How tyres can put the skids on passing your driving test

Revising for your theory test and preparing for your practical exam are very different tasks, but when it comes to tyres, there’s a lot of overlap. In both assessments you will be asked a variety of questions about tyres to ensure your knowledge is up to scratch. Not knowing the answers can put the skids on getting your licence, so make sure you’re au fait with our pointers on best tyre practice.

Testing your tyre theory

There are a number of potential questions your theory test could throw up in relation to tyres and braking and they all tend to base themselves around the following scenarios:

Cold weather
Cold weather can reduce the pressure in tyres, so this should be checked regularly during cold snaps. The opposite happens during very hot weather. You should be able to find the recommended pressure for your tyres on a small sticker on your bodywork, or in the vehicle handbook.

Under-inflated tyres
Tyres that aren’t inflated to their designated pressure point can lead to poor braking, increased fuel consumption and heavy steering – all of which make driving more dangerous. A correctly inflated tyre improves safety and rolls more easily, saving fuel and reducing your running costs, in addition to CO2 emissions.

Tread depth
The minimum tread depth must be 1.6mm over three quarters of the tyre’s tread width and around the entire outer circumference. You may have heard of the 20p test before… and it’s really simple! Place a 20p coin inside the main tread groove of the tyre. If the outer band of the 20p piece is obscured by the tread, then your tyres have adequate tread. If you can see the outer band of the 20p piece your tyres could be approaching the legal limit, so it’s advised to have them checked as soon as possible.

Excessive and uneven tyre wear can be caused by a defective braking or suspension system, or poor wheel alignment, so make sure to check these if you notice any issues with your tyres.

Tyres that have cuts, gouges or bulges in the side walls are illegal and must be replaced. The test will not go ahead!

Tyre types
There are two different types of tyres: cross ply and radial ply. They’re made slightly differently. A rule of thumb is that cross ply tyres will be thicker walled, cheaper, last a little longer and have slightly worse grip. Radial ply tyres perform in the opposite way and for that reason, it is illegal to mix cross-ply and radial-ply tyres across the same axle in the UK.

Practical test tyre questions

Before you even set foot in the car, the examiner may ask you to answer tyre-related questions as part of the “show me, tell me” element of the practical assessment.

The DVSA website has an extensive list of questions you might be asked, but we’ve picked out the most relevant tyre questions below. It’s likely you’ll only be asked one of the two on your test, but it’s best to be prepared!

Q: Tell me where you’d find the information for the recommended tyre pressures for this car and how tyre pressures should be checked.

A: You can find the recommended tyre pressure information on the side of the tyre or in the manufacturer’s guide. When checking the pressure, you should use a reliable pressure gauge, check and adjust pressures when tyres are cold and remember to refit valve caps. It’s also vital to have a back-up plan to deal with punctures, so be sure to carry a spare tyre, a space-saver spare wheel or a tyre sealant and inflator kit.

Q: Tell me how you’d check the tyres to ensure they have a sufficient tread depth and their general condition is safe to use on the road.

A: The tyres need to be free from cuts and bulges. The minimum tread depth must be 1.6mm over three quarters of the tyre’s tread width and around the entire outer circumference of the tyre. You can verify this with the 20p coin test.

Before the test, the examiner will make a cursory vehicle check, including tyres, to make sure it meets the minimum standard for driving. One of the rules your car must adhere to before testing is that there is no tyre damage and each tyre must meet the legal tread depth. You cannot have space-saver spare tyres fitted for a driving test.

Unfortunately, if you get a flat tyre, the test will be abandoned, and you’ll have to rebook a future timeslot. The DVSA doesn’t make any concession for this.

Making sure your tyre knowledge is up to scratch stands you in the best stead for a successful driving test experience.