Tesla, can we please have the option to put 18” wheels on the model Y in the tire/wheel settings? Lots of 18’s out there from the 3 that fit on the Y that would be perfect for winter. Would love to have the option to select 18’s so the Speedo is correct.
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18” wheels on model Y
- Thread starter Jillmark99
- Start date
As long as you have tires that match the overall diameter of the 19 or 20 factory wheel and tire package (28 inches) you can set one of those as the setting in the car and the speedo will be correct.
Interestingly, the front wheels / tires on the MYP have the same diameter as the 19's and 20's (28 inches) but the rear wheels are 28.6 inches. I wonder if for simplicity they use the front wheel revolutions per min to calculate speed since it is the same for all of the factory optional wheel and tire packages?
Keith
fiehlsport
Tire Guy
Yep - the settings in the computer shouldn't be changing anything relevant to revolutions per mile. The speedo cannot be calibrated using this. You are expected to use the correct diameter tires whether they be 19, 20, or 21".
255/50-18 is the correct size for Model Y fitment - this size does not exist (outside of a few specialty tires), which is probably why Tesla doesn't officially support 18" fitment on the Model Y. 245/50-18 is ever so slightly smaller in diameter, but works great, and has plentiful options.
255/50-18 is the correct size for Model Y fitment - this size does not exist (outside of a few specialty tires), which is probably why Tesla doesn't officially support 18" fitment on the Model Y. 245/50-18 is ever so slightly smaller in diameter, but works great, and has plentiful options.
TomB985
Member
I had a winter set that was purchased for my Model 3 back in 2019. I re-shod them with taller 225/65R18s to fit a Subaru Outback in 2021, and those happen to be about 1% off from the factory size on the Model 3.
Clearance is TIGHT. I had to move the wheel weights around to clear the front brake calipers, but they're working great. I didn't check the speedometer against GPS with the factory set, but it reads about 1 MPH over actual speed at 75 MPH with the skinny 225s.
Clearance is TIGHT. I had to move the wheel weights around to clear the front brake calipers, but they're working great. I didn't check the speedometer against GPS with the factory set, but it reads about 1 MPH over actual speed at 75 MPH with the skinny 225s.
You got it!
Another option with lots of results is 235/55/18. Same diameter as stock so zero difference in speedometer reading, but narrower if you are chasing after efficiency and wanted to go that size in an EV specific design for less rolling resistance. I actually went slightly larger overall diameter (255/55/18) on my 18's to compensate for the built in 2mph speedometer error.
Keith
It makes the speedometer match GPS speed reading at around 60 mph, and above that you are actually going faster than shown on the speedometer. At 74 mph indicated I am doing 75 mph by GPS. Since it is a percentage difference, the slower you are going the closer it matches up to the stock tires. For example, at an indicated 30 mph, you are going 29 mph instead of 28 mph like you would be on the stock tires. I will lay it out more logically below:
Speedo reading . GPS speed on stock tires . GPS speed on my tires
. . . . . . . 30 . . . . . . . . . . . . . . . . 28 . . . . . . . . . . . . . . . . . . . . 29
. . . . . . . 60 . . . . . . . . . . . . . . . . 58 . . . . . . . . . . . . . . . . . . . . 60
. . . . . . . 75 . . . . . . . . . . . . . . . . 73 . . . . . . . . . . . . . . . . . . . . 76
. . . . . . . 90 . . . . . . . . . . . . . . . . 88 . . . . . . . . . . . . . . . . . . . . 93
Later,
Keith
PS: Now that vision only cars can do 85 mph indicated in Auto Pilot it is not as big of a deal to have the 2 mph speedometer offset... but when driving in Texas at an indicated 80 mph (old vision only limit) on a road with an 80 mph speed limit you were actually doing 2 mph under the speed limit when the majority of traffic was traveling at 5 to 10 mph over the speed limit. Being able to do 82 in an 80 instead of 78 in an 80 is a big deal when you have traffic around you that is in a hurry!
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Thanks Keith. So which tire size would be best for the complete accurate speedometer?
None of them
If you want complete accuracy with an offset, stick with stock size and just drive an indicated 2 mph over what ever speed you want to be traveling. Want to do 75? Set the AP to 77. Want to do 30? Set AP to 32. On the stock size tires it is 100% linear 2 mph offset.
If you want the speedometer to match reality AT 60 MPH get the same size tires I am running... but you will be off at any other speed you are driving since it is a percentage change from the stock size, not an integer change of a set value.
Keith
fiehlsport
Tire Guy
19: 255/45-19
20: 255/40-20
21: 255/35-21 (front tires)
These are all the stock sizes that will show you the speed Tesla has designed the car to show you at any given speed. (Factory sizes)
thesmokingman
Active Member
thesmokingman
Active Member
TomB985
Member
My super-skinny 225/65R18s that are mounted now are closer than factory. I'm reading 75 MPH on the speedo at a GPS-indicated 74. These chicken feet are a bit taller than the factory tires.
235/55/18 and 255/50/18 are exact matches in diameter to the stock tires listed.
Keith
TomServo
Active Member
I dumped the 21” UT tires/wheels from my PMY for some 18s from TSportLine. So when I asked them what wheel setting I should use they said to just leave it on 21”. Looking at tire specs on Tire Rack there wasn’t significant difference in rolling distance between the 21” Michelins and the 18s.
I did do some BEFORE and AFTER testing with my DRAGY and the speedometer read exactly the same at speeds up to 80 mph. The upside is my Y is more efficient and faster than it was on the 21s and I no longer live in fear of curbs or potholes.
I did do some BEFORE and AFTER testing with my DRAGY and the speedometer read exactly the same at speeds up to 80 mph. The upside is my Y is more efficient and faster than it was on the 21s and I no longer live in fear of curbs or potholes.
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