[Vwdiesel] mileage

[Erik Lane]

I don't disagree with anything about there being differences in the
brakes, and that causing differences in braking. I'm more interested
in differences in stopping distances between a passenger car and a
semi truck with brakes locked up. No slipping of the brakes, pure
kinetic friction between the road and rubber. Ever since I first heard
that mass didn't come into the equation it's interested me.

But I also suspect, after further reflection, that truck brakes are
somewhat limited from locking up, at least on the cab, from a
standpoint of retaining control. If you have too much more braking in
front you're in danger of jack-knifing and losing all control. I am of
the opinion that it is likely more dangerous to have complete loss of
control and jack-knifing, with the trailer going all over the place,
than having a longer stopping distance while limiting the amount of
braking going to tires at the front of the 'train.' This would also be
consistent with an unloaded trailer having a longer stopping distance
than a loaded trailer. I bet it's not a simple thing, but is very
closely controlled to optimize braking while retaining control.

I know that ABS can have a drastic difference on stopping, because of
its superior properties, but in this I'm thinking that neither vehicle
would have ABS to simplify and make the two more similar.

Erik