Finepost · Fines · Codes · CU30
CU30 : using a vehicle with defective tyre(s)
Checked 22 July 2026 · How we check our figures
What it means
CU30 is the code that multiplies: each defective tyre is a separate offence, so one stop can produce four charges, though for offences from the same occasion the court normally endorses only the highest points, s. 28 RTOA 1988, unless it decides otherwise. The legal floor is 1.6 millimetres of tread across the central three quarters of the width, reg 27 of the Construction and Use Regulations 1986, and a cut or exposed cord fails a tyre at any depth. The strictness and the latent defect argument track CU10; blaming the garage changes nothing at the kerb.
Points and how long it stays
3 points.
On the licence for 4 years from the date of the offence.
The CU codes are the vehicle's own offences: brakes, tyres and steering under s. 41A RTA 1988 (CU10, CU30, CU40), dangerous condition and dangerous loads under s. 40A (CU20, CU50), and the control-of-vehicle code CU80 alongside. All carry 3 points on the 4-year offence clock, CU80 alone ranging to 6. The arithmetic multiplies before it settles: each defective item is its own offence, so four worn tyres are four charges, though for offences from the same occasion the court normally endorses only the highest points, s. 28 RTOA 1988, unless it decides otherwise. An MOT certificate does not answer any of it, it speaks to the test day, not the roadside. And where a defect is minor, the stop can end in a vehicle defect rectification notice, proof of repair in place of a penalty (gov.uk, checked 2026-07-22). The points arithmetic sits in the penalty points calculator at /fines/penalty-points.
The usual route
A roadside stop can end three ways: the endorsable fixed penalty of 100 pounds and 3 points, a vehicle defect rectification notice where proof of repair replaces the penalty, or a summons where the defect is serious (gov.uk, checked 2026-07-22).
If it goes to court
In court the fine is income-banded at the lower bands, with a higher ceiling for goods vehicles; mechanics in the fine bands guide.
Read next
Guide: Single justice procedure →
Calculator: the code decoder, every code on the official list →
Authority
gov.uk, Penalty points (endorsements), checked 2026-07-22