Funny I was giving this some thought this weekend and stumble on this post. Maybe this helps.
Currently I have a 24 foot trailer GVWR 10400. It weighs 2800 on a scale and matches the VIN sticker. I got it because it matched my 2013 toyota tundra 'work truck' max tow for 10400. I'm not sure why the trailer is only 10k rated because all the parts state 14k (2 7k dexter axles each has breaks and 6 inch structural C channel frame that's double up front). I think the weak link are the tires...I run them at 80 PSI and still decent amount of flex when turning hard.
On a scale, my L47 weighs 7800 LB. That doesn't include my weight, though fuel tank was almost full...basically when I'm on it, it would weigh 8000 LB (4 ton) despite the specs stating 7200 operating weight. I have the 72 inch heavy duty bucket, 18 inch backhoe bucket with quick attach bracket and thumb. There's some accessories as well, but those don't weigh much. I was thinking of filling the tires to add +500 LB...if I did that, it would weigh 8300, which is too much for my trailer. I'm a bit bummed because after all my planning, I discovered the tractor weighs +500 more than expected, but I was a good learning experience. Often stuff weighs more than you think (not the other way around) and it's best to consider that, getting stuff to exceed the supposed capacity. If I take the backhoe off, that takes off ~2000 LB (though the specs are less), letting me easily haul it with a heavy 3PT attachment, filled tires, and even bring multiple attachments on a 10k rated trailer. Even if I known the tractor was heavier, the truck I still wouldn't be rated for it.
I would say a 1/2 ton truck is a bit undersized to haul the L47. My truck GCWR (truck + trailer) is 16000 and on a scale I'm at 16500. Even though I'm towing 10600 (200 over limit of truck or trailer), I'm still exceeding GCVR.It's kinda of a catch for fullsize trucks...they're rating to tow a lot more than their payload/ GCVR allows especially if they have 4 doors and stuff inside. I discovered that technically the tundra should only have 1000 in the bed despite the sticker saying 1800 because on the scale with just me in it, the truck weights 6k and the GVWR is 7k, though I've put 2500 LB in the bed plenty of times and it handled it fine. Towing 10k+ the truck drives fine though you can tell the truck is at it's limit, which isn't exactly being safe. It's no worse than putting 2500 in the bed and in both situations if some clueless car turns in front of my without look, I probably wont be able to stop in time.
I take extra care that the trailer is level with a slight tilt to the front. The most unsafe thing to do is have it tilted backwards (too much weight on the rear) because that will cause it to wag/sway and that turns messy quickly (easy fix to just mash the trailer brakes). Same way when loading a truck bed, you want the weight in front, not behind the rear axle. I have anderson weight distribution hitch that works good... a big plus over the others is it has chains instead of bars letting it ride smoother and it's much lighter (better for towing and installing).
A 20 foot trailer is too short. You wont have room to position the tractor to level out the trailer correctly and get the appropriate tongue weight. The backhoe would hang off the rear, which legally is okay, but not good for weight distribution....just depends on the trailer design if it works or not. A longer rear 3 PT attachment wont fit. My tractor is parked in a 24 foot long garage. The backhoe is 1-2 feet from hitting the wall when the bucket tip is a few inches from the door. 22 foot would work MINIMUM for a tight fit. 24 feet gives you some flexibility and room to take a boxblade with backhoe and bucket. I went with 24 foot because the price of 22 vs 24 is the same...for a 22 foot trailer, they just cut the beams shorter. A longer trailer drives better and is easier to back up so don't be scared of that.
I saw some people on youtube showing how you can use a gooseneck dump trailer and place the loader on top of the gooseneck... I seriously doubt this will work because it forces the tractor too far forward giving you too much payload weight (I can see in the videos how much the truck is sagging in the back to confirm this). A dump trailer is REALLY heavy empty especially a 16 foot long one, rear wheels are further back, and a gooseneck transfers even more weight on the payload...in order to haul that legally and safely, you're probably over 26k GCVR and need a DOT number.
Here is how I load my L47 on the trailer: I drive up on the ramps (not back up like you should a skidsteer), which are barely wide enough. The rears wheels are spaced wider than the fronts, where the rears will be partly off the ramps and the fronts are center though close to the other end. If I had weigh spacers, I just wouldn't work. As I climb the ramps, the backhoe is about 1 inch from scraping on a level surface. If the rear of the trailer has an uphill, it will probably scrap...likewise it wont if you have a downhill. All those other smaller kubota tractors with a backhoe would scrap for sure, requiring you to use wood blocks etc. I drive it forward till the rear wheels basically line up between the two axles. I've found that I actually need to drive up a little further to level the trailer better. Considering trying to drop the front ball a slot to fix that, though that is already kinda low and pulling up forward is no big deal.
Here is how I strap it down: I have a long 7k rated chain that I pass through the two rear tow hooks (chain goes along the trailer). Each end of the chain connects to the slots on the backhoe frame (I guess they are there specifically for towing). I have rachet chain binder that I can then use in the center, however I found that all I need to do is just drive forward to tension it (no racket required). Up front, I take a racket strap around each wheel and loop it to the lower tow hooks. There isn't a good spot up front to tie down to and I discovered that since the front pivots, if you don't attach to the wheels, once side can get loose as you drive around. IMO this a big miss... why can't kubota design these tractors with hauling loops to attach to??? The backhoe has it so don't doesn't the front? The front bucket as some nice hooks on them, but it clearly says that is the level gauge and not to use for hauling...they seem plenty strong for it though.
A TLB is flexible, but you quickly realize the (un)practically on a job. If you want to use a 3PT attachment, you must make multiple trips. This adds to your cost because so many jobs are less than 1 day. If I had a larger trailer and truck to bring everything with me to do a job in a single day, that would be a HUGE saver. Mainly for any kind of dirt or driveway work, you want/need a box blade. So many situations where you want to bring multiple attachments, including backhoe buckets etc. You could try to put something in the truck bed, but in my case, I my truck is maxed out.
Future plans:
- I need a heavy duty 3/4 ton truck with 16000 towing capacity. Ideally it should have 24000-26000 GCWR (the cut off needing a CDL) and about 3k payload. The truck itself will be 10k GVWR so wont be able to pull anything more than a 16k rated trailer otherwise you need CDL (even if it's empty and you're not using the capacity, DOT will just look a your truck door sticker, the trailer sticker, and then do the math). I wont be getting a diesel because the it takes away from payload capacity and the emissions crap they put on are nightmare. Don't need diesel to tow 14k...a gas engine could handle that...heck even F150 with a turbo V6 can do it easy. Don't need dually either...just adds weight, cost, and makes the truck ride worse. Used to be a 'regular cab, no options, and 8 foot bed' kinda guy, but with 3 kids, I kinda need the 4 doors (even though I got a family car, still end up using a truck to move kids around), and with a trailer, having an 8 foot bed becomes less of a requirement (though I'd still prefer 8 ft, 6.5 probably good enough).
- The trailer should be 16k rated. Ideally want a 24 foot gooseneck, which is heavier and would leave maybe 12k to haul. This gives a buffer and lets me potentially get equipment at 10-12k weight (M62 for example, though I'm happy with my L47 for now). An 8 foot trailer where the fenders are under would be nice. Going to give aluminum trailers more consideration...they save a significant amount weight at adds to you towing ability. The trailer should have wider longer ramps.
- Legally you don't need chains for equipment that weighs under 10k. I'm going to switch over to racket straps only. Each one is rated 4k working load (12k break), so 4 of them is 16k...legally you only need 1/2 the weight supported. This means for an 8k tractor, you actually only need to support 4k....this can be done using 4 straps rated 1k each. If you use 4 7k chains, that is enough to support something that weighs 56k LB on a flatbed semi. 3-4k working load straps aren't expensive and 4 of those is 12-16k of working load that basically exceeds the weight of the tractor 2 fold and the minimum recommendation 4 fold. Working with chain/ binders is a pain and takes too much time plus it's heavy and adds weight.
After having an 4 ton machine, I can see the appeal of lighter equipment. I takes a lot to legally and safely haul 8-10k. It's scary to think some 'bubbas' out there are hauling stuff improperly...I always keep a distance when I see someone towing. Thankfully 4 tons can do a lot and I'm not really wanting more. It's what's popular for a reason.
Hope this helps.