Skip to content

Ask an Expert The effect of tread depth Tyres

You are in... Forums > Ask an Expert > Tyres > The effect of tread depth

Got something to say?

Got something to say?

Go to most recent reply



Feb 09

Posts: 4758

philehidiot says:

The effect of tread depth

I was looking at the new Shell fuel when I came across their advanced driving tips - one was on tyre tread depth and is quite startling:

"When tyre tread depth falls below 3mm your braking performance deteriorates, according to research by MIRA Ltd.

Tyres with a 3mm tread have a 25% better performance than those at the legal minimum of 1.6mm. In terms of stopping distance this represents an extra 8 metres, or 25 feet, in wet conditions. In one test, when a tyre with a tread depth of 8mm was compared to one with only 1.6mm, the stopping distance increased by 13 metres, slightly more than 42 feet.

The research has led to the majority of motoring experts recommending that motorists change their tyres when tread has worn down to no less than 3mm."

Personally I don't let mine get past 2mm or so and usually change well before the 1mm wear limit for motorcycles.

Reply to this Topic  
  • Posted 2 years ago (23 July 2013 19:01)

Post a message in Tyres

Fields marked with an asterisk * are required


Please note. You cannot submit more than 4000 characters as a message.

Upload image(s) from your computer (up to 3 images)


Terms of use

Use of our community areas and forums is subject to important terms of use. By joining our community and using the features you agree to be bound by these terms. See terms of use below. 



May 09

Posts: 2562

ally600 says:

and thats why

part worn car tyres over here are so four mm they are advised they are getting near the legal limit........................over here thats almost a new tyre:wink:

Reply to this Topic


Nov 08

Posts: 879

Stuff and nonsense...

Most 3mm claims are based on aquaplaning at a certain speed (can't remember the speed), with a certain amount of standing water  (0.5mm I think) and a typical summer block to void ratio.  Do the test faster or with more standing water and you can show 4mm tread is needed.  Do it slower, or with less standing water, typical of a camber or porous tarmac, and you can prove 1.6mm is enough!

Tyresafe promotes the 3mm idea and suckers like RoSPA go along with it.  The Tyresafe initaitive is sponsored by tyre manufacturers.  If folk swap at 3mm instead of 1.6mm they will sell 28% more tyres...!

This amounts to lobbying, where profit comes before the environment or common sense.

Where does it stop?  Should everyone change at 6mm in case they all do 90mph through every deluge??

For what it's worth I find 3mm to be the sweet spot in summer (car) tyres, even highly rated tyres.  They're just too loose before that and they tram-line too much as they approach 1.6mm.  Even at 2mm a good tyre with broad circumferential grooves can give excellent grip and feel in heavy rain, resisting aquaplaning at 70mph on the lake that is the M60 clockwise at Audenshaw on a rainy day.

Reply to this Topic


Oct 11

Posts: 2465

Piglet2010 says:


Here in the US, tires for "showroom stock" automobile racing are commonly shaved to 3/32-inch (about 2.4mm) before use.

Reply to this Topic


Aug 02

Posts: 808

steveb says:

I generally

change bike tyres as a pair (on the road bike)

By the time the back tyre is through the rubber, the front has usually started to lose some of its shape and scollop a bit.

Front tread is more important than rear tread (imho) as that's where all the weight is under braking when you need the grip.

Reply to this Topic


Compare Insurance

Save money by comparing quotes. It's quick and easy

Motorcycles for sale


It's only £13.99 to advertise your motorcycle on MCN

Sell your Motorcycle

Motorcycle pricing tool

New! Find used bike prices