In the last two issues, we built a trailer to haul our race car. It was rather inexpensive at about $306 for everything but the wheels, axles, and tires. They came from under a mobile home at no cost other than crawling underneath to get them out. Even so, they are usually available cheap from mobile-home transporters. Since the trailer was originally built, I checked and the steel cost had risen to about $340. The steel and steel pricing came from Eagle National Steel LLC, Hutchens, Texas (www.eaglesteel.com).

One of the better things about mobile-home axles is that all the ones I've seen have a capacity of 6,000 pounds each. This gives the trailer an axle rating of 12,000 pounds--more than the weight of several race cars.

The downside is that you will be using 14 1/2-inch mobile-home wheels. A 14-inch tire won't go on, and a 15-inch tire will blow off and hurt you. However, I never purchase a 14 1/2-inch tire. I go to a mobile-home transporter and get a good tire already mounted on a wheel, usually for less than $25. There is one other option. A wide-five race car wheel bolt pattern is the same as the mobile-home hub. Check this out closely because the hub may need a bit of grinding to clear the wheel. There is something else that needs to be addressed here. I've heard from readers that mobile-home axles are not legal in some states. This may or may not be a myth; check your own state regulations. Don't just get the opinion of someone who thinks heknows--go to the state department of motor vehicles. In the states where I have been able to check and get what I feel to be accurate information, there is no problem using mobile-home axles on a trailer such as this.

When selecting axles, there are usually plenty of them available with electric brakes. If you choose to use store-bought trailer axles of 3,500-pound capacity, with brakes, springs, and hubs for automotive wheels, expect to spend about $550. The original trailer I built in Parts 1 and 2 now has about 6,000 miles on it and no problems have shown up. Still, there are a few things I need to share as an update.

There is certainly nothing wrong with using a store-bought hitch. I have at times, however, seen stamped sheetmetal hitches with a load rating that is too low for use on race car trailers. These are inadequate. A ductile iron/welded steel type with a side-clasp style hookup is much better. Hammer Blow and Bull Dog are two names that come to mind. Never use a hitch ball smaller than 2 inches; 2 5/16 inches is better.

I have found this type hitch to be strong and cheap. They have served me well for many years. With one of these hitches, I have been able to lift the rear of a tow vehicle off the ground with a jack under the trailer.

For years I have made my own hitch to attach to the trailer. More specifically, I have built six trailers using this hitch. First, I build a short square tube of 1/4-inch-thick, 3-inch steel angle. The length of this box should be the same as the width of the channel forming the tongue of the trailer. Trim the legs of the angle as necessary so that the steel angle forms a tube that fits almost snug around the hitch ball. You should have 1/64-1/32 inch clearance.

A square is welded inside the tube to keep the ball from going too far inside. Now the tube fits the hitch ball, but nothing keeps it from coming off--yet. Drill a hole (7/16 inch) through the tube. Locate it so it's against the rear wall of the tube. Place it at a height where it will allow a high-strength bolt to pass through the area of the ball's neck. I use a Chevy head bolt for this. Use a nut or drill a hole for a hairpin to retain the bolt. With the tube/ball socket completed, weld it to the tongue of the trailer. Doublers on the outside of the tube, which are also welded to the tongue, add strength to the attachment.