There have been a number of people (thread, thread) wondering about fitting the 18" Aero wheels from Model 3 on Model Y. The motivation for me is installing winter tires on a more efficient wheel that allows a taller sidewall. There are a couple things to consider:
Brake caliper clearance
I expect the regular Model Y brakes will fit within the barrel section of the Aero wheels but I haven't seen this demonstrated. The question is whether the regular rear calipers are different between the 3 and Y. If they're the same, the 18" Aeros should fit. It looks like the Aero's will NOT fit the Model Y Performance Upgrade brakes per this post (H/T @RoBoRaT).
Wheel size
The 18" Aeros are 18x8.5 ET40, narrower than the 9.5" wide and ET45 19" and 20" wheels on Model Y. Using something like a 245/50R18 or 245/55R18 tire results in a similar outside tire fit as the regular Model Y. The inside of the tires would have about 10mm more clearance to the suspension. This is all good, especially for winter tires that can benefit from the slightly narrower tread.
Wheel load rating
The 18" Aero's are marked with a 700 kb (1543 lb) rating (picture, H/T @RoBoRaT). This is where the challenge lies and what led me down the rabbit hole looking at Model Y Load limits.
I plotted the Gross Axle Weight Ratings from pg 189 of the Model Y Owners Manual and added an equivalent line for 18" Aero wheels based on the 1543 lb individual wheel limit. I also plotted the 5302 lb Gross Vehicle Weight Rating for Model Y Long Range. As would be expected, the OE 19"-21" wheels allow the full range of possible axle weights given the GVWR limit. That is, the dashed gray, orange and blue lines are outside the brown diagonal GVWR line. The 18" Aero wheel, assuming a 3046 lb GAWR, would not allow very heavy, rear loading of Model Y without overloading the rear wheels.
Let's zoom in and look at these different load configurations to see how big of an issue this could be.
Config A: Curb weight, no payload
Config B: Driver only
Config C: Two front passengers
Config D: Driver, two kids in back, and some stuff in the frunk and trunk
Config E: Two big guys in front and a full frunk
Config F: Four adult passengers
Config G: Fully laden with four adult passengers and 205 lb cargo
Config H: Fully laden with two adult and two smaller passengers and 295 lb cargo
Config I: Fully laden with driver and 715 lb cargo
Config J: Same as I but with cargo moved forward to stay ahead of 18" Aero rear axle limit
Config K: Fully laden with speculated 320 lb tongue weight trailer
Config L: Same as K but with only 265 lb tongue weight to stay ahead of 18" Aero rear axle limit
Config M: Driver and minor cargo with 320 lb tongue weight trailer
Caveats:
- The axle loading calculations assumed approximate locations for the respective weights in the table, but they're pretty close.
- Nothing has been officially published yet on Model Y tow rating.
- This only applied to Model Y LR AWD. The RWD and/or Standard Range cars will have different results.
From this, I conclude the 18" Aero can be used on Model Y LR AWD as long as special consideration is paid to keeping the payload forward when close to the GVWR. YMMV and all that.
Brake caliper clearance
I expect the regular Model Y brakes will fit within the barrel section of the Aero wheels but I haven't seen this demonstrated. The question is whether the regular rear calipers are different between the 3 and Y. If they're the same, the 18" Aeros should fit. It looks like the Aero's will NOT fit the Model Y Performance Upgrade brakes per this post (H/T @RoBoRaT).
Wheel size
The 18" Aeros are 18x8.5 ET40, narrower than the 9.5" wide and ET45 19" and 20" wheels on Model Y. Using something like a 245/50R18 or 245/55R18 tire results in a similar outside tire fit as the regular Model Y. The inside of the tires would have about 10mm more clearance to the suspension. This is all good, especially for winter tires that can benefit from the slightly narrower tread.
Wheel load rating
The 18" Aero's are marked with a 700 kb (1543 lb) rating (picture, H/T @RoBoRaT). This is where the challenge lies and what led me down the rabbit hole looking at Model Y Load limits.
I plotted the Gross Axle Weight Ratings from pg 189 of the Model Y Owners Manual and added an equivalent line for 18" Aero wheels based on the 1543 lb individual wheel limit. I also plotted the 5302 lb Gross Vehicle Weight Rating for Model Y Long Range. As would be expected, the OE 19"-21" wheels allow the full range of possible axle weights given the GVWR limit. That is, the dashed gray, orange and blue lines are outside the brown diagonal GVWR line. The 18" Aero wheel, assuming a 3046 lb GAWR, would not allow very heavy, rear loading of Model Y without overloading the rear wheels.
Let's zoom in and look at these different load configurations to see how big of an issue this could be.
Config A: Curb weight, no payload
Config B: Driver only
Config C: Two front passengers
Config D: Driver, two kids in back, and some stuff in the frunk and trunk
Config E: Two big guys in front and a full frunk
Config F: Four adult passengers
Config G: Fully laden with four adult passengers and 205 lb cargo
Config H: Fully laden with two adult and two smaller passengers and 295 lb cargo
Config I: Fully laden with driver and 715 lb cargo
Config J: Same as I but with cargo moved forward to stay ahead of 18" Aero rear axle limit
Config K: Fully laden with speculated 320 lb tongue weight trailer
Config L: Same as K but with only 265 lb tongue weight to stay ahead of 18" Aero rear axle limit
Config M: Driver and minor cargo with 320 lb tongue weight trailer
Caveats:
- The axle loading calculations assumed approximate locations for the respective weights in the table, but they're pretty close.
- Nothing has been officially published yet on Model Y tow rating.
- This only applied to Model Y LR AWD. The RWD and/or Standard Range cars will have different results.
From this, I conclude the 18" Aero can be used on Model Y LR AWD as long as special consideration is paid to keeping the payload forward when close to the GVWR. YMMV and all that.
