Pay attention cause math class is now in session:
Per dodge.com a 1T Mega cab 4x4 dually has a curb weight of 7,810 lbs. At a 60/40 split that would give you a safe winter towing capacity of about 5200 lbs:
7800 + 5200 = 13,000 total combined gross weight, x .4(40%) = 5,200
Or 7800 divided by 13,000 = .60 (60%)
5,200 of trlr and sleds would in my opinion be a max winter ice towing load in this application. Keep in mind as you add fuel and gear to the truck it also raises max trlr weight. 5200lbs – 2800lbs of sled leaves 2400lbs of empty trlr. Better be looking for an all aluminum.
In my case I have a GMC 1T crew 4x4 dually which is about 6,700 lbs, a sled rack at about 400lbs two sleds wet at about 700lbs each or about 8,500lbs not including gear or truck fuel. My trlr is a 12’ floe enclosed at about 1,100lbs plus 2 sleds wet at 700lbs each or 2,500 total trlr weight. Math is as follows:
8500 + 2500 = 11,000 total combined gross vehicle weight, x .23(23%) = 2,530
Which is a ratio of 77/23, with truck fuel and gear is pretty dam close to a very safe ideal ratio of 80/20.
An example mentioned above was a 4 place steel trlr (4,000lbs) loaded with 4 sleds 700lbs each is about 6,800lbs total trlr weight. Then hook up a 2001 Tahoe with a curb weight of 5,050lbs. Math is a follows:
5050 + 6800 = 11,850 total combined gross vehicle weight,
5050 divided by 11850 = .43 (43%)
Which is a ratio of 43/57. It’s a no brainer.
We are in agreement on one statement, a 6800lbs trailer needs about a 9000lbs + tow rig in front of it.
80/20 = very comfortable towing.
70/30 = very safe towing
60/40 = reasonably safe towing
50/50 = marginal towing in good conditions.
43/57 = suicide
Again we are talking about winter ice conditions. To many people are pushing the envelope with these big trlrs and light tow rigs partly due to the light winters we have had over the last few years and partly because they haven’t had the sh!t scared out of them yet If you are in the 43/57% ratio area and are towing in winter mountainous conditions you will find your disaster. Plus the word CAR doesn't even enter into this conversation.
Now if your talking about July, you can toss this all out and start over.
While your theory is great and definantly a safe idea to go with, it's also by far too conservative. A 1 ton dually, like yours, or ours, can pull a 4-6 place enclosed without much issue, in winter icy driving conditions.
IMHO, from doing LOTS and LOTS of towing with multiple rigs, a 45/55 ratio is still safe, but the limit. (45% truck weight, 55% trailer weight.)
With a half ton, I'd prefer something like a 54/46 max ratio, as the squishy soft springs are what are the most dangerous.
Your 80/20 ratio is definantly safe, but that is so conservative, it's even a little silly. We'd need F650 Fords or Kodiak Topkicks to get our 4 places around, and it's a proven fact that a 3/4ton SRW and larger has no problem in the worst conditions with a 4 place enclosed, providing the rig has a proper driver.
In the end, it mostly boils down the the driver. If you feel your driving abilities only allow you to pull 2,500lbs with your 1 ton dually that is rated for 20K+, then that is wise of you to relize that.