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Old 08-09-2023, 01:48 AM   #81 (permalink)
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While some trucks up to Class 5 in my country have hydraulic brakes, often with front discs and rear drums, bigger ones are mostly fitted with air brakes. And drums all around.

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Old 12-23-2023, 06:09 PM   #82 (permalink)
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"Explain like I've five' part ends at 5:07

The part I wasn't expecting is that drums contain brake dust better than disks.
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Old 12-24-2023, 02:13 AM   #83 (permalink)
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Spending a few days in Bagé, where EVs won't have a chance so soon, I noticed so many Beetles and a few Kombis still fitted with drum brakes all around...
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Old 12-24-2023, 10:55 AM   #84 (permalink)
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Why not? They're fine until they catch fire from over use.
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Old 12-25-2023, 11:03 PM   #85 (permalink)
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I'm glad I never had a car with drum brakes on the front. I came off Pikes Peak in B14 Sentra hoping I wouldn't need more than engine braking. Luckily, just about the time I was ready to stop because of brake fade the gradient decreased significantly.

I'd like to see them race down the mountain, then we'll get to see who can really drive. That carnage would be horrendous.
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Old 12-26-2023, 11:00 AM   #86 (permalink)
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I might have mentioned this, but the 70-passenger buses I drove all had drum brakes.
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Old 12-29-2023, 02:58 AM   #87 (permalink)
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Quote:
Originally Posted by Isaac Zachary View Post
I might have mentioned this, but the 70-passenger buses I drove all had drum brakes.
I guess I didn't see any bus with disc brakes this week
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Old 12-29-2023, 11:56 AM   #88 (permalink)
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Bluebirds had the option for 4 discs, but I have never seen one equipped that way possibly because they wont be equipped with automatic chains. Heaven forbid you have to stop and hang iron in the snow.
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Old 12-29-2023, 12:51 PM   #89 (permalink)
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Quote:
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Yes, a drum can stop as fast as a disk - once. Then they start overheating and fading. Overheating a set of brakes on even a modern vehicle with discs is not that uncommon. Maybe you don't see in in Florida were passes are 3 feet above sea level but in mountainous areas where crossing a pass is thousands of feet up and then down people ride their brakes and overheat them all the time. The smell of cooked brakes is an every trip occurrence when I head across the Cascades and I've actually stopped and used a fire extinguisher to put out a fire where someone is an old 80's Chevy Malibu had ridden their brakes for so long that the brakes caught on fire.

Cars got front brakes first because the front axle does the bulk of braking so that is where strong and fade resistant brakes are needed most. Rear brakes rarely do enough braking to require disks outside of performance cars. Drums are also cheaper than discs so budget cars generally got drums. Combine these together and cars that don't need discs in the rear got them because the public (and automotive editors) complained about perfectly adequate drum brakes.

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Your first comment here is cherry picked. It's extremely rare condition a drum or any brake will fade in its first application. Nobody is arguing a disc brake can have better heat dissipation, but a large drum brake has more thermal mass and both can eventually catch fire when abused. The point few here are noting, Drums by design have a hard time cycling when ABS is activated, which discs excel at. Rear wheel lock up is the most difficult skid for the average driver to control and can be where most skids begin. Proper rear wheel ABS control favors discs greatly and helps the driver driving beyond their skillset.

If somebody here is repeatedly overheating their brakes in familiar driving locations, they likely IMO have a driver issue of not knowing the limits of their vehicles braking system in whatever conditions they face and should correct that before focusing on a brake shortcoming.
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Old 01-02-2024, 08:10 PM   #90 (permalink)
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Originally Posted by j-c-c View Post
Your first comment here is cherry picked. It's extremely rare condition a drum or any brake will fade in its first application. Nobody is arguing a disc brake can have better heat dissipation, but a large drum brake has more thermal mass and both can eventually catch fire when abused. The point few here are noting, Drums by design have a hard time cycling when ABS is activated, which discs excel at. Rear wheel lock up is the most difficult skid for the average driver to control and can be where most skids begin. Proper rear wheel ABS control favors discs greatly and helps the driver driving beyond their skillset.

If somebody here is repeatedly overheating their brakes in familiar driving locations, they likely IMO have a driver issue of not knowing the limits of their vehicles braking system in whatever conditions they face and should correct that before focusing on a brake shortcoming.
Nobody is talking about the first application except for you. Continually use of brakes will overheat them and cause them to fail. This is not uncommon - if it was we would not have runaway truck ramps all over this country and others.

A drum does have more mass. However, when a drum heats up it expands and the diameter gets larger. That moves the drum away from the shoe and reduces braking force.

I work for a manufacturer of commercial vehicles. I have told you why we switched from drums to discs as our standard offering. You can chose to believe me or not - but that doesn't change why we changed to discs on air brake Class 8 trucks.

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