Wheel Sizing & Markings

Wheels

Wheel sizes and markings can seem somewhat intimidating at first, especially if you are just looking for a new set of wheels for your car and are being bombarded with letters, numbers and offsets. What we will do is break down the jargon and explain each part of the wheel markings.

6.5J x 17 H ET35

Firstly lets break this down into the seperate parts.

  • 6.5 - This is the wheels width in inches from the front of the rim to the back.
  • J - The J indicates the bead profile, a full table of these is below.
  • 17 - This is the wheels diameter in inches.
  • H - This represents the hump type and will be a good indication of wheel rigidity.
  • ET35 - This is the wheels offset. A measurement in mm showing how far away from the wheel centreline the wheels meet the hub. Check below for a diagram on offset.
That covers most of the markings you will encounter on alloy wheels.

Wheel Offset

Wheel offset is how far away from the centreline (the red dashed line on the diagram below) your allow wheel makes contact with the hub.

The greater the offset the closer your wheel is to the axle and steering and suspension components, and the lesser the offset pushes the wheels out to the road side and closer to the the wheel archers and body panels.

Zero offset means that the centreline of the alloy is in line with the point at which the wheel is attached to the car.

Tyres

Along with wheel sizing, tyres have their own various markings, these are similar in the way wheels are marked in that they show the sizing, construction and safety information for the tyre.

215x45R17 107W

Again, lets break this down into its parts

  • 215 - Tyre width in mm from sidewall to sidewall
  • 45 - Aspect Ratio for the tyre, the height of the sidewall of the tyre as a percentage of the width. In this instance 45% of 215 is 96.75mm meaning that is the height of the tyre sidewall.
  • R - Tyre construction type. Most modern tyres today are manufactured as radial tyres and have the R type, other types include B for bias belt and D for diagonal.
  • 17 - Tyre diameter in inches, Easier to match to the wheel size which is usually represented in inches too.
  • 107 - Load Index. A numerical code referring to the maximum load the trye can carry.
  • W - Speed rating. A table of these is below but this tells you the maximum speed the tyre is rated for at its maximum load.

Reference Tables

Load Index Table

Load Index Kilograms Load Index Kilograms Load Index Kilograms
65 290 80 450 95 690
66 300 81 462 96 710
67 307 82 475 97 730
68 315 83 487 98 750
69 325 84 500 99 775
70 335 85 515 100 800
71 345 86 530 101 825
72 355 87 545 102 850
73 365 88 560 103 875
74 375 89 580 104 900
75 387 90 600 105 925
76 400 91 615 106 950
77 412 92 630 107 975
78 425 93 650 108 1000
79 437 94 670    

Speed Index Table

Speed Symbol Approx MPH Approx KM/H
Q 99 160
R 106 170
S 112 180
T 118 190
H 131 210
V 149 240
VR 131 210
W 168 270
Y 186 300
ZR 149 240

Wheel Marking table

Marking Meaning
A Bikes, Motorcycles, light and heavy trucks and forklifts
B Passenger cars
D Bikes, Motorcycles, light and heavy trucks and forklifts
E Light & heavy trucks
F Heavy trucks
G, H Heavy trucks
J Passenger cars
JJ 4x4 vehicles
P, K Antique cars
S, T, V, W Utility vehicles
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