> -----Original Message-----
> From: John McK Lambert [mailto:[log in to unmask]]
> Sent: 07 November 2002 09:12
> To: [log in to unmask]
> Subject: Re: New arrival to list
>
>
> John
>
> Cannot contribute to your specific standards
Thank you for your feedback,
It seems the concensus is that although theoretical and track work proves
you need tread to perform in the wet the presence of good surface textures
and the fact "nutter drivers" seldom care about their tyres has made proving
poor tyres increases accidents difficult though the US did a trial to
see if the "idiot factor" could be considered.. tracking this down now...
work in 1980s in AUS said 3mm was the breakpoint for accidents envolving "utility poles"
Fox Good & Joubert 1979
Also enforced minimum tread reduces the likelyhood of exposure & corrosion of braiding cording /
leading to explosive failure of tyres....
ANYONE With any references regarding the link between tyre condition &
accidents are most welcome to contribute emailled pdfs much appreciated
John
=======================================
ROAD SURFACE CHARACTERISTICS AND SAFETY:
A Project Jointly Funded by The AA FOUNDATION FOR ROAD
SAFETY RESEARCH and CSS being undertaken by HAMPSHIRE COUNTY COUNCIL
http://195.167.162.28/aafoundation/
http://www.cssnet.org.uk/
John C Bullas BSc MSc MIHT FGS - Research Officer - AA Foundation / CSS
Hampshire UK
======================================
>
> In Australia the limit was 1/16 inch which converted to 1.5 mm on
> metrication in the 1960's.
>
> The current standards are of the form:
>
> 54. Tyre tread (1) A tyre on a motor vehicle must not have
> cleats or other
> gripping devices that could damage road surfaces.
>
> (2) Except at tread wear indicators, a tyre fitted to the
> vehicle must have
> a tread pattern at least 1·5 millimetres deep in a band that runs
> continuously--
>
> (a) across--
>
> (I) for a vehicle with a GVM over 4·5 tonnes net
> least 75% of the
> tyre width that normally comes into contact with the road; or
>
> (ii) for another vehicle the tyre width that normally
> comes into
> contact with the road; and
>
> (b) around the whole circumference of the tyre.
>
> (3) A vehicle must not be fitted with a tyre that has been treated by
> recutting or regrooving the tread rubber, unless the tyre was--
>
> (a) constructed with an extra thickness of rubber
> designed for recutting
> or regrooving; and
>
> (b) labelled to indicate the construction.
>
> I have never seen any research supporting this limit.
>
> It is of course well recognised that slick tyres and a wet
> road are a safety
> problem because a wedge of water builds up in front and causes loss of
> traction.
>
> But as the water film on the road builds with flatter roads
> and/or heavier
> rain and/or the degree to which the road surface is self
> draining, the size
> of the drainage slots through the tread must increase in
> order that the
> rubber maintains contact with the road surface.
>
> At 1.5 mm and limited numbers of grooves, the tyres ability
> to handle films
> of water would be limited. More open tyre tread designs will
> perform better.
>
> Regards
>
> John Lambert
>
>
>
>
>
> ----- Original Message -----
> From: "Bullas, John C" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, November 02, 2002 2:35 AM
> Subject: New arrival to list
>
>
> Fellow "listers"
>
> I am researching (amongst other things) the reasoning behind
> the choice of
> 1.0mm and then 1.6mm
> minimum tread depth for tyres for cars (PLG) in the UK
>
> If anyone can shed any light on the "how & why" these tread
> depths were
> selected is more than welcome to
> contribute!
>
> Regards
>
> John
>
> winchester UK
>
> =======================================
> ROAD SURFACE CHARACTERISTICS AND SAFETY:
> A Project Jointly Funded by The AA FOUNDATION FOR ROAD
> SAFETY RESEARCH and CSS being undertaken by HAMPSHIRE COUNTY COUNCIL
>
> http://195.167.162.28/aafoundation/
> http://www.cssnet.org.uk/
> ======================================
>
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