Drum vs Disk Brakes

Skilletface

Senior Member
RV LIFE Pro
Joined
Aug 1, 2020
Messages
140
Location
Nicholson, Ga.
First I’m not down playing the increased braking power of a disk brake upgrade. Riddle me this; I attended a seminar explaining how a disk brake upgrade works and is installed. In this seminar it was demonstrated that once the hydraulic actuator receives the electric signal to apply, there is a delay of 2 to 4 seconds.
In my mind I am thinking if I have an electric signal going to a electric drum brake system there would be a mili second of delay in brake application.
So should the delay cancel out the increased braking gain and who adjusts there brake gain to off set the delay?
The last thing I would want is my TT not working evenly, or at least close together with the TV!
Thoughts!:confused:
 
First I’m not down playing the increased braking power of a disk brake upgrade. Riddle me this; I attended a seminar explaining how a disk brake upgrade works and is installed. In this seminar it was demonstrated that once the hydraulic actuator receives the electric signal to apply, there is a delay of 2 to 4 seconds.
In my mind I am thinking if I have an electric signal going to a electric drum brake system there would be a mili second of delay in brake application.
So should the delay cancel out the increased braking gain and who adjusts there brake gain to off set the delay?
The last thing I would want is my TT not working evenly, or at least close together with the TV!
Thoughts!:confused:
The delay is a perception, it takes less than a couple of milliseconds for the electric signal to travel to the hydraulic system, then it takes about .2 seconds for the hydraulic actuators to engage and begin the breaking process.

Sent from my phone using Tapatalk
 
In this seminar it was demonstrated that once the hydraulic actuator receives the electric signal to apply, there is a delay of 2 to 4 seconds.
I have a Kodiak electric/hydraulic system on my older toy hauler and the delay is definitely there and definitely perceptible. When I first got them and went about adjusting the gain, I thought I'd forgotten to plug the trailer into the truck.

So should the delay cancel out the increased braking gain and who adjusts there brake gain to off set the delay?
There really isn't a way to offset the delay. If you change the gain, all that happens is the trailer brakes come on harder after the delay.

All that said, I got used to the delay in a couple of weeks. The increased braking power was WELL worth putting up with the delay. I'm just waiting for my factory installed drum brakes to either go out of warrantee or to just wear out so I can justify getting another set of discs.
 
Last edited:
A SUPERIOR way to demonstrate would be for one of the disc brake system guys to mock up a drum set up and disc setup that are spun up and the clutched off while actuated with an identical controller and braking force measured and rotations counted... Why you ask? Because even with a delay, the superior clamping force over contact patch of a disc brake setup with outperform a drum every time. It's just not easy for folks to visualize. Show and tell would be huge. That aside, the algorithms in factory trailer brakes controllers are making this delay imperceptible too.
 
A SUPERIOR way to demonstrate would be for one of the disc brake system guys to mock up a drum set up and disc setup that are spun up and the clutched off while actuated with an identical controller and braking force measured and rotations counted... Why you ask? Because even with a delay, the superior clamping force over contact patch of a disc brake setup with outperform a drum every time. It's just not easy for folks to visualize. Show and tell would be huge. That aside, the algorithms in factory trailer brakes controllers are making this delay imperceptible too.

The SUPERIOR way would actually involve an INDEPENDENT TESTING LAB do the testing, not a disk brake system guy. Testing by those with a self interest may not be unbiased.


2020 2600RB,
2017 Silverado Crew Cab 1500, 6.2L
 
After owning 2 trailers with drum brakes and converting my 5th wheel to Disc Brakes I will never have anything with drum brakes again. The difference is amazing, short delay or not.
 
Last edited:
I am no engineer and cannot "Prove" this. But I think disk brakes work a lot better than drum brakes, I have owned many trailers with both. PS surge brakes suck.
 
I've got a small dent in my front fender that demonstrates the "slight" delay experienced with disk brakes. It's real. You'll want to allow an extra second behind someone, especially in slow traffic.

Other than that, and I knew about the delay, I really appreciate them. In a few panic stops on the freeway they proved their worth over and over again.

They work so well that sometimes I "fool" the truck into slowing down a bit on grades by just applying the trailer brakes with the brake controller rather than tap the truck's brakes causing a downshift I really don't need.
 
I am no engineer and cannot "Prove" this. But I think disk brakes work a lot better than drum brakes, ...

I think all motorcycle, car, and truck design engineers, as well as NASCAR, F1, MotoGP, Boeing, Airbus, McDonnell Douglas, Rockwell, and Lockheed-Martin vehicle designers would agree with your thought. :)
 
Last edited:
I think all motorcycle, car, and truck design engineers, as well as NASCAR, F1, MotoGP, Boeing, Airbus, McDonnell Douglas, Rockwell, and Lockheed-Martin vehicle designers would agree with your thought. :)

I've had disc brakes on my mountain bikes for 20 years. I think RV's are the only vehicle left on the planet that still use drum brakes.
 
I've had disc brakes on my mountain bikes for 20 years. I think RV's are the only vehicle left on the planet that still use drum brakes.

“. . . On the planet . . “ is surely a stretch.

Although newer semi truck trailers are more likely to have air disk brakes, there are plenty of older semi truck trailers on the road today ( and therefore are still “on the planet”).

There are also still plenty of older cars and pickup trucks with drum brakes on the rear axle.


2020 2600RB,
2017 Silverado Crew Cab 1500, 6.2L
 
once the hydraulic actuator receives the electric signal to apply, there is a delay of 2 to 4 seconds.

As others have mentioned, up to 4s delay seems excessive and that might indicate another issue. Thought I read somewhere that any air in the system could contribute a little bit to the delay.
 
I've had disc brakes on my mountain bikes for 20 years.

Good one. I didn't think about that! If you consider bike rims as discs, road bikes have had discs since .. forever?

I think RV's are the only vehicle left on the planet that still use drum brakes.

I think some semi-trailers have drums. I'm not sure why the towable RV industry hasn't converted wholesale to discs. I can't imagine there's *that* much cost savings.

Is there anyone here who knows why the trailer industry seems to have this fixation on drums? I know they're probably easier to install, but so is a hole in the floorboards where you can drag your feet.
fredflinstonebraking1-54edfdbc0e571.jpg
 
Last edited:

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top Bottom