Laurel caynon causes my brake to smoke.

How about keeping speed down too? I'm not sure, but would think that reduces the overall amount of braking needed, less braking for corners? Also, periodically lifting off the brakes (sort of the opposite of pulse-and-glide) might help to cool them?

 

Well, in a Prius, your only choice is to B or not to B, so if the descent is steep enough that B can't hold your speed, some braking is needed.

There must be some ongoing controversy I wasn't aware of then ... the U. Mich Transportation Research Institute study UMTRI-92-11 involved comparing a constant-dragging strategy with a snubbing strategy (3 seconds on, 6 seconds off), and ended up with these basic findings:

Of course they don't leave out the importance of just taking the descent slowly enough overall:

(page 62 of report, 76 of the PDF).

That third point, in the basic findings, was a bigger effect than I realized: with two different lining types tested, the area of drum surface discolored by overheating was seven times greater under dragging than snubbing for lining type A. (They reported eleven times worse for dragging with lining type B, but either there's a typo or that's compared to snubbing with lining A, so apples/oranges.) Page 50 of report/62 of PDF.

-Chap

 

When the wind is southerly I know a hawk from a handsaw.

-Chap

 

Let's define terms:
Dragging brakes = gentle pressure on brakes, enough to slow the vehicle on a flat road gently
Snubbing brakes = application hard enough to definitely feel the vehicle slow, would result in a moderate stop on level ground
Stabbing brakes = application of brakes to near lock-up, would result in a "hard stop" on level ground

There is absolutely ZERO debate that STABBING brakes is a method that is ill-advised on any vehicle.

The idea I was attempting to promote, but did not communicate clearly is that: a) STABBING is VERBOTEN and b) control of the speed is the most important factor.

It takes FOUR TIMES MORE braking power to stop a vehicle from 60 MPH than from 30, because kinetic energy increases as the SQUARE of speed. So double the speed = 2^2 the kinetic energy. This means that if the "safe" downhill speed is 40 MPH, you should not start down the hill at say 50 or 60 THEN try to slow down; but begin the descent at 40 using gearing to maintain that speed.

At the end of the day, going down a grade too fast is too fast.

 

What's the total elevation change? (Forgive me if it's earlier in the thread; too tired to look back.)

And how long does that change take overall, at 35 mph?

-Chap