|
| |
Courtesy of Mike, a fellow Hayabusa owner.
Road Surfaces
Lets get this tyre thing in context....
Road surfacing and the materials used in it , is an ever developing science, 20
years ago it was thought that the "hard" aggregate made good a
material for macadams and asphalt .......but not true at all , hard aggregate
polishes after the bitumen has worn off the surface (a bit like your
knuckles) and then it becomes lethal in the wet.
Aggregate is measured by it's PSV ......Polished Stone Value , the higher the
PSV the better it is , and it's measured by passing a pendulum device over the
surface of the road , which is done in the dry and the wet.
Hot Rolled Asphalt (HRA) unlike macadam is impervious to water , and that's
when, falls, cambers and gulley's come in ....to drain the water of the surface,
to make it have a high PSV , pre-coated chippings of a good PSV are rolled into
the surface when it's laid, and the vehicle tyres run on them , not the asphalt
so much which is just there as a binder.
Now on some A roads , and some Motorways , resurfacing is being done with porous
asphalt , now this has drainage properties of macadam , the silent running
surface of macadam , but the strength, and skid resistance properties of Hot
Rolled Asphalt, and because its made up of lots a different types of aggregate
with different PSV it's nearly the best surface for skid resistance after proprietary
surface materials like ShellGrip and Delugrip.
Overbanding.....
this is the black bitumen paint that is used around patches to
prevent water ingress and is to be avoided at all costs in the wet and dry.
White Lines...
some white lines have some marginal skid resistance material
added to them when laid , but it is at extra cost , and not usually found in
Europe except parts of the UK and Germany......avoid white lines as you can't
tell what the material is in the wet and dry
Now .....
unless you are running a bike , car or whatever over the same bit of
road time and time again , in the wet ,in the dry , in the warm, in the cold ,
in a mixture of all, the average driver/rider may have an ill informed
opinion of a tyres performance under certain conditions , but it is just that
,........an ill informed opinion .....did they measure the PSV of the surface ?,
had a lorry or tractor been round the island 10 minutes ?before spewing out
exhaust smoke onto the road surface ?, or even a spray of diesel ?, or the
liquid from some recently culled sheep ??.....THEY DON'T KNOW
I've run Pilots,56's and 010's, Avons , Metzlers , some are more grippy than
others 'cos it says they are , and they are designed to be, some are all round
tyres and some all round sports tyres, but whatever the tyre everyone wants the
best grip , with the greatest longevity, but unless you are prepared to go a
test and a place like TRL (Transport Research Laboratory) or MIRA (Motor
Industry Research Association) use their track facilities , with all of the
various surfaces they offer , your opinion will be based upon a "
feel" and little else
These threads I've read , that certain tyres slipped on white lines
........now there's a surprise........all tyres will slip on white lines , and
overbanding , so don't blame the tyres!!
Most public road surfaces are a compromise, they are not done in DeluGrip
like Brands/Donnington / Silverstone , you'll have a different surface with
different properties within yards.
Some tyres are best for sprints and drag racing , COME ON .......these are road
tyres , for road bikes , no one on this board rides flat out on the Queens
Highway and you can't push a tyre to it's full capability on the road anyway.
010's ,HPX's or whatever it's down to cost and longevity/economy at the end of
the day.
Just remember before you criticise a particular make of tyre , think of the
surface etc etc etc , and then probably your best to keep your own council and
say nothing !!
| |
|
