The cut n' paste job below is specifically for johnners who i sincerely hope does not drive a vehicle on the public roads if his ignorance as shown above is anything to go by - or he may have been trolling - if so?, he's won, it may be interesting reading for others, personally i would welcome at least a 3mm tyre tread minimum legal depth.
The following chart shows the increase in stopping distance of worn tyres. The second arrow (100%) shows the stopping distance required to brake a vehicle from 60 mph to rest with a new (assumed to be 8mm) tyre.
The first arrow shows the stopping distance required in dry conditions. As you can see, as the tread depth reduces so the required stopping distance increases. This increases to a point where a tyre with just 1.6mm tread remaining takes an extra 60% of stopping distance to bring the car to a halt.
Although the legal limit for tyres is, in general terms,1.6mm most motoring organisations recommend changing tyres at 2.0mm. Many manufacturers recommend a minimum tread depth of 3.0mm.
Obviously there also an adverse effect on (wet) vehicle handling as tread depth reduces, the chart shows stopping distances in a straight line only.
The adverse effects on wet performance are due to the loss of the tyres ability to remove water from the road surface therefore inreasing the danger of the vehicle aquaplaning.
Many manufacturers now introduce special compounds to improve wet grip. These compounds usually contain a higher content of silica.
In 2004 Government statistics showed that one fifth of all serious road traffic accidents were caused as a result of skidding. Test results from the Motor Industry Research Association show that there are significant increases in stopping distances in wet conditions once the tyre treads have dropped to below 3mm. The legal minimum in the UK is only 1.6mm however recent research has shown that tyres with a 3mm tread depth have a 25% better performance over those that have the legal minimum of 1.6mm. In terms of stopping distance this is a substantial 8 metres.
Stopping distances for those with new tyres and a tread depth of 8mm are substantially better. In a test carried out by the Motor Industry Research Association comparing old and new tyres, the stopping distances increased by 13 metres when tyres with tread depths of 8mm and 1.6mm were compared.
Stopping distances in wet conditions will increase even more dramatically for a car with tread below 3mm. Recent research has suggested that a car travelling on a motorway at the legal speed limit can take up to 44metres to stop in the rain if the tyre rubber is completely worn down.
In addition to dramatically increased stopping distances on both wet and dry roads, tyres with tread depth of less than 3mm are also far more susceptible to aquaplaning.
Many tyre manufacturers and independent safety councils are now warning that the minimum tyre depth should be increased to 3mm to try and improve safety on the roads. The current legislation dates back to 1992 when tyres were skinnier and smaller in diameter, however in recent years tyres have become wider, meaning the contact patch on the road is greater, in dry weather this is suitable as it allows the vehicle to gain more grip. In wet conditions, however, cars with wider tyres are far more likely to start aquaplaning and breaking is drastically reduced.
In 23 yrs of driving i've never had an accident, insurance claim or a bump/nudge or whatever that was my fault, but i've been ran into, rear-ended ,front ended, had cars written off etc by other drivers, if the penalties for causing injury by dangerous or poor driving were increased perhaps folk would drive with more respect for others and remember they're piloting a 1 ton bullet.