FLAT TOWING. SCHOOL ME.

Aight. I'm planning a trip with my son for later this year. It's his 13 year old man trip where he and I will leave for some place in the 88 IDI, go hunting for his first truck project, do some fishing, and maybe see some sights.

My plan is the 5 speed swap my 88. Once that is done, I need to decide if my 7k trailer will handle towing or not, possibly a supercab truck. I personally feel like upgrading to e or f rated tires will do the trick, as this trailer is really well built for a 7k. It's brand new also.

With that said, I've thought about just flat towing. Less weight to tow. However, the safety of that depends on the condition of the tires on the truck, and it's alignment. That obviously cannot be forecasted as we do not know what truck we will end up with.

So, school me on flat towing an old bullnose or bricknose. I'm assuming I'll need a nice tow bar, and will need enough tools to remove the front bumper of the truck being towed. Remove driveshafts. Check tires. Check wheel bearings.

We will likely be in Gary's neck of the woods, from Bartlesville to Dallas looking for something.

What else should I consider when towing?

Brakes are the biggest issue with flat towing.  It's not legal in most states to tow a 4000 - 6000 lb trailer with no trailer brakes.  Whether it's safe or not is an argument I won't really get into, but at the very least it's pushing the limits.

There are products available that will actuate the brakes on a towed vehicle.  On my Bronco (that I flat tow a lot) I have a home-brewed setup where a proportional solenoid controls air pressure (from an on-board compressor) to pressurize an air cylinder that pushes on the brake pedal.  It works pretty well, but it cost me about $1000 in parts and was a project to set up.  If you're going to flat-tow a lot you can justify something like that (probably one of the off-the-shelf options). But if it's a one-time thing you probably won't bother, which gets back to brakes being the biggest issue.


Another issue is that you almost can't back up when flat towing.  Assuming you have good caster in the towed vehicle, when you are moving forward the front wheels of the towed vehicle will follow the direction they need to go.  But when you back up they will tend to go to full lock.  And if you are turning while backing up they will very quickly go to full opposite lock.  your only options here really are don't back up or have someone in the towed vehicle to turn the steering wheel when you are backing.  But even that seems to be difficult to do for most people.  I certainly wouldn't recommend a married couple try to do this together!

That does bring up a potential issue.  If you don't have good caster the steering can go to opposite lock when you are going forward.  That could be a disaster.  But if you have good caster that doesn't happen.


Trailer lights need to be figured out, but that's usually pretty obvious.  The one thing I'll mention here is that if you only add lights at the back you might get the towed vehicle hit by some moron changing lanes at night when only 5' behind you.  Yes, people are that stupid.  So I'd suggest getting the front side marker lights to light up too.


The other thing I'll mention is one you already brought up, removing the driveshaft.  That isn't necessary on all vehicles, but a lot of transmissions and transfer cases are lubed by the input shaft turning.  If you put them in neutral the output will turn but not the input, so you can burn up bearings or wipe out gears.  Some are designed to be flat towed and have an oil pump driven by the output shaft or something.  But you need to know what you're dealing with.  And it's always safe to remove the driveshaft

Sorry, one more thing to add.  Assuming the alignment is good (especially the caster, which, as noted, needs to be good), the towed vehicle wants to go straight.  If it's close to the towing vehicle in weight, and especially if the towing vehicle doesn't have much weight on the rear tires, the towed vehicle can go straight when you are trying to turn, pushing the back end of your truck with it and jack-knifing you.  Being on the brakes, or on slippery surfaces makes this worse.  It usually works OK, but it is a "gotcha" to be aware of.  Trailers have much less tendency to do that because they don't track straight as strongly as a car or truck and they add tongue weight to the towing vehicle to help give it more traction.

Hey Bob!

Thanks for the information. I hadn't thought about the lack of brakes on the towed vehicle. Thanks for pointing that out.

My trailer does have brakes, and I haven't finished installing the trailer brake controller just yet.

With the points you bring up, seems that upgrading my trailer tires to be overkill for the job, and making sure I have good axle bearings might be the way to go here.

I think we are aiming for a regular cab long bed, but you never know what you will find. A 7K trailer is designed for 7000lbs INCLUDING the weight of the trailer.

Do we have a chart on here showing the various weights of the various configurations of our trucks?

A 2WD regular cab long bed IIRC was about 5000lbs? So, that right there is already starting to push the limits of my trailer's "rating".

Im an engineer, so I know there is a safety factor designed into these trailer. But how much I want to push that is the question.

I think its a great idea to get some F rated tires (~3,000lb rating per tire) and have that peace of mind.

The frame on this trailer is by far capable of handling a full sized supercab long bed. The axles and leaf springs are the next big weak link. Theses are Arched 3500lb axles with brakes. Would they fail if I had a 7000-8000lb truck on there? I doubt it. They might need bearings a lot sooner though.

Thoughts?

One other thing I haven't really though of until now. Tongue Weight.

So...lets say I put a 5000lb truck on this trailer. Lets say the trailer is 2000lbs. So I have a total of 7000lbs. About 20% of that 7000lbs (1400lbs) is resting on the trucks rear axle. So, I am only running a true 5600lbs on the trailer's axles.

So. Lets do some math

Lets say a Long bed Supercab 7.3/6.9 4x4 is 8000lbs.

8000lb+2000lb = 10,000lb

10,000lb * 20% = 2000lbs tongue weight.

10,000lbs - 2,000lbs = 8000lbs

So, I'd only be running an extra 1,000lbs on the axles. 1000/2 axles = 500lbs overweight per axle.

I'd say 500lbs overweight on a 3500lb axle with brakes and upgraded tires is nothing to worry about.

Thoughts? Maybe add a leaf on the spring pack or see if I should upgrade spring packs also?