Surge Brakes

[angib]

Whats so difficult about...........

Doesn't sound difficult at all. So how come many people only talk about it, rather than just doing it?

Like I said, electric brakes seem a better system...... but only if they're fitted.

Incidentally, backing up surge brakes isn't a problem in Yurp, as all the trailer brakes are 'auto-reverse' - they don't work in reverse, except when the handbrake is used. How this bit of magic works, I don't know, as the handbrake only pulls on exactly the same rods or cables as the coupler does.

Andrew

[brian_bp]

Trailer brakes are not required on trailers under 1500kg (1650 pounds) unless the weight of the trailer is over 50% of the weight of the tow vehicle

Good info, and similar to most North American requirements - thanks.

... my car certainly can't stop as short with the trailer as without it

That looks like a definition of "inadequate" to me, and the reason why I'm sure Mazda does not endorse this configuration. The car probably has great brakes, but it just doesn't have the traction needed for best stopping performance because the trailer weight is not carried by the car's tires.

... but this has nothing to do with surge versus common electric brake setups.

[brian_bp]

Incidentally, backing up surge brakes isn't a problem in Yurp, as all the trailer brakes are 'auto-reverse' - they don't work in reverse, except when the handbrake is used. How this bit of magic works, I don't know, as the handbrake only pulls on exactly the same rods or cables as the coupler does.

I assume that the "magic" is in the brake assembly at the hub, not at the coupler... the hub is rotating, and thus can respond differently under forward and backward moving conditions. The parking brake is (hopefully) applied while stationary.

From a Dexter catalog...

Another variation is called a “free backing” brake which is commonly used on trailers with a surge hitch system. When backing with a surge brake hitch, normal brakes are applied through the surge mechanism and if there is more brake force on the trailer than the tow vehicle can override, no backing is possible. The free backing brake was developed to allow backing in this application. This brake has a primary shoe on a pivot which allows normal application in the forward direction, but allows the primary shoe to rotate away from the drum surface when backing.

This is a description of a hydraulic drum brake uni-servo wheel assembly. They appear to mention no free-backing solution for their disk brakes, but a solenoid valve can be used in the hydraulic line, activated by a reverse light signal from the tow vehicle.

[Alphacarina]

... my car certainly can't stop as short with the trailer as without it

That looks like a definition of "inadequate" to me, and the reason why I'm sure Mazda does not endorse this configuration. The car probably has great brakes, but it just doesn't have the traction needed for best stopping performance because the trailer weight is not carried by the car's tires

By your definition of 'adequate' then, anything towing anything would require trailer brakes, but even in very conservative Europe, they aren't required on trailers under 1650 pounds (or less than 1/2 the weight of the tow vehicle, which is also a pretty conservative rule) - When they ARE rquired there though, they are required on EVERY trailer axle, which isn't the law here even for the heaviest of trailers - Many 10,000 pound triple axle trailers have brakes on only one or two axles and I would bet that the trucks towing those can't stop as short as they can without the trailer

Sure there are instances where trailer brakes should be (and are ) required, but certainly not for every small trailer being towed, even though towing just 100 pounds adds to the stopping weight of most vehicles - Here, even on commercially built trailers, brakes usually aren't offered for loaded weights under 1000 pounds or so and we don't have a hard and fast rule requiring them at 1650 pounds like they do in Europe either. If there was a rash of accidents caused by lack of or faulty trailer brakes on lightweight trailers, I'm sure there would be stiffer laws and mandatory inspections, but that doesn't appear to be the case in most states

My tear is a commercially made Little Guy and they don't offer trailer brakes, even though most of their trailers are designed to be towed by smaller vehicles

If no laws require them, their use is at the discretion of the owner/driver - Whatever the driver is comfortable with should prevail in the absence of any laws to the contrary

Mazda, like the manufacturers of most smaller cars just recommends against towing ANYTHING, no matter how light or whether it has brakes or not, which is what I would recommend too if I were selling anything in our litigious maket - Recommending anything else would set you up for lawsuits galore

Don

[angib]

I assume that the "magic" is in the brake assembly at the hub, not at the coupler...

Quite correct - it's actually in the trailing brake shoe which is free to slide down a ramp when applied in reverse. Here's a diagram and a photo, 'cos I think you like the tech-y stuff as much as me:
http://www.towitall.co.uk/images/lockheed_brakes_10.gif
http://www.autow.co.uk/images/products_large/BSK2501.JPG

However from looking at this, you would think that the handbrake wouldn't work in reverse, but I can tell you they certainly do. This is where the 'magic' comes in......

Andrew

[George Kraus]

I have to agree with Don, I am building with electric brakes. The courts and Insurance companies of today are to say the lest unpredictable. I know many people, including myself, have towed trailers thousands of miles without incident. Many state laws have minimum stopping distance requirements for trailers under 3000 lbs., some states go as low as 1500 lbs. on requiring brakes, some require operator compartment control, including the feds, if you have them. Remember, the law for everyone changes when you cross the state line or get on a Federal Highway. I have never had an accident while towing but if I do get into one I don't want my Insurance company or the Court to find me at fault due to having the wrong type of brake or no brakes at all. There are a lot of little enforced laws out there, trailer braking being one of them. This still does not prevent the Insurance companies or Courts from enforcing them when it is to their convenience. I believe this forum is made up of a large group of safe drivers, but no matter how safe we drive the unexpected can still happen.

George

[Dale M.]

If any body is interested...

7. Information Regarding Federal Requirements for Trailer Brakes, Tow balls, Safety Chains and Breakaway Devices.

NHTSA has requirements about hydraulic and/or air brake hoses if the trailer is manufactured with either of these systems. The requirements are found in FMVSS Nos. 105 and 121. The Federal Motor Carrier Safety Administration (FMCSA) publishes requirements for commercial users of trailers with respect to brake requirements for certain weight trailers. The FMCSA regulations are found in Title 49, Code of Federal Regulations, Part 393. The FMCSA also has requirements for commercial users of trailers. Some of those requirements are for the use of tow balls, safety chains, and break-away devices.

Source is from this site....

http://www.nhtsa.dot.gov/cars/rules/imp ... page4.html

IF you want to take it further..

http://ecfr.gpoaccess.gov/cgi/t/text/te ... ain_02.tpl

Dale

[Alphacarina]

Interested reading

It seems that here in the states, the upper limit is 3,000 pounds for trailers without brakes, as opposed to the 1650 requirement for Europe - I knew they were more conservative on their regulations than we are

"4) Any full trailer or four-wheel pole trailer (laden or unladen) with a gross weight of 1,361 kg (3,000 pounds) or less which is subject to this part is not required to be equipped with brakes if the sum of the axle weights of the towed vehicle does not exceed 40 percent of the sum of the axle weights of the towing vehicle."

For my 2500 pound car, that means a trailer under 1,000 pounds is exempt - Those of you towing with a full sized pickup would probably still be legal at 1500 pounds

One thing we should all consider with respect to the descison to incorporate trailer brakes or not is that if you DO have them, then you must employ a breakaway system where the trailer brakes are automatically engaged when the trailer breaks away from the car - This means you must have a (fresh) battery mounted on the tongue capable of applying the brakes if the trailer comes uncoupled . . . . I suppose you could wire them into the tears 12 volt battery if you have your tear equipped with one

"d) Breakaway braking requirements for trailers. Every trailer required to be equipped with brakes shall have brakes which apply automatically and immediately upon breakaway from the towing vehicle. With the exception of trailers having three or more axles, all brakes with which the trailer is required to be equipped must be applied upon breakaway from the towing vehicle. The brakes must remain in the applied position for at least 15 minutes"

The '15 minute rule' means you need a pretty hefty battery on the tongue if you aren't connecting it to the deep cycle one in the tear

Interestingly, there is an exception for cars, trucks or motorhomes towing another vehicle with a tow bar - They are not required to have operable brakes on the towed car (no matter what it weighs) so long as the combination can stop from 20 MPH in 35 feet or less. I guarantee you my Mazda with 4 wheels discs towing 1500 pounds could meet or beat that requirement

Don

[Dale M.]

But then you have STATE laws the may also have bearing on situation.... Here is note on California...

http://www.dmv.ca.gov/pubs/vctop/d12/vc26303.htm

26303. Every trailer coach and every camp trailer having a gross weight of 1,500 pounds or more, but exclusive of passengers, shall be equipped with brakes on at least two wheels which are adequate, supplemental to the brakes on the towing vehicle, to enable the combination of vehicles to comply with the stopping distance requirements of Section 26454.

Amended Ch. 1536, Stats. 1971. Operative May 3, 1972.

http://www.dmv.ca.gov/pubs/vctop/d12/vc26454.htm

Control and Stopping Requirements

26454. (a) The service brakes of every motor vehicle or combination of vehicles shall be adequate to control the movement of and to stop and hold such vehicle or combination of vehicles under all conditions of loading on any grade on which it is operated.

(b) Every motor vehicle or combination of vehicles, at any time and under all conditions of loading, shall, upon application of the service brake, be capable of stopping from an initial speed of 20 miles per hour according to the following requirements:

[This table shows the maximum stopping distance in feet for certains types of vehicles when moving at an initial speed of 20 miles per hour.] * [Vehicle type] * Maximum Stopping Distance (feet)
(1) Any passenger vehicle ......25
(2) Any single motor vehicle with a manufacturer's gross vehicle weight rating of less than 10,000 lbs. ..... 30
(3) Any combination of vehicles consisting of a passenger vehicle or any motor vehicle with a manufacturer's gross vehicle weight rating of less than 10,000 lbs. in combination with any trailer, semitrailer or trailer coach .......40
(4) Any single motor vehicle with a manufacturer's gross vehicle weight rating of 10,000 lbs. or more or any bus ....40
(5) All other combinations of vehicles ... 50

* The bracketed information has been added editorially to meet accessibility requirements and is not part of statute.

Amended Ch. 443, Stats. 1965. Effective September 17, 1965.

Dale

[brian_bp]

The state (and provincial) laws vary quite a bit, but are often expressed as both an absolute weight limit (e.g. anything over 3000 lb) and a relative limit (e.g. anything over 40% of tug weight).

The car-behind-motorhome exemption is only for motorhomes in some jurisdictions, and even then still subject to the relative weight limit.

The 15-minute breakaway requirement doesn't sound so bad. With 4 ohm resistance (as per Dexter spec and my measurement) and 12V supply, that's only 3 amps each, or 6 amps per axle. 6 amps for 15 minutes is only 1.5 amp-hours, which is why the batteries sold specifically for breakaway applications are quite small.

I suppose I should have described the Mazda and unbraked trailer setup with some kinder term. True, it's better than many trucks and motorhomes... but why settle for that? The car is very capable, before the trailer is added.

For models which are rated for towing by Mazda, a no-brake limit still applies; for the MPV van, that is (was?) 1000 lb.

The fact that a manufacturer does not offer brakes is, in my opinion, no indication of good design practice. Trailers in general have the cheapest junk under them that the manufacturer can get away with. Compare any trailer component to the corresponding part on any mass production motor vehicle, and I think you'll see what I mean. Brakes - or the absence of brakes - are no exception.

[Alphacarina]

The fact that a manufacturer does not offer brakes is, in my opinion, no indication of good design practice. Trailers in general have the cheapest junk under them that the manufacturer can get away with. Compare any trailer component to the corresponding part on any mass production motor vehicle, and I think you'll see what I mean. Brakes - or the absence of brakes - are no exception.

My undercarriage isn't 'junk'

Unlike the HF 1740 trailers, the frame under my 800 pound tear is all 2 by 3 box steel and the axle is a 1500 pound torsion setup - It's all much heavier duty than most of what we homebuild here, but since it's not at all heavy, brakes would be overkill, IMO

After towing 1500 pounds across the country several times, I can hardly tell the tear is back there . . . . even when braking

I suspect our federal '40% rule' probably dates to the era of drum brakes and when towing with a modern 4 wheel disc vehicle, it's probably very conservative

From lots of personal experience, I don't consider 1500 pounds unbraked to be a problem except perhaps in an emergency situation, which is why I add some additional following distance when towing anything . . . . with anything - Brakes or not

Don

[Mini Renegade]

I regularly strip and rebuild overrun braking systems on caravans and large trailers, they are easily maintained and modern ones, (1990) onwards have an auto reverse release, when the trailer wheels turn backwards this releases the brakes so no need to put a pin in etc. The only problem with these are if you uncouple on a hill If they are correctly adjusted it is easy to feel what the trailer is doing and compensate, it will be gently braking going down hill of its own accord

[brian_bp]

Don, I don't mean to personally attack anyone's trailer.

The typical trailer rubber torsion axle has 6-inch long control arms allowing less than 3" of total suspension travel, and has no shock absorbers... that's exactly the low-priced hardware I'm talking about. The tires are similar (in overall size and aspect ratio) to what would have been used on a car of the same weight decades ago... more minimum-cost hardware (I realize that Don has upgraded his rolling stock).

If using a 3000 lb car to tow 1500 lb of trailer without trailer brakes is okay, then driving the same car (a front-heavy vehicle) without a trailer and without any rear brakes at all (the rear brakes do much less than half of the vehicle's braking work) would be fine, too. It wouldn't be good enough for me, but for many (perhaps most) people, I suppose it would be acceptable.

[H@nk]

Hope I'm not to late to post, but now I have some problems.
Here in Europe, on the continent, you can tow the trailer without brakes only what is set up in your towingletter at the carpapers. For me, it will be with a Chrysler Voyager only 450 KG. When I like to tow anything more heavy, than I need brakes. Most of the time we use normal brakes, I don't know how you call them, but when the car brakes, the trailer is coming up the end of the car and brakes also. They are not electric or hydrolic. We can tow normaly not over 3500KG without a "big"driverslicence. So the total towing-combination can also not be over 7000KG. Any trailer need to have brakes when it is over
751 KG . When you have only B-licence you can't towe anymore than the empty weight of your car. F E when the car weights 1000 kg and the trailer wieghts 999 kg you can tow with B. Car is 1000 kg trailer is loaded 1200, needs BE, car is 1000 kg , trailer is 1200 kg, but you load it till 999 kg, you see the cops and can go home without trailer. It has a lot of terms I can't unfortunaly explaine in english, but when you learn Dutch it will be a pleasure to me to complaine you everything.
Henk

[brian_bp]

Thanks for the information, Henk!

The restriction for the Voyager is just like the restrictions which some of us mentioned earlier: even though not legally required, the manufacturer of the tow vehicle (such as my Sienna) specifies that trailer brakes must be used if the trailer is over 100 lb (which is 454 kg). If government authorities there enforce that type of restriction, I think it's a good idea.

That European braking system is apparently normally called an "overrun" system in English in Europe, but in North American terms it would be a cable-type surge brake system. The only trailer I've seen which is made here and has this setup is the Tab, which is a European design. The only Tab owner I've spoken with said that he liked the braking system.

Sorry Henk, but the chances that I'll be learning Dutch any time soon as pretty slim...