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On 5 Sep,
Peter Clinch <[email protected]> wrote:
> Tony Raven wrote:
>
> > I stand corrected then but going back to the OP, do you think the
> > situation of "on an MTB pointing down a 60 degree loose slope you need
> > very precise braking control" is realistic. I recognise there are 60
> > degree slopes but there is unlikely to be any loose material on them and
> > I somehow doubt the rear wheel would stay down if you tried to brake.
>
> I can see such a slope existing if one takes "loose" as "stuck on... but
> not at all well, and not enough to stay put when a bike hits it", but I'd
> agree that anyone going down 60 degree slopes on a bike is pretty much
> wasting their time with the brakes! 60 degrees is actually typical of
> lower grade rock climbing, and IME people very often over-estimate true
> steepness of steep slopes (where "steep" starts at about 20 degrees).
A slope of 45 degrees would require a coefficient of friction of one just to
stay on it. Coefficients higher than one are unusual, perhaps limiting at
about 1.1 with sticky tyres. It would be impossible to stay put, nevermind
brake to a halt, on a 60 degree slope, unless there was an interlocking rack
and pinion arrangement.
--
BD
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Peter Clinch <[email protected]> wrote:
> Tony Raven wrote:
>
> > I stand corrected then but going back to the OP, do you think the
> > situation of "on an MTB pointing down a 60 degree loose slope you need
> > very precise braking control" is realistic. I recognise there are 60
> > degree slopes but there is unlikely to be any loose material on them and
> > I somehow doubt the rear wheel would stay down if you tried to brake.
>
> I can see such a slope existing if one takes "loose" as "stuck on... but
> not at all well, and not enough to stay put when a bike hits it", but I'd
> agree that anyone going down 60 degree slopes on a bike is pretty much
> wasting their time with the brakes! 60 degrees is actually typical of
> lower grade rock climbing, and IME people very often over-estimate true
> steepness of steep slopes (where "steep" starts at about 20 degrees).
A slope of 45 degrees would require a coefficient of friction of one just to
stay on it. Coefficients higher than one are unusual, perhaps limiting at
about 1.1 with sticky tyres. It would be impossible to stay put, nevermind
brake to a halt, on a 60 degree slope, unless there was an interlocking rack
and pinion arrangement.
--
BD
Change lycos to yahoo to reply