Davidss

So there has been some discussion on this forum before about the lack of commercially available lightweight trailers for small and light cars. I have decided to build my own and post up some info for anyone else looking to do the same.

Here is the basic design I am going with:


The main deck will be 13' long and 6' wide which will fit a Civic, CRX, Miata, and the S2000. I am going to use all box tubing for maximum strength and low weight, and leave the center of the trailer open. For axles I am going to use dual 2000lb torsion axles and tie them into the frame. Why dual axle? I could have easily gotten away with a single axle with a sub 1900lb car. But with a single axle I would have to use heavy duty trailer tires. With dual axle I can safely use much shorter car tires which mean shorter ramps, massively lower CG, and the ability to open the doors over the fenders.

So today I went and picked up most of the steel and tires:

I am going to build the main rectangular section of the trailer first and then attatch the tongue and axles later.

Then I needed to break in an engine so I took the CRX to pick up the wheels:

I think they are 13x4.5. I would have loved to find a nice set of lightweight aluminum wheels but the price of steel trailer wheels was too hard to pass up: 5 new wheels for $100 with tax!

The trailer supply store had a few different styles of wheels to choose from. I asked to go back into the warehouse so I could compare them and figure out which was lighter. They thought I was crazy...


12.4lbs is not too bad! From what I have seen 14's are considerably heavier but have much higher load capacities.

The next thing I need to figure out is decking. While aluminum would be nice I think I am going to go with steel that way I can weld it on which will add a ton of strength. Then make the decking super thin and brace (or double up) the 4 areas where the car will rest on.

So I would love some input on this. The two main sections of decking will be one foot wide. My car's maximum corner weight is only 600lbs. What thickness would be safe for the sections that will only be driven across in loading/unloading? What thickness would be safe for the sections that the car will actually ride upon?

VTECIntegra9

I would say use the a truss support like so under the wheel sections. One note about the steel (I assume you will use diamond plate) is that if at all wet.. it gets very very slippery, because you'll have to paint the steel to prevent the rust from starting.

My art skillz:
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Our old steel trailer needed a respray every year or two and replaced the boards that ran through the middle because they would rot out quickly and paint would flake off (you said you won't be covering the middle which is fine, but maybe a bit to bridge the gap at the front/rear of the car for easier load/unload.

Will you be welding the plate to the frame, correct?

Andy Hollis

Gee, that looks familiar.

Make sure and check those wheels for runout. I had a really hard time trying to find one that was straight when I had to replace one. Went through a bunch and none were straight when you spun them on a tire machine (or the axle).

You've seen my trailer, but for those that haven't...my decking is 1/8" aluminum diamond plate. Underneath, I have welded in steel cross braces made of angle or channel (whatever I had handy at the time) at each of the places where a tire would land from whatever car I was currently carrying. New car, new brace (which reminds me...).

Using the standard 2x rule of thumb, I'd bet you could easily go as thin as 1/16 steel. Maybe even less. The key is to attach it well to the rails. With steel on steel, you can weld, whereas mine are bolted and that's where it fatigues. Another material to consider is "expanded metal". Very light, very cheap. But I wouldn't put it where the tires sit as it will chew them up.

If using steel and painting, toss some sand into the mix to create traction spots. Or use some of that stick-on material.

How much were the axles? I am debating replacing one of mine.

dirty19

iTrader: (1)

Subscribed!

chuwi_pty

+1000

Root of all Evil

in too, I need a trailer for spring.

Gustav129

Nice I can't wait to see the finished product.

Do you have to only go through an inspection to register it?

Davidss

Ok I just ordered (2) 2000lb dexter brand torflex axles. I went with a 22.5 degree down start angle which should give me a pretty low deck height of around 15.75". I found another brand that had a cool adjustable ride height setup but the prices was more and I would have to pay for shipping. Here are the two styles:




One of the issues I have run into is brakes for 2000lb axles are expensive and harder to find. The far more common 10" brakes (typically under $100) won't fit only 7" brakes will work ($200). I tried to figure out a way to make the 10" brakes fit, the backing plates will bolt right up so it's just a matter of finding 1 odd size bearing. But I don't have time to reinvent the wheel so I ended up buying one axle with brakes and one idler. I can always add brakes to the other axle later but with a car/trailer that are this light I might never want to.

7 inch brakes look tiny!



$194 for a bare axle
$225 for an idler axle
$365 with brakes
Add $20 for EZ Lube

Is there a difference between EZ lube and Bearing Buddies?

I have no idea. I was planning on figuring that out later.

SCoupe 5sp

Yes, the steel will need to be coated. Rustoleum metal primer in that weird red color and then two coats of the Rustoleum Black paint and I'd highly recommend Rustoleum Truck Bed Liner Spary on the working surface of your trailer (nothing else is as durable, protective, grippy, tough, textured, just the way you want it!)

Also, you would do yourself a favor and factor straps into the master plan. The safest would be tire hold downs, possibly feed through a slit in the tire track to a ratchet mechanism or an E Track.

What about an electric wench?

The ultimate self created rig would be self tilting, drive on ramp style.

known

iTrader: (1)

awesome, good luck with this...interested to see how it comes out. I have a home-ade trailer I purchased not too long ago made out of steel weighing about 1200lbs/19ft long.

admassa

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VTECIntegra9

Since you are keeping weight as low as possible I assume you won't be adding a tire rack?

Btw electric winch and electric tongue lift is the way to go for the lazy-man... Best two items evar - can sit in the car and steer it into place without driving it, just holding the controller. And to tilt the trailer just a push of a toggle switch to go up/down.

These of course are all to be added on later once it's functional. And +2 on the bedliner I didnt think of that... wish we had that with the old open trailer!

ohsnapzafingcu

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SCoupe 5sp

You're both feet in the bucket already... but why dual axle on a lightweight trailer build to haul a lightweight car? Single axle can handle that.

Huge weight savings, lower rolling resistance, easier build, more maneuverable.

VTECIntegra9

Agreed. Ours was a single axle. Best part about a dual tho is if you have a blowout you can still make it to the next truck stop.

known

iTrader: (1)

Great point.

My small trailer I mentioned has 2 3500lb axles so its over kill but nice to know if I do have a blow out I should be ok until I pullover.

SMHero

dirty19

iTrader: (1)

13 inch wheels.. this will sit low enough and might not ever need a winch, plus he wants it to sit low anyway right?
Tilt bed might not be needed if it sits that low.
I agree with david in as much as you want a gripy surface on top, but why not consider painting the bottom with that POR stuff.
Make sure the rust dont start.

Davidss

Update! I got a killer deal on some 14ga steel diamond plate at the local metal yard. It was already cut up into a bunch of 4 foot by 14 inch pieces which are perfect for the decking. And as they were already cut up I got them for drop steel prices ($0.55 a pound!). I ended up buying every piece they had as I'm sure I can find uses for cheap diamond plate lying around the shop!



Also my secret weapon came in the mail:

You are looking at a 100 pack of roll cage gussets. These will add a TON of strength and weight almost nothing. I plan on using as many as I can! Total cost for all of them was only $35 shipped.

So now that I have all the parts I actually got to work today. I am going to build the outer rectangle of the deck first, then add the bracing, then attatch the tongue, and finally the decking and axles. I almost got through with the decking frame today (ran out of mig wire). In it's current state 2 people can still pick it up.


Gussets!!!


I have never built anything of this scale before so I was figuring things out as I went. I started by tacking up the outer rectangle. A great tip to quickly square the frame is to measure the distance from opposite corners (front left/back right and front right/back left), and get them to equal out using a ratchet strap.

I consider myself a decent welder but I'm not great at welding uphill/downhill/etc. So I just kept flipping the trailer frame over and on it's side to weld everything at my preffered orientation. With some careful planning in only took a few full rotations.

Here is a closeup of a typical weld. I learned mig on my own, so are these are good/bad?:


I also found a spreadsheet made to calculate tongue weight. It was designed for teardrop trailers but I modified it for car haulers. Here is the link:
https://docs.google.com/spreadsheet/...UJMWmxvZ0dsRVE
To edit it you will need to save a copy. If anyone knows of an easier way to host a spreadsheet that people can edit but can not save let me know. Also please note that the spreadsheet is setup for single axle. It will give you a good idea of a starting point of a dual axle just assume the tongue weight number it gives you is high.

Davidss

I'm going to use either rustoleum gallon paint or rustoleum bed liner. Both say they can be applied over bare metal.

We need to get Hollis back in here as he has the perfect strap setup!

No tire rack for now. I have consider making a detachable one using off the shelf hitch parts.

If it was just me I would totally go single axle. But my codriver and my wife (who also autocrosses) are both very anti-single axle.

Not knocking your trailer. But personally I am really against getting a bigger spring package than you need. With a light car/trailer a 7000lb total spring package is going to ride much worse than a 4000lb total package.

My calculations say that deck height will be a little over 16".

I have looked into POR before but it isn't cheap or easy to apply. And with rustoleum I can touch it up anytime anywhere with a perfectly paint matched rattle can!

90efhatch

Good stuff, subscribed.

q16racer

Scribed

NorCal_HC

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known

iTrader: (1)

nice progress!

Davidss

Didn't have much time to work on the trailer today. The axles came in so I went to pick them up. Disappointingly they are really heavy. The idler axle is 72lbs and the axle with brakes is 106lbs. The only positive is to all that weight is that torflex axles can be used as a stressed part of the chassis.

With a new spool of mig wire and a fresh bottle of gas I finished up on the gussets and built the tongue. With the frame skeleton finished my dad and I could still pretty easily pick the whole thing up. We estimated 200lbs or so: