MYP Square Setup

[MJP.P3D-]

I'm about to take delivery of a MYP to replace my unfortunately deceased M3P Stealth that met an early demise (you'll always have a special place in my heart, Tux). I loved the Stealth for it's go-fast bits but comparatively sedate wheels (and thus better ride and pothole resistance). Alas, there is no Stealth option for the MYP so I will take delivery of the car with the beautiful but susceptible 21" Uberturbines.

My thought, if you'll indulge me, is to buy two additional "front" wheels (9.5" width), install on the rear axle and then clad all four wheels in 265 rubber thus adding a bit of additional road imperfection resistance, perhaps a touch better ride and the ability to rotate the tires as needed. The numbers all seem to work with regard to spacing, suspension clearance, etc however I'd love to hear from someone who has done this (or something similar) to better understand the pros/cons and/or if this truly does work. I thought I read somewhere that the front Uberturbines don't fit on the rear but cannot seem to find the thread. Apologies if this has been discussed elsewhere, I'd be happy to have a link if so, or just the thoughts from this seasoned and experienced group. Thanks in advance. MJP

 

[jcanoe]

This has been done. The wheels will fit however the tires may not have the required load index for the rear: 103.

 

[MJP.P3D-]

This has been done. The wheels will fit however the tires may not have the required load index for the rear: 103.

Ah, ok—will investigate. Thanks!

 

[MJP.P3D-]

@jcanoe is wise: my proposed 265/35r21 setup would have a 101 rating (1819 lbs) vs the OEM 103 rating (1929 lbs). Hmmm….

 

[MJP.P3D-]

It’s interesting (perhaps only to me) that the 19s come from the factory with a 104 rating, the 20s with a 101 rating and the 21s with a 103 rating. It would seem that the lowest rating should be sufficient so maybe 101 is ok on the 21s? Any thoughts—what am I missing? Thanks.

 

[jcanoe]

It’s interesting (perhaps only to me) that the 19s come from the factory with a 104 rating, the 20s with a 101 rating and the 21s with a 103 rating. It would seem that the lowest rating should be sufficient so maybe 101 is ok on the 21s? Any thoughts—what am I missing? Thanks.

The OE Pirelli P Zero (PZ4) front tires, size 255/35R21, that come on the Performance Model Y have a load index of 98.

Tesla provides a table of Gross Axle Weight Rating (GAWR) Front and Rear for the 19", 20" and 21" wheel sizes.

The Tesla Long Range and Performance Model Y gross vehicle weight is stated as 5712 lbs. The weight distribution is (Front/Rear: 2462 lb/3250 lb, 43%/57%) puts more of the weight of the vehicle and passenger/cargo load over the rear axle(s).

GAWR (front) - all tire sizes: 3005 lbs
GAWR (rear) 19" tires - 3607 lbs
GAWR (rear) 20" tires - 3307 lbs
GAWR (rear) 21" tires - 3505 lbs

See Tesla Model Y Owner's Manual Page 186: https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

I don't believe a major tire chain would knowingly install tires that did not have the proper load index for the vehicle.

 

[SDM44]

I'm running Toyo Proxes Sport A/S 265/35-21 tires with a 101Y XL load rating on a square setup with my MYP with 21x9.5 wheels with +30mm offset. I've put 900 miles on the car/tires in the past 3 weeks since I took delivery of it, most of that being freeway driving.

Zero issues with it, and a 103Y vs. 101Y load rating isn't going to "make or break" my car as it's intended purpose is to be a daily commuter for work in the LA area, so 98% of the time the rear is completely empty and there's no rear passengers. I won't be tracking or racing this car, and if I ever do it won't be on these tires.


Lots of people have done a square 19" and 20" wheel setup on a MYP without any issues. I haven't seen anyone else with a square 21" setup like what I'm running, but there may be some out there.

My main reasons why I went with a 21" square setup instead of a 20" square setup were that 265/35-21 tires are cheaper and have more of a selection to choose from than 255/40-20 (or 265) tires.... although you more options when you move up to 275/40-20. And, the other reason I went with the 21's is because it just looks better on a Model Y

 

[jcanoe]

Found this - Lowering load index on sidewall is dangerous

 

[jpy1980]

Found this - Lowering load index on sidewall is dangerous

Link doesn't work! I'd love to know what it says though!

 

[jcanoe]

Link doesn't work! I'd love to know what it says though!

Lowering load index on sidewall is dangerous: Tire Talk: Lowering load index on sidewall is dangerous – WHEELS.ca

 

[MJP.P3D-]

The article discusses going from a 111 rating to 107 (loss of 250# per corner) which is significant but makes no reference to the fact that the proposed tire has a one inch smaller overall diameter (295/40r21 OEM vs 295/35r21 Proposed) which is the bigger issue in my opinion. In my case, the proposed change would result in ostensibly the same overall diameter (within the industry standard 3%) AND would have a load rating identical to that which ships from the manufacturer for this model vehicle (albeit on a different size wheel) as described in my Post #5 above. So, the article, while accurate, doesn’t seem overly applicable to this scenario. There are 1000s of Model Ys on the road with 101 rated rear tires; the same cannot be said for M-B GLs with 107 rated tires…

 

[jcanoe]

My take aways from the article include that for a given size wheel tires with a shorter profile will have a lower load index than tires with a taller profile (more sidewall) unless the tire manufacturer reinforces the sidewall resulting in a higher load index.

Tesla specifies a tire load index of 103 for the 21" Uberturbine rear wheels and a 101 tire load index for the 20" Induction wheels (front and rear.) Perhaps Tesla engineers anticipate that owners of the Performance Model Y may drive the vehicle on a race track or otherwise push the vehicle to its handling limits and the tires need to be able handle the additional load as the weight shifts. During hard acceleration from a stop the weight is shifted to the rear wheels, already biased at 43% Front / 57% Rear.

Of concern is squaring up the wheels on the Performance Model Y using two additional front Uberturbine wheels and tires. The front tires have a load index of just 98. This would create a dangerous overload for the tires, sidewall blowout could occur.

98 (1653 lbs)
101 (1919 lbs)
103 (1929 lbs)
104 (1984 lbs)

If you square up the wheels on the Performance Model Y using the front wheels on all corners the load index is under the rating for the rear wheels by 276 lbs per rear tire.

Tire load index: Understanding Tires Load Index VS Load Range

 

[Cares]

I don't really understand all this but I went from Uberturbines to TSV 19" with Michelin Pilot AS4s. Are these okay for load rating?

It says 104 XL.

 

[jcanoe]

I don't really understand all this but I went from Uberturbines to TSV 19" with Michelin Pilot AS4s. Are these okay for load rating?

It says 104 XL.

Should be OK.

 

[MJP.P3D-]

My take aways from the article include that for a given size wheel tires with a shorter profile will have a lower load index than tires with a taller profile (more sidewall) unless the tire manufacturer reinforces the sidewall resulting in a higher load index.

Tesla specifies a tire load index of 103 for the 21" Uberturbine rear wheels and a 101 tire load index for the 20" Induction wheels (front and rear.) Perhaps Tesla engineers anticipate that owners of the Performance Model Y may drive the vehicle on a race track or otherwise push the vehicle to its handling limits and the tires need to be able handle the additional load as the weight shifts. During hard acceleration from a stop the weight is shifted to the rear wheels, already biased at 43% Front / 57% Rear.

Of concern is squaring up the wheels on the Performance Model Y using two additional front Uberturbine wheels and tires. The front tires have a load index of just 98. This would create a dangerous overload for the tires, sidewall blowout could occur.

98 (1653 lbs)
101 (1919 lbs)
103 (1929 lbs)
104 (1984 lbs)

If you square up the wheels on the Performance Model Y using the front wheels on all corners the load index is under the rating for the rear wheels by 276 lbs per rear tire.

Tire load index: Understanding Tires Load Index VS Load Range

265 rubber has 101 rating but really not wanting to debate this any longer—thanks.

 

[jcanoe]

265 rubber has 101 rating but really not wanting to debate this any longer—thanks.

This is not a debate; simply stating facts.

A tire shop can easily lookup the tire load index requirements for any vehicle. For liability purposes the tire shop would not install tires that do not meet spec.

Should the tires fail, resulting in a blowout and an accident, the insurance company investigating the accident claim would determine that the vehicle had been fitted with out of spec tires.

I'm not trying to change your mind. Your mind is made up. I am providing this information for others.

 

[jpy1980]

This is not a debate; simply stating facts.

A tire shop can easily lookup the tire load index requirements for any vehicle. For liability purposes the tire shop would not install tires that do not meet spec.

Should the tires fail, resulting in a blowout and an accident, the insurance company investigating the accident claim would determine that the vehicle had been fitted with out of spec tires.

I'm not trying to change your mind. Your mind is made up. I am providing this information for others.

Exactly and thank you for doing so.
In your opinion, if one would want a square setup on the MYP, what would be the best option? I’m thinking that there really would be a decent option that would hit all the boxes.

 

[jcanoe]

Exactly and thank you for doing so.
In your opinion, if one would want a square setup on the MYP, what would be the best option? I’m thinking that there really would be a decent option that would hit all the boxes.

If you don't mind the weight and width of the factory 21" rear Uberturbine wheels (range would be reduced) you could square up using 4 of the OE rear Uberturbines. Other popular options to square up the wheels on the Performance Model Y include:

19" Tesla Gemini wheels
20" Tesla Induction wheels
TSportline TSV wheels
Martian wheels
TireRack

 

[jpy1980]

If you don't mind the weight and width of the factory 21" rear Uberturbine wheels (range would be reduced) you could square up using 4 of the OE rear Uberturbines. Other popular options to square up the wheels on the Performance Model Y include:

19" Tesla Gemini wheels
20" Tesla Induction wheels
TSportline TSV wheels
Martian wheels
TireRack

I was actually thinking of putting the rears up front as well. Just haven't found anyone that actually did that. I'm wondering if they would fit. I'll need to take my jacks out of storage and try putting the rear up front!!

 

[jcanoe]

I was actually thinking of putting the rears up front as well. Just haven't found anyone that actually did that. I'm wondering if they would fit. I'll need to take my jacks out of storage and try putting the rear up front!!

According to this thread 275/35-21 tires will fit the front. Confirmation on 275/35R21 on front.