Supplemental Brake Systems - update 8/7/06
Updates: 1/1/06: Roadmaster has stopped making BrakePro and replaced it with a revised system that it calls Even Brake. A DRAFT review of the Even Brake System has been added. Like the other rev...
Forum Discussion
Somewhat lengthy; a cautionary tale, and few comments about toad braking:
I had a BLUE OX “AUTOSTOP” toad braking unit. It is contained in a special ball mount. When it senses the toad is pushing on the ball mount (the toad wants to keep moving, while the towing vehicle is stopping), a mechanical cable (“wire rope”) coming out of unit is retracted into the unit. This cable extends backward to the front of the toad, and then enters a flexible guide tube or “conduit” where it continues traveling to the toad’s firewall. It then is looped around the arm above the toad’s brake pedal, so the cable pulls on the brake pedal.
It’s a cheap system compared with some of the others. But from my perspective, it is not a very satisfactory system.
For one thing, the cable is not guided between the ball mount unit and the front of the toad. It hangs freely between them. The cable must have a few inches of slack to allow the toad to swing sideways relative to the towing vehicle when going around a sharp turn. This means that the cable doesn’t start pulling on the toad’s brake pedal as soon as the force on the ball mount occurs. Instead, the toad’s brakes aren’t applied until the toad is already pushing fairly hard on the ball mount. The manufacturer justifies this by saying the unit is “only for surge braking”.
The only time the unit really seems to work is during a hard panic stop. In a really fast stop, such as at a traffic light, the toad suddenly gives a jerk backwards. Otherwise, the toad’s brakes never seem to do much.
Notably, Going down a hill, the cable usually does not pull in enough to engage the brakes, and the towing vehicle must do all the braking for both the towed vehicle and the toad.
A couple of years ago we were traveling in Arizona on route 89A, that passes through Jerome, AZ, with our toad. We knew there was a hill there, but had done it previously in a passenger car, and didn’t remember that it was all that bad. It is actually about a 3300 foot vertical descent, from the top of the pass, down to Clarkdale. (Big rigs, especially with toads, should probably avoid this highway altogether, whether going up or down. Unhitch, and drive the toad by itself up to Jerome, to enjoy a really unique town.)
I took the precaution of crawling down the hill in first gear all the way, occasionally touching the emergency brake to take the load off the front disks (a somewhat controversial practice, in itself). It was slow going, and we had to keep pulling over to let other people pass, but things where proceeding without incident.
After we made it through the winding switchbacks in downtown Jerome, the road straightened out and the speed limit increased. Believing that we had put almost all the hill behind us, I relaxed; and shifted into second. While I had to occasionally apply the brakes, it didn’t seem they were working too hard, and second gear seemed to be doing most of the work holding the rig back. But although it looked like we were near the bottom, we actually had about another 900 vertical feet to go. When we arrived at the intersection in Clarkdale, I couldn’t stop, and went straight through. I was literally standing on the brakes, but they hardly worked at all. Fortunately, there was no oncoming traffic. Heavy acrid smoke was pouring out of the front brakes. We thought the vehicle was on fire. I grabbed the fire extinguisher and we both bailed out of the rig. After a few minutes of extreme agitation, we determined that it was the just front brake pads that were smoking, and the rig wasn’t on fire.
The front brake pads, which were only half worn at the start of the trip, were worn down all the way to the “tell-tales”, which made screaming noises when the brakes were applied, all the rest of the way home. The front bearings were making nasty rumbling sounds. When I got home, as well as the front pads; I had to replace all the front bearings, and have the rotors turned.
The toad’s brakes didn’t appear to have been applied, at all. The toad’s brake disks didn’t show even a slight hint of warmth. I don’t fault the brake systems manufacturer too much for this, they did make a disclaimer that it is a “SURGE” system.
(1) The moral to be drawn from this tale is that SURGE-TYPE BRAKES ARE COMPLETELY UNSUITABLE FOR USE ON A DOWNGRADE OF ANY APPRECIABLE LENGTH. It is imperative to have “PROPORTIONAL” type toad brakes that apply themselves in relation to how much force is being applied to the towing vehicle’s brakes, or at least in DIRECT (NOT DELAYED) PROPORTION to the amount of force that the toad is pushing against the towing vehicle.
(2) I would also note that the “DE-ACCELERATION”-based systems may not work well on ice, loose gravel, or rain-soaked surfaces. If the towing vehicle is sliding, it may not be de-accelerating fast enough to activate the sensors, and the toad’s brake may not be applied. This applies whether the de-acceleration sensor is positioned in the toad, or in a controller in the towing vehicle. This is the kind of situation where the toad’s brakes want to come on at least as hard as the towing vehicle’s brakes. A jackknife could easily result.
(3) For the reason in #2, as well as to suppress fishtailing in an emergency, there should be a way of MANUALLY APPLYING THE TOAD’S BRAKE without applying the towing vehicle brakes.
(4) Some “INVASIVE” systems that sense the towing vehicle brake pressure give true proportional braking. They are probably worth the extra time to install. Often such systems involve tapping into the towing vehicles brake lines, so the job must be done by a COMPETANT person, who knows what they’re doing.
Several years ago, most (trailer) brake controllers tapped into the brake lines. People that used them often think they worked better than the modern ones, which are usually based on some combination of de-acceleration and signals from the brake light. 95% of them worked just fine. The problem was with the other 5%, that were incompetently installed. Because of liability concerns, most brake controller companies now use another scheme.
Somewhere, I think I also remember seeing a system that used a sensor pad that fits over the top of the brake pedal. The main concern with such a system is that it might change the position of the brake pedal surface, making it easier to miss the pedal in an emergency.
I had a BLUE OX “AUTOSTOP” toad braking unit. It is contained in a special ball mount. When it senses the toad is pushing on the ball mount (the toad wants to keep moving, while the towing vehicle is stopping), a mechanical cable (“wire rope”) coming out of unit is retracted into the unit. This cable extends backward to the front of the toad, and then enters a flexible guide tube or “conduit” where it continues traveling to the toad’s firewall. It then is looped around the arm above the toad’s brake pedal, so the cable pulls on the brake pedal.
It’s a cheap system compared with some of the others. But from my perspective, it is not a very satisfactory system.
For one thing, the cable is not guided between the ball mount unit and the front of the toad. It hangs freely between them. The cable must have a few inches of slack to allow the toad to swing sideways relative to the towing vehicle when going around a sharp turn. This means that the cable doesn’t start pulling on the toad’s brake pedal as soon as the force on the ball mount occurs. Instead, the toad’s brakes aren’t applied until the toad is already pushing fairly hard on the ball mount. The manufacturer justifies this by saying the unit is “only for surge braking”.
The only time the unit really seems to work is during a hard panic stop. In a really fast stop, such as at a traffic light, the toad suddenly gives a jerk backwards. Otherwise, the toad’s brakes never seem to do much.
Notably, Going down a hill, the cable usually does not pull in enough to engage the brakes, and the towing vehicle must do all the braking for both the towed vehicle and the toad.
A couple of years ago we were traveling in Arizona on route 89A, that passes through Jerome, AZ, with our toad. We knew there was a hill there, but had done it previously in a passenger car, and didn’t remember that it was all that bad. It is actually about a 3300 foot vertical descent, from the top of the pass, down to Clarkdale. (Big rigs, especially with toads, should probably avoid this highway altogether, whether going up or down. Unhitch, and drive the toad by itself up to Jerome, to enjoy a really unique town.)
I took the precaution of crawling down the hill in first gear all the way, occasionally touching the emergency brake to take the load off the front disks (a somewhat controversial practice, in itself). It was slow going, and we had to keep pulling over to let other people pass, but things where proceeding without incident.
After we made it through the winding switchbacks in downtown Jerome, the road straightened out and the speed limit increased. Believing that we had put almost all the hill behind us, I relaxed; and shifted into second. While I had to occasionally apply the brakes, it didn’t seem they were working too hard, and second gear seemed to be doing most of the work holding the rig back. But although it looked like we were near the bottom, we actually had about another 900 vertical feet to go. When we arrived at the intersection in Clarkdale, I couldn’t stop, and went straight through. I was literally standing on the brakes, but they hardly worked at all. Fortunately, there was no oncoming traffic. Heavy acrid smoke was pouring out of the front brakes. We thought the vehicle was on fire. I grabbed the fire extinguisher and we both bailed out of the rig. After a few minutes of extreme agitation, we determined that it was the just front brake pads that were smoking, and the rig wasn’t on fire.
The front brake pads, which were only half worn at the start of the trip, were worn down all the way to the “tell-tales”, which made screaming noises when the brakes were applied, all the rest of the way home. The front bearings were making nasty rumbling sounds. When I got home, as well as the front pads; I had to replace all the front bearings, and have the rotors turned.
The toad’s brakes didn’t appear to have been applied, at all. The toad’s brake disks didn’t show even a slight hint of warmth. I don’t fault the brake systems manufacturer too much for this, they did make a disclaimer that it is a “SURGE” system.
(1) The moral to be drawn from this tale is that SURGE-TYPE BRAKES ARE COMPLETELY UNSUITABLE FOR USE ON A DOWNGRADE OF ANY APPRECIABLE LENGTH. It is imperative to have “PROPORTIONAL” type toad brakes that apply themselves in relation to how much force is being applied to the towing vehicle’s brakes, or at least in DIRECT (NOT DELAYED) PROPORTION to the amount of force that the toad is pushing against the towing vehicle.
(2) I would also note that the “DE-ACCELERATION”-based systems may not work well on ice, loose gravel, or rain-soaked surfaces. If the towing vehicle is sliding, it may not be de-accelerating fast enough to activate the sensors, and the toad’s brake may not be applied. This applies whether the de-acceleration sensor is positioned in the toad, or in a controller in the towing vehicle. This is the kind of situation where the toad’s brakes want to come on at least as hard as the towing vehicle’s brakes. A jackknife could easily result.
(3) For the reason in #2, as well as to suppress fishtailing in an emergency, there should be a way of MANUALLY APPLYING THE TOAD’S BRAKE without applying the towing vehicle brakes.
(4) Some “INVASIVE” systems that sense the towing vehicle brake pressure give true proportional braking. They are probably worth the extra time to install. Often such systems involve tapping into the towing vehicles brake lines, so the job must be done by a COMPETANT person, who knows what they’re doing.
Several years ago, most (trailer) brake controllers tapped into the brake lines. People that used them often think they worked better than the modern ones, which are usually based on some combination of de-acceleration and signals from the brake light. 95% of them worked just fine. The problem was with the other 5%, that were incompetently installed. Because of liability concerns, most brake controller companies now use another scheme.
Somewhere, I think I also remember seeing a system that used a sensor pad that fits over the top of the brake pedal. The main concern with such a system is that it might change the position of the brake pedal surface, making it easier to miss the pedal in an emergency.
