Req expert opinions about one trailer wheel locking up when braking

[Raz]

Darrel, I don't think the distance between the shoe and the drum has much to do with it as long as the magnets are within the range of the surfaced area on the drum. I've done adjustments with the shoes close and with the shoes out further. It doesn't seem to matter. Remember, the magnet grabs the drum and rotation moves the magnet swing arm, which pushes the shoes against the drum. If you can lock the wheels, that means the force of the magnet has overcome the friction of the tire. Since we both have Dexter #9 axles, and yours locks and mine won't, I'm guessing it's tires.

[Raz]

Dave, I believe Gordon has a new Scamp.

[Carol H]

Originally Posted by Raz

Since we both have Dexter #9 axles, and yours locks and mine won't, I'm guessing it's tires.

Could you expand on the tire theory a little?

My first thought was the your Outback may weigh in at a few hundred pounds more than the pretty low weight of 1740lbs Darral's trailer does.
Looking at the weights on the Real World chart there are many a 13''s in the 2000/2200lb range and one all the way up to 2560lbs!!! Can not imagine what all was stuffed in the later trailer!

[Darral T.]

Makes perfect sense what you said. I went back and studied the diagram from Dexter on the shoes layout. I was thinking the adj was on the opposite end of the magnet but it's not. But adjusting the shoes with the screw does exactly the same thing as the magnet! I guess it would just cause them to engage quicker but not really change the contact area.

In my opinion? I have to go with Carol on this one thinking it's going to be a "weight" difference and not tires...especially on the gravel since "traction" may not would be the issue? Wish we had'm side by side to do some testing....I love that!

Originally Posted by Raz

Darrel, I don't think the distance between the shoe and the drum has much to do with it as long as the magnets are within the range of the surfaced area on the drum. I've done adjustments with the shoes close and with the shoes out further. It doesn't seem to matter. Remember, the magnet grabs the drum and rotation moves the magnet swing arm, which pushes the shoes against the drum. If you can lock the wheels, that means the force of the magnet has overcome the friction of the tire. Since we both have Dexter #9 axles, and yours locks and mine won't, I'm guessing it's tires.

[Raz]

Originally Posted by Carol H

Could you expand on the tire theory a little?

My first thought was the your Outback may weigh in at a few hundred pounds more than the pretty low weight of 1740lbs Darral's trailer does.
Looking at the weights on the Real World chart there are many a 13''s in the 2000/2200lb range and one all the way up to 2560lbs!!! Can not imagine what all was stuffed in the later trailer!

Trillium Rv Carol, not an Outback. Weighs about 1700 lbs.

My previous trailer had 10" drums and was easy to lock up. To adjust I would lock the brakes and then back off slightly. When the OEM bias ply tires needed replacing I bought radials. When the time came to adjust the brakes it took a considerably higher voltage to lock the brakes. The only difference was the tires. Better tread, different profile, different rubber compound may all contribute to an increase in fiction? If the magnet can't overcome the rotation then there is no lock up. Most folks with a #9 axle will say you can't lock the brakes because the pads are too small but I think tires come into the equation as well.

[gordon2]

Took the Scamp camping and did 128 miles on secondary highways and side roads (even a few miles on gravel roads) so the brakes got a good test. I am very happy with the performance of the brakes after cleaning up the grease and readjusting the brakes and the controller. For those who later read this, I offering the following.

The grease may have contributed to the problem, and certainly was not a good thing, but I think the readjustment was mostly responsible for the improvement.

Although I thought I had enough experience to check the adjustment by the sound of the brake shoes barley dragging, there is no substitute for properly going through the adjustment procedure. I can lock up the brakes now with no problem and I now have my controller set lower and performing very well (4.5 and boost level one, or 5.5 and no boost).

[Jon in AZ]

Good news, Gordon! I admire your steady patience as you worked through so many new trailer bugs. I am rooting for an uneventful (trailer-wise) camping season!

[gordon2]

Originally Posted by Jon in AZ

Good news, Gordon! I admire your steady patience as you worked through so many new trailer bugs. I am rooting for an uneventful (trailer-wise) camping season!

Thanks.. I think we are on our way to that objective. This trip was only three days but it was the first "boondock" with the new Scamp and everything went perfectly. 12 volts is all anyone needs! (at least when the weather is fair)