Switching MYP wheels down to 19s with unconventional tyre size

Double check with actual specs on the tires. There is usually some small variance in the overall diameter between manufacturers from the sizes obtained using the aspect ratio calculation.

I also changed rim size with T Sportline. Their pre installed tires run about 3%% small for diameter compared to the factory tires. Same boat as you, was hoping to fix it when these tires lose tread.

Overall diameter of all stock tire is 28 inches. Anything over/under will cause a misread in calculating the speed which is calculated using the front wheels. edit: info found using the tire guide on TSportline. https://tsportline.com/blogs/tesla-aftermarket-support/the-tesla-model-y-wheel-and-tire-guide you can also use this tire size calculator to figure out the overall diameter and difference in speedo read by inputting the tire sizes you are swapping to. 275/40s are roughly 28.7 inches and the 255/50 are 29 inches in diameter so the 255's will over read slightly more than the 275's https://tiresize.com/calculator/

That's weird, because the car is supposed to recalibrate the speedometer after a wheel change. Have you told the car, via the settings menu, that you changed your wheels and tires? This triggers a re-calibration.

255/50r19 is a different height than all factory sizes. Settings will be off accordingly.

correct but in the menu I have selected 20" wheels - and I think the 20" wheels with the stock tyres are almost the same overall size as my 19s with 255/50s...but using the calculator shared above it seems i am 1 inch off stock.

i did. in the menu I have selected 20" wheels - and I think the 20" wheels with the stock tyres are almost the same overall size as my 19s with 255/50s...but using the calculator shared above it seems i am 1 inch off stock.

thanks...in the menu I have selected 20" wheels - and I think the 20" wheels with the stock tyres are almost the same overall size as my 19s with 255/50s...but using the calculator it shows a 1 inch diameter difference. this helps thanks

Your formula is wrong. Overall height should be wheel+ 2xsidewall

There we go! That's what's caused my brain to go numb for weeks. Thanks.

Maybe try also selecting the tire swap option. When I do this, it pops up a message asking me to drive easily for a while so that it can calibrate the tire size. Maybe it only works within the range of tires they're expecting, not sure.

How'd the 275/45's work out? I'm swapping my 21 uberturbines down into 19x9.5 tsportline TSS and planning to go 275/45 both front and back with them

In the future, knuckledraggers use inches. Keep things in inches and it would be easier for me to see the discrepancy. I usually convert sidewall height to inches before adding to wheel diameter.