Grouped mainly by physical size and suspension type. Trials vehicles are categorised on wheelbase and suspension type and divided into Standard and Modified.

Class	Suspension Type	Wheelbase Range	Applicability
Standard:-
1	Leaf	Up to 84″	80  only.
2	Leaf	Over 84 to 90″	86, 88, Lightweight.
3	Leaf	Over 90″	101, 107, 109, 110 (includes FCs).
4	Coil	Up to 95″	90.
5	Coil / air	Over 95″	Range Rover, Discovery, Freelander, 110, 127 / 130
Modified:-
6	Leaf	Up to 84″	80  only.
7	Leaf	Over 84 to 90″	86, 88, Lightweight.
8	Leaf	Over 90″	101, 107, 109, 110 (includes FCs).
9	Coil	Up to 84″	80 only.
10	Coil	Over 84 to 95″	86, 88, Lightweight, 90.
11	Coil / air	Over 95″	All types over 95” wheelbase.

Amalgamations. Where event entry is small, suggested amalgamations are shown below:-

Class	Suspension Type	Wheelbase Range	Applicability
1 & 6	Leaf	Up to 84″	80 only.
2 & 7	Leaf	Over 84 to 90″	86, 88, Lightweight.
3 & 8	Leaf	Over 90″	101, 107, 109, 110.
9	Coil	Up to 84″	80 only.
4 & 10	Coil	Over 84 to 95″	86, 88, Lightweight, 90.
5 & 11	Coil / air	Over 95″	Range Rover, Discovery, Freelander, 101, 107, 109, 110.

This reduces 11 classes to 6 in a practical and fair way.  Amalgamation depends upon how many of each class turn up at the event, but the six classes above would be close to the norm at small-club level.