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Old 09-02-2021, 01:52 PM   #12 (permalink)
Isaac Zachary
High Altitude Hybrid
 
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 1,977

Avalon - '13 Toyota Avalon HV
90 day: 40.45 mpg (US)

Prius - '06 Toyota Prius
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When I drove school bus over the mountain passes for games and such the mechanic said he never had needed to change a bus brake.

All the buses had drum brakes both front and back. These vehicles were rated for over 35,000lbs GVWR. They also all had an electromagnetic eddy current retarder that worked wonders IMO. Of course we all were also trained to downshift and keep our speed under control. Between the retarder and downshifting none of the bus drivers ever needed (or need still) to use the mechanical brakes.

Decades ago there was a bus that had once lost it's brakes going down Monarch Pass and several children died. From what I understand, that influenced the driver training and retarder choice after that.

The same mechanic said at one point he was changing the disk brakes on the company sedans nearly every trip because the teachers didn't know how to downshift going down mountain passes and would warp the rotors. So eventually he changed all the company car brakes to oversized drilled and slotted racing rotors with large ceramic brake pads. After that, the cars didn't come back with warped rotors all the time.

My Conclusion
Drum brakes work. The vehicle may need and benefit from other types of braking, even if it's just engine braking. But that braking must be applied, and with so many drivers out there that don't have a clue what the numbers past PNRD mean it's probably best to impliment downshifting as an automatic feature. That or regenerative braking.
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