Trailer Frames

A solid tiny house starts with a solid trailer.

If you can locate an inexpensive, high-quality used box or flatbed trailer, it will simplify things. In my previous build I was able to locate a solid 4' x 8' welded steel flatbed for $100, but you can't always get so lucky. A previously owned trailer is a snap to transfer and register tags to.

Many states (like Pennsylvania) have sucked up to the trailer build companies and will punish you for registering a new scratch-built or kit trailer in state – it can cost well over $150.00 to register a roll-your-own. Spending that kind of cash makes a homemade or kit trailer in PA less of a bargain, and means you either pay up like a sucker, or you register them out of state. I registered my trailer in Maine, and I will explain that process after we discuss the actual trailer assembly.

Harbor Freight has several different frames with different weight ratings. Since we are building a permanent enclosed box onto the frame, we need strength. The 4 x 8 super duty trailer kit is rated for nearly a full ton. It retails for $499.00, but you can catch them on sale for as little as 299.00, and if you are a regular customer you may be able to apply a 20% or 25% coupon to that price like I did.

There are two issues with the red trailers that you need to plan for and accept the need to fix.

First off, the factories that build these do NOT pack the bearings.

The HF assembly directions are explicit and state that the hubs must be cleaned and packed before use or the trailer will be out of warranty, and they are not joking; the hubs are NOT road-ready.

I am going to repeat this: THE BEARINGS ARE DRY.

The factories ship the hubs assembled, but with the cheapest Vaseline-colored assembly grease you can possibly imagine holding everything together. Inside that assembly goo you will see metal shavings, welder sputter, dirt and God only knows what else.

You cannot put those hubs onto an axle and just drive it off somewhere.

The forums are full of 30-mile first road trips ending in fires and all kinds of insanity because people did not follow the assembly directions, or do not understand that the hubs MUST be cleaned, and then properly packed with grease. This is not a complex subject, and there is a lot of good YouTube videos out there to explain the technique, but the basic system goes like this:

1) Clean bearings and hubs with laquer thinner and a stiff brush. Repeat. Get every bit of crap out.

2) Take a glob of good quality grease in your off-hand palm and hold the bearing in the other.

3) Press bearing edge into grease with a cutting motion, as if you were scraping the grease off of your hand. This will use a surprising amount of grease up.

4) Repeat this until grease works out the top of the bearing, then rotate bearing slightly and continue. Once the bearing is packed, fit it into the hub. There are two (2) bearings in each hub.

5) Clean the axle spline area carefully. Scrape off all welding sputter, and sand any rough area smooth where the bearing's rubber seal will touch. Dings and sharp edges are bad.

The second problem is much easier to deal with: do not trust the nylon insert lock nuts alone. Buy some Loctite red (permanent use) and use it on every single nut. Most of the frame will be inaccessible or damn hard to reach once the box is on the trailer. Discovering a loose nut halfway into your build will mean taking a lot of work apart. If you have a welder, good for you; weld that shit. But if you don't, Loctite every nut.

By way of example, I personally had one nut work loose on this trailer build.

The main locking nut fell out of the bottom of our coupler the third time I closed it over the tow ball. It hadn't occurred to me to Loctite that one since it was pre-assembled in the kit. 

Do not assume anything with the fasteners.

Next post we'll do some show and tell about the harbor freight deck build.



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Tags: HF Trailer, Packing Bearings, Insulating trailer beds, HF Trailers, Tiny house foundations, Trailer assembly, Harbor Freight Trailer,  DiY Trailer build, Tiny House on the cheap, DiY Trailer, Do it yourself trailer build, DiY Tiny House.