Motorcycle Tyre Tread Depth for Roadworthy in Queensland
I inspected this Yamaha MT-09 in Sunnybank today. Tyres were fine on this one, but worn tyres are one of the most common reasons motorcycles fail a roadworthy. Here’s what you need to know.
The minimum is 1.5mm
The legal minimum tyre tread depth for a motorcycle roadworthy in Queensland is 1.5mm. This applies across the entire contact surface of the tyre – the area that normally touches the road.
If any part of the contact surface is below 1.5mm, the tyre fails.
This is the same limit as for cars. It applies to both the front and rear tyres.
How to check your tread depth
If you want to measure precisely, you can buy a tread depth gauge from any auto parts store for a few dollars. Place it in the main grooves at several points across the tyre and check the reading.
On motorcycle tyres, wear is often uneven. The centre of the tyre wears faster than the edges because that’s where most of the contact happens during straight-line riding. Check the centre of the tyre, not just the edges – the centre is where it’s most likely to be below the limit.
Tread depth isn't the only thing I check
During a roadworthy inspection, I don’t just measure the tread. I also check for:
Cracks in the rubber. Old tyres dry out and crack, especially if the bike has been sitting unused for a long period. Cracked tyres fail regardless of tread depth.
Bulges or deformities. Any visible bulge in the sidewall or tread area indicates internal damage. The tyre could fail at speed. That’s an instant fail.
Damage from punctures or objects. A nail or screw in the tyre, cuts, or chunks missing from the rubber are all fail points.
Correct tyre size. The tyres must be the correct size for the wheel and within the manufacturer’s specifications for the bike.
Motorcycle tyres wear faster than you think
Motorcycle tyres have a much smaller contact patch than car tyres, which means they wear down quicker – especially on the rear. Sporty riding, heavy braking, and hot Brisbane roads all accelerate wear. A rear motorcycle tyre can go from new to below the limit in as little as 3,000-10,000km depending on the bike and riding style.
If you’re planning to sell your motorcycle and need a roadworthy, check your tyres first. Replacing a worn tyre before the inspection is cheaper than paying for a re-inspection because you didn’t notice.
