I am getting ready to do the exact same thing! Can you PLEASE share the specific details? I am trying to figure out what axle length, adapters etc will work, and do not want to mess it up as the return policies suck! I have stock JK rubicon wheels and tires that I am hoping to use...
I was planning to do a more formal write-up on the mods but I don't want to keep you waiting. Here's what I did:
I had
originally set up my trailer to fit 31x10.5R15 tires on the OEM axle, but after moving to a JK I found that it sat a bit too low and I wanted to be able to fit my Jeep's 315/70R17 wheels and tires so I wouldn't have to lug around an extra spare dedicated to the trailer. I bought some OEM JK "Moab" 17x7.5" wheels and used 285/75R17 Toyo All Terrains for a similar height but slighly narrower and lighter. I made sure with my measurements that I'd have enough clearance between the sidewalls of the 315's and the trailer's frame rail. Here's what I came up with:
OEM wheels have a lot of backspacing, and they are hub-centric with a small center bore so they don't fit around a trailer hub. I picked up some spacers from
Lenny at Motorsport Tech that he makes specifically for this application. They are 1.75" thick which is the minimum needed to clear the trailer hub's grease cap. I then bought a custom-made 70-inch-WMS-WMS
non-cambered 3500lb axle from
Brandon at Down2Earth Trailers with 5x5" hubs (for reference, the OEM axle's WMS-WMS measurement is 65 inches). Because I wanted to move the axle forward for better weight distribution and I wanted the trailer to ride smoother over rough trails (I never carry the heavy loads that the short 2000lb-rated springs are designed for) I had him include some 1150lb-rated 29"-long springs, shackles, spring hangers, U-bolts, and U-bolt plates. Shipped to my door, all of these parts cost about $100 less than I could locally source just the axle.
I kept the shackle hangers in the same location, but I welded the new spring hangers 9 inches forward from the OEM hangers. This put the axle 4.5 inches forward, which brought my trailer's tongue weight down from 115lbs to 86lbs. I obviously needed some new fenders to cover these bigger tires in their new location, so I ordered some
13x36" fenders from etrailer.com and bolted them directly to the trailer's box sides rather than the fender brackets.
Please forgive the boring driveway cellphone picture instead of a scenic backcountry trail glamour shot:
With the longer and softer springs, the trailer rides so much better over bumps. I haven't taken it on any trails yet, but the "nuisance rocks" that always caused the trailer to bounce all over the place should be soaked right up. The tongue jack and support legs still reach the ground, but I carry some short segments of 4x4" pressure treated wood to place under the feet when I'm camped on uneven ground. The step up into the trailer is pretty tall even with the step stool, but the additional height not only gives good frame clearance from the rocky trails I frequent, but it also keeps our beds up high out of reach of lions and tigers. Frame height is at 24.5" ground clearance.
Don't rely on my measurements for your trailer build - double check everything to make sure I'm not screwing up your build for you! If you're only going to be using OEM-size tires, you won't need quite as much axle width so you could probably get away with a 69" axle. And you could use some narrower fenders too.
Unrelated to the axle and suspension, I also upgraded the tongue from 3x3" 0.095"-wall square tube to 3x3" 0.188"-wall square tube that I picked up locally, and I lengthened it by 16 inches. I also added an inexpensive
Harbor Freight hitch cargo rack ($49 with coupon!) and adapted it to the tongue to carry stuff:
I haven't yet used it since I've only just completed all these upgrades, but this gives you an idea what kind of capacity it provides:
I use a
Lock'N'Roll hitch which has performed flawlessly both on- and off-road and makes my trailer a bit harder to be stolen when I unhitch it and leave it at camp while I'm out 4wheeling for the day.
