Speed ratings for agricultural tractors
Design speeds and speed discs.
This content is for general information only. It does not, and is not intended to, provide legal or technical advice or to represent a legal interpretation of the matters it addresses.
Frequently asked questions
This means fitting a speed disc to the vehicle to show its design speed in kilometres per hour (km/h) as shown.
You can contact the original manufacturer or authorised distributor.
|Vehicles||Speed disc required||Speed disc not required|
Agricultural tractors, self-
propelled agricultural machinery, agricultural trailers and pieces of interchangeable towed equipment
Tractors first registered on
or after 01 January 2016, regardless of design speed, must be fitted with a speed disc showing their maximum design speed.
Tractors registered prior to 01 January 2016 which are capable by design of being driven at speeds over 40 km/h, must also be fitted
with speed disc.
Tractors first registered prior
to 01 January 2016 which are not capable by design of being driven at speeds over 40 km/h.
Yes. Agricultural tractors, self-propelled agricultural machines, agricultural trailers, and pieces of interchangeable equipment manufactured or first registered before 01 January 2016 do not need to have a speed disc fitted if their design speed is 40 km/h or less.
Speed discs must only be fitted by the original vehicle manufacturer or authorised distributor.
- The speed disc should always be in a prominent position on the rear of vehicle.
- For self-propelled agricultural machines it should be displayed in a prominent position on both sides and on the rear of the vehicle.
- On an agricultural trailer or interchangeable towed equipment where due to its design or use the disc cannot be seen from behind, it should be in a prominent position on the right side of the vehicle when looking from behind.
- If a speed disc cannot be attached directly to a vehicle a plate has to be attached to the vehicle to display the disc.
See our booklet on Revised Standards for Agricultural Vehicles.
You may draw such a trailer or another piece of interchangeable towed equipment with a tractor which is capable of speeds over 40km/h but when it is in use in a public place you must not exceed the maximum design speed of the slowest vehicle in the combination e.g. if a trailer or piece of interchangeable towed equipment does not have a speed disc fitted the law considers that the vehicle combination – no matter what the design speed of the tractor is – is not capable of speeds over 40km/h.
They must be capable of maintaining a minimum speed of 50 km/h. From 01 January 2016 if they are towing a trailer, the trailer must also be capable by design as indicated on its authorisation plate and speed disc of being drawn at a speed of 50 km/h or higher. See our Class R Agricultural Trailers FAQ information.