Part worn tyres: what are they and are they safe?

Maintaining your car costs money. And if you want to stay safe on the road, your only option is to pay for whatever repairs come your way. 


But if money is tight, it’s only human to look for ways you can save a few pounds. One solution, at least for some, is to buy part worn tyres. 


On the outside, part worn tyres might seem like a bargain. Truth is, they have serious safety implications — as you’re about to find out. 


In this post, we’ll have an in-depth look at what they’re all about. Paying close attention to whether they’re legal, what they cost, and the all-important safety issues. We’ll finish with our verdict on whether you should buy them. 


What are part worn tyres? 


Part worn tyres are exactly what they sound like, second-hand tyres. Typically, part worn tyres are sourced by scrap merchants, who deal with old cars and write-offs and sell the tyres to make extra cash. Or, if a vendor is scraping a vehicle, they’ll try to salvage the tyres too. 


But it’s not just a UK thing. Part worn tyres also come from European countries like Germany. Here, it’s common for motorists to change their tyres at 3mm, rather than at 1.6mm.

But here’s the thing. What counts as salvageable will be different for everyone. A tyre that’s ‘safe’ to one person might be lethal in the eyes of another. This is where the problems lie. 


A 2017 survey by Tyresafe found that over 63% of part worn tyres they inspected were unsafe to return to the road, and 22% were ten years old or older, and 18% were incorrectly repaired. 


Are part worn tyres legal? 


In Ireland and the UK, it’s legal to buy and sell part worn tyres. And you can even sell a tyre that had previously had a puncture, so long as it’s been properly repaired. It’s said that 5.5 million part worn tyres are sold each year in the UK


But you can’t just sell any old tyre. At least you shouldn’t, anyway. Part worn tyre sellers must comply with strict legislation set out by Consumer Protection Act, Motor Vehicle Tyres (Safety) Regulations. And thus, it’s an offence to sell part worn tyres that don’t meet the following requirements: 


  • Tyres should show no internal or external bulges, cuts, lumps, tears or other unrepaired damage.
  • Tyres should have no piles or cords (usually metal wires) exposed.
  • Tyres must pass an inflation test before they go on sale.
  • The original grooves must be visible in their entirety.
  • Tyres must have 2mm tread depth all the way around and across the full breadth of the tread. 
  • Tyres must have “PART WORN” stamped in capital letters at least 4mm high. 


Part-worn tyres that have been re-treaded must have one of the following:


  • BS AU 144b, 144c, 144d, or 144e markings on the sidewall next to the ECE approval mark (which is required if first supplied as a re-tread on or after 2004)
  • Permanent markings to identify the original manufacturer and model
  • A speed category symbol and load capacity marking for tyres marked BS AU 144e


Despite these regulations, not all sellers adhere to them—and it shows in the numbers. Three quarters (74%) of used tyres checked by Trading Standards failed to meet safety standards. While 34% had dangerous and potentially life-threatening defects. 


So it’s not looking good so far. 


What are the risks of buying part worn tyres? 


The risks of buying part worn tyres outweigh the cost-saving ten-fold. If you’re thinking of buying used tyres, ask yourself, “why have the tyres already been removed from a vehicle?”. 


Tyres are often removed from vehicles when there’s 3mm of tread left. At which point, they start to lose grip fast. Not only does this affect a vehicle’s efficiency, but traction, cornering and braking suffer too — especially in the wet. 


It’s recommended that you replace tyres in axle pairs. This keeps the tread patterns in sync, which is vital for channelling water equally. It also prevents unstable pressure on the axle shaft. 


Replacing tyres in axle pairs is easy when you’re buying new tyres. But less so if you opt for part worns. Finding two used tyres from the same garage with a similar tread pattern will never be easy. 


And then there’s the longevity of part worn tyres. At 3mm, which is when it’ll get taken from the previous vehicle, it’s already very close to the UK limit of 1.6mm. With just 1.4mm of tread left, it will only last a few hundred miles (at best). 


For context, new tyres can last upwards of 20,000 miles. And so, the argument that part worn tyres are cheaper isn’t really valid because they’ll need replacing more often. 


How much do part worn tyres cost? 


You can buy a part worn tyre for as little as £10, depending on the size, brand and condition. Either way, that’s a lot cheaper than even a budget tyre. But here’s where things get interesting. 


Research by Tyresafe found that the cost per millimetre of a part worn tyre is £6.33, compared to just £5.33 for a new tyre. When people buy part worn tyres, they forget that they’re getting much less tyre. Yes, they’re a fraction of the price, but they’re a fraction of the rubber too. 


To echo this point, the difference between the minimum tread depth a part worn tyre can be sold and the legal limit for a tyre on the road is just 0.4mm — half the thickness of a bank card. 


So what does that tell you? Well, that you won’t get very far before you’re at the legal limit — at which point you could face three penalty points (for each tyre) and a £2,500 fine. 


Why is tread depth so important? 


A tyre’s tread is what gives you grip and traction. In the dry, it’s responsible for helping you stop, corner and accelerate. But when the roads are wet, your tyres not only have to grip but shift standing water too.


A tyre with less than 3mm tread depth won’t be able to shift water as effectively, which will lead to aquaplaning. Simply put, this is when water builds up between the tyre and the road, causing it to spin. 


Aquaplaning tends to happen when the water is above 2.5mm. But it can happen more often if your tyres lack tread. And when you consider that part worn tyres have 3mm at best, aquaplaning can be an issue. 


Here’s how the type of tyre and tread depth affects braking when travelling at 50mph.  And for context, the average car is around 4 metres.

So, should I buy part worn tyres? 


Short answer, no! 


If you hadn’t clocked, First Stop gives part worn tyres a huge thumbs down. As do many specialists in the automotive industry. 


Fact is, part worn tyres are a massive gamble. And when you’re gambling with the only point of contact between you and the road, safety comes first. And not just your own safety, but the safety of others too. 


If you could guarantee that part worn tyres are safe, it wouldn’t be so bad. But — and it’s a big but — with unknown history and the potential for failure, you can’t. And as you’ve seen from the Tyresafe figures, there are far too many unsafe tyres on the market to consider it a safe option. 


Buying a new set of tyres may not be cheap. But skimping on your tyres is a dangerous thing to do. And thus, you should avoid part worn tyres at all costs. 


Get quality new tyres for peace of mind 


At First Stop, you’ll find quality tyres from the best manufacturers. To find a tyre that suits your vehicle, use our online registration tool to find the correct tyre size and book online or head to your local First Stop garage. Once you’ve found a tyre, we can help fit it for you too. Stay safe on the road with quality new tyres.