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Posted by Bruce Richmond on September 22, 2008, 9:11 pm
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> >> I told them that it was patently unfair to hold an MSF basic rider cou=
rse
> >> in
> >> the rain. =A0The issue in my mind is that for most motorcycles, the fr=
ont
> >> brake takes an awful lot of force to lock up on dry pavement. =A0In th=
e
> >> rain,
> >> it gets easier.
>
> >> Opinions? =A0Advice?
>
> > Would they accept a motorcycle license that prohibits riding in the
> > rain? If not, they should learn it, too.
>
> > The physics is exactly the same when it rains, it's just the limits tha=
t
> > are lower.
>
> I don't think so. =A0The physics are similar, but not the same.
>
> There is hydroplaning.
I can assure you there is no hydroplaning going on in a MSF class. We
race in the rain and it takes standing water and much higher speed
than you go in class to get a motorcycle to hydroplane.
> I also get the impression -- perhaps erroneous -- that the gap between
> static and kinetic friction is larger when the road is wet. =A0Once you g=
et
> the wheel a'sliding (rather than a'rolling), it doesn't always seem that
> easy to get it a'rolling again.- Hide quoted text -
Both go down in the wet. One thing that does make it tricky for new
riders is that when a disc brake gets wet it has reduced grip for a
few turns as the water gets wiped off. The grip then increases while
holding the same pressure on the lever. If the rider has increased
pressure because they weren't getting the grip they wanted they can
suddenly find the wheel locking up. Some brakes are worse than others
in this respect. One way to get around this problem is to frequently
drag the brake a bit. That wipes the water off and heats the disc up
so that any water that does get on it will evaporate quickly. If the
bike is particularly bad in this respect it can be improved with
different pads or drill patterns in the rotor.
The fact that both of them and others went down makes me wonder if the
students were adequately instructed on what to expect. On the street
in the wet I use a bit less front brake and a bit more rear brake than
I do in the dry, particularly if braking while turning.
Bruce
Bruce
> - Show quoted text -
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