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fifty New Reader
3/18/09 7:38 p.m.

I could use some forum wisdom.

I'd like to build a lightweight (max. 1200# - 1300#) tandem axle car hauler, like this one: http://www.econotrailer.com/

I'd actually buy this one, but I'm in Little Rock and the trailer's in Pennsylvania. The dirtbag in me also thinks I could build it cheaper, with drop axles to keep the center of gravity lower.

Anyhoo, I'm a competent welder, but need some help putting together some plans. Again, I'd like it as light as possible, but also sturdy. I've found a few plans online, was wondering if anyone else has ever done this? Specific info that would be helpful would be technical info like tubing sizes for the frame (eg. 3"x2", 2"x4" and what thickness), whether angle iron or channel would be a lighter alternatice than tubing etc etc.

Here's a plan I found online:

Toyman01 Reader
3/18/09 7:48 p.m.

Norther Tool has a good selection of trailer plans. I would give them a try.

Woody Dork
3/18/09 8:19 p.m.

I haven't built one, but here's a suggestion:

Check with your local powder coater. Find out how big their oven is. Design the trailer so that it can fit inside and have it coated when you're done.

fifty New Reader
3/18/09 8:30 p.m.
Toyman01 wrote: Norther Tool has a good selection of trailer plans. I would give them a try.

Thanks for the tip - I did look at the plans, but the trailers look a little beefier than what I had in mind. Weight is the issue: I'm only towing a 2000# vehicle.

MrJoshua SuperDork
3/18/09 8:41 p.m.

Buy some really long used aluminum ladders to use as tracks, Proper size aluminum channel for the end caps/tongue, enough diamond plate to cover the ladders, a couple of torsion drop axles that double as two of the cross rails, lots of giant rivets and a device to install them to hold it all together. Tadaa-ultralightweight trailer. Please do this, I really want to see if it works!

Toyman01 Reader
3/18/09 9:30 p.m.
MrJoshua wrote: Buy some really long used aluminum ladders to use as tracks, Proper size aluminum channel for the end caps/tongue, enough diamond plate to cover the ladders, a couple of torsion drop axles that double as two of the cross rails, lots of giant rivets and a device to install them to hold it all together. Tadaa-ultralightweight trailer. Please do this, I really want to see if it works!

I don't think I want to be behind him when he is testing it. Be sure to post pictures.

fifty New Reader
3/18/09 9:56 p.m.

thanks and no thanks :)

Here's another: http://forums.vwvortex.com/zerothread?id=4225375

Any disadvantages to using channel as opposed to rectangular tubing for this type of design?

DILYSI Dave SuperDork
3/18/09 9:56 p.m.

Tubing is lighter for it's strength than angle / channel.

Jensenman SuperDork
3/18/09 9:56 p.m.

i've done some digging for the same thing. I think I could build a 3500# capacity trailer that weighs ~ 1000# pretty easily.

A big weight saver: torsion axles. You lose all the weight of the springs etc. http://www.dexteraxle.com/torflex_axles It looks like the 10 degree start angle is the best compromise between low fender height and low deck height. The trick to mounting them is to use a tube through the side members so that bolts won't crush the tubing. I'm not sure I'd weld them, the mounts are too close to the rubber torsion members for my comfort zone. Use 13" wheels, 4 of the D rated tires will handle 5200 pounds.

The C channel most trailers are made of is super heavy stuff. If you aren't afraid to fab some, use 3x2 x .120 wall rectangular tubing. The fab part comes from the tongue; just like in your frame picture it would need to be a triangle, not a single 'neck' and start under the main frame, not cantilevered off the front. Use 3x2 x .120 angle for the cross braces and also to stiffen the inside of the decking. If you use a single 8-12" wide piece of .120 diamond tread decking across the front and the rear you add tremendously to the stiffness without adding a lot of weight.

Northern Tool and other places sell diamond tread aluminum fenders, another weight saver. Ramps can be stinkin' heavy, make them of 2x2x .120 angle rectangular boxes with 1 center crossmember and use the .120 decking on the top. You could get aluminum ramps but they are pricey in car weight capacities.

Most trailers I see have way too thick angle steel (it's cheap!) for the ramp carriers. I'd go with something around 16 gauge angle, that should save another 20 pounds or so and be more than strong enough.

If I ever do get the time to build a trailer like I describe, it will have an aluminum toolbox across the tongue and the space between the treads will have expanded mesh metal so I can walk from side to side without killing myself.

Naw, I haven't considered this at all.

MrJoshua SuperDork
3/18/09 10:04 p.m.


billy3esq Dork
3/18/09 10:11 p.m.

A guy I see at the track from time to time (who's probably in his late-40s/early-50s) drags a Spec Miata behind a Ranger on a trailer he built when he was a teenager for a sprint car. (It's held up for a while.)

The trailer has I-beam for the runners, a 4-6" steel pipe for a spine, with about 3" angle iron tying the runners together and to the spine. It sits on a single torsion axle (around 5k lb). The ramps are hinged off the back of the runners, and are made from gusseted sheet steel. I don't remember how the tongue is made, but I think it's just 3" pipe that picks up from the front of the runners and the spine.

On the front it has a rack made from 1-1/4" or so square tubing that serves as a tire rack and a mount for a truck tool box. The tool box sits over the hood of the Miata. He has an electric winch to drag the car up on the trailer because once it's on the trailer the doors won't clear the fenders.

IIRC, he told me he thought it weighed around 1200 lbs, including the toolbox, winch, and battery. He certainly seemed to have no trouble towing it with a 6-cyl Ranger.

BTW, J-man, you should build two according to your plan. If you'll do the welding for both, I'll pay for the steel for both. Heck, I might even come out to help you and maybe learn something. I assume you'll want me to sign some sort of waiver/disclaimer.

fifty New Reader
3/18/09 10:13 p.m.

Thanks Jensenman, that's exactly the information I was looking for.

I'll add a picture and discussion from Honda Tech on the merits of single -vs- tandem axle: http://www.honda-tech.com/showthread.php?t=2334128&highlight=trailer

My single axle trailer tows far better than the double axle trailer it replaced. I built the single axle trailer myself, so I made it light and low. Before, I had a normal double axle car hauller that weighed 1800lbs and had a deck height of around 18". My trailer weighs about 800lbs and has a deck height of about 10". Lowering the CG height of the car by 8+ inches is a huge benefit in handling. I have used this single axle trailer for over 10yrs now, and it probably has at least 50k miles by now.

Pros for the single axle - lighter - less rolling resistance - easier to turn - less likely to get a flat (1st tire kicks nail up, 2nd tire runs it over on dual axle) - less stress on bearings from low speed cornering (scrub)

Cons for single axle -not sure how it would handle with a flat, but I doubt it would be a problem. -must carry a spare tire -placement of load is more critical, but once you get it right it isn't any big deal


2008 E Prepared National Champion

AND... http://honda-tech.com/showthread.php?t=2275326

oldopelguy HalfDork
3/19/09 4:56 a.m.

The green trailer I sold one of the guys on here was a fully decked single axle sporting a single 6k lb axle with trailer brakes. It is way overbuilt for what it is, hauls even decent-sized cars with ease, and only weighs 1400#. For a light car and light trailer I'd go single axle every time.

My current big trailer is built out of a pair of main front-to-back runners of 2x3" tubing separated by as much as I could and still open the door of the lowest car we've got (lowered C5 Vette) and I used 3/16" wall for the lower tubes and 1/8" wall for the upper. Seems plenty strong, but I find the 1/8" wall tubing dents easier than I would like. For a smaller single axle I'd go with a pair of 3/16" wall 2x2 tubes, one on top and one underneath the cross bars. Way stronger than you'll ever need and still plenty light.

So, assuming your local metal supplier stocks 24' sticks, I'd get 4 of them, 2 cut in half to 12' and two cut into 6' quarters. Lay out the bottom pair of 12' rails, lay 6 of the braces across with equal spacing, single torsion axle replacing the 4th back brace from the front so they are on 2' centers, then toss the second set of front to back rails on top. Then lay the last two 6' chunks out to be the tongue at an angle attached to the bottom of the cross braces and tied in to where the second brace meets the main rails. Clamp it all together and make it square, space the cross braces up to the bottom of the top rail with whatever you need to make up for the thickness of the torsion axle, then weld away.

At 4.5 lbs per foot that's 450lb for the steel, add another 150 for a torsion axle, coupler, and lights, then maybe 50 for 6 12' 5/4x6" decking boards and you're at 650lb plus tires and fenders. Easy to be under 800lb total, even with trailer brakes.

914Driver Dork
3/19/09 6:16 a.m.

My plan is to take a pickup and cut the frame behind the cab, or a FWD car and build a similar trailer but with no tongue. The frame rails of the trailer will be welded to the back, a continuation of the original line.

A question about the torsion type suspension, what dampens rebound or is it necessary?


Jensenman SuperDork
3/19/09 6:30 a.m.

billy3esq, if you bring the beer and sign the waiver in blood we gotta deal.

Steel weight differences: 2x3x.313 C channel is 7.12 lb/ft, 3x2x.120 rectangle is 3.89 lb/ft, 3x2x.187 angle is 3.07 lb/ft. I had a seriously tough homemade trailer which was made from a pair of mobile home axles which had no suspension. That one had been made from angle with the 'leg' pointed up and then it had .120 diamond plate welded to that. It was tough and didn't flex, but the 'runners' collected and held rain water which made the diamond plate steel rust out.

Dexter's site doesn't go into detail about dampening. Just about every conventional spring trailer I have seen (including mine) runs without shocks and so far I haven't seen a problem. It would be pretty simple to add shocks if required.

About single vs tandem axle: last year I had a blowout on my tandem trailer at highway speed. The other axle took the load so smoothly that I didn't even know it happened until I saw the white center of the painted rim in my mirror (the tire had shredded). Maybe I's jus' not real observant. Anyway, that told me that tandem > single axle, way easier to control if something bad happens.

I priced the Torflex axles here in town, with electric brakes they were ~ $300 each, in line with conventional spring setups. BTW: it appears the DOT requires brakes on both axles, which may or may not be important. I want the top of my fenders to be a max of 9" above the deck, that way just about anything can be loaded and tied down and the doors will still open. That's where the 10 degree start angle and 13" tires come in.

alfadriver Reader
3/19/09 7:06 a.m.

If you can find someone with a HUGE metal brake, I can make some detailed measurements of my trialer. It's mostly aluminum with a steel tounge/small front structure, dual torsion axles (great suggestion Jensen), and small aluminum ramps.

Total weight- just over 700lb (it was weighed prior to shipping in a bundle, with everything), and it's rated at 3000lb. A friend has a different version with a slightly different tounge design, and it's rated at 3500lb.

SUPER easy to pull.

Some of you saw it in 2002, 03, and 04 in Florida, and there were quite a few comments about it.

Basically, all of the strenth is in the 2 1/4" aluminum bent channels.


stumpmj Dork
3/19/09 7:47 a.m.

I've seen alfa driver's trailer in person. It is VERY nice.

rl48mini New Reader
3/19/09 8:30 a.m.

Any pictures?

SVreX SuperDork
3/19/09 12:49 p.m.
MrJoshua wrote: Wimps!

If it means anything to you, I know of a contractor who in his younger more foolish days was known to use laders with boards laying on them as scaffolding walkboards- often times in excess of 40' in the air spanning over 25'!

He weighed a lot less then, too!

Jensenman SuperDork
3/19/09 1:05 p.m.

There's a saying: 'there are old pilots, there are bold pilots, but there are very few old, bold pilots.'

oldopelguy HalfDork
3/19/09 1:15 p.m.

Oh, and for decking, not that I'm advocating anything, but a 20' uhaul truck loading ramp makes two lightweight and strong 10' car trailer runners. Just saying....

billy3esq Dork
3/19/09 2:54 p.m.
Jensenman wrote: billy3esq, if you bring the beer and sign the waiver in blood we gotta deal.

How 'bout I bring good beer, but use someone else's blood?

Jensenman SuperDork
3/19/09 2:58 p.m.

I'm not sure just where that is going...

billy3esq Dork
3/19/09 3:02 p.m.

I just don't want to be the one who ends up bleeding.

N Sperlo
N Sperlo PowerDork
8/10/12 11:14 a.m.

In reply to fifty:

Did you ever go through with building the trailer?

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