Hi Jim,
I think it's highly unlikely that driveline components would be damaged
by the rapid application of the handbrake. Remember that it has the
mechanical advantage of the gearing in the rear end, which would reduce
the torque load on the driveline accordingly.
I've started engines on various vehicles with dead batteries dozens of
times by popping the clutch when the vehicle was rolling down a
hill...never any damage. Similarly, if you pop the clutch with the
engine running, it will apply as much, if not more, shock load to the
driveline than the brake would. Even a tight automatic transmission can
apply a tire-chirping torque load to a driveline when it shifts.
It's true that most clutch plates have built-in springs to reduce shock
load and chatter, but even if you pull a handbrake lever as fast as you
can, the application of braking force will probably still be slower than
a rapid clutch engagement. I don't think there would be much initial
shock effect.
One thing to consider: If you are moving at a pretty good clip and apply
the handbrake slowly, I'd say there's a good chance that the handbrake
could overheat quite rapidly, since the handbrake drum would be spinning
four to six times faster than the rear wheels...plus the handbrake media
surface area is quite small.
Of course, there is also the danger that you could lock up the rear
wheels and lose control of the vehicle. When tires suddenly stop
rolling, some interesting things happen. Oversimplified, if the vehicle
has any turning tendency at the time that the rear wheels lock, the mass
that was previously being forced to follow the vector of the rolling
wheels will suddenly go in the direction that the mass wants to go.
In general, handbrakes are designed to be parking brakes, but if your
regular brakes fail, then I suppose that the handbrake is worth a try.
How well it works will depend on the situation. Still, any port in a
storm...
Regards,
Alan
(Salt Lake City, Utah)
*********************************
===
To unsubscribe from the mil-veh mailing list, send the single word
UNSUBSCRIBE in the body of a message to <mil-veh-request@skylee.com>.