How to Use a Tyre Tread Wear Chart
When moving at a speed of 40 miles per hour, it takes around 36 metres to come to a full stop. However, that supposes that your tyre tread is in sufficient condition, and your tyres are otherwise in good health. The more worn your tyre tread is, the longer it will take you to stop, and the more susceptible you'll be to accidents.
This is why you need to do a tyre inspection every month or so. When doing this, it can be handy to consult a tyre tread wear chart just like the one below :-)
Need help knowing how worn your tyres are and how to use a chart? Then read on. Here's everything you need to know.
What Is a Tyre Tread Wear Chart?
First, let's talk about what a tyre tread wear chart is. This chart displays different tyre wear levels and then designates how safe they are at a given tread depth. The purpose of this is to indicate whether a tyre replacement is needed.
You should inspect your tyres every month or so, assessing tread depth, in particular, but also paying attention to general condition, cracks, bulges and that all important tyre pressure. When checking your tyres and trying to make these assessments, it can be handy to consult a tyre tread wear chart. This will help you determine whether you're driving safely (or legally, for that matter).
Understanding Tyre Tread Depth
The primary thing to consider when assessing tyre tread is tyre tread depth. The refers to the height of the treads left on the tyre. These naturally wear down over time, causing them to grow shorter and shorter. This progressively reduces tyre tread depth, but more importantly, it means it takes longer to stop your car, especially in the wet!
At their peak, standard car tyres have a tread depth of 8mm. If your tyre treads measure 8mm high from the base of the tyre, your tyre has suffered no wear and is in perfect condition.
Equally, if your tyre treads measure less than 1.6mm high, they're at a dangerously low depth and are illegal to drive on. Not only could they cause you to lose control of your vehicle, but they could also result in you receiving 3 points per defective tyre on your driving licence and monetary fines on top of that up to a maximum of £2,500!
Adequate tyre tread depth is vital to keeping your vehicle in control when the weather is bad and when you're making quick turns. Driving on an extremely low tyre tread for too long will almost certainly result in an accident at some point.
Fun Fact... well for the maths geeks out there at least. Tyre wear deteriates mostly in a linear process up until about 3mm tread remaining. However, after 3mm tyres wear in an exponential fashion hence taking drastically longer to stop the vehicle. This is why tyre manufacturers recommend recplacing tyres at 3mm and not waiting until the legal limit of 1.6mm
Gauging the Effects of Different Tyre Tread Depths
We've discussed the importance of tyre tread depth when it comes to keeping a vehicle in control. The less depth, the less traction the tyre will provide and the longer it will take to stop. Infact between new tyres in perfect health and bad tyres approaching the legal limit that distance is maybe more than you think. At 30mph it can be as much as 2 double-decker busses in length (20m), so maybe much further than you may think.
That said, let's gauge the effects of different tyre tread depths.
8mm
For a standard vehicle tyre, 8mm is optimal. For most tyres on the market, this indicates a brand-new tyre with zero wear and tear. Tyre tread of this depth allows for maximum safety and performance.
7mm
7mm of tyre tread is still great. At this point, the tread is only 15% worn. As such, the tyre will perform more or less, like new.
6mm
6mm of tyre tread depth is still relatively good. This indicates around 31% of the tyre tread has worn. By and large, a tyre with this tread depth will still perform like new.
5mm
At 5mm, you should start to notice a slight loss in performance. Not only will it take you longer to stop, but you'll also have a little more trouble keeping the vehicle in control throughout turns and in dangerous weather.
Nonetheless, this is still suitable to drive on. This indicates around 45% tyre tread wear.
4mm
At 4mm, your tyre tread depth is just barely above the level for recommended replacement. The tyre will now be approximately 62% worn. You'll unquestionably notice a difference in performance at this depth, both in terms of control and stoppage time.
However, that doesn't mean you need to replace the tyre yet. It's more or less safe and will still serve you well on the road; but you should start to keep a closer eye on your tyres perhaps increasing your monthly inspection to weekly.
3mm
It's at 3mm that your tyre tread depth starts to reach dangerous levels. At this point, the tread is around 78% worn.
You can continue to drive on the tread of this depth. Beware, however, that you'll need to take it a little slower around corners and in bad weather.
All major tyre manufacturers recommend the replacement of tyres at this tread level...and honestly, it's not only for their benefit they are saying this. Tyres at this level will take somewhere between 1 to 1.5 double-decker bus lengths additional distance to stop, and that's only at 30mph! One to keep in mind on the school run on a wet winter day!
2mm
At 2mm in depth, your tyre tread is around 94% worn. We highly recommend a tyre replacement at this point, as having such a worn tread is undoubtedly going to impair your ability to keep the vehicle in control.
That said, there is no legal requirement to replace tyres at this depth. The legal bar for replacement in the UK is actually very low compared to other EU countries, hence if you choose to drive on, you may want to consider doing so at a tortoise pace! Between this level and the UK legal limit, you could have as little as 100 miles remaining.
1.6mm
As noted above, 1.6mm is the legal minimum for tread depth on a tyre. Once your tyre tread depth falls below this figure, your tyres are no longer road-legal and need to be replaced.
We can't advise enough that replacing your tyres before they reach this point is highly recommended. If you skirt the lines of legal acceptability, you could accidentally go under this limit alot easier than you might think - it could be as little as a jont down the shops away. An untimely traffic stop could, therefore, result in you receiving points, and likely a sizable fine.
Plus, it's plainly unsafe to drive on tyres of this tread depth. You'll become a danger not only to yourself but to other drivers as well. 27,000 lives in the UK are changed each year on our roads through death or severe life-changing injuries...the only thing in contact with the road is those scraggly tyres! A few extra mm could be the difference between stopping in time or not.
How Long Does It Take For Tyre Tread to Wear Down?
We hate saying this, but "it depends". There are so many factors that affect the rate at which tyre treads wear down. The biggest factor is the distance that the vehicle has travelled since the tyres have been installed. Some tyres are can be as low as 10,000 miles; others can last for well over 40,000 miles. Local road conditions, of which the UK doesn't exactly excel in, as well as temperature changes and if your vehicle is kept indoors or not can all play a part.
Another important factor is time. The more time that passes, the more the tyres will deteriorate, and the faster their tread will wear. Apart from tread tyres will naturally oxidise in the sun and could start to look cracked, if this happens replace the tyre ASAP; that tyre is now at a greater risk of blowout. Generally, this happens around 5 years after manufacture, but can be sooner or indeed longer.
Top tip, Tyres have a date of manufacturer or DOT code printed on the side of every tyre. It tells you the week and year of manufacture i.e. 1023 is the 10th week of 2023. If this is over 5 years on your tyres you might want to think about replacing them, no matter the tread depth remaining.
The last big factor is braking severity. The harder and more often you apply your brakes, the more wear and tear you'll put on your tyres. The more wear and tear they receive, the quicker their tread will deteriorate.
You can combat tyre tread wear by maintaining your tyres properly. This will add a few thousand miles to your tyres, at the very least.
Ready to Buy Tyres?
Now that you know a thing or two about reading a tyre tread wear chart, you might be ready for a tyre replacement. If so, you're in the right place. Tyre Runner has you covered.
We don't sell tyres. We simply compare tyres, retailers and prices and then help you find the right retailer or fitter in your area to get you back on the road safely again.
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