On or around Mon, 20 Jun 2005 10:20:43 +0100, Paul Brown
<firstname.lastname@example.org> enlightened us thusly:
>They do already pay 10x the roadtax of a PLG vehicle - how much more damage
>do they do?
>The main reason the inside lane on motorways is so damn trashed is that
>*every* truck spends most of its life there, whereas cars all tend to be in
>the outer lanes - It's relatively little to do with the individual vehicles
>and more to do with the sheer concentration.
However, there's a worrying trend to fit the semi-trailers with super-single
tyres. These are about 14" wide or more compared with 11" for "normal"
ones, but of course there are only half as many; the weight is thus
concentrated on a smaller area of the road. I see the widest tyre
Bridgestone offer is 445mm, about 17", in fact. Still, 6 of them gives you
102 sq.in. per inch of contact patch - compare this with for example 8x11"
ones, which would be 88, on a tandem axle trailer with twin wheels, it's not
that much better - a twin-wheel tri-axle has an area of 132, so you've lost
30" of area by swapping to super-singes, and that's if you buy the ginormous
ones - if you have the ones that are 14" wide, or thereabouts, you've got
less area from your 6 super-singles than the twin-tandem. Yet the tri-axle
trailer gets you a significant reduction in road fund licence.
They're even worse on narrow roads, as not only is the weight more
concentrated, but it's concentrated right at the edge of the road, where
it's not so strong. The twin-wheel configuration has an overall width of
about 24", with a couple of inches in between the 2 tyres, and spreads the
weight more onto the middle of the road, which ordinarily gets less use.
Austin Shackles. www.ddol-las.fsnet.co.uk
my opinions are just that
"Quos deus vult perdere, prius dementat" Euripedes, quoted in