Tema 19: tyres and suspension in the DGT exam
Tyre tread has a legal minimum, and when chains are needed, they go on the driving wheel, not whichever one you prefer.
Reviewed on 11 October 2026 · sources: BOE and DGT
This tema asks what minimum tread tyres must have and how chains are fitted.
- Tyres must show tread in their main grooves throughout their use on the road.
- On cars (turismos), vans and their light trailers, the minimum depth is 1.6 mm. On buses, trucks and heavy trailers, the minimum is 1.0 mm.
- When chains or another anti-skid device are mandatory, fit them on at least one driving wheel on each side, or use special tyres.
- Carrying them in the boot is not enough: the obligation is that they are actually fitted.
- Every vehicle must have an elastic suspension system that helps grip and stability while moving. It is distinct from the braking system.
Watch out: 1.6 mm is the figure everyone remembers, but it only applies to cars and vans; a truck is measured against a different one.
In DrivingLingo: see the warning signs, tema 20 on brakes, steering and transmission, tema 36 on rain, fog, snow and tunnels and the .
Source: RGV art. 12 (points 5.1, 5.2 and 7) and annex VII.
Key rules of topic 19
Minimum tread depth
Tyres must show tread in their main grooves throughout their use on the road.
- On cars, vans and their light trailers, the minimum depth is 1.6 mm.
- On buses, trucks and heavy trailers, the minimum is 1.0 mm.
Source: RGV art. 12, punto 5.1; RGV anexo VII
Chains on the driving wheel
If chains or similar are compulsory, you fit them on at least one driving wheel on each side, or use special tyres.
- Carrying them in the boot is not enough: the obligation is that they are actually fitted.
Source: RGV art. 12, punto 5.2; RGV anexo VII
Elastic suspension
Every vehicle must have an elastic suspension system that helps grip and stability while moving.
- This system is distinct from the braking system, even though both affect the vehicle's stability.
Source: RGV art. 12, punto 7
Wear and damage
A tyre with exposed cords, cracks, blisters or deformations may not be used, even if it still has tread.
- The wear indicator shows that the main grooves have reached the legal minimum.
- Wear only at the edges, or only in the centre, usually points to wrong inflation pressure.
Source: RGV anexo VII, ap. 3 y 4; DGT, manual del permiso B (criterio)
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