[adi555]

What would be the minimum tyre thread depth for 225/50/R18 in mm?

[adi555]

Anyone?

[Skyline2.0]

In the US, legal minimum tread depth is 2/32 inches, or 1.6 mm. An easy visual indicator is to change your tires once the tread reaches the wear bar on your particular tires. I do not recommend waiting until your tread is exactly even with the wear bar as performance, handling and safety will be negatively affected once you reach minimum tread depth.

2/32 is the US standard. You should be able to easily search online the standard for your locality.

[oakey46]

The tyre wear indicators on UK cars are at 1.6mm and I would think that's a general set-up across most, if not all markets. Again, in the UK, the advice from most sources is to change the tyres once they are down to 3mm remaining tread as this would help prevent aquaplaning in heavy rain. I have experienced that on a company car that was approaching the legal minimum and it was quite an unnerving moment. So, yes, I will stick to changing at 3mm (just look at how small the difference is in wear from 3mm to 1.6mm). Not worth the risks involved for the sake of using that other 1.4mm!

Here's what the UK Automobile Association has to say, but also search in your own country to see what advice may be given:
How does wear affect grip?
'Wet grip in particular gets worse as the tread on your tyres wears. This is more marked as the tyre wears below 3mm of tread and approaches the legal limit.
Check your tyre’s tread depth more often once it gets down to 3mm and aim to replace tyres before the tread wears below 2mm.
This is more important as autumn and winter approach – better new tyres now than struggle through the cold and wet with tyres approaching the legal minimum tread depth.'

[adi555]

But RFT's come with low tyre tread. I think my new set came with just 5-6mm tread. In such case it wouldn't be feasible to replace tyre at 3mm life.

[oakey46]

Originally Posted by adi555

But RFT's come with low tyre tread. I think my new set came with just 5-6mm tread. In such case it wouldn't be feasible to replace tyre at 3mm life.

It depends on how you regard your safety whilst driving. No one but you can decide on that.

[00max00]

Originally Posted by adi555

But RFT's come with low tyre tread. I think my new set came with just 5-6mm tread. In such case it wouldn't be feasible to replace tyre at 3mm life.

My stock tires are RF Goodyears, they were 11mm new.

[kavatski]

Just checked our stock Pirelli P7 RFTs. Brand-new tread depth is 10/32" or 8 mm.

[adi555]

So knowing that RFT's have low tread depth from factory, is it safe to let the tyre run till 1.6mm or 2mm?

[oakey46]

Originally Posted by adi555

So knowing that RFT's have low tread depth from factory, is it safe to let the tyre run till 1.6mm or 2mm?

Just have a look at the last couple of responses, one of which from Kavatski states the RFT tyres had 8mm at new, plus my comment regarding potential safety issues by running the tyres down to 1.6mm and, as I said, no one but you can decide on what may be safe for you. Personally, I wouldn't wish to risk that for my own safety, and/or that of my family/passengers.

[rice_rocket88]

In my particular state in the USA... the legal minimum tread depth is 3/32" which means a) if you're getting an inspection sticker you will fail b) if you are stopped for a ticket and they decide to measure it your car will be towed. c) if you get into an accident and they figure out that it is below that you will not be covered.

Other than the mentioned safety concerns.. you can do whatever you want. Manufacturers make the wear bar at 2/32" because that would literally be what they deem that you need to change them.

[oakey46]

Originally Posted by rice_rocket88

In my particular state in the USA... the legal minimum tread depth is 3/32" which means a) if you're getting an inspection sticker you will fail b) if you are stopped for a ticket and they decide to measure it your car will be towed. c) if you get into an accident and they figure out that it is below that you will not be covered.

Other than the mentioned safety concerns.. you can do whatever you want. Manufacturers make the wear bar at 2/32" because that would literally be what they deem that you need to change them.

The legal minimum in the UK and Europe is 1.6mm (which equates to 2/32") and independent research by the (respected) UK Motor Industries Research Association (MIRA) shows that tyres with 3mm of tread have an average 25% better performance than those at 1.6mm - which represents an extra 8 metres (8.75 yards) stopping distance in wet conditions.
That’s good enough for me!