I have an interesting dilemma..I tow a 8300 lb 24' enclosed car trailer. I've scaled it and all weights are in spec, and it goes down the road fantastic. A buddy of mine was critiquing how high I have the gain set up on my TBC (8.5), but the trailer comes smoothly to a stop and doesn't lock up. When I use the "standard" method of going 20 mph and engaging the trigger switch, I can lock up the trailer wheels all the way down to 6.0 on the gain. However, driving the truck and trailer at 6.0 makes the brakes get HOT and it doesn't stop all that well. With my new Powerstops, it felt much more natural around 7.5-8. Is this OK? Or is that an indication that I don't have enough truck?

 

If the lockup test works, tell your buddy to go suck an egg. My TT is a 5k tandem and I also have mine set to 8.5. Works fine.

I assume your car hauler is a tandem axle as well. So the truck needs to push out more current to use the 4 brakes instead of the usual 2. I'm guessing your buddy tows single-axle trailers?

 

My trailer is about 5,000 and has dual axles but only brakes on one. I have it set at 6 and it works great. I would expect that a heavier trailer would require more gain, as would one with 4 brakes rather than 2.

 

I think the point is that when the gain is set to not lock up the brakes, then the trailer "pushes" the truck under normal braking conditions, making the truck work harder. But when the gain is set so that the trailer naturally stops with the truck the tires lock up.

Which do you choose?

 

The truck stops great with the gain set at 8 (wow that rhymed). My buddy who commented is one of the "I'd never tow that with a half ton" folks, despite my truck being almost as large, having bigger brakes and significantly more power than his old 3/4 ton. I get that a lot

 

People underestimate the 11-14 F150's. They are heavy MFers(mines 6140lb empty on a cat scale). With a little suspension massaging they tow quite well.

 

I've got Bilstein shocks and struts and the truck is otherwise stock, and I have zero complaints (aside from the OE brake pads and rotors, which I remedied). I may add a Hellwig Swaybar out back but that's about it. It goes down the road pulling over 8k in 6th gear as straight as an arrow. I've panic stopped with it too, and it was perfect

 

Well I said the "lockup test" which doesn't mean your wheels lock up when squeeze the brake controller... You test it out by increasing gain until the wheels lockup when you squeeze the TBC, then you dial it back down 0.5-1 and make sure they don't lock up anymore. Remember that when you're doing this test, only the trailer brakes are braking, don't brake with the truck. So the trailer is trying to stop both the trailer AND the truck. With normal driving, the truck will also be braking.

That's the ideal braking power so that the trailer is helping you stop. This method just ensures the trailer is braking as hard as it can without locking up the wheels. Locking trailer wheels when actively braking with the truck will be worse because now your trailer wheels lose all lateral grip, and the trailer could slide sideways on you. It's also very bad for the tires of course.

Yeah the most important thing is that you know what you're doing is the proper way, and it sounds like it is. The goal is to make sure the truck and trailer are both stopping together and not one more than the other.

 

As folks doing these lock-up test with only the TBC on gravel road for best results, how fast should one be going? I get different opinion on speed but curious to know how fast do you need to go? 2,4,8 MPH?

 

The proper method is doing it at 20-25 MPH (30-40 km/h).

I don't know if testing it on a gravel road is a good idea but I suppose it would still work if you will be towing mostly on gravel road... Setting it up on a gravel road however will leave it a little weak for a paved highway, but it should still be fine. If the gravel road is only a small part of your drive, like near your house or near your destination, I would recommend finding a paved stretch to set your brakes. You normally don't drive as fast on a gravel road, and they aren't as busy, so the chances of you needing to do any high-speed emergency braking are lower. It's much more important on a paved highway in my opinion.

The only downside would be that if you were to brake hard on gravel, then the wheels might lock up on the trailer. But at lower speeds it may not be an issue. This is something that you'll have to decide yourself to be honest because only you know the length, speed and conditions of the gravel roads you're talking about. So take my opinion with a grain of salt

For me, I set it on pavement. I hit gravel roads at the farm and at many camping spots I go to, but I've never had any problems because the speed limit is lower, there's hardly anyone else on the road, and it's very easy to keep a very long distance if there is another car in front of me. The only danger I guess would be a deer running out in front of me, but at lower speeds and with nobody around, I wouldn't worry about slamming the brakes.