When do I need to have my tyres replaced?
Updated 10 Aug 2021
Worn out tyres are a fact of life when you own a car.
The simple truth is that every day of driving and every click you put on the odometer brings you closer to that expensive service.
Eventually, you’re slipping and sliding around on the road because your tyres don’t have tread left.
Worse yet, you could have an unfortunate puncture or blowout, and you’re looking at changing your tyres before you expected it.
There isn’t an exact formula for when to have your tyres replaced.
These are a few guidelines for when it’s necessary to change your car’s tyres.
When the tread is worn out
If your tyre tread is worn out, it’s time to change them . . . but what do you consider ‘worn out’?
If your tread depth measures 1.6mm or less their safe operating life is over.
It’s at this point that there isn’t enough tread to properly grip the road, and you’re at risk of losing control.
You’ll want to replace your tyres well before this point – at around 3mm remaining is best.
Measure the depth between tread blocks to get an accurate reading.
Don’t have a tread depth gauge?
No problem! Insert a 20c coin between the treads.
If the platypus’ bill isn’t at least touching the tread, you have less than 3mm remaining.
An irreparable puncture
You don’t have to replace tyres for every nail or screw puncture – they’re often repairable.
But if the hole is on the shoulder between the sidewall and the tread, or in the sidewall itself, it can’t be fixed.
Also, if the hole is larger than 2mm in diameter, there’s a good chance it won’t seal properly and you’ll need to change the tyre.
If you whack a curb or pothole with enough force, your tyre could pop like a balloon.
After your heart returns to normal from the pace of a hummingbird, you’ll quickly realise that there’s no fixing this type of hole.
When tyres are expired (it's a real thing!)
They don’t last forever.
Tyres are susceptible to dry rot with cracks along the sidewall, bead, and between tread blocks.
Typical guidelines state that tyres should last around six years from their date of manufacture, but how do you know when they’re expired?
On the sidewall, you’ll find a sequence of four numbers at the end of the DOT code.
These four numbers are the date of manufacture – when the clock starts on their six good years.
The first two digits are the week of the year, from 01 to 52.
The second set are the last two digits of the year.
For example, ‘0613’ would indicate that the tyres were manufactured in the sixth week of 2013 and, consequently, would expire the same week in 2019.
How tyres should be replaced
For the best performance and handling, all four tyres should be the same or close in tread depth.
To achieve that, replace tyres in pairs at minimum.
If you have a 4WD or AWD vehicle, it’s strongly suggested that you should replace your tyres as a complete set of four.
Looking to replace your tyres?
You can quickly and easily book in with a local tyre specialist through AutoGuru.
Jason is a Canadian automotive content writer with a background in the auto service industry, but he’s been hooked on cars and mechanics since childhood.
One of his first cars was an ’80 Mazda RX-7 that’s sorely missed to this day. A ’68 Ford Torino GT, a ’66 Ford Country Squire Woodie station wagon, and a ’96 Suzuki GSX-R 750 have spent time in his fleet of cars, bikes, and trucks over the past two decades.
Jason’s pride and joy is under construction – a turbocharged ’88 Mazda RX-7 convertible. Also on his resume is CASCAR official certification.