How can I find the correct tyre size that fits my truck or trailer? 

Witte vrachtwagens op de parkeerplaats van BAS TyresWitte vrachtwagens op de parkeerplaats van BAS Tyres

Finding out which tyre sizes fits your truck or trailer can be a difficult task. On this page we will explain where you can find the tyre size on you tyre and how you can understand this number.
We will also elaborate on the topics of most common truck and trailer tyre size, the load index of a truck or trailer tyre and the speed index of truck and trailer tyres.


Where do i find the tyre size on my truck?

The tyre size of a truck tyre is printed on the side of the tyre. We call this the 'sidewall' of the tyre. This is a string of information that consists of a combination of letters and numbers. The image on the right shows the tyre size of a light commercial vehicle. You can find the truck tyre size on the exact place.

How to read truck tyre sizeHow to read truck tyre size

Hot to read a Truck tyre size?

A truck tyre consists of different elements; the trucktyre width, height, and inch size.

We have found the following number letter combination on the sidewall of a random truck tyre in our warehouse.

Sidewall information: 315/70R22.5

Through this combination we will explain the reading of a truck tyre 

The trucktyre width 

The width of the tyre is indicated by the first three digits in the tyre size. For example, 315/70R22.5 156/150L is the tread width, 70 is the percentage of tyre height and 22.5 stands for the wheel's inch. Tyre height is indicated after the / in the tyre size.

The trucktyre height

Tyre height is indicated after the slash ( / ) in the tyre size. The height of the tyre is given in percent, a height of 65 means 65% of the width of the tread.

The trucktyre size / Radial tyres

The tyre size of a truck and trailer or semi-trailer is indicated in millimetres. This applies to all radial tyres, a characteristic of a radial tyre is that the tyre size is marked with an R, for example 385/65R22.5.

The trucktyre inch size

Trucks, trailers and semi-trailers can have the following inch sizes 22.5 inch, 20 inch, 19.5 inch and 17.5 inch. The inch size is always indicated at the end of the tyre size. For example, tyre size 245/70R17.5, 245 is the tread width, 70 is the height percentage and 17.5 is the wheel's inch size.


Load index and speed index
After the rim size there are is always a number and a letter. in this case it is 156/150L. The number 156/150 The number indicated the load index of a truck/trailer. We have described the overview that corresponds to the load index number a few paragraphs down.

The last letter in this case stands for the speed index of the truck/trailer. You can also find this a number of paragraphs down.

BAS Tyres warehouseBAS Tyres warehouse

Overview of the most common truck and trailer tyre sizes 

In the overview on the right you can see the most common truck and trailer tyre sizes. 
The first 3 digits are the width of the truck tyre. The 2 digits after the slash ( / ) indicates the height of a tyre in a percentage.
The letter R indicated that the tyre is a Radial type tyre.
The diggets after the R represent the size of the tyre in Inches.

Load index of a truck or trailer tyre

The load index stands for the maximum load capacity of a tyre at the ideal pressure, whereby it is important that you never overload the tyres.

During the periodic inspection (APK or TÜV), this is checked and enforced. If you do not have the correct load index on your vehicle, the inspection authority will reject your vehicle. The load index is indicated by codes on the tyre.

The code for the load index is always found on the sidewall of the tyre.


On the right side is a diagram of the index and associated load capacity. 


Loadindex  KG's  Loadindex  KG's
115 1215 139 2430
116 1250 140 2500
117 1285 141 2575
118 1320 142 2650
119 1360 143 2725
120 1400 144 2800
121 1450 145 2900
122 1500 146 3000
123 550 147 3075
124 1600 148 3150
125 1650 149 3250
126 1700 150 3350
127 1750 151 3450
128 1800 152 3550
129 1850 153 3650
130 1900 154 3750
131 1950 155 3875
132 2000 156 4000
133 2060 157 4125
134 2120 158 4250
135 2180 159 4375
136 2240 160 4500
137 2300 161 4625
138 2360 162 4750

Speed index of truck and trailer tyres 

The speedindex of a tyre refers to the maximum speed the tyre can handle. The speedindex is indicated by a letter after the loadindex. For example for a 315/70R22.5 truck tyre the load and speed index is 156/150L, 156/150 is the load index and the letter L stands for the speed index of up to 120 kilometres per hour.

Speed symbol Maximum speed (km/h) Speed symbol Maximum speed (km/h)
A1 5 K 110
A2 10 L 120
A3 15 M 130
A4 20 N 140
A5 25 P 150
A6 30 Q 160
A7 35 R 170
A8 40 S 180
B 50 T 190
C 60 U 200
D 65 H 210
E 70 V 240
F 80 ZR >240
G 90 W 270
J 100 Y 300
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