Trailer surge brakes

Considering building a compact trailer - something like an M101.

How are the surge brakes on these? I’m guessing they’ll lock up under hard braking. Do more modern trailers and brake controllers have anti-lock performance? I haven’t towed long distance or owned a trailer in years so I have no idea where things are in this regard.

 

All of our boat trailers equipped with brakes are surge brakes. This is from bass boats up to ski boats. The surge brake system is reliable as long as you maintain the fluid, just as you would in your truck. The biggest problem I see is from people not checking the fluid level.
The surge brake system applies pressure to the brake shoes (drum brakes), when you slow down. The pressure is differentiated by the actuator, which means the harder you brake, the more pressure on the trailer brakes. When you are going forward you are pulling the actuator forward, thus releasing pressure on the brake shoes. If our company trust surge brakes on bass boats and ski boats, I would think the small trailer you want is just fine.
In fact, depending on the trailer weight on what you will be hauling, you may not even need trailer brakes at all. I say this because the line up of smaller aluminum boats we have, do not come with any brake system. Even the smallest fiberglass bass boat we offer (Nitro Z 17) is single axle with no brakes as standard package, you can upgrade to brakes on it. But that is around 1500 to 2000 pounds with boat,motor,trailer.

 

Interesting. I had no idea.

So what happens when the road is wet and you need to brake hard while swerving to avoid a deer etc?

 

Trailer brakes would not matter in that scenario. If you hit the brakes hard on a wet road while swerving with a trailer, you are screwed no matter what.
Sway bars may help, but it depends on how much you swerve.

 

Your surge brakes work when you brake firmly in any condition. Can they lock up? Sure but if it happens chances are you need them to stop as quickly as possible.
ABS was developed so you would be able to steer in hard braking situations. If your wheels are sliding, you can't steer. A trailer does not steer, the truck does.
If you do a side by side brake test, sliding tires stop faster than ABS.

 

That’s surprising. My understanding was that ABS had decreased stopping distance as well as better steering.

Does your statement hold true in all weather conditions?

 

No. In snow and Ice ABS is king.

Think about it... ABS basically (many times a second) lock and unlock the brakes which let's you control the vehicle and steer.

In normal braking, the only thing stopping you is pad on disc or shoe on drum. When you use non abs and lock it up, you now have the coefficient of friction of rubber on pavement.

On ice, you don't want to slide lol.

 

Yea that’s what I thought. So - in those conditions the risk of jack knifing would be mitigated by abs trailer brakes. Or am I still missing something?

 

Let's see...
Pulling a trailer
On ice
A deer runs out
You swerve
You brake hard
The trailer will then be sliding!

Except, it will be sliding abs or not. As soon as you swerve on ice that trailer's gonna slide abs or not.

Bottom line... ABS is good on vehicles that steer. Surge brakes are good on lightweight trailers. ABS is not needed, because, what if you were on a gravel road and a deer ran out and you swerved and braked hard? Then the non ABS trailer would be better lol.

For those of us who learned to drive (and were good drivers) before ABS, we laughed at ABS because we could stop much faster with non ABS. But, you had to be a really good driver to lock it up, release to steer, lock it up again, etc. It didn't take long to realize for those drivers that were not so good, it made the world a safer place.

 

There’s very low friction between rubber tires and ice and snow. That is quite understood and I’d probably avoid towing, and, generally speaking, driving on ice anyway.

There is probably a clearer way to ask than the way I’m asking, and my initial question has evolved at this point, but what I’m trying to figure out is essentially the following:

How do you best proportion the braking of a trailer to the braking of the tow vehicle so that you don’t jack-knife in fair to moderate driving / weather conditions? I get that there’s no way really do this 100%, but what steps can be taken to maximally achieve the objective?

So now that I’m actually thinking more about it, in addition to the tow vehicle and trailer having very different velocity factors (don’t actually know if that’s the right physics), axle widths, etc., maybe the tire type should match the tv’s exactly, and the tire pressures should be adjusted to all have the same (maximum) tread contact. What else?

As far as which brake system is on the trailer, it sounds like so far the win is for surge brakes over electric and even abs.

 

Surge is fine for light trailers up to 5K or so. After that, proportional brakes with a nice controller is what is needed. This way, you can tune the trailer brakes to match the tow vehicle brakes.