This is almost exactly what I did! I checked the tire diameter for both the stock fronts and rears. The goal was to make sure the front/back tire diameter difference was minimal.
The big worry I could not do much about up front was that going to wider rear tires would rub, or be too close for...
They are on my 4S for the past few weeks on the stock mission-E wheels. No issues so far. They are quiet and I don’t hydroplane except in deep puddles. Handle well around corners too.
I checked the sizing on a tire size calculator (https://tiresize.com/calculator/) to make sure the diameter was...
With stock sizes, the front tires are .1" larger than the rears. With the 315's on the back, the front tires are .1" smaller than the rears. We're literally playing in the "decimal dust" here.
Also, in the US, consumers are protected by the Magnuson-Moss Warranty Act.
I would have preferred to stay with the stock size in the rear, but Michelin doesn’t make them. They jump from 295 to 315 on 21” rims. https://www.michelinman.com/auto/tires/michelin-pilot-sport-all-season-4?tyreSize=21
20250518 Update
They are still going strong. Still Recommended.
20231110 Update
Having used the tires for over a month now, I'm quite happy.
Unscientific Observations:
Car handles a LOT better in the wet and dry performance is quite good as well.
I have seen a small decrease in range, but...
My car has been at Porsche Bellevue for over two weeks now for the PCM update. They have a bit of a backlog... Apparently the PCM update is very difficult to apply - it fails to apply properly a significant percentage of attempts. The good news is that I'm driving a nice Macan loaner, so I'm in...
You are overthinking this! Go take an extended test drive. Try it on the highway and in tight parking lots. If you love it - buy it. The price is right.
Live in Seattle and have the stock 21" Continental all-seasons. Definitely not as good as summer tires for performance, but they behave in the rain and don't turn hard, slippery, and unsafe, at 45F either.
In short, like all all-seasons, they are a compromise. I look forward to having more...
Have a 2019 Jaguar i-Pace as the family SUV. Its not a Taycan, but it works well as a 5-person SUV. It has Land Rover suspension and software, so it behaves very well in snow and ice. (Tested!)
The i-Pace had some early really annoying software teething pains. Get it upgraded to current...