Problems of a dolly with surge brakes on steep downgrades

[The Gritz Carlton]

That's cool!! I did notice the "overload spring", which could possible serve as a "push back" device, once you let off the MH brakes, as Ted mentioned, thus relieving some the braking pressure.

[dpbain1]

Being the person who began this topic, I did some research including looking at another RV forum. In it was one response from a person who received a document from UFP, manufacturer of surge brakes entitled "Boat Trailer Brake Operation and Potential Effects of Long/Steep Downgrades".

The entire document is too long for this forum however it did say "Second, most boat trailers are equipped with “Surge” operated brakes. The standard “Surge” brakes apply when the brakes are applied on the tow vehicle and the trailer then tries to outrun the tow vehicle, compressing the master cylinder in the tongue and applying the trailer brakes. In 95% of customer situations, they work extremely well, are simple, and require little input from the tow vehicle driver. The issue arises when a customer travels in a location with long downgrades of several miles, and say a 5% or greater grade. In that case, if the tow vehicle is downshifted at the top of the summit to use engine braking down the grade, and the trailer brakes are automatically and continually applied by the surge actuator on the trailer tongue, the effect is the same as riding your vehicle brakes all the way down the hill. Eventually the brakes will overheat.

The document further suggested that an "Electric over hydraulic pump unit" be installed. And how is this applied? With an electric brake controller!

It seems to me that anyone living in the West Coast or near the Rockies would be foolhardy to consider a surge brake dolly system when the company who makes them sort of suggests otherwise.
I noticed those who had no problems with surge brakes lived in virtually flat terrain states so I guess where you will be driving most should be a primary factor in choosing a dolly.

[The Gritz Carlton]

Good report...that's what I was trying to say from my own experience with surge brakes, but haven't used them specifically with a tow dolly. Unless something causes the actuator to back off/extend back out, they will continue to be applied to some degree and burn up/overheat the brakes...resulting eventually into "no brakes". Electric over hydraulic seems complex. Electric only brakes give you complete control. Even in a situation where you get the wigwag from a passing truck or something, you just slightly and temporarily apply trailer brakes only and they pull you back straight.

[16ACE27]

Electric over hydraulic just locks out the surge brakes unless the TV brakes are applied. Just like reverse locks out boat surge brakes when the backup lights are on.

[The Gritz Carlton]

Interesting subject, no doubt. As I read through the available guru's opinions on the web, it's like one of those "my daddy can beat up your daddy" scenarios. One recent poster on another forum said..."there you have it, you've heard both sides of the story...whatever you choose, we hope you're happy with it". It's a matter of perceived benefit of each. As for me...electric...period! I like having full control with options.

[SuperD]

Sounds like a good article but IMHO not entirely true. I’ve pulled a tow dolly and boat trailer thru Colorado, Kentucky, Virginia, lots of BIG mountains and steep grades, never had a problem with overheating and I check my brakes.

You’ve read both sides of the opinions now. Bottom line, it’s your decision and your money, buy what you feel comfortable pulling. Best wishes in your decision, let us know how do.

[gmtech16450yz]

Originally Posted by Tfryman

Electric over hydraulic just locks out the surge brakes unless the TV brakes are applied. Just like reverse locks out boat surge brakes when the backup lights are on.

There are electric over hydraulic systems that are actual pumps. They work just like electric trailer brakes, with a trailer brake controller. They build the brake pressure just like the ABS/traction control system in your does, it's capable of putting full brake pressure on electrically regardless of your foot on the brake pedal.

Electric over hydraulic is a good upgrade for boat trailers, I would assume it would work well for car dollies too.

[gmtech16450yz]

Originally Posted by SuperD

Sounds like a good article but IMHO not entirely true. I’ve pulled a tow dolly and boat trailer thru Colorado, Kentucky, Virginia, lots of BIG mountains and steep grades, never had a problem with overheating and I check my brakes.

You’ve read both sides of the opinions now. Bottom line, it’s your decision and your money, buy what you feel comfortable pulling. Best wishes in your decision, let us know how do.

Didn't bother reading the article but surge brakes can/do drag on downhills. Especially if your tires/ tire pressures/wheel bearings/etc are optimized well and there's little rolling drag on a heavy trailer. If you have low tire pressures, a big trailer that has a huge wind drag or simply a heavy boat that's on a single axle trailer and should actually be on a double, you could have enough drag that even on downhills the surge brakes wouldn't apply and drag.

Even the way you drive can effect surge brakes a little. For instance when I'm towing a trailer with surge brakes, I make it a point to accelerate hard when first starting after a full stop to make sure that tongue gets a good tug on it. Old or worn tongues do have a tendency to be sticky and can drag the brakes.

[The Gritz Carlton]

Let's buy a trailer with surge brakes, then spend more money to modify it to operate like electric brakes because electric brakes are a better concept. Now, that makes sense!


gmtech...the guy that starts down the hill with all that drama you described above...well, that's why we have the runaway truck ramps.

[gmtech16450yz]

Originally Posted by The Gritz Carlton

Let's buy a trailer with surge brakes, then spend more money to modify it to operate like electric brakes because electric brakes are a better concept. Now, that makes sense!

The problem is that you don't always have a choice of what brakes your trailer comes with. The other issue is that electric DRUM brakes aren't even in the ballpark of electric over hydraulic DISC brakes. A large portion of trailers these days that come with surge brakes are also disc setups.

So if you have disc surge brakes and you upgrade to electric over hydraulic, you end up with the best trailer brakes you can buy. Far better/stronger/more efficient than electric drum brakes.

If you have DRUM surge brakes, you're screwed. haha.

[Beau388]

How many over the road trucks and trailers weighing 80,000 lbs have disk brakes? I venture to say 5% at most. The reason you see disk brakes on automobiles is they work much better (more predictable) with anti-lock brakes and are less susceptible to water brake fade than drum brakes. Also, disk brakes work much better at temperatures above 800 degrees so the are used in racing. Other than those exceptions, well maintained drum brakes are as good, most times better and just as reliable. I have two vehicles with power, anti-lock disk brakes and a convertible and truck with manual, drum brakes. All four can lock up the brakes with moderate brake pressure (anti-lock off).

[The Gritz Carlton]

Brakes are like pick-up lines in a bar....doesn't matter what kind you use, as long as they work!!

[Bob Denman]

I gotta remember that...

[rverdlm]

I've had my tow dolly with surge disc brakes for 4 years and been all over the west from the Pacific coast highway through the cascades over through Yellowstone over the Rockies at togwatee pass. Then the next year east through the mountains of Pa, NY, VT, ME, VA. This year through the Davis Mt, then Santa Fe. I've had no problems and the brake pads are not worn. I run my MH in tow/haul mode so it down shifts automatically on down grades. I highly recommend the surge disc brakes. If you go to electric brakes they will not be disc and from my experience electric trailer brakes are crap!!!

[jb1911]

We have a Demco Tow Dolly 3 with surge brakes, haven't used it yet. Should we use tow/haul mode only when in hilly country?

[JamieGeek]

Originally Posted by jb1911

We have a Demco Tow Dolly 3 with surge brakes, haven't used it yet. Should we use tow/haul mode only when in hilly country?

I hit tow/haul when we're pulling a car as soon as I start the RV and it stays in Tow/Haul until we stop.

[rverdlm]

I do the same thing. As soon as I start the engine it goes into tow/haul. The reason is that it not only changes shift points, but when you need to stop for a light or stop sign or just pulling into a rest area the transmission down shifts saving your breaks.

[jb1911]

Thank you.

[John Volk]

Hi the best way to tow is 4 on the ground I have both a tow dolly with doc brakes and a Roadmaster tow bar set. The dolly with disc bk has a surg bk witch has a lockout for backing witch is not recomended but sometimes vou have to you can reach me at 805=350-0929

[AndyT1183]

Originally Posted by dpbain1

I am trying to decide what dolly to buy. I prefer surge brakes however I've read in numerous places that they are not ideal in mountainous locations as they have a tendency to overheat on long and/or steep downgrades. Apparently this can happen even without the towing vehicle's brakes being applied. A manufacturer who sells both types also informed me that "all surge brakes will do this". I live in WA so whether I travel East or South, I will encounter long 5% or 6% grades.
On the other hand, I understand electric brake dollies need the addition of a brake controller. I haven't found if one can simply tie into the brake lights of the towing vehicle to activate the dolly's brakes.
So, I'm a dilemma as to which way to go. I must use a dolly as my 2015 Ford Escape cannot be towed 4 wheels down. Any suggestions would be greatly appreciated.

After much research we choose the Demco Tow Dolly with surge brakes. It was one of our best purchases. We have never encountered any problems. To avoid mountain / hill issues, utilize your "tow haul" mode on your transmission. If you don't have "tow Haul" mode utilize lower speeds and reduced transmission gear.