In short. A wheel must be rated for at least the heaviest load its position on the car can carry: half of the maximum load allowed on its axle, which the car maker prints on a plate or a door-jamb label (GAWR in North America). It is not a quarter of the car's weight. On a Tesla Model Y, the handbook's maximum laden mass of 2,503 kg gives 626 kg a wheel if you divide by four, but the rear axle's share is 1,370 kg, so 685 kg per rear wheel. The wheel's rating must reach that figure, the tyre's load index too, and towing adds to the rear figure on top of that.
What a wheel load rating is, and what it is not
A wheel load rating is the largest static load, in kilograms or pounds, that one wheel is designed to carry: one wheel, not the set. It is a design figure, not a breaking point, since the wheel standards test at several times that load (see the margins below).
The rating is not always stamped on the wheel. The UN rule on replacement wheels lists "maximum load capacity" among the characteristics that define a wheel type (Regulation No 124, § 2.2.5), but the marking it requires is the maker, the rim contour, the offset, the date and a part number (§ 5.1), with no load. Many aftermarket wheels show a "MAX LOAD" figure on the back; our guide to reading wheel markings explains each stamp. If no load is marked, ask the seller for it in writing.
From GVWR and axle ratings to the load on one wheel
Three numbers are printed for most cars. In the United States they are the GVWR, the gross vehicle weight rating, which may not be less than the unloaded vehicle weight plus the rated cargo load plus 150 lb (68 kg) for each designated seating position, and a GAWR, gross axle weight rating, "for each axle, identified in order from front to rear" (49 CFR 567.4, (g)(3) and (g)(4)). The British equivalent of the GVWR is the maximum authorised mass (MAM), which GOV.UK says "is also known as gross vehicle weight (GVW) or permissible maximum weight" (Vehicle weights explained).
The method. Take the larger axle rating and divide it by two. That is the most one wheel on that axle can be asked to carry, and it is the figure the wheel's rating and the tyre's load index must both reach. The US tyre rule uses the same logic: it defines "vehicle maximum load on the tire" as the load "determined by distributing to each axle its share of the maximum loaded vehicle weight and dividing by two" (FMVSS No. 110, S3).
Why not divide the car's weight by four? Because the load is not spread evenly, and because the empty weight leaves out the people and the luggage. Our sums on figures published by the car makers:
| Car, maker's document | Maximum laden mass | Front / rear axle | Quarter of the maximum | Half the rear axle | Gap |
|---|---|---|---|---|---|
| Tesla Model Y Premium AWD (5 seats) | 2,503 kg | 1,133 / 1,370 kg | 626 kg | 685 kg | +9.5 % |
| Tesla Model Y L (6 seats) | 2,651 kg | 1,133 / 1,518 kg | 663 kg | 759 kg | +14.5 % |
| BMW XM (2022) | 3,300 kg | 1,500 / 1,825 kg (axle maxima) | 825 kg | 912.5 kg | +10.6 % |
Tesla figures: the handbook's split of the technically permissible maximum laden mass by axle, English edition for China (Tesla, Dimensions and Weights); the axle maxima themselves are on the car's product plate and may be higher. BMW: XM technical data, 09/2022. Quarter and half: our arithmetic.
The BMW line shows a second trap: the two axle maxima add up to 3,325 kg, more than the 3,300 kg the whole car may weigh, so the wheel is sized from its axle, never from a share of the total. The XM's empty weight divided by four (2,710 kg to DIN, so 677.5 kg) falls a quarter short of the 912.5 kg a rear wheel may carry.
Where your car's numbers are printed
| Country | Where the weights are | What it shows | Text |
|---|---|---|---|
| United States | A label on the hinge pillar, door-latch post or the door edge next to the driver | GVWR and GAWR front and rear | 49 CFR 567.4, (c) and (g) |
| United States | "Tire and Loading Information" placard on the driver's side B-pillar | Combined weight of occupants and cargo, original tyre sizes, cold pressures; load index optional | FMVSS No. 110, S4.3 |
| Canada | Tyre placard, in both official languages | Same content as the US placard, through Technical Standards Document 110 | Motor Vehicle Safety Regulations, s. 110 |
| United Kingdom | Manufacturer's plate, "normally under the bonnet or inside the driver's door" | Four weights: car alone, car and trailer, front axle, rear axle | GOV.UK, towing; DVSA, safety checks |
| Australia (New South Wales) | Tyre placard "usually located in the glove box, the engine bay or on a door pillar" | Wheel and tyre combinations, load capacity, speed rating, pressures | Transport for NSW, VSI 09, Rev. 5, 2019 |
DVSA adds that "the maximum weight includes passengers, other loads, and fuel", and sends you to the handbook if no plate is fitted. On a Model Y, the handbook edition we read says both labels, the Tire Information label and the Product Plate, "are visible on the front passenger door pillar when it is open" (Tesla, Vehicle Loading).
What the rules require of the tyre on that wheel
No text we read sets a load rating for the wheel of an ordinary car directly. They all set it for the tyre, and the wheel receives everything the tyre carries.
United States. For passenger cars, "the vehicle maximum load on the tire shall not be greater than the applicable maximum load rating as marked on the sidewall", and the normal load must stay within 94 % of the tyre's rating at the car maker's recommended pressure (FMVSS No. 110, S4.2.1.1 and S4.2.1.2). For multipurpose vehicles and trucks, "the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR", and a passenger-car tyre fitted to one of them has its rating divided by 1.10 first (S4.2.2.1 and S4.2.2.2). In numbers, two passenger tyres rated 1,000 kg each cover an axle of at most 1,818 kg on such a vehicle, not 2,000 kg. The rim must match a rim the tyre maker lists as suitable, and hold a deflated tyre at 60 mph (97 km/h) until a controlled stop (S4.4.1).
Canada. Section 110 of the Motor Vehicle Safety Regulations applies Technical Standards Document No. 110, the Canadian counterpart of FMVSS 110, to vehicles with a GVWR of 4,536 kg or less, and to "every tire rim manufactured for use on those vehicles". Subsection 110(7) defines the load rating as "the maximum load a tire is rated to carry at a given inflation pressure" (C.R.C., c. 1038).
Europe and other countries applying UN rules. UN Regulation No 142 asks that the maximum load rating of every tyre, the standard spare included, be "at least equal to half of the technically permissible maximum axle mass for the most heavily loaded axle", or of its own axle when front and rear tyres differ (§§ 5.2.2.1.1 and 5.2.2.1.2, 01 series, Official Journal L 293 of 16 August 2021).
United Kingdom. The MOT checks the load rating only on classes 5 and 7, not on cars. For those, the manual tells the tester to "make sure the tyre load rating is suitable for the axle weight", read on the manufacturer's plate, and a tyre load capacity insufficient for the axle weight presented is a dangerous defect (MOT inspection manual, 5.2.3). For every vehicle, regulation 27 forbids using a tyre that "is unsuitable having regard to the use to which the motor vehicle or trailer is being put" (Construction and Use Regulations 1986).
Australia. In New South Wales, "all replacement tyres must have a load rating equal to or higher than the rating of the original tyres fitted by the vehicle manufacturer", which the tyre placard or the car maker gives (VSI 09, Rev. 5, 28 February 2019). We read no other state's document.
The load index on the sidewall converts to kilograms through a table in UN Regulation No 30 (Annex IV). Some values that matter for heavy cars:
| Load index | 101 | 103 | 104 | 106 | 108 | 110 | 112 | 115 | 120 |
|---|---|---|---|---|---|---|---|---|---|
| Kilograms per tyre | 825 | 875 | 900 | 950 | 1,000 | 1,060 | 1,120 | 1,215 | 1,400 |
Source: UN/ECE Regulation No 30, Annex IV. An XL ("Extra Load") tyre has a carcass "more resistant than that of the corresponding standard tyre" (§ 2.3.4), and its pressure matters: see XL tyres and pressure.
How much margin the wheel tests build in
Wheel standards do not stop at the rated load: the two public texts we read multiply it.
| Test | Japanese standard (JWL, MLIT annex 2) | UN Regulation No 124 (replacement wheels) |
|---|---|---|
| Base load | F, the highest load capacity among the tyres specified for the wheel; or, for a wheel limited to named vehicles, their highest static wheel reaction (§ 2.1.1) | FV, the maximum load capacity of the wheel (Annexes 6 and 7) |
| Rolling under load | Drum test at 2.25 × F (2.5 allowed for a front wheel), at least 500,000 revolutions (§ 2.2) | 2.5 × FV for passenger cars, 2.25 for steel disc wheels, over an equivalent of 2,000 km (1,000 km for steel) (Annex 7) |
| Cornering fatigue | Bending moment 1.5 × F × (0.7 × r + d), at least 100,000 revolutions (§ 2.1) | Moment 2.0 × FV × (0.9 × r + d), run at 50 % and at 75 % of it (Annex 6) |
| Impact | A mass of 0.6 × W + 180 kg dropped from 230 mm onto the rim flange, wheel tilted 13° (§ 2.3) | Light-alloy wheels: 0.6 × the wheel's maximum static load in kg + 180 kg, dropped from 230 mm, wheel tilted 13° (Annex 8) |
r: the tyre's static loaded radius (JWL) or dynamic radius (Regulation No 124); d: the offset; W: F expressed in kilograms. The Japanese text adds that dimensions must follow JIS D 4218 (§ 3.4). Read in MLIT annex 2 (in Japanese) and in Regulation No 124 (French edition).
A worked case, our arithmetic. Take the Model Y's original 19-inch tyre, load index 104, 900 kg. Under the Japanese default rule, F is 900 kg, or 8.82 kN at the text's 9.8 kN per 1,000 kg. The rolling test then presses the wheel with 19.8 kN, about 2,025 kg, for half a million revolutions: 2.96 times the 685 kg a rear wheel of that car may carry. The impact test drops 720 kg. Under Regulation No 124 the base would be the wheel's own rated load instead: a wheel rated exactly 685 kg would roll at 2.5 × 685, about 1,713 kg, and take an impact mass of 591 kg. A wheel calculated on its tyre inherits the tyre's reserve. Our reading: the multipliers are there to cover fatigue and impacts over years of use, not to make up for a rating below the axle's need.
Towing: what the towbar adds
A trailer's nose weight sits behind the rear axle, so it loads the rear wheels by more than its own weight and unloads the front. BMW lists a "towbar download" of 140 kg for the XM, with 2,700 kg braked behind it, and a 3,105 mm wheelbase (figures marked provisional in the 09/2022 data). With the ball assumed 1.1 m behind the rear axle (our assumption, not a BMW dimension), 140 kg on the ball adds 140 × 4.205 / 3.105 ≈ 190 kg to the rear axle, about 95 kg per rear wheel, and takes about 50 kg off the front axle.
The UN tyre rule allows for this on cars built to tow: the load at the coupling "may cause the rear tyre maximum load ratings to be exceeded", for ordinary car tyres, "but not by more than 15 per cent", provided the handbook then limits speed to 100 km/h at most and asks for at least 0.2 bar (20 kPa) more in the rear tyres (Regulation No 142, § 5.2.4.1). For the XM's 115 rear tyres, that ceiling is 1,215 × 1.15 = 1,397 kg each, and only on the handbook's conditions. No tolerance of that kind exists for the wheel in the texts we read: if you tow, the wheel's rating should cover the rear axle as the plate gives it, and the trailer must stay within the car-and-trailer weight.
In Britain, GOV.UK says that if the VIN plate "does not list a train weight, you should not use your vehicle for towing", and that an unbraked trailer "must not weigh over 750kg" and "should not weigh more than 50% of your car's weight" (Towing with a car; DVSA). DVSA also wants the tyres "inflated to the manufacturer's specification for the load being carried". Towing figures differ by market: the Chinese edition of the Model Y handbook we read says "towing is not permissible". We did not read the other editions; use the handbook for your country and your version.
Heavy EVs and the Tesla Model Y
A battery's weight never leaves the car. The Model Y's empty weight is 1,992 kg (AWD), already 80 % of its 2,503 kg maximum. The handbook gives the minimum tyre for each wheel:
| Model Y, original fitment | Tyre and minimum load index | Kilograms | Rear wheel load (half the rear share) | Reserve |
|---|---|---|---|---|
| 19-inch (5 seats) | 255/45R19 104 XL | 900 | 685 kg | 31 % |
| 20-inch (5 seats) | 255/40R20 101 XL or 104 XL | 825 or 900 | 685 kg | 20 % or 31 % |
| 19-inch (6 seats), rear | 275/45R19 108 XL | 1,000 | 759 kg | 32 % |
Tyres and indices: Tesla, Wheels and Tires, English edition for China; reserve: our arithmetic on the axle split, not on the plate's axle maxima.
On these figures, the method gives a minimum of 685 kg for a rear wheel of the five-seat Model Y and 759 kg for the six-seat Model Y L, which uses a wider rear tyre with a higher index. Check the plate on your car before using either number: Tesla notes that a car on accessory wheels "may include an additional label indicating that values may differ". For sizes, offsets and the tyre side of an EV, see Tesla Model 3 and Model Y wheels and do EV tyres wear faster.
What we do not choose for you
Onyx Forged does not recommend a size or an offset. We explain the method; the numbers that decide are on your car's plate, label and handbook. Our wheels are designed to JWL/VIA standards; we do not publish a load rating per wheel in this guide, and the design office checks the car's axle loads with the other dimensions of each order before anything goes into production. The full sequence of checks, from bolt pattern to weight, is in how to choose aftermarket wheels, and the sidewall is decoded in how to read a tyre size.
If a wheel shows a crack, a bent flange after an impact, or was run overloaded on a long trip, do not drive on it: have it inspected before you take the road again.
Frequently asked questions
How do I calculate the load rating a wheel needs?
Find the maximum load allowed on each axle (GAWR in North America, the axle weights on the manufacturer's plate elsewhere), take the larger one and divide it by two. The wheel's rating, and the tyre's load capacity, must be at least that.
Can I divide the GVWR by four?
No: on a Model Y the rear share gives 685 kg per wheel against 626 kg for a quarter, on a BMW XM 912.5 kg against 825 kg.
Where is the GAWR on my car?
In the United States, on the label by the driver's door. In the United Kingdom and Europe, on the manufacturer's plate, under the bonnet or inside a door. The Model Y handbook we read (Chinese edition) puts both labels on the front passenger door pillar.
Is the wheel's load rating the same as the tyre's load index?
No. The load index is the tyre's capacity (104 means 900 kg); the wheel has its own rating. Both must reach half the heaviest axle load.
Does towing change the load rating I need?
Yes. The nose weight sits behind the rear axle: 140 kg on the ball adds about 190 kg to the rear axle in our example. UN rules let car tyres run up to 15 % over their rating when towing, on the handbook's conditions; we found no such tolerance for wheels.
What load rating does a Tesla Model Y wheel need?
On the handbook's axle split, at least 685 kg per rear wheel for the five-seat car and 759 kg for the six-seat Model Y L. The axle maxima on your car's plate are the figures that decide.
Is a higher load rating always better?
It is a minimum to reach, not a score to maximise. Whatever the wheel's rating, the tyre's load index still limits what each corner can carry.
Where is the load rating marked on a wheel?
When it is marked, it is among the stamps on the back of the wheel, as "MAX LOAD", a figure in kg or lb, or a VIA load. UN Regulation No 124 does not require it on the wheel, so if it is absent, ask the seller for the rated load in writing.
To see how a forged set is specified for your car, start with customise your wheels.
Sources
- United States: 49 CFR 571.110, FMVSS No. 110; 49 CFR 567.4 (both read on Cornell LII).
- Canada: Motor Vehicle Safety Regulations, C.R.C., c. 1038, section 110.
- UN rules: Regulation No 142, tyre installation; Regulation No 30, load-capacity indices; Regulation No 124, wheels (French edition).
- Japan: MLIT, technical standard for light-alloy disc wheels, version of 7 July 2008 (in Japanese).
- United Kingdom: MOT inspection manual, 5.2.3; Construction and Use Regulations 1986, regulation 27; GOV.UK, towing with a car; GOV.UK, vehicle weights explained; DVSA, towing safety checks.
- Australia: Transport for NSW, VSI 09, Rev. 5.
- Car makers: Tesla Model Y handbook, English edition for China: Dimensions and Weights, Wheels and Tires, Vehicle Loading; BMW XM technical data.
All pages were read on 16 October 2026.
The Onyx Forged design office.