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Old 02-01-2023, 10:17 AM   #41 (permalink)
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I ve seen where drum brakes are preferred in adverse climates to keep crud out of the brake pads. Sand thrashes a disk really fast.

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Old 02-01-2023, 10:27 AM   #42 (permalink)
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Such option remaining available just shows how drums might not be that bad at all, for the right applications, or if the operator or a fleet manager is too concerned about discs bending under harsh operating conditions.
The feedback that comes back to me is that some fleet managers prefer drums to discs because disc brakes work too well. They don't overheat nearly as fast as drum brakes so drivers use the brakes more instead of relying so heavily on compression braking. The more the driver uses the brakes - the faster they wear out - the more trips to the shop for brake replacements.

There are also some severe use conditions like Piotrsko mentioned. Loggers and dump trucks tend to prefer drums for example.
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Old 02-01-2023, 12:13 PM   #43 (permalink)
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I had the drums and rotors on the Superbeetle cryogenically tempered.

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Old 02-02-2023, 07:27 PM   #44 (permalink)
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Quote:
Originally Posted by JSH View Post
The feedback that comes back to me is that some fleet managers prefer drums to discs because disc brakes work too well. They don't overheat nearly as fast as drum brakes so drivers use the brakes more instead of relying so heavily on compression braking. The more the driver uses the brakes - the faster they wear out - the more trips to the shop for brake replacements
Is it any bad at all? A properly trained driver who knows how to operate the truck will make it last longer and even improve fuel economy sometimes. BTW in contrast to an American driver who may be too lazy to engine-braking, a Brazilian would make better use of it and of adaptative cruise control, which may not only require fewer input on the pedals but also lead to overall more efficient driving. Being able to not use the brakes so often gives a clue about the driver's ability/efficiency.


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There are also some severe use conditions like Piotrsko mentioned. Loggers and dump trucks tend to prefer drums for example.
See why most trucks, and even buses, in Brazil are still fitted with drums? Operating conditions here are often quite harsh.
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Old 02-03-2023, 11:30 AM   #45 (permalink)
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Originally Posted by cRiPpLe_rOoStEr View Post
Is it any bad at all? A properly trained driver who knows how to operate the truck will make it last longer and even improve fuel economy sometimes. BTW in contrast to an American driver who may be too lazy to engine-braking, a Brazilian would make better use of it and of adaptative cruise control, which may not only require fewer input on the pedals but also lead to overall more efficient driving. Being able to not use the brakes so often gives a clue about the driver's ability/efficiency.
Friction brakes vs compression braking isn't much of a concern today for on-highway trucks as the vast majority of them have computer controlled manual transmissions. The computer will match RPM to speed and automatically downshift as needed. They will also shift in anticipation of conditions around the bend as the truck has a map of the road and knows the grades before the driver.

It is the vocational side of things that we still see drum brakes - and manual transmissions.
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Old 02-04-2023, 01:13 AM   #46 (permalink)
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Friction brakes vs compression braking isn't much of a concern today for on-highway trucks as the vast majority of them have computer controlled manual transmissions. The computer will match RPM to speed and automatically downshift as needed.
AMTs are quite widespread on the heaviest side of the medium-duty truck market in Brazil, and more recently it's becoming more common on Class 5 too, as a cheaper alternative to a conventional AT which is still considered expensive and hard to mantain by most fleet managers.


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It is the vocational side of things that we still see drum brakes - and manual transmissions.
Drum brakes are quite widespread here, and so are manual transmission too, yet AMTs are taking much of its market share on vocational applications, as long as a PTO is not needed. Otherwise the best option for vocational trucks is a real automatic. I don't remember seeing many AMTs with a PTO.
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Old 02-04-2023, 11:31 AM   #47 (permalink)
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Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
AMTs are quite widespread on the heaviest side of the medium-duty truck market in Brazil, and more recently it's becoming more common on Class 5 too, as a cheaper alternative to a conventional AT which is still considered expensive and hard to mantain by most fleet managers.

Drum brakes are quite widespread here, and so are manual transmission too, yet AMTs are taking much of its market share on vocational applications, as long as a PTO is not needed. Otherwise the best option for vocational trucks is a real automatic. I don't remember seeing many AMTs with a PTO.
An Allison automatic behind a Cummins engine is still the most common combination in the USA for Class 5 - 7. For the Class 8's Freightliner / Mercedes added a PTO to their AMT last year.
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Old 02-09-2023, 03:19 AM   #48 (permalink)
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An Allison automatic behind a Cummins engine is still the most common combination in the USA for Class 5 - 7.
At least up to Class 6 nowadays in Brazil a 4-cyl engine is the most common. Some models use a Cummins engine. Mostly manuals, either Eaton or ZF when outsourcing is the case, and some AMTs more recently. Already a good measure to improve comfort, but a conventional automatic may be more effective to the integration with a brake retarder.
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Old 02-09-2023, 12:33 PM   #49 (permalink)
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drum brakes

Since drum brakes require 'arcing the shoes', it poses a greater asbestos risk to all associated with them vs pads on disc brakes.
I may have already been exposed to enough to kill me. We'll see.
And disc brakes may be more profitable than drum brakes, especially with corporate-owned dealers, whom would profit directly.
https://www.epa.gov/asbestos/current...lutch-repair-0
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Old 02-11-2023, 12:43 PM   #50 (permalink)
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Asbestos is no longer used for brake shoe liners.

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