Drum Vs. Disc

[1972RedNeck]

Originally Posted by mrein3

I look at it this way. In this world of lawyers and sue happy public, what are ALL the car manufacturers putting on the front and in lots of cases the back of new cars?

If drums were that great, wouldn't they still be putting them on new cars?

Very good point.

Originally Posted by 406 Q-ship

Drum brake fade...bad. I went through an intersection in a 69 GTO cause all the pedal pressure in the world was not gonna stop that thing in the distance. How often does a vacuum booster fail, brakes get hot alot more than booster failure. Disc brakes is the first modification on any drum brake vehicle, car or truck. Once you have been in a bad place with drums fading, you'll dump them soooooooo fast.

Knock on would I have never had that happen. Maybe I'll go to disc brakes before it does happen to me.

Originally Posted by trkfrk

Before you can appreciate the difference between drum and disc brakes, you have to understand the common principles that both systems use when stopping a car: friction and heat. By applying resistance, or friction, to a turning wheel, a vehicle's brakes cause the wheel to slow down and eventually stop, creating heat as a byproduct. The rate at which a wheel can be slowed depends on several factors including vehicle weight, braking force and total braking surface area. It also depends heavily on how well a brake system converts wheel movement into heat (by way of friction) and, subsequently, how quickly this heat is removed from the brake components. This is where the difference between drum brakes and disc brakes becomes pronounced.

It is all making sense to me now.

Thanks for being patient with me. Sometimes (all of the time) I am a little thick headed.

[1972RedNeck]

Originally Posted by N2TRUX

What I want to know is why we have to have threads like this every so often. Seriously, does the advantage of modern technology need to be explained?

Maybe I am not the sharpest tool in the shed, but what is the advantage of the very thin steel used in today's vehicles?

[trkfrk]

Drums

* Pro - Less expensive since they're already stock on most of our trucks
* Pro - Drums work better then discs as emergency brakes
* Con - They stop poorly when wet and can get clogged with mud
* Con - Stopping power can fade with repeated hard braking
* Con - Larger tires


Discs

* Pro - More consistant, straight line stopping power
* Pro - Dissipate heat better to stay cooler
* Pro - Less affected by water or mud
* Pro - Easier to maintain and faster to replace pads then shoes
* Con - More expensive to install (but maintenance costs should be less)

[mrein3]

Originally Posted by 1972RedNeck

Maybe I am not the sharpest tool in the shed, but what is the advantage of the very thin steel used in today's vehicles?

Weight.
When the government tells you your fleet miles per gallon average has to be X, and you can remove 10 pounds of steel from each vehicle by using thinner metal, you do it.

Besides, with air bags, crumple zones, and a ton of other safety features your 3600 pound 72 Chevelle is less safe than your 2850 Chevy Cruze. Yes your fender gets totally mashed in a small fender bender but what price do you put on safety? Ask an ambulance chasing lawyer that question.

Why does Ford spec 5W-20 oil for their engines? Same reason. Oils are better now and if you can shave .1 mpg off the fleet by specifying thinner oil, you do it. Those tenths of a mile per gallon add up.

[MARKDTN]

Another thing is that drums can explode outward with no warning if overheated and they crack. Mostly on big trucks, but it can happen on smaller cars and trucks too. Disc rotors can be worn down to nothing, but you have warning over time.

[1972RedNeck]

Originally Posted by mrein3

Weight.
When the government tells you your fleet miles per gallon average has to be X, and you can remove 10 pounds of steel from each vehicle by using thinner metal, you do it.

Besides, with air bags, crumple zones, and a ton of other safety features your 3600 pound 72 Chevelle is less safe than your 2850 Chevy Cruze. Yes your fender gets totally mashed in a small fender bender but what price do you put on safety? Ask an ambulance chasing lawyer that question.

Why does Ford spec 5W-20 oil for their engines? Same reason. Oils are better now and if you can shave .1 mpg off the fleet by specifying thinner oil, you do it. Those tenths of a mile per gallon add up.

Ok, I'm done arguing and being an inquisitive idiot.

[67chevemall]

Drums are better and so are carbs.....old school = less parts and better built.
computers are better on your desk. ABS and FI, no thanks...I like me and my steel parts doing the thinking.


$0.02

[GASoline71]

Originally Posted by 69heavychevy

thats like saying carbs are better than fuel injection...

Carbs ARE better than FI... depends on who ya ask...

Gary

[Dano69c10]

For those of us who were around "back in the day",
Remember disc brakes were implemented when the compression ratios of engines were decreased for emissions reasons.

I figure that unless you're running an old skool high compression engine, where your truck almost stops when you take your foot off the accelerator, discs would be the way to go.

Just my $0.02
Dano

[69sixpackbee]

Originally Posted by 69heavychevy

thats like saying carbs are better than fuel injection...

They ARE! F**K injection Lets see a carb leave you stranded and with an empty wallet once you fix it.

[oldgold70c10]

Originally Posted by 69 1/2 Six Pack Bee

They ARE! F**K injection Lets see a carb leave you stranded and with an empty wallet once you fix it.

YES!!!!

[406 Q-ship]

Originally Posted by Dano69c10

For those of us who were around "back in the day",
Remember disc brakes were implemented when the compression ratios of engines were decreased for emissions reasons.

I figure that unless you're running an old skool high compression engine, where your truck almost stops when you take your foot off the accelerator, discs would be the way to go.

Just my $0.02
Dano

Not in cars........GM put disc brakes on the option list when the 375 HP/396 Ci and the 425 HP/ 427 CI was king, the trucks may have not gotten them until 71 but then none of the other manufactures were putting disc brakes on a truck until after 1971. In fact on SS Chevelles after 1969 Disc Brakes were a required option, so GM knew that they were much better than drums.

[Dano69c10]

Originally Posted by 406 Q-ship

Not in cars........GM put disc brakes on the option list when the 375 HP/396 Ci and the 425 HP/ 427 CI was king, the trucks may have not gotten them until 71 but then none of the other manufactures were putting disc brakes on a truck until after 1971. In fact on SS Chevelles after 1969 Disc Brakes were a required option, so GM knew that they were much better than drums.

1970 beginning of new smog regulations for car manufacturers.

[ProStreet68SB]

Originally Posted by 69heavychevy

thats like saying carbs are better than fuel injection...

Each has their own advantages.
Carb will make more peak power. But Fuel Injection will make more AVG power over the given RPM band.

Originally Posted by Dano69c10

1970 beginning of new smog regulations for car manufacturers.

What does smog have to do with brakes?

[Dano69c10]

Originally Posted by ProStreet68SB

...What does smog have to do with brakes?

I guess nothing.

[406 Q-ship]

Originally Posted by Dano69c10

1970 beginning of new smog regulations for car manufacturers.

Not right either, there was emission equipment as early as 1967 (A.I.R and PCV). The compression didn't start to drop until 1971 (minor drop) and plumeted in 1972.

[VWBeamer]

Drums are lighter.

[Tkmadone]

What do the big semis use? Last I checked it was drum, and I'm pretty sure it's not because of cost.

Like has been said, there are advantages and disadvantages to both systems.

[ProStreet68SB]

Originally Posted by Tkmadone

What do the big semis use? Last I checked it was drum, and I'm pretty sure it's not because of cost.

Like has been said, there are advantages and disadvantages to both systems.

Big trucks are slowly switching to front discs.

[Dano69c10]

Originally Posted by 406 Q-ship

Not right either, there was emission equipment as early as 1967 (A.I.R and PCV). The compression didn't start to drop until 1971 (minor drop) and plumeted in 1972.

The new regulations that were implemented for 1970, were what led to lower compression engines.
What I've researched is that when GM engineers were testing vehicles with lower compression engines they found that the drum brakes were inadequate, and stopping distances greatly increased. (Implementation of PVC and A.I.R. had no effect on stopping distances, on pre-disc brake vehicles.)
Disc brakes then became mandatory in order to stop the newer vehicles in an acceptable distance with respect to safety.
Obviously if drum brakes were not doing to do the job and disc brakes can do the job, then it logically follows that disc brakes are better.

If my research is wrong, then so be it. I'm man enough to admit when I'm wrong.
But either way, (research right or wrong) my conclusion is disc brakes stop better than drums.

[Longhorn Man]

i'm not sure that discs were ever mandated... and if they were, it was much later than most think. The ford escore EXP in the early 80's still had drums up front.

[69sixpackbee]

Originally Posted by Longhorn Man

.The ford escore EXP in the early 80's still had drums up front.

That's because it was a roller-blade with two extra wheels

[406 Q-ship]

Originally Posted by Dano69c10

The new regulations that were implemented for 1970, were what led to lower compression engines.
What I've researched is that when GM engineers were testing vehicles with lower compression engines they found that the drum brakes were inadequate, and stopping distances greatly increased. (Implementation of PVC and A.I.R. had no effect on stopping distances, on pre-disc brake vehicles.)
Disc brakes then became mandatory in order to stop the newer vehicles in an acceptable distance with respect to safety.
Obviously if drum brakes were not doing to do the job and disc brakes can do the job, then it logically follows that disc brakes are better.

If my research is wrong, then so be it. I'm man enough to admit when I'm wrong.
But either way, (research right or wrong) my conclusion is disc brakes stop better than drums.

Disc brakes and emission equipment had nothing to do with each other, it is that both were coming into their own at approximatily the same era. It was that vehicles were getting bigger and heavier. Drum brake work great and are self energizing requiring less pedal pressure.......but only really work for one stop, that is when Disc brake become the clear cut winner.

[MARKDTN]

Originally Posted by ProStreet68SB

Big trucks are slowly switching to front discs.

Correct-this week actually is a major decrease in allowable stopping distance for road tractors. A lot are going to discs. There are some going with bigger drums and/or more aggressive shoe materials. The cost does increase some either way.

[stich626]

Originally Posted by treveiger

I know a guy with a 71 nova with a healthy 454 with a pro charger bolted to it an as of right now he has around 450whp he "thinks" an once tuned he's hoping to have 700 an he has all drum breaks so must not be to hard to stop
Posted via Mobile Device

drag cars , drum brakes cause less drag, and can be worth a tenth or two.