Fitment reference
The basics of tyre sizing, ratings, offset, bolt patterns and centre bore. Free for everyone.
Reading a tyre size
Passenger tyre size as printed on the sidewall
- P
Tyre type
P stands for P-metric, or passenger. Tyres with higher ply ratings usually start with LT, for light truck. An LT-metric tyre always has a load range shown. Never substitute a P-metric tyre where the vehicle calls for LT-metric, even if every other dimension is the same.
- 215
Section width
The width of the tyre in millimetres at its widest point, sidewall to sidewall, when mounted on the recommended rim width. The actual width changes with the rim it's fitted to.
- 65
Aspect ratio
The section height divided by the section width, multiplied by 100. Here, the sidewall height is 65% of 215 mm.
- R
Construction
R is radial: ply cords run to the beads at 90 degrees to the tread centreline, held by a circumferential belt. B means belted and D means diagonal, where the cords are laid at alternate angles under 90 degrees.
- 15
Rim diameter
The wheel diameter in inches that this tyre fits. Older TRX rims use metric sizes such as 390. TRX rims and regular tyres can't be mixed either way.
- 89
Load index
The maximum load each tyre can carry. 89 is 580 kg. See the load table below.
- H
Speed symbol
The top safe speed under specified load. H is 210 km/h. See the speed table below.
Speed ratings
The speed rating is the top safe speed at which a tyre can carry a load under specified conditions.
| Speed symbol | J | K | L | M | N | P | Q | R | S | T | U | H | V | W | Y | VR | ZR |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| km/h | 100 | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 | 190 | 200 | 210 | 240 | 270 | 300 | >210 | >240 |
Load ratings
The load index is the maximum weight each tyre can support. A replacement tyre's load index must be equal to or higher than the figure on the vehicle's tyre placard.
| Index | kg per tyre | Index | kg per tyre | Index | kg per tyre | Index | kg per tyre | Index | kg per tyre |
|---|---|---|---|---|---|---|---|---|---|
| 62 | 265 | 75 | 387 | 88 | 560 | 101 | 825 | 114 | 1,180 |
| 63 | 272 | 76 | 400 | 89 | 580 | 102 | 850 | 115 | 1,215 |
| 64 | 280 | 77 | 412 | 90 | 600 | 103 | 875 | 116 | 1,250 |
| 65 | 290 | 78 | 425 | 91 | 615 | 104 | 900 | 117 | 1,285 |
| 66 | 300 | 79 | 437 | 92 | 630 | 105 | 925 | 118 | 1,320 |
| 67 | 307 | 80 | 450 | 93 | 650 | 106 | 950 | 119 | 1,360 |
| 68 | 315 | 81 | 462 | 94 | 670 | 107 | 975 | 120 | 1,400 |
| 69 | 325 | 82 | 475 | 95 | 690 | 108 | 1,000 | 121 | 1,450 |
| 70 | 335 | 83 | 487 | 96 | 710 | 109 | 1,030 | 122 | 1,500 |
| 71 | 345 | 84 | 500 | 97 | 730 | 110 | 1,060 | 123 | 1,550 |
| 72 | 355 | 85 | 515 | 98 | 750 | 111 | 1,090 | 124 | 1,600 |
| 73 | 365 | 86 | 530 | 99 | 775 | 112 | 1,120 | 125 | 1,650 |
| 74 | 375 | 87 | 545 | 100 | 800 | 113 | 1,150 | 126 | 1,700 |
Offset
Offset is the distance from the wheel's mounting surface to the true centreline of the rim.
With positive offset, the mounting surface sits in front of the centreline, toward the street side, which tucks the tyre further into the guard. With negative offset, the mounting surface sits behind the centreline, which pushes the tyre out from the vehicle.
Section through the wheel from above. Vehicle side on the left, hub shown in grey.
Bolt patterns
Bolt patterns are usually written as two numbers, such as 4/100. The 4 is the number of stud holes. The 100 is the diameter of the circle through the centre of each hole, in millimetres or inches. Some wheels are drilled with two patterns so they fit more vehicles.
On 4-, 6- and 8-stud wheels, measure from the centre of one hole to the centre of the hole directly across. On a 5-stud wheel there's no hole directly opposite, so measure from the centre of one hole to the imaginary circle midway between the two opposite holes.
Centre bore
The centre bore is the hole in the middle of the wheel that centres it on the vehicle's hub. Most aftermarket wheels have a large centre bore so that one design fits many vehicles.
In that case, fit a hub ring: a hard plastic or metal ring between the wheel and the hub. It centres the wheel exactly, so there's no run-out. Without one, you can get vibration even when the wheel and tyre are perfectly balanced.