF0 285/40 is slightly smaller than the 29" standard due to the Taycan front tire size of 245/45 at a standard diameter of 28.7".
Here's the sidewall profile. Much less bulge and unneeded mass than the OE sizes without a decrease in comfort. The front could clean up a bit from going to 255/45 but I didn't want to waste the 275/40 just yet.
The narrow bulge will allow the wheels to reach the curb easier.
Fair point but the wheels are not anymore exposed than on the factory 21" setup. The surround view/side view cameras essentially eliminate that risk plus my wife wouldn't be driving this car anywhere that a rare parallel parking event would occur. Somehow she manages to ding up her wheels even with thick sidewalls but I've never had that happen on my car over the decades.
Fair point but the wheels are not anymore exposed than on the factory 21" setup. The surround view/side view cameras essentially eliminate that risk plus my wife wouldn't be driving this car anywhere that a rare parallel parking event would occur. Somehow she manages to ding up her wheels even with thick sidewalls but I've never had that happen on my car over the decades.
This car is wide. Going around corners creates similarities to what happened with the Key Bridge.
This car is wide. Going around corners creates similarities to what happened with the Key Bridge.
Depending on where you live, it may make sense to have a thicker sidewall. The OE setup is a compromise that is best suited for the average buyer, giving extra tire sidewall and width for both minor off-road and on-road uses in most areas. A reason why for the non-GTS models, the 21" wheel is an option that many do not take for their local reasons. In my specific area that has wide roads and little to no parallel parking, I can run 21" wheels with the smaller sidewalls no problem and I figured the 20" wheels can have that same treatment for improved driving dynamics from a lighter tire and smaller sidewall.
I just ordered a set of 255/45/20 for the fronts to better match the diameter of the rears. The OE setups like to have the front tires slightly larger in diameter, from my best guess, thats to assist the AWD coupling in the 5/95 F/R split. While the cicumference of the 275/40 and 285/40 was very similiar, when loaded with weight, the 275 fronts became slightly smaller in overall rolling diameter. While still only a fraction of a percent of a difference, I felt its safer to follow the OEM pattern.
Depending on where you live, it may make sense to have a thicker sidewall. The OE setup is a compromise that is best suited for the average buyer, giving extra tire sidewall and width for both minor off-road and on-road uses in most areas. A reason why for the non-GTS models, the 21" wheel is an option that many do not take for their local reasons. In my specific area that has wide roads and little to no parallel parking, I can run 21" wheels with the smaller sidewalls no problem and I figured the 20" wheels can have that same treatment for improved driving dynamics from a lighter tire and smaller sidewall.
I just ordered a set of 255/45/20 for the fronts to better match the diameter of the rears. The OE setups like to have the front tires slightly larger in diameter, from my best guess, thats to assist the AWD coupling in the 5/95 F/R split. While the cicumference of the 275/40 and 285/40 was very similiar, when loaded with weight, the 275 fronts became slightly smaller in overall rolling diameter. While still only a fraction of a percent of a difference, I felt its safer to follow the OEM pattern.
Rolling diameters should be as close to stock as possible so that traction control and ABS systems work as intended. Wheels spinning faster or slower due to incorrect diameters may fool traction control to think there is wheel slippage where there is none, causing braking on an axle where there should be none.
Rolling diameters should be as close to stock as possible so that traction control and ABS systems work as intended. Wheels spinning faster or slower due to incorrect diameters may fool traction control to think there is wheel slippage where there is none, causing braking on an axle where there should be none.
Yes, but the tolerance for the AWD system is tighter than TRACS/ABS systems (estimate of <1% vs. 3%) so its assumed its covered if the AWD tolerances are addressed. I even ordered the new tires shaved to 8/32 to match the wear of the rear tires.
I got in the shaved tire from Tire Rack. It was an easy experience and I installed it to match the rear diameters.
This combo is a winner and I highly recommend it for a 20" setup if you are not in need of a larger sidewall for off-road uses. 255/45/20 and 285/40/20 are one size smaller than OE but without the excess sidewall and bulge, provide a full contact patch on the rubber, weigh a little less, and most importantly provide significantly improved driving dynamics, steering precision, feedback. and less sidewall flex. They feel much better than my 21" set, which may just come down to using the PS4S vs. PS4 AS. My prior 20" OE size set was PS4 SUV and while a great tire, they did not feel as good as this setup.
The sidewall is slightly shorter at 29.1" and 29" for the front and rear, respectively. Compared to the OE sizes that are 2/10" taller, the difference is very minimal, if noticeable at all. There's a small benefit from a tighter effective gear ratio.
Unfortunately I burned cash on experimenting on the 245/275 combo but worth it to arrive here.
04-15-2024, 06:21 AM
