Posted on 02/03/2024 11:04:12 AM PST by cba123
“Drum brakes have the advantage of being cheaper, longer lasting and zero drag.”
Then why don’t EVs use drum brakes?
“Then why don’t EVs use drum brakes?”
Some do.
What happened to the Wankel engine?
“Disc brakes are simply less variable than drum brakes, regardless of how frequently they are used.”
Heat is not a concern in a panic stop. However disk brakes degraded due to lack of use is.
Concerning the unsprung weight, there have been advances in the hub motors to reduce their weight.
When I was a younger man, most all of the cars had a REAR DIFFERENTIAL CASING made entirely of CAST IRON and extended from one side to the other. Inside were a jam packed cluster of GEARS and TWO HALF AXLES.
I would guess that that rear axle assembly weighed more than this new hub motor (which eliminates even the drive axles). The rear axle on a Cadillac probably weighed more than an entire PRIUS (minus the batteries).
Those old vehicles had a VERY SMOOTH ride.
That was partly my point. Unsprung weight vs overall vehicle weight was a more important measure.
The whole auto industry “expert” claims that “usprung weight is bad” was questionable if not downright bogus to begin with.
But it came from the days when the elite decided that rwd cars with heavy rear axles were bad. And unsprung weight was therefore bad.
Now the elite wants to build electric cars with in-wheel motors, it turns out unsprung weight is not so bad after all !
Which ones?
1. It’s not a MASSIVE amount of unsprung weight. Think back to the 60’s through 90’s vehicles with rear drive.
2. The unsprung weight is not the major problem, but is a factor due to the COOLING SYSTEM required for each hub motor. That is what has slowed down the marketability of the hub motors. Cooling system involved complexity, added cost, and added weight.
SO.. weight is a factor, but not because it drastically added to unsprung weight.
There have been advances in motor design and streamlining of the cooling system recently and that is why this article was done. The technology is ready for production on a large scale and that will reduce COSTS.
It is if you're stopping with drum brakes. I also don't understand where you get the idea that disc brakes degrade more than drum brakes from lack of use. Drum brakes are notorious for bad behavior from low usage.
“It is if you’re stopping with drum brakes.”
Nope. In a 3 second panic stop there is almost no meat dissipation on either disk or drum brakes.
“I also don’t understand where you get the idea that disc brakes degrade more than drum brakes from lack of use.”
Common knowledge. I am surprised you are not aware.
“Think back to the 60’s through 90’s vehicles with rear drive.”
Mustang went to IRS in 2015. Reduced unsprung weight over 100 pounds.
A lot of people believe ‘old wives tales’. That doesn’t make them true.
“A lot of people believe ‘old wives tales’. That doesn’t make them true.”
Then stop spouting them since they don’t apply in this modern Era.
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