Trail(er) Braking

[Newbie]

Hi,

While looking for an open trailer, I found one that does not require a brake control in the tow vehicle. It's some sort of automatic system based on inertia. The guy that had it said he just replaced the master cylinder, and would tow a Chevy S-10 drag truck with a Chevy S-10 and had no problem at all.

Even more attractive is that it is some sort of low profile trailer. His S-10 drag truck has only 3" of clearence and he does not scrape the nose while loading.

Can anybody share some knowledge on this type of brake system for towing a race car.

Thanks

[Greg Amy]

The principle is the same general idea as the hydraulic brakes on your car and truck.

The hitch "floats" from the main part of the trailer. As you brake the truck, the trailer moves forward relative to the hitch. Connected between the hitch and the trailer is a hydraulic master cylinder; when you brake that cylinder is shortened due to the trailer float and interia, and that creates hydraulic pressure on wheel cylinders on the wheels. When you accelerate the trailer pulls back, the cylinder rod is retracted, and the hydraulic pressure is released.

[ITANorm]

Most of the larger rental trailers have this arrangement. The biggest downside to them is that they don't back up hills worth a darn. If you do get it, make sure it has a "lockout" lever on it, so that issue becomes merely an inconvenience (you have to get out and throw the lever).

My personal opinion is, it's hard to beat electric brakes with a good controller (at least on smaller trailers; i.e.: 16K and under).

[racer_tim]

It's called a "surge" brake. They work OK except when you have to back it up, "up" a driveway. They are also the easiest for multiple tow vehicles. As long as you the common light setup, you can "share" the trailer much easier than an electric brake trailer.

My parent's boat has surge brakes and it's a PITA to reverse up hills.

I converted by surge brake dual axle open trailer to electric about 3 years ago. I like the flexibility to adjust the controller depending upon how much weight you have on in the trailer.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

[Matt Rowe]

You know a "line lock" solenoid triggered by the reverse lights and plumbed into the hydraulic line between the master and wheel cylinders does wonders in eliminating the reversing problems.



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~Matt Rowe
ITA Shelby Charger
MARRS #96

[bill f]

Actually, there is another fault with the design of the "surge" system: you don't have independent control over the towed object. Remember, the brake force applied to the trailer is TOTALLY DEPENDENT on the braking of the tow vehicle...if it fails for any reason, the trailer will not be able to be retarded.

Think of towing during a rain storm, with the tow vehicle possibly aquaplaning...you are not able to use the trailer brakes independently to slow the rig down.

Think ice...or gravel...

Don't think it'll happen? The extension of this is: IF you lock up the tow vehicle brakes (panic stop), the sliding tow vehicle will not supply any brake force to the trailer thru the coupler. (I know this example is different than slippery roads)

I had this happen in D.C., and hit the damn Jeep, instead of being able to stop. Seems the front wheel were unloaded due to the tongue weight.

Personally, I dislike electric because of the combination of feel from the driver seat, but like them for the adjustability and the above safety factors.

The only positive for surge brakes is that they are "dumb"... work everytime, and when the trailer is connected, the brakes are too...no separate connection.That is why they are good for rentals...Can't be "not connected".

Good racing.

Bill

[This message has been edited by bill f (edited February 15, 2005).]

[racer_tim]

Bill, it also happens because the tow vehicle won't properlly "nose down" during braking, because of the additional tongue weight.

I'm glad I converted my trailer to electric bakes.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html