How to Measure Tire Tread Depth #mechanictips #techtips #autocare #mechanicvideos #toolsofthetrade, by Faye Hadley on YouTube. 2 min 2 s.
- Video length
- 2 min 2 s
- Time to do it
- 10 minutes
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Park on flat ground and switch off the engine. Put the handbrake on so the car cannot roll while you work around the wheels.
Find the main tread grooves running around the tyre. These are the wide channels between the raised blocks, not the thin lines at the edge.
Push the probe of the tread depth gauge into a groove until the flat base sits on the tread blocks. Read the depth on the scale.
Take a reading in at least three places across the tyre: the outer edge, the centre and the inner edge. Write each number down.
Repeat on all four tyres, and check the spare if you have one. Worn inner or outer edges often point to bad alignment.
No gauge? Push a coin into the groove. On a UK 20p the outer band is about 3 mm, and on a US penny Lincoln's head is about 1.6 mm.
Compare your lowest reading with the legal minimum. In the UK it is 1.6 mm across the central three quarters of the tread.
Replace any tyre at or near the limit, and check for cracks, bulges or objects stuck in the tread before you drive.
Tips and common mistakes
Measure when the tyres are cold and the car is unloaded, since heat and weight can change the reading slightly.
Check the tread wear indicator bars inside the grooves. If the tread is level with them, the tyre is worn out.
A tyre can pass in the centre and fail at the edge, so always take three readings across the width.
Never rely on a visual check alone. A tyre that looks fine can be below the legal limit.
Questions
What is the legal minimum tread depth?
In the UK it is 1.6 mm across the central three quarters of the tread around the whole tyre. Many drivers replace tyres at 3 mm for better wet grip.
Can I check tread depth without a gauge?
Yes. A coin works well. Push it into a groove and see how much of the coin edge is covered by tread. A gauge is more accurate and cheap to buy.
How often should I check my tyres?
Check tread depth and pressure about once a month and before long trips. Do it more often if you drive a lot or notice uneven wear.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
