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Model 3 tire size for maximum sidewall 18” or 19”

Coxwain

Member
Aug 28, 2020
65
18
Etobicoke, ON, Canada



From Manual Page 217-218




Wheels Location Width (in) Offset (mm) SIZE
19" Sport Wheels 19" Front/Rear 8.5 40 235/40R19
20" Zero-G Wheels (Performance) 20" Front/Rear 9 34 235/35ZR20
20" Zero-G Wheels (Non-Performance) 20" Front/Rear 9 40 235/35ZR20
19" Gemini Wheels (Performance) 19" Front/Rear 8.5 35 235/40R19
18" Aero Wheels 18" Front/Rear 8.5 40 235/45R18

I am wondering if there is any room in these specs to go with a thicker sidewall? Any other resources?
 

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Sam1

Member
Sep 11, 2019
951
865
NV
Why would you want to go with a taller sidewall, than what is posted? You’re wanting to intentionally kill the handling of the car?
 

Perscitus

Member
Jan 29, 2019
807
495
New York
You can start very simple and just get a tad wider 245mm tire (perfectly fine on the OE 8.5). You will gain 4% of sidewall and go from a measly meh 3.7" to nearly 3.9" of sidewall. Speedo error will be minimal within street-legal velocity ranges.

235/40-R19 vs 245/40-R19 Tire Comparison - Tire Size Calculator | Tacoma World

Or you can switch it up a bit by crossing the magical anti wheel-bending >4" of sidewall and likely fit some 235/45R19s without any fender liner rubbing or stock suspension interference. Speedo will be a bit more off, but nothing to post about on the fora.

235/40-R19 vs 235/45-R19 Tire Comparison - Tire Size Calculator | Tacoma World
 

cypho

Member
Dec 20, 2018
761
897
USA
Or you can switch it up a bit by crossing the magical anti wheel-bending >4" of sidewall and likely fit some 235/45R19s without any fender liner rubbing or stock suspension interference. Speedo will be a bit more off, but nothing to post about on the fora.

235/40-R19 vs 235/45-R19 Tire Comparison - Tire Size Calculator | Tacoma World


Have you actually tried fitting 235/45R19 to a model 3? Because there are reports that 235/50R18 not physically fit and that would be the same total height and width.

Sorry for seeing this late.
235/50-18 will likely NOT clear the upper suspension mount on OEM offset tires, unless that particular brand/model of tires runs narrow compared to the stated specs. They could probably fit with like +20 offset wheel.

Here's a pic of a 235/50-18 horizontal view, with tires being about 2/32nds worn from new. Full tread tires will likely rub.
img_20191016_224221-jpg.29977


It's basically level with the suspension arm. Not every 235/50-18 tire is the same and one might get a lucky draw. These were effectively on a +11 offset wheel and there was probably a 10-15mm clearance to the suspension arm horizontally. So, a +20 wheel would probably make this borderline clear.

225/50-18 should fit though.
 

Perscitus

Member
Jan 29, 2019
807
495
New York
I have not, waiting for brave beta testing guinea pigs to trailblaze. Thanks OP!

The overall diammeter of a 235/45R19 is 0.3" larger vs say a 255/40R19s and very close to the 235/50R18s you quoted as a close or too close of a fit (mind you the offset mentioned is borderline wild).

Maybe then its worth looking at some 225/45R19s? Likely just what you're looking for in terms of sidewall while clearing the suspension, wheel lines and keeping the stock Stiletto wheels.

235/50-R18 vs 225/45-R19 Tire Comparison - Tire Size Calculator | Tacoma World

My vote would be:
1st preference: 225/45R19 ET40
2nd preference: 255/40R19 ET35
 
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android04

Member
Apr 1, 2016
361
338
Crete, Nebraska
If you want more comfort, maybe one of the"comfort" coilovers like the ones sold by Mountain Pass Performance is something you want. Otherwise, the main restriction to taller tires (assuming you are using the OEM wheels or aftermarkets with the same offset) is the knuckle in the front suspension being about 0.5" above the tread. You will also want to avoid tires much wider than stock because it will push the tread closer to the curve on the knuckle.
IMG_20181106_130342.jpg
 
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SomeJoe7777

Marginally-Known Member
Mar 28, 2015
2,174
5,603
Houston, TX
There's only 2 things you can control here to protect rims:

1. The distance that the edge of the rim is from the ground. This distance is calculated from the tire aspect ratio, given in the tire size by the second number (after the slash). Example:

Stock 19" tire size: 235/40R19

The section width (width of the tire) is 235 mm, the aspect ratio is 40, so the sidewall height is 0.40 * 235 = 94 mm. This is the distance from the edge of the rim to the ground (when tires are properly inflated).

Stock 18" tire size: 235/45R18

The section width is 235 mm, aspect ratio is 45, so the sidewall height is 0.45 * 235 = 106 mm. This places the edge of the rim 12 mm (1/2 inch) higher off the ground than the stock 19" tire. If the edge of the rim is higher off the ground, you have more room to clear objects that might hit your rim, like curbs. The object is more likely going to hit the tire instead of the rim.


2. You can control how far out the sidewall of the tire sticks outward from the rim by adjusting the section width. If the section width (width of the tire cross-section across the maximum width, i.e. bulge-to-bulge) is larger, then the tire sticks out from the rim slightly. This means an object that bumps into the wheel/tire combo hits the tire first, not the rim. Example:

Stock 18" wheel: 18" x 8.5", meaning that the rim width is 8.5". Stock tire is 235/45R18, so section width is 235 mm = 9.25", so the tire sticks out (9.25 - 8.5) = 0.75" / 2 = 0.375" = 3/8" from the rim on each side. For more protection, we can upsize the tire to a 245/45R18. Section width is now 245 mm = 9.65", so the tire sticks out (9.65 - 8.5) = 1.15" / 2 = 0.57" = 9/16" on each side, giving you 3/8" more tire cushion for an object before it can hit the rim.

The 245 section width also raises the rim to 0.45 * 245 = 110 mm height above the ground, so the edge of the rim gains 4 mm in height from the ground compared to the stock 235/45R18 tire.

Overall diameter of the tire will increase, however, from 26.3" to 26.7", an increase of 1.5 %. The overall diameter is the critical number that needs to stay the same (or as close as possible) when moving to alternate tire sizes, because this affects handling and speedometer error. Ideally, this number should be less than 1%, but up to 2.5% is tolerable. 1.5% in this case is acceptable.


If you want maximum rim protection, use 18"x8.5" wheels (stock wheel size for the Aero wheels) with 245/45R18 tires. If you also want a comfortable ride, then you need a Grand Touring tire. You're in Canada according to your profile, so an all-weather tire may fit the bill nicely. Appropriate choices would therefore be:

Vredestein Quatrac Pro
Goodyear Assurance WeatherReady

If you have another set of winter-only tires, then you don't need all-weather, so other choices could be:

Pirelli Cinturato P7 All-Season Plus II
Continental PureContact LS
Michelin Primacy MXM4 (this is the OEM tire, but not the OEM size)
 

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