On-trailer anti sway
10-16-2016, 12:30 PM
#12
In a panic stop, I want the trailer to remain behind the tow vehicle. While the tow vehicle needs the control of ABS to allow it to steer, I want the trailer wheels to act as a boat anchor or pulling-tractor sled, causing maximum friction between the road surface and the trailer tires. Since the fully locked-up non-ABS trailer tires would be rotating at a slower speed than the still-rotating (due to ABS) wheels and tires of the tow vehicle, it would naturally be snapped back to a location lagging or behind the tow vehicle, which is where we want it. If instead a trailer-mounted ABS system was pulsing the trailer brakes to keep the wheels rolling, independently of the truck's ABS system, the trailer wheel speed could exceed the speed of the tow vehicle's wheels; not a good thing.
It seems to me that much greater improvement in braking would be replacement of electric brakes with electric controlled hydraulic disc brakes. The higher response time of voltage triggering the magnets to activate electric drum brakes would be a barrier to effective ABS or sway control on a trailer.
If sway starts, a tap of the brake controller manually slows the trailer down slower than the tow vehicle and "slaps" the trailer back into place.
I still argue that preventing sway is more important than controlling sway. A real technological improvement would be Ford providing a factory installed weight-sensing truck receiver hitch which provides an on-dash digital readout on the hitch weights, and compatible with all types of hitches, including weight distributing hitches. The tech exists, (https://www.weigh-safe.com/) but is should be built into the receiver instead of a non-weight distributing hitch.
Feel free to buy a automatic trailer-based sway control if you feel you need it. I would currently avoid it. Like the trailer backing assist, this system may be especially useful for inexperienced drivers. If you have enough sway to trigger this system, you are not set up properly, using an undersized truck, an oversized trailer, or driving to fast for conditions in weather not suited for towing.
If you read the owner's manual on the sway controlling device whose link posted above in an earlier post, the trailer mounted sway control device is not compatible with several years of factory installed brake controllers, which would potentially reduce the trailer resale value and create liability issues .
It seems to me that much greater improvement in braking would be replacement of electric brakes with electric controlled hydraulic disc brakes. The higher response time of voltage triggering the magnets to activate electric drum brakes would be a barrier to effective ABS or sway control on a trailer.
If sway starts, a tap of the brake controller manually slows the trailer down slower than the tow vehicle and "slaps" the trailer back into place.
I still argue that preventing sway is more important than controlling sway. A real technological improvement would be Ford providing a factory installed weight-sensing truck receiver hitch which provides an on-dash digital readout on the hitch weights, and compatible with all types of hitches, including weight distributing hitches. The tech exists, (https://www.weigh-safe.com/) but is should be built into the receiver instead of a non-weight distributing hitch.
Feel free to buy a automatic trailer-based sway control if you feel you need it. I would currently avoid it. Like the trailer backing assist, this system may be especially useful for inexperienced drivers. If you have enough sway to trigger this system, you are not set up properly, using an undersized truck, an oversized trailer, or driving to fast for conditions in weather not suited for towing.
If you read the owner's manual on the sway controlling device whose link posted above in an earlier post, the trailer mounted sway control device is not compatible with several years of factory installed brake controllers, which would potentially reduce the trailer resale value and create liability issues .
As far as your trailer staying behind you or being "snapped back" behind the truck because the trailer wheels are locked, that simply is not true either. Again, think of the Hot Wheels car with a locked up rear wheel. If you push and release it, it will flip around backwards every time. This is exactly why you are supposed to set your trailer brake gain below the threshold of locking the trailer wheels during maximum braking. Locking the trailer wheels absolutely reduces the stability of both the trailer and tow vehicle and can lead to a crash. Emergency maneuvers and changing roadway conditions can cause this. Antilock brakes on the trailer can help control it under all conditions and avoid those problems.
Last, properly loading a trailer to prevent sway, and having a system to control sway if it happens anyway, are not mutually exclusive. This is a logical fallacy that you keep promoting. Of course you should properly load your trailer and use a WDH with an effective sway control device. No one said otherwise. That argument has no place here.
Last edited by VTX1800N1; 10-16-2016 at 12:32 PM.
10-17-2016, 09:39 AM
#14
Here's the thing with Anti-Lock, with Hydraulic brakes, good, electric brakes, not so good. Because it is magnetic based on the trailers, the pulses required for anti locks would most likely cause premature wear of the electromagnets, not to mention what would be required to actually make it work. For most trailers to use an antilock system, it would be very expensive, so only high end trailers would actually have them. If you were to price out all the components required for the F150 antilock system, you would be well over $1500 between wheel sensors, pickup rings, brain box, and the module that drives the brakes. Good idea, but not very practical for the minute number of times it would ever be needed.
Set the trailer up properly and that is all you really need, after all, how many decades have trailers been being pulled with the standard electric brakes currently in use? What it all comes down to is, if the rig is properly set up, sway will be at most an annoyance, and braking under extreme conditions will be fine. Lets face it, if road conditions are so bad that even a properly setup rig would jackknife, stay off the road until conditions improve.
Set the trailer up properly and that is all you really need, after all, how many decades have trailers been being pulled with the standard electric brakes currently in use? What it all comes down to is, if the rig is properly set up, sway will be at most an annoyance, and braking under extreme conditions will be fine. Lets face it, if road conditions are so bad that even a properly setup rig would jackknife, stay off the road until conditions improve.
The following users liked this post:
Velosprout (10-17-2016)
10-17-2016, 10:38 AM
#15
Oh, I have no doubt that it's going to add to the cost of the trailer. It would likely have to be an option offered by the trailer manufacturer, as retrofitting would probably be even more expensive than what you've detailed above. There's also little doubt that if manufacturers start offering systems like this, they would only be on the most expensive trailers to begin with. Over time, that technology is likely to trickle down to the lower models, much as technology has in automobiles since they were invented.
I'm guessing that the anti-sway devices here would not work with electric over hydraulic brakes, since those are likely run off a single master cylinder? If they are, the system would have no way to separate the left/right brakes as it was designed to do.
Even with a properly set up trailer, unforeseen road conditions and emergency situations (animals, idiot drivers) cannot be predicted. Saving the trailer and tire vehicle just one time would make it worth it.
I'm guessing that the anti-sway devices here would not work with electric over hydraulic brakes, since those are likely run off a single master cylinder? If they are, the system would have no way to separate the left/right brakes as it was designed to do.
Even with a properly set up trailer, unforeseen road conditions and emergency situations (animals, idiot drivers) cannot be predicted. Saving the trailer and tire vehicle just one time would make it worth it.
Last edited by VTX1800N1; 10-17-2016 at 10:40 AM.
10-21-2016, 09:45 AM
#16
Senior Member
ABS brakes have been on 18 wheelers for several years and are proven to reduce collisions.
One must never assume that all of the preparation to the vehicles, and experience of the driver are enough to prevent loss of control and a crash. Technology is a good thing. BRING it on.
One must never assume that all of the preparation to the vehicles, and experience of the driver are enough to prevent loss of control and a crash. Technology is a good thing. BRING it on.
10-21-2016, 01:44 PM
#17
Senior Member
For now, I will enjoy driving while I can. Within my grandchild's lifetime, I would expect that human-driven vehicles will become unlawful to operate on public roads.
10-22-2016, 11:04 AM
#18
Well, when they can make hack proof computers, then it would be a viable solution, but until then, all autonomous driven vehicles would be at risk of being hacked and causing chaos. We already have vehicles that can be hacked and taken control of.