School me on trailers

School me on trailers a bit. I've got a 4x8 utility and have experience with small boat trailers, but actual car and equipment hauling trailers are a new world for me.

I'm not buying now, or maybe even not at all, but I'm trying to find out what I should buy if the time ever comes.

For me, its primary job would be towing a machine around 5,000 pounds fully loaded. I'm ASSUMING a trailer that could handle that would be able to handle a car or truck every now and then, correct?

I would want brakes, but I know nothing about them other than there are surge brakes and electric ones. Can they be added aftermarket? Is one setup better than the other?

Let's assume the tow vehicle will be from the 2000s. My ranger claims a 5500lb towing limit, I suspect if I went this way I'd be upgrading, would F150/Chevy 1500 with v8 and tow package be big enough or would I need to go bigger? I would be changing vehicles anyway because I don't trust me to tow with a clutch.

Is it worth going overkill on the trailer? $2500 cash seems to buy anything from a motorcycle trailer to a 10k+lb 5th wheel hauler that needs a little work. I don't want 5th wheel just mentioning it as the extreme end of what I've seen in that price range.  But say the machine I want is 12ft long and 6 or so wide in towing mode, would it be dumb to get a 18-20+ foot long one instead of something more "form fitting"? Where is the point of diminishing returns as far as weight capacity versus weight of trailer?

For the tow vehicle, if it's rated beyond my combined load, would it still be worth upgrading to a weight distribution hitch? All I know about them is that they exist. Can a regular hitch be modified into a distribution hitch?

I think that's all my questions for now.

Whatever trailer you decide on will be too small the minute after you buy it.  Seriously though, figure out what you think you will use it for and get the appropriate size right off the bat. I started with an 18' open trailer with tandem 3500# axles with electric brakes. I towed an RX7 with a 1/2 ton Suburban and it was a breeze. I had all sorts of different things on that trailer, a broken down Suburban, pallets of pellets, scrap metal and a friend now uses it for his Fox body Mustang and tows with a Colorado. If you are going for small excavating equipment you will likely need something beefier and a big truck. If just cars and small stuff a 1/2 ton with a tow package should be sufficient. I upgraded to a 20' enclosed trailer a couple of years ago and still use the Suburban but it works hard on the hills. If you want to haul bigger loads go with a 3/4 ton tow pig, you will be happier especially if you live near mountains. And definitely get brakes on all the axles/wheels, you will thank me after your first panic stop. Hope this helps

First... don't listen to tow ratings.  Some are accurate, some are complete BS.  The Ranger tow rating is probably pretty close to accurate, but you'll notice a good bit of tail wagging the dog.  Tow ratings are a nice suggested guideline.  I frequently tow 3500 with my 94 Ranger/B-series and it does very well aside from being underpowered.  I would not two my double-axle trailer with a car on it though.  That would just be too much.

Half-ton truck would be fantastic.  If you were just occassionally towing a car on the trailer - as in, oh crap, I need to get this thing to the shop down the street - Ranger will be fine.  The more often and further distance you tow, you want more truck to tow it.  Maxing out the tow buggy's capacity means white-knuckle driving and it gets incredibly fatiguing.

You definitely will need a double axle trailer... primarily because they will be 3500-lb axles each, but also because more rubber on the road means more stability.  Doubles are pretty much a bare minimum in your weight range unless  you have a really beefy axle and a stripped-down, tin-can race car.  Brakes are a good idea.  As far as brake controller (if you don't get a truck with one already built-in) the Tekonsha Voyager is the Cadillac of brake controllers.  They aren't expensive, either.

As far as weight distro- Depends on a lot of factors.  I stopped using distributing hitches when I tow my 9k lb travel trailer with the dually.  The Class 5 hitch can take it, and the truck is glorious overkill.  I used to tow 10k with a 3/4 ton truck, and I definitely used distro.

A regular hitch can't be modified into a distro hitch.  There are a few proprietary designs and all the parts work together as a system.  You can usually find some used ones on CL for not a ton of money... but 

For a beginner user, I suggest getting the trunnion style distro instead of the tubular style.  The Trunnion style is a bit more forgiving of going too tight while you figure out how much weight to torque onto those bars.

You can google how to set up the distro hitch and there are tons of videos.  Most of them show the "correct" way to do it which takes three moon cycles and a fortnight, but after a while you'll get the feel of it... not only how it feels as you're installing it, but how the vehicle feels as you drive it.

Well to be a little more specific, I'm really looking hard at an RK24 sub compact utility tractor. With front end loader, backhoe, and all fluids looking like just shy of 4000lbs, and 14 feet end to end. That, in my opinion, means 16 foot minimum trailer length and 7-10k pound capacity, but I didn't know how off I was with that guess or if I could go wrong by going bigger.

From what I've seen shopping used trailers on and off the past couple years, I might as well spend the extra couple hundred bucks and just buy new unless I really find a right place right time situation. I rarely have cash on hand when a deal comes around though. 

It would, hopefully, see use a few days a week so that it would pay for itself, but that also means reliability and ease of maintenance take priority over most other features. 

There will have to be a tow vehicle purchase though, that is my current bottleneck. I wouldn't mind the hour drive home under the speed limit in the ranger because it's mostly flat, actually taking it to places to work and use it though? Definitely want an upgrade for the hills around here. 

So electric brakes over surge, on one axle or both?

In reply to RevRico :

Trailers are all about space, everything else falls down the list of priorities.  

Too much trailer takes up too much space.  Too little trailer doesn’t have enough space.  It won’t do what you need it to do.

 Too much  trailer requires too much truck ( or other tow vehicle)  which in turn needs too much space to park, to store. To turn around in.  To deal with.  

Plus more people will want to borrow it and your tow vehicle.   People will bend and break, damage and cause problems.   Not return it on schedule or clean or some other issue which will cost you a friend or problems with family member.  

A perfect trailer will only work for your use.  Not the use of others. Maybe require a 10 inch ball or a 27 pin connection.  But you know a secret trick to make it work behind. any tow vehicle. 

Here are my 2 cents.

• For me, its primary job would be towing a machine around 5,000 pounds fully loaded. I'm ASSUMING a trailer that could handle that would be able to handle a car or truck every now and then, correct?

Yes it would handle it.  If you get a flat trailer it makes hauling cars much easier.  If you get a "landscape" trailer (some people call them "utility") it has angle iron around the perimeter about a foot off the deck.  This makes cars a pain sometimes.  It usually seems landscape trailers are a little narrower.

Something like this may work great for a tractor, but may be a pain hauling the latest project car from GRM classifieds

• I would want brakes, but I know nothing about them other than there are surge brakes and electric ones. Can they be added aftermarket? Is one setup better than the other?

I have always had electric.  They are cheap, easy to fix, reliable, ands its easy enough to add a controller to any vehicle.  Get a good one.  I am spoiled by the factory integrated controller on our RAM now, but the Prodigy was very good to us for a long time.  The current model appears to be called a P2.  Etrailer is your friend for service parts.

Make sure to get brakes on both axles.  most states require it anyway but some dealers will sell "economy" models with 1 axle brakes.  

• Let's assume the tow vehicle will be from the 2000s. My ranger claims a 5500lb towing limit, I suspect if I went this way I'd be upgrading, would F150/Chevy 1500 with v8 and tow package be big enough or would I need to go bigger? I would be changing vehicles anyway because I don't trust me to tow with a clutch.

Ive towed horses with a Cherokee that was technically within its weight range when I was younger but I wouldn't do it now.  Its nice to have some wheelbase and weight in a tow rig.  A half ton will do what you want no problem.  Go to any racetrack and you will see lots of open trailers behind half tons.

You can tow anything with anything if you are brave or creative enough.

• Is it worth going overkill on the trailer?

Yes.  Always Yes. 

• $2500 cash seems to buy anything from a motorcycle trailer to a 10k+lb 5th wheel hauler that needs a little work. I don't want 5th wheel just mentioning it as the extreme end of what I've seen in that price range.  But say the machine I want is 12ft long and 6 or so wide in towing mode, would it be dumb to get a 18-20+ foot long one instead of something more "form fitting"? Where is the point of diminishing returns as far as weight capacity versus weight of trailer?

$2500 will easily get you a nice basic 18ft car hauler with a wood deck, 2 3500lb axles with brakes.   18 feet gives you a lot of flexibility in loading and positioning weight.   Keep it in good shape and it will always be worth what you paid.  That's what I would buy based on what you have said.    Its what I used to have before we upgraded to an enclosed trailer (that's a whole other debate...).  I added lots of extra tie downs to mine.  Easy enough to weld them on.  Trailers almost never come with spare tires at the lower price points.  I always carry 2.  It has bailed me out more than once.

The best trailer deals seem to be in Michigan or Georgia.  Going to either location should save you some money compared to PA.  I suggest buying new.  The two times I bought trailers that only needed "a little work", I would have been ahead to buy new.  

In reply to logdog :

The trouble with electric brakes is you are pretty well stuck to one tow vehicle.  If that breaks or is being used etc  a replacement will be needed. Even if the replacement has a controller chances are very good it’s wired differently. (unless you like to rewire connectors ).  Or don’t really need brakes.  ( you do but when you’re out of options you do what you have to do).  

Surge brakes work on anything with the right sized ball, and 90% of all 4 pin connectors are wired the same.  So it’s a much better chance of hookup and go.  

As for wood decking,  That’s just fine if the trailer is new, or stored inside out of the weather, or in the dry southwest, or they don’t use white oak planks to prevent rot.  ( and regular steel bolts)  

I've used several tow vehicles with electric trailer brakes, and haven't had any issues with incorrect wiring, so you aren't stuck to one vehicle. If someone wired the truck incorrectly (differently), then the trailer would have to be wired incorrectly to match that truck. Then that would be a problem. Trailer wiring is standarized, so unless someone screwed it up, there shouldn't be a problem.

To the OP, having used both surge and electric brakes, I will take electric every time. Just work better in my opinion.

Used trailers tend to hold their value pretty well. Check the cost for a set of tires, brakes, and bearings. When I was looking, every used trailer + maintenance was more than the cost of the same trailer new. 

In reply to tomtomgt356 :

You’re right.  Used often means used up! Trailers are usually sold when they are no longer needed, not because a new model comes out that offers a good deal.  

The ironic thing is when I shut down production, good used ones sold for 80% of my selling cost years afterwards.  

When I had my trailer mfg company, ignoring the cost of tools, equipment, jigs, molds, and shop space.  Even with volume discounts wheels, suspension, brakes etc. cost so much my profit per hour was a few dollars.  

Now true as a start up company I never approached the high volume discounts my competitors  got, plus shipping efficiencies, etc.  

One of my customers when I sold equipment was Featerlite, and it shocked me how little they paid for stuff compared to what I did with my low volume.  

Useful discussion. I would like to broaden the topic a bit.

There's three options for steel open trailers: full wooden deck, full steel deck, and open deck. 

Compare and contrast. 

I never had a surge brake that worked correctly.  Ever.  They are very difficult to set up to provide proportional braking over the range of potential tow vehicles.  For that reason 99% of them out there are set up for emergency braking only.  You really have to stomp the pedal to get the surge to work, meaning you are relying on the tow vehicle's brakes to do nearly all the braking.

Plus, unless you keep it dry you have the same issues as vehicle brakes; rusted lines, dry-rotted hoses, water absorption.

Then, every time you try to back the trailer up, the brakes lock themselves unless you get out and put the lock pin in to deactivate the surge function.

Just my opinion, but every trailer I've had with surge brakes I have converted to electric.  I detest surge brakes with a passion.

As far as decking, I personally prefer a wood deck.  Easy and cheap to replace if it rots (but with PT lumber, that likely won't happen for 15+ years.).  Steel decks tend to be noisy, and if they dent or rust it is neither cheap nor easy to replace.  Open deck never appealed to me.  They are a tad bit lighter, but they are single-purpose.  Even if right now all you think you will ever transport is one car or one tractor, it will be about a week until you kick yourself and say "dangit, if only I had a full deck I could haul that [insert a non-wheeled item]

To me, the best is a true flat-deck with no permanent sides, but stake pockets so I have the option of putting sides on.  I have an 18' flat deck (wood, 7000 gvw) which will transport any of my tractors, vehicles, etc.  I can stab some sidewalls in it and lay a tarp (if I want) and carry mulch, dirt, sand, gravel, firewood, and other loose things.  It really is a lovely utility to have.  Removable sides are also really nice when you buy something on a pallet and it can be loaded or unloaded with a forklift

Mine has two ramps that slide in a pocket under the deck.  On the subject of ramps, I do like the ones that are attached to the tail and fold down, but it can cramp the deck space.  It's a trade off.  When I had my 66 Bonneville on the trailer, the ramps wouldn't fold up very high without hitting the bumper.  Detachable ramps = more hangover ability for longer cargo, but also = lugging and storing heavy steel ramps.

I'm also not a fan of beavertails.  Some people love them because ramp, but to me, a good flatbed with good ramps solves that issue without wasting deck space with a beavertail.  You are effectively removing that length from use for some cargo.

I don't have a picture of mine so I stole this from the intarwebs, but mine is like this... but with detachable ramps instead of fold-up ramps.  I love it.  I use it at least once a month; tractors, mulch, firewood, cars, set pieces for the theater, moving friends, whatever.

I used to tow it with an HD F150 (the half-ton that has 7-lugs, and the driveline/suspension/brakes from an F250).  I sold that truck because it rusted to heck and now I have a Ranger/B-series.  It will tow it just fine, but I have to carefully choose what goes on it.  It won't do a car or a large tractor, but I also have access to both of Dad's Duramax trucks.

Floating Doc said:

Useful discussion. I would like to broaden the topic a bit.

There's three options for steel open trailers: full wooden deck, full steel deck, and open deck. 

Compare and contrast. 

When you're at the track, an open deck can double as a four post lift  

In Germany you need a hand brake on your trailer so it does not roll away , 

Good idea but i have not seen it used in the USA.

californiamilleghia said:

In Germany you need a hand brake on your trailer so it does not roll away , 

Good idea but i have not seen it used in the USA.

This exactly.  I have owned a dozen travel trailers and 5th wheels as well as another dozen utility trailers.  Why don't they have a handbrake?  You have to chock the wheels, and not only is that a PITA, they don't do a good job.

I can imagine that frozen/rusted pads/shoes might become an issue, but how friggin easy would it be to park and yank a handle before unhitching?

Keith Tanner said:

Floating Doc said:

Useful discussion. I would like to broaden the topic a bit.

There's three options for steel open trailers: full wooden deck, full steel deck, and open deck. 

Compare and contrast. 

When you're at the track, an open deck can double as a four post lift  

I don't think my manly beer gut would fit under my trailer.

Curtis said:

As far as decking, I personally prefer a wood deck.  Easy and cheap to replace if it rots (but with PT lumber, that likely won't happen for 15+ years.).  Steel decks tend to be noisy, and if they dent or rust it is neither cheap nor easy to replace.  Open deck never appealed to me.  They are a tad bit lighter, but they are single-purpose.  Even if right now all you think you will ever transport is one car or one tractor, it will be about a week until you kick yourself and say "dangit, if only I had a full deck I could haul that [insert a non-wheeled item]

To me, the best is a true flat-deck with no permanent sides, but stake pockets so I have the option of putting sides on.  I have an 18' flat deck (wood, 7000 gvw) which will transport any of my tractors, vehicles, etc.  I can stab some sidewalls in it and lay a tarp (if I want) and carry mulch, dirt, sand, gravel, firewood, and other loose things.  It really is a lovely utility to have.  Removable sides are also really nice when you buy something on a pallet and it can be loaded or unloaded with a forklift

Mine has two ramps that slide in a pocket under the deck.  On the subject of ramps, I do like the ones that are attached to the tail and fold down, but it can cramp the deck space.  It's a trade off.  When I had my 66 Bonneville on the trailer, the ramps wouldn't fold up very high without hitting the bumper.  Detachable ramps = more hangover ability for longer cargo, but also = lugging and storing heavy steel ramps.

I'm also not a fan of beavertails.  Some people love them because ramp, but to me, a good flatbed with good ramps solves that issue without wasting deck space with a beavertail.  You are effectively removing that length from use for some cargo.

I don't have a picture of mine so I stole this from the intarwebs, but mine is like this... but with detachable ramps instead of fold-up ramps.  I love it.  I use it at least once a month; tractors, mulch, firewood, cars, set pieces for the theater, moving friends, whatever.

I used to tow it with an HD F150 (the half-ton that has 7-lugs, and the driveline/suspension/brakes from an F250).  I sold that truck because it rusted to heck and now I have a Ranger/B-series.  It will tow it just fine, but I have to carefully choose what goes on it.  It won't do a car or a large tractor, but I also have access to both of Dad's Duramax trucks.

Wood rots. Pressure treated rots around the bolts if you use regular bolts.  ( interaction between the preservative and steel every time the trailer is rained on. 

Against that stuff slides on metal a lot easier than on wood.  That’s both good and bad.  Easier to drag a dead car on a metal deck but really adds to the strapping requirement.  

if your surge brakes require “ stomping” on the brakes to activate you failed to grease the slider.  Properly lubricated sliders work beautifully.  Since trailers often sit outside until they are used, sometimes for years, I  believe in bearing buddies.  Pump a little grease in   Each wheel and a stroke or two to the slide activating the surge brakes.  You’ll never have bearings fail on you again.  You do a walk around don’t you when you hook up?  Check the tires, make sure the trailer lights are working,  fenders aren’t rubbing, load properly secured?  

As far as backing up?  Yes you can use a simple pin, or fit the trailer with a line lock activated by the back up lights if you’d rather not get out.  

Anecdotal data point: my friend's wood deck open trailer got a new deck when he got it 10+ years ago. Sold it earlier this year and it was just getting to the point where he was considering re-decking it if he kept it. But realistically had at least another year or two before it NEEDED it. It lived the vast majority of its life outside and was towed through all kinds of weather: rain, snow, hot, cold, and coated in mud at least a few times. I've only used a steel (well, aluminum) deck trailer once. It was fine but we ended up needing a rolling start at getting the car on because walking it up slowly it would just start doing a burnout halfway up (rwd car being loaded on backwards) which was a little sketchy with only like 3" of clearance to the fenders on either side.

frenchyd said:

Curtis said:

As far as decking, I personally prefer a wood deck.  Easy and cheap to replace if it rots (but with PT lumber, that likely won't happen for 15+ years.).  Steel decks tend to be noisy, and if they dent or rust it is neither cheap nor easy to replace.  Open deck never appealed to me.  They are a tad bit lighter, but they are single-purpose.  Even if right now all you think you will ever transport is one car or one tractor, it will be about a week until you kick yourself and say "dangit, if only I had a full deck I could haul that [insert a non-wheeled item]

To me, the best is a true flat-deck with no permanent sides, but stake pockets so I have the option of putting sides on.  I have an 18' flat deck (wood, 7000 gvw) which will transport any of my tractors, vehicles, etc.  I can stab some sidewalls in it and lay a tarp (if I want) and carry mulch, dirt, sand, gravel, firewood, and other loose things.  It really is a lovely utility to have.  Removable sides are also really nice when you buy something on a pallet and it can be loaded or unloaded with a forklift

Mine has two ramps that slide in a pocket under the deck.  On the subject of ramps, I do like the ones that are attached to the tail and fold down, but it can cramp the deck space.  It's a trade off.  When I had my 66 Bonneville on the trailer, the ramps wouldn't fold up very high without hitting the bumper.  Detachable ramps = more hangover ability for longer cargo, but also = lugging and storing heavy steel ramps.

I'm also not a fan of beavertails.  Some people love them because ramp, but to me, a good flatbed with good ramps solves that issue without wasting deck space with a beavertail.  You are effectively removing that length from use for some cargo.

I don't have a picture of mine so I stole this from the intarwebs, but mine is like this... but with detachable ramps instead of fold-up ramps.  I love it.  I use it at least once a month; tractors, mulch, firewood, cars, set pieces for the theater, moving friends, whatever.

I used to tow it with an HD F150 (the half-ton that has 7-lugs, and the driveline/suspension/brakes from an F250).  I sold that truck because it rusted to heck and now I have a Ranger/B-series.  It will tow it just fine, but I have to carefully choose what goes on it.  It won't do a car or a large tractor, but I also have access to both of Dad's Duramax trucks.

Wood rots. Pressure treated rots around the bolts if you use regular bolts.  ( interaction between the preservative and steel every time the trailer is rained on. 

Against that stuff slides on metal a lot easier than on wood.  That’s both good and bad.  Easier to drag a dead car on a metal deck but really adds to the strapping requirement.  

if your surge brakes require “ stomping” on the brakes to activate you failed to grease the slider.  Properly lubricated sliders work beautifully.  Since trailers often sit outside until they are used, sometimes for years, I  believe in bearing buddies.  Pump a little grease in   Each wheel and a stroke or two to the slide activating the surge brakes.  You’ll never have bearings fail on you again.  You do a walk around don’t you when you hook up?  Check the tires, make sure the trailer lights are working,  fenders aren’t rubbing, load properly secured?  

As far as backing up?  Yes you can use a simple pin, or fit the trailer with a line lock activated by the back up lights if you’d rather not get out.  

I would much rather replace a wood deck every 15 years than a steel deck every 20.  Never had a bolt rust or corrode because of the PT.  Old PT treated with Arsenic would eat steel.  New stuff treated with the copper stuff doesn't.  The deck on my trailer lasted 22 years, and it never spent a day inside in its life.  I replaced it in an afternoon for $100.  I do agree with your "dead car" comment.  I have purchased many a heap of junk in my day.  Steel would have been nice.

I have to completely disagree on the surge brakes.  It has nothing to do with sliders being greased.  There are massive differences in lever lengths, spring rates, master cylinder sizes, wheel cylinder sizes...  Saying that all surge brakes work the same if they're lubed is like saying a Miata master cylinder will work fine with a brake pedal from a Dodge Ram, all fitted into a Semi.  Surge brakes represent  maximum complexity and they work great IF they're setup for your rig, IF your reverse light connection works to the solenoid, IF the components don't rust, IF the hoses don't blow.... I understand they are your preference, but I will pay really good money to buy electric brakes to retrofit a surge-brake trailer.  Electric brakes are a potentiometer, a single wire, and magnets.  Simple, effective, adjustable, bulletproof.  There is a reason they are the industry standard.  Surge brakes were a big thing in the 60s when you had a 23-amp generator under the hood and before electric brakes were really figured out by modern electronic controls.  Ever rent a U-haul with surge brakes?  They are set up with short levers and stiff springs so they specifically don't engage except under panic braking.  They do this to save their brakes, but still cover their asses.  Then if you switch tow vehicles, you may need less or more braking from the trailer which can't be done with surge brakes.  On electric brakes, you turn a dial.  The other BIG reason I like electric brakes is that they can be actuated independently of the vehicle.  Fishtailing has happened to me before.  One little application of electric brakes cures it.  If you touch the vehicle service brakes during fishtailing, you'll likely end up upside down in a ditch.

Not knocking your choice... they obviously work for you, but from an engineering standpoint they are just a less user friendly choice.  Great when they work properly... which is almost never.

In reply to Curtis :

Well, respectfully I guess we will just have to disagree.  

That doesn’t make you wrong, just that since my first car trailer in 1970, every electric brakes trailer I’ve used has had terrible brakes that I couldn’t get fixed in time to make the race.  Surge brakes mostly have worked.  

When I was selling my own trailers not a single customer opted for electric brakes except the triple axle  28 foot trailer.  The owner of that loaded his trailer tail heavy and counted on the trailer brakes to stop him swaying. A few years later He lost control and totaled it.  

My trailer was purchased in late 1995. It's an open, steel deck model. It has sat outdoors ever since, through Ontario and Michigan winters. It does need new fenders and a coat of paint. It has surge brakes that work just fine as long as I adjust them occasionally. Where they do create an issue is if you set them for a 2500 lb car and then double the load.  With proper maintenance surge brakes don't bother me at all. It's also the only trailer I've owned , so I may not know what I'm missing with electric brakes. 

Note that surge brakes are not legal on all trailers used for interstate commerce. They are not allowed on any vehicle that has a trailer:truck GVWR ratio of 1.75 or higher. If your trailer has a pair of 5000 lb axles, you will need a tow vehicle with a GVWR of just over 5700 lbs.  

Yes, that doesn't apply to random guys running around with their own stuff, but like the hours of service regulations the FMCSA regs are a good guide to follow. Personally, I've never had a problem with electric brakes on my trailers but I also keep on top of maintenance.

I've personally owned two trailers and have spent a lot of time with two others - including "my" trailer at FM, which has basically been my baby since new. One minimalist open, three enclosed. I only use them for dragging cars around, not for something to live in at the track. I tend to go for the smallest I can use, because they're the easiest to work with. A 16' trailer will fit the same Miata as a 24', but is easier to move around. A 28' trailer will fit two Miatas and feels significantly bigger. This does limit your ability to pick up random stuff, but that's what rental agencies are for!

The minimalist one was originally built for a sandrail back in the 70's. Fastest, easiest loading trailer you've ever seen. Towed like it wasn't there. Perfect for my 1200 lb Seven, worked fine for a 2000 lb Miata, but any more than that started to show structural deficiencies. Open deck meant I did actually use it to work on cars. A torsion axle kept the deck very low. No brakes which is probably the biggest thing I'd change today. I'd build a variation on it if I was going to run another open trailer. I'd be happy to share some sketches on what it would take to scale it up.

My car trailer is basically the 16' scaled up version of Keith's  little trailer, sitting on a 7k# torsion axle. I like it *a lot* for pulling cars around. The open deck does limit its usage, but I have several trailers and am fine with that in exchange for the reduced stress of pulling a light, easy to pull trailer.

I want to like surge brakes, and have all the parts for my next trailer to include them, but my experience has been that they just don't work as well.

Wood is far, far easier to slide something on than steel, if you get it wet.  Bring a water bottle along if that's a concern for you.  The best feature of a wooden deck is being able to sink a screw into it.  That way once you find the sweet spot for loading your car you can just screw down a chunk of 2x4 as a wheel stop and hit that exact spot every time. Maybe you are 1/2" too low for the door to open over the fender? Screw down a couple 2x4s on the driver side that one or both of the tires can park on top of.  Maybe you keep getting too close to one side or the other? A couple of boards as curbs will fix that.  All easy with a wood deck, much less so with steel.

That said, plywood is never the right answer on a trailer, no matter how many times my Dad tried it.  Pressure treated 2x for crossmembers more than 12" apart or 5/4" decking if the crossmembers are closer.