18" tire options and larger wheel range impact

[Zoomit]

The Model Y Unveil cars had either 19" or 20" wheels with corresponding tires that were 1.6" larger in diameter than Model 3. They were also 255 width vs 235 on Model 3.

To match the width and diameters, tires sizes would be:

255/50R18
255/45R19
255/40R20

The larger two sizes have plenty of options listed on tirerack.com; 43 and 55 options respectively. However, 255/50R18 only has one option listed. It is not a standard tire size.

I see three scenarios:

1. Tesla convinces a manufacturer to build a tire in that size, like a Michelin Primacy MXM4 with TO spec
2. Tesla uses a 19" wheel and tire as the standard size
3. Tesla uses a 235/55R18 tire as the standard size, this is the same diameter just narrower.

I think they'll do #3 and reduce the width to the same as the Model 3. Tirerack lists 79 tires in 235/55R18, including the Primacy MXM4. This is the tire found on the Model 3 18" wheel in 235/45R18.

What does this mean? The EPA ranges that we've seen for the Model Y are determined with the standard wheel and tire. Therefore, the 19 and 20" wheel/tire combinations will have a larger impact on range than they do on the Model 3. This is due to the extra 20mm width resulting in more drag.

The saving grace may be the higher total drag of the Model Y. The tire drag by itself will be a smaller portion of the total drag due to the Model Y's larger frontal area.

 

[gilscales]

You could see the tire size? looking at a pic from the unveil is a pilot 4s for sure so here are the sizes


Truck Tires, Car Tires and more – Michelin Tires

 

[Zoomit]

There are images available of both the 19" tires on the white Model Y and 20" tires on the blue one.

 

[gilscales]

There are images available of both the 19" tires on the white Model Y and 20" tires on the blue one.

Got it, thanks

The 20" link does not show me but assume it is the pilot 4s that is 28" dia.?
tires.jsp

This is definitely the 19" tire in the pic
https://www.tirerack.com/tires/tire...ewall=Blackwall&partnum=545VR9CPCN1&tab=Sizes

FWIW, I recently changed to a 255/40/19 and the 27" tire did not affect the speedo AFAIK as my iPhone gps speedo is spot on at 80 mph
this is the tire I chose for the low weight compared to others
https://www.tirerack.com/tires/tire...9DWS06XL&vehicleSearch=false&fromCompare1=yes
When I first put them on I was not happy, handling seemed sluggish and cornering not improved as much as I hoped for, psi was initially 40, I was going on a road trip in a couple of days and pumped up the air to 44 psi cold, night and day for handling and cornering improved, I read somewhere after my road trip that this particular tire shined when within 3 to 5 psi of max (51 max) so I tried 47 psi cold and even better handling and as a bonus efficiency returned to near stock or maybe 5% more on wh/mi.

 

[wwu123]

I think they have to be doing Option 3 with the narrower 235 width to keep the 300-mile range within 10% of the Model 3 (325 miles). Given the Model Y losses due to both more weight and larger drag cross-section, I can't see where they can afford additional 20 mm width on the tires as well and get 300 miles.

But I'm not sure what the contribution of tire width is to mileage. If the mileage hit is so small, then I'd prefer to start running 255/40R18's on the Model 3 instead of the stock 235/45R18's as well.

 

[Brando]

Got it, thanks

The 20" link does not show me but assume it is the pilot 4s that is 28" dia.?
tires.jsp

This is definitely the 19" tire in the pic
https://www.tirerack.com/tires/tire...ewall=Blackwall&partnum=545VR9CPCN1&tab=Sizes

FWIW, I recently changed to a 255/40/19 and the 27" tire did not affect the speedo AFAIK as my iPhone gps speedo is spot on at 80 mph
this is the tire I chose for the low weight compared to others
https://www.tirerack.com/tires/tire...9DWS06XL&vehicleSearch=false&fromCompare1=yes
When I first put them on I was not happy, handling seemed sluggish and cornering not improved as much as I hoped for, psi was initially 40, I was going on a road trip in a couple of days and pumped up the air to 44 psi cold, night and day for handling and cornering improved, I read somewhere after my road trip that this particular tire shined when within 3 to 5 psi of max (51 max) so I tried 47 psi cold and even better handling and as a bonus efficiency returned to near stock or maybe 5% more on wh/mi.

Considering the weight of Tesla cars, I'd go toward higher pressures - what does Tesla say??
(also help protect against pot hole damage to wheels)
Keep a close eye on the wear pattern - IF the CENTER is wearing too high a pressure and cut back.
I'd expect the large tire sellers to have useful information. I just stuck with factory suggested sizes Michelin for Saabs.

good luck with tire hunting
and thanks for your actual experiences which may help others decide what to try