Construction of a rim

With rims, a number of dimensions play an important role, which are also often mentioned in the description of the relevant rim. We are happy to explain what these dimensions mean and how you can read them with the help of the article description.

Rim width

The width of the rim is measured between the outer rim edges. This is therefore the distance between the upper and lower edge of a rim. The rim width is indicated in inches. A rim measuring 14.00x19.5 has a width of 14 inches. 1 inch equals 2.54 cm so in this case 35.56 cm. There are different dimensions in terms of the width of a rim.

Diameter of the rim

The rim size or the size of the rim often means the diameter of the rim in inches. The rim diameter is measured standing outside the bead seats of the rim. It corresponds to the inner diameter of the tyre to be used and is displayed in inches. You measure the diameter of a rim by drawing an imaginary line at the centre of the rim and measuring its length. You divide the number of centimetres by 2.54 and then you know exactly how many inches comprise the diameter of the rim. 1 inch equals 2.54 cm, so a 14-inch rim is 35.6 centimetres in diameter.

ET value of a rim

The ET value of a rim indicates how much the mounting point deviates from the centre of the rim. The determination of the ET value relates to the technology, the construction of the truck wheel. This usually consists of two parts: the rim and the plate or disc. Our knowledge article on the ET value of a rim explains this further.

Horn rim

The function of the rim horn is to keep the tyre bead in shape.

A = Inner diameter of rim
B = Rim width​​​​​​​
C = Horn rim height

Diameter of a rim

G = Diameter of the shaft hole
S = Bolt hole pitch and number of bolt holes
N = Diameter of boss pitch and number of bosses
W = Wheel shot depth (not wheel bulge)
D = Bolt hole diameter and bolt hole finish
E = Additional bolt holes for possible wheel weights
B = Outer diameter of disc

Wat is de steekmaat van een velg?

The pitch of a rim refers to the attachment of the wheel. The pitch is defined by two digits, the number of bolt holes times the diameter of the imaginary circle that can be drawn through the centre of the bolt holes. An example to clarify; a pitch of 6x110 therefore means that the rim has six bolt holes with a pitch circle of 110 mm.

With four or six bolt holes, it is easy to measure and use the opposite bolts to determine the pitch size. With five bolt holes, however, it is a bit trickier but we are happy to explain it to you!

There are two ways to calculate the pitch with five bolt holes.

1. An imaginary circle should be drawn across the centre of the holes to measure the diameter of the pitch circle. When this is 100, the pitch is thus: 5x100.
2. Take the end of one bolt hole. Measure the length to the centre of an opposite bolt hole. So you are NOT measuring from centre to centre, but from the outside of one bolt hole to the centre of the opposite bolt hole. If this is 105, the pitch is thus: 5x105.