Quote:
Originally Posted by rickst29
...I hope that I misinterpreted your post...
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I'm pointing out the weaknesses in trailer brakes and controllers as a reason for caution while towing. Anyone thinking they are going to do a panic stop while towing in the same distance as their solo tow vehicle with its computer controlled anti-lock braking system is mistaken, though admittedly by an amount that's pretty hard to determine without actual measurements.
I get this by the following logic:
1) The point of maximum braking is infinitesimally short of a skid because static friction is greater than dynamic friction. Your tow vehicle's anti-lock brakes know how to find this point independently for each of your four tow vehicle tires, but your trailer has no similar features.
2) Even without anti-lock brakes on the TV, you'd have enough braking capacity to lock all four of your tow vehicle tires. With your trailer brake controller at maximum, you probably can't lock the trailer tires on dry pavement (don't try this in traffic). Therefore, your trailer is not equipped with the same braking capacity at each wheel as your tow vehicle.
3) You don't want your trailer brakes to lock, ever. A skidding trailer behind your better-braking tow vehicle would try to pass you. Therefore a trailer braking system that is not able to lock up the wheels is a feature, not a bug, as we used to say in the software business.
4) Not all road surfaces provide the same traction. There are bigger braking problems on slipperier surfaces.
Therefore, even the smartest available brake controller can't make our trailer brakes completely do their share. The controller can make the trailer brakes start earlier and manage themselves through the stop. But, the trailer system has to be compromised enough so that the trailer doesn't lock up on a wet road (you might not have time to readjust the controller settings while you're concentrating on a rainy panic stop).
My proposed rule of thumb would be that your tow vehicle routinely has to stop itself plus 1/3 of the trailer's weight not just because your tow vehicle is carrying a good chunk of it on the tongue but also because your tow vehicle is also a substantially better stopper than your trailer. Your stopping distance will accordingly be longer.
Is a longer stopping distance unsafe? Yes, when you are going too fast for your vehicle, load, and conditions. Absolutely, when it's longer than the distance to the problem in front of you.