I'd like to see the statistics that show people today are braking more per mile than they were when drums were common.
I know I’m braking more now. Mainly has to do with increased traffic. The more traffic…the more you’re going to brake.
Me too. There’s been a dramatic increase in traffic in NH these past decades.
By the way, Mike, those brakes in the video… they come already warped?
^My guess is that he means, “an astute driver can anticipate stuff like a light turning red and an upcoming traffic slowdown, and coast down well in advance of a need to brake. Also, don’t drive like a nut!”
I’m among the “retro-grouch” set, here, on most subjects…and even I can’t get behind drums. In addition to working better, discs are fundamentally simpler in means of operating (which is usually what I cite when I profess a love of “old tech.”)
As far as pedal effort, I’ve owned motorcycles with twin drums, and a disc/drum setup. The disc fronts were MUCH easier to modulate, and featured a reduced effort relative to the drums, despite a (perhaps) 40% heavier road weight! ('84 Honda VF700 vs '72 Honda CB350). That’s in direct contradiction to the theory of “efficient” drum braking.
I suppose other factors…(ahem, cable actuated drums)…overwhelmed whatever self-actuating properties drums brought to the table!
I’d like to say here that the comparison of drum brakes in cars to drum brakes in trucks is not valid. The brake drums on the rear of my minivan are good-sized ones as passenger car drums go, and I can lift one off the ground with two fingers. The brake drums on air brake-equipped trucks and busses are massive…It takes two men to lift one of those drums! Another factor here is on a truck or bus, all of the axles contribute to the braking, where on a car, the weight tends to shift to the front under heavy braking leaving the rear brakes 80% out of the equation. Trucks and busses tend to carry more weight in the rear and the weight doesn’t shift as much with the axles being farther apart.
Quoting sgtrock21
Nevada_545 You are absolutely correct I owned 1960 and 1962 MGAs a 1966 MGB with manual front disc brakes
I have driven TWIN CAM MGAs a few times. (Not my cars.) Those were equipped with disc brakes on all four wheels. They definitely required greater pedal pressure to slow their cars. They were, however, very good at stopping them. Later MGBs all had a power booster, but continued the front disc/rear drum set up.
As far as greater pedal pressure is concerned, SO WHAT? If my right leg is strong enough for me to stand on, it’s strong enough to step on the brake pedal to stop the car.
I got the impression that Ernest P. Worrell (or a very good impersonator since Jim Varney died in 2000 according to IMDB) was trying to sell drum brake set ups for street rod use. Would you by brakes from Ernest P. Worrell? I wouldn’t.
“Most drivers todayuse the brakes excessively”
“I don’t know what this means”
I live near a city corner with stop signs, and stop signs at the surrounding intersections, plus a couple of speed bumps.
About 1/3 of the drivers zoom from stop to stop, engines roaring.
Half are not as extreme, but still lead footed.
I think the increase in safety requirements has a lot to do with the use of brakes along with abs and related traction control devices to make safer cars. Repeated braking of traction control can be done with drum brakes, but even the owner’s manual will tell you that the brakes can overheat using these traction devices; hence, discs.
I do know too, that when I drove a manual transmission, I went through fewer braking cycles then with automatics. I feel that too has a big impact. Autos have much less drag by design with higher mileage requirements and as a result, we have to use our brakes more.
Mike, sign me up for a set of those brakes in the video…and the hair cut too.
The Duralast brake commercial reminds me of Bugs Bunny’s “air brakes” in the nose-diving airplane.
I’ll do you guys one better
When I was still living in Germany, I had a 1986 Toyota with manual brakes
Front solid rotors, rear drums
Admittedly, it was a small car
I put up with the first couple of minutes of the video. Waste of time. I’m happy to pay for a booster to get better brakes.
@Nevada_545Rick, you must have a real sense of humor posting an Ernest P. Worrell type video about brakes.
Mr. Haney would fit also.
MG McAnick I have seen a couple MGA Twin Cams but never drove one. I did test drive a 1960 1600 Mk 2 that had been fitted with rear discs. I don’t recall excessive pedal pressure but my 18 year old legs probably had a lot to do with that. I remember the 1960s US power brakes that could inadvertently give your front seat passenger a dash board face plant. Also the non-variable power steering that was great for parallel parking your 2 tons of fun but scary on the highway.
I was just stating that there are efficiency advantages of drum brakes, not saying we need them back. I will say that drum brakes didn’t have anywhere near the trouble with warping that disc brakes do.
Also why do disc brakes corrode and peel to the point there are deep pits? Poor quality steel?
As far as the video I posted, well that guy is a self proclaimed “brake expert” and he seems like he knows his stuff.
I would say 20% of the people around here drive like maniacs, they floor it from a red light and stay on the gas until they brake hard for another red light, not a light that just changed to red either. Why must people drive this way?
Obviously, they’re trying to pump more CO2 into the air to prevent the coming ice age…
;-]
Unless you are talking about energy recovery braking, I don’t see how anyone can describe a brake as being more efficient than another. Every brake in the world converts 778 ft-lb of kinetic energy into one BTU of heat with 100% efficiency. Now if you could invent a heat engine that converts one BTU of heat back into 778 ft-lb of kinetic energy, you would become rich and famous not to mention literally doing the impossible according to the laws of thermodynamics because in order to pull something like that off, you would be decreasing entropy.
Efficiency makes sense when you talk about energy recovery braking in electric and hybrid cars. For example, if a 60 to zero stop puts enough charge in the battery to reaccelerate the car to 42.4 mph without any help from the engine, that would represent an energy recovery of 50%. If a 60 to zero stop puts enough charge in the battery to reaccelerate the car to 51.96 mph, that would represent an energy recovery of 75%.
If you define efficiency as lest amount of energy applied vs maximum work done, then the drum brakes are more efficient. There were many full sized cars that stopped fine with manual drum brakes but only a few very light cars have ever had manual disc brakes.
However most efficient does not always mean most effective. Considering all the limitations of drum brakes, disc brakes are clearly more effective.
I think the more appropriate term would be mechanical advantage rather than efficiency. A self proclaimed brake expert who use the correct lingual is not an expert in any engineering topic. Efficiency is a basic physics concept.
For those who don’t keep up with commercial vertical technology, there are trucks and buses in Europe with air disc brakes. I’ve driven a vehicle so equipped and it makes me wonder why new trucks don’t have them. Despite doing everything I was supposed to, I had overheated a set of drum brakes just from getting off the freeway. If it was hydraulic brakes, I don’t know if I would have stopped. I would rather have corroded disc brakes instead of crashing with shiny drum brakes.
BTW, I think 4 wheel disc on the Prius is appropriate. Keep in mind that it is a 3000# car. Regenerative braking only works when the battery isn’t full. Once it is, the car switches to friction brake. And there are those who would ride the brakes down hill rather than switching to brake mode
Regenerative braking is also limited to the horsepower of the traction motor. In a panic stop, a Prius or even a Tesla is always going to use the friction brakes.
If the traction motor is powerful enough to accelerate the car from zero to 60 in six seconds, it is also powerful enough to stop it from 60 to zero in six seconds. To stop it any faster is going to take the friction brakes.
Since only the drive wheels brake the car during regenerative braking, regenerative braking effectiveness is also limited by two wheel traction, especially on a RWD electric like the Tesla.
“Efficiency” is almost always measured in percent, energy in verses energy out, time used to be productive verses time available, etc.
The term we need to use when comparing braking performance is “effectiveness”. You can use the term “efficiency” when measuring percentage of energy returned to the battery during regenerative braking.