Are the brake pads special?

Most 'braking' is the motors making electricity, only emergency braking and under 7 MPH use the pads. (the motors are spinning too slowly under 7 MPH)

 

That depends strongly on the driving style. For many drivers, even 'normal' braking exceeds the maximum regeneration and breaks over to include the friction pads.

For example, I've been unable to train my spouse to start braking earlier and use less pressure in order to stay within the regeneration zone. (She is otherwise very good at DWB (driving without brakes), just hasn't adapted the necessary braking to fit Prius regen.) I've also been unable to break her of the ancient habit of 'pulse' braking on long downhills. That is the use of repeated short hard pulses to more evenly spread the heat around on non-balanced brakes, something that is still needed on most tractor-trailer combinations but is unnecessary on modern cars and actually wastes potential regeneration on the Prius.

But even the drivers who don't make the best use of regenerative braking still get substantial benefit from it, including extended brake pad life.

 

The UK drivers report much shorter disc brake pad life vs US Prius owners. Speculation is UK pads are a ltitle bit softer material vs US pads.

 

That was one owner that mashed the throttle at every start and mashed the brakes at every stop and was singular.
The idea was to get Toyota to pony up money for periodic replacement parts.

The brake pads only make contact below 12mph, they last forever

 

The pads are always in contact, cmon. If I've washed the car and it's sat overnight, the rotors have got a bit rusty, for the first few blocks of driving I'll hear the brakes every time I apply them, even at 40~50 kmh.

We're around 50,000 kms, front pads are a bit worn, 2~3 mm. The rear pads I replaced already, due to uneven wear, another story though. Might have been due to misassembly when we had rear suspension replaced in a repair.

 

One of the merits of driving a Prius with a ScanGauge is that, with some mental processing, you can use it to see how hard you can brake at various conditions before you get friction braking in addition to Regen. The trick is to set the SG to display traction battery charge/discharge Amperes. For a given state of the system (I think mostly battery temperature and perhaps charge state) there is a maximum regen current that will be sent to the battery--and thus a maximum deceleration "power" the regen system will generate. It is easy enough to see in high speed braking, applied with gently increasing force, as during the early part of your increase the current increases proportionately, then stops increasing as you brake ever harder.

Just as it takes much more propulsion horsepower to give you 5 mph/sec acceleration at high speed than at low, it takes much more regen power (and thus current) to slow you down at a given rate at high speed than low.

I forget the typical maximum current I observed, but it was not very different than 100 Amperes, so for this discussion I'll just use 100A.

At residential street speeds 100A is a considerable deceleration rate, and those of us who drive gently are quite unlikely to exceed it. On the other hand, at freeway speeds, it is a surprisingly modest deceleration rate, and pretty easy to exceed if you have the habit of driving in freeway traffic at close proximity to your neighbors, using frequent brake applications to keep your spacing and fend off other drivers who might slip in ahead of you. Here in the mountain West, if you let your speed get higher than you wish on a long downgrade, it will be only the gentle driver who gets back down to desired speed without triggering friction--and of course on a really long downgrade the battery will get both fully charged and warm, and the computer will dial down your allowed maximum regen current.

So I think that at freeway conditions the Prius brake wear rate is strongly dependent on traffic conditions, topography, and driving style.

 

The rear brakes have a self adjusting mechanism; ours always have a slight drag, definitely not free spinning. All in all, think I'd prefer if they were drums.

 

Yes the brake pads are special.
They are made out of fairy wings and unicorn horn.