?Riddle Me This?? (Trailer braking question)

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Memtb

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  A correct me if I?m wrong! Please be nice....I?m very sensitive!  :)

  I recently saw a posting on an RV forum, where a party sold his truck and upgraded to a larger truck because.....his truck was ?not? stopping the RV (RV was within limits of his truck).

    So, isn?t the tow vehicle?s primary responsibility to tow and steer said RV.....not to stop it?  If the trailer brakes are working properly and gain is properly set on brake controller.....then brake effort on tow vehicle should remain equal or nearly so towing or not. If the truck is required to ?stop? the trailer... then we have a trailer brake issue... not an inadequate tow vehicle!!!

    If I am correct....maybe some folks can lear from the discussion!
 
      Let the  ?stoning? begin!
 
I have never owned or towed a RV trailer, but I have owned a couple of enclosed race car trailers.  One had 4 wheel (2 axle) electric Drum brakes, the other had 2 wheel (1 axle) electric Disc brakes

I have always held that 65%-75% of the stopping force comes from the towing vehicle and that while the trailer brakes DO assist in stopping, a large part of the trailer brake's job is to keep the trailer from trying to pass and jackknife the tow vehicle.

The brakes & tires on most semi-trailers do not provide a lot of stopping power, that is why so many big-rigs jackknife during an accident.

Many smaller trailers, utility, motorcycle, pop-up campers, do not have brakes and provide NO stopping assistance to the towing vehicle.

Tim
 
I have owned and towed many trailers, and two large 5vers. The brakes on the tow vehicle should be able to lock up and stop the wheels from turning on a heavy brake. That being said, no amount of braking by the trailer will change the laws of Physics. If a tow vehicle is pulling a 12,000 pound trailer with a 7,000 pound truck, in a panic stop the trailer WILL push the truck. If the brakes on the trailer are poor or not functioning, it will push it even further.  The best scenario would be if the truck and trailer had ABS brakes to avoid the locked wheels sliding on the asphalt. 

Will a bigger truck with bigger brakes stop the trailer quicker? Sure. As a matter of fact, trucks these days often take much of the responsibility of stopping the trailer because braking systems are so much better than they used to be.  Many towables out there have mediocre brake systems and the owners never know it.  Unless a panic brake situation occurs.  Which is usually a horrible time to find that out.
 
  Maybe I?m just spoiled, but...Since around 2003 we?ve been blessed with 5th wheels that had good (if anything slight overkill on brakes....if that?s possible). Our present unit has 3 axles and hydraulic disc brakes. I?m a little aggressive on the gain, and on a normal stop... can feel the trailer slowing the truck. On a panic stop, I don?t think that my stop would be significantly longer than the truck alone. I may have to perform that test one day.  ;)
 
If you feel the trailer pushing the truck with brakes applied, you don't have your gain set high enough. When you apply the brakes, you should get the same feel you get when you are driving the truck by itself.  That's the way mine is set up.  On the way to the storage unit, I apply my truck brakes hard at about 45 mph a couple of times to get the feel.  After I hook up my TT, I repeat the process and the stopping should be about the same. I'm not talking about making a "panic stop" with pedal to the floor, just a good hard brake check.
 
We recently upgraded to the Tekonsha P2 controller. I am so much happier and confident in this unit. This is a much safer controller.  If you do not have one that is responsive and progressive to harder braking conditions like the Tekonsha P2 or P3, you need to get one. The new Garth Brooks song applies-"Ask me how I know?" 

We got very lucky in a panic stop that resulted in the flattening of the front license plate and holder against the rear bumper of a passenger car. It could have been much worse.  I dragged all 4 wheels of the TV in the last 4 feet.  There is no doubt in my mind I wound not have hit the car in front of us if we had the Tekonsha controller. Spend the money on one! It was a very easy install. It also performs much better in stop and go traffic where the other unit was applying too much current in these conditions yet not enough when I needed it most.
 
healeyman said:
The brakes & tires on most semi-trailers do not provide a lot of stopping power, that is why so many big-rigs jackknife during an accident.

Many smaller trailers, utility, motorcycle, pop-up campers, do not have brakes and provide NO stopping assistance to the towing vehicle.

Tim
Try to move a semi trailer with the brakes locked and you will find out how much the brakes work.

The trailer brakes should provide most of the stopping for the extra weight that the trailer adds I adjust the gain until i don't feel it pushing me.
 
    Thanks for your input....it appears that most of us feel the same on several points.

    One point being... as with most things in rv’s today, the brakes are another item lacking

    Another point... many do not have the “gain” set high enough

    And as viceprice  suggested (I’m taking the liberty to expound on his statement)...the old style controllers are technologically outdated.  With the newer technology you can have adequate “panic stop” braking, while not having the “jerk” you feel in “stop and go” traffic felt with the old technology

    Since around ‘07 we’ve had a controller that “Tee’d” into the brake line off of the master cylinder. A “transducer” converts the brake fluid pressure into an electrical signal to the RV brake system. The harder you apply the tow vehicle brakes,  the higher the electrical signal to the RV brakes (master cylinder if you’re running hydraulic disc brakes). Of course...this means nothing “IF” you don’t have the gain set properly.
 
[Sigh]. As with so many techie things, this can get complicated once you try to pin it down.

The trailer brakes are tied to the axle ratings, i.e. a 5000 lb axle has brakes adequate to stop [at least] a 5000 lb load.  The problem is, the trailer axles are typically  responsible for only 80% (5W) or 90% (travel trailer) of the total trailer weight, so the tow vehicle has to handle the rest. If the tongue or pin weight is within the towing trucks cargo capacity, then the truck's brakes should have no problem doing so.  Obviously, though, if the truck is loaded the max, and the trailer as well, the brakes are going to be working hard in a panic stop and the stopping distance is going to be longer than a more lightly loaded truck & trailer.  So yes, a bigger truck, i.e. one with a greater cargo capacity and GVWR,  will probably stop it more quickly. A bigger GCWR may not.  Upgrading the axles on the trailer is another way  to get more trailer braking capacity, and it also reduces the risk of bent axles. Further, larger trailer axles can probably handle larger tires with a greater load capacity, so the tires aren't operating at max load 24/7/365.
 
Hi Gary,

Gary RV_Wizard said:
Upgrading the axles on the trailer is another way  to get more trailer braking capacity, and it also reduces the risk of bent axles.

Another interesting upgrade idea is to replace the commonly used purely-electric trailer brakes for an electric-over -hydraulic braking system like these folks did:

http://roadslesstraveled.us/trailer-electric-over-hydraulic-disc-brake-conversion-fifth-wheel-rv-upgrade/

Cheers,
--
  Vall.
 
viceprice said:
There is no doubt in my mind I wound not have hit the car in front of us if we had the Tekonsha controller. Spend the money on one! It was a very easy install. It also performs much better in stop and go traffic where the other unit was applying too much current in these conditions yet not enough when I needed it most.

A friend of mine is Mr. Terry Hampton. .Mr. Hampton lives in a little town it appears I will be visiting tomorrow called Tekonsha, MI.. Yup, the town I grew up in.... Once tried (And alas failed) to date a young lady there..  her daddy.. Owned Tekonsha Engineering as I recall.

When last I looked up the company profile (Oh about 30 years ago) Terry ran it.
 
One elephant in the room no one talks about is the way the trailer brake controller knows how hard to apply them.

When electric brakes were first developed, the brake controller was connected to the tow vehicle's brake system and energized the trailer brakes in direct proportion to how hard the driver applied the brakes.  They worked very well and provided seamless braking under all conditions, including when the vehicle is skidding on a slick surface.  I had a later version of one of these controllers, the MasterBrake and the difference between it and any of the present day brake controllers was like night and day.  You literally did not know the trailer was there while braking.

Trucks with a factory installed brake controller still work this way, reading the truck's brake pressure and sending the correct amount of current for that amount of braking to the trailer brakes.

Unfortunately, concerns about the liability of tapping into the tow vehicle's brake lines along with the introduction of dual brake circuits in the 1960s spelled the end of aftermarket controllers that responded directly to the tow vehicle brake input.

All of the present day aftermarket controllers lack direct input from the tow vehicle's brakes, so all they can do is guess at how hard to apply the trailer brakes.  They do this by various means, some by just gradually ramping up the trailer brakes based on how long the brake lights remain on, others by using a pendulum or other means to determine how hard the truck is stopping and applying the trailer brakes in proportion to the slowing.  If the truck loses traction and skids on a slick surface, there's no slowing for a proportional controller to detect so it doesn't apply the trailer brakes.

Some controllers play the guessing game better than others, but since none of them are 100% right all of the time, you can't assume the trailer never adds additional loading to the vehicle brakes.
 
Hi Lou,

Lou Schneider said:
Trucks with a factory installed brake controller still work this way, reading the truck's brake pressure and sending the correct amount of current for that amount of braking to the trailer brakes.

Thanks for this info. Do you know whether this is indeed the case for the new RAM HD trucks? We are planning about getting one with the trailer package (which includes a factory trailer brake controller) and were considering whether to get one controller-less and installing a Tekonsha instead, given its great reviews.  But if the factory-installed is so good, we might as well not bother...

Cheers,
--
  Vall & Mo.
 
Yes, the Ram and Ford factory controllers read the brake pressure and send the appropriate amount of current to the trailer brakes.  They're way superior to any of the aftermarket controllers.
 
Thanks again, Lou. We will be definitely getting the factory controller then.
 
Lou Schneider said:
Yes, the Ram and Ford factory controllers read the brake pressure and send the appropriate amount of current to the trailer brakes.  They're way superior to any of the aftermarket controllers.

Thanks,too, Lou!

I had the same question!
 
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