have to slide axles back on trailer

I have a 8' x 16' trailer, that I built 14 years ago, from a mobile home frame. It has always worked well for hauling tractors and machinery, but I generly watch the truck bed, and tires, to determine tounge weight, and move the load accordingly. It pulls down the road well at 55 empty, and I do need the tounge jack, to hook it to the truck. Life has been good with it , till I started hauling small square bales on it. With a perfect cube shaped load,(128 bales), that is 20 to a layer, and 5 high, and 8 down the center, to tie it. With that load, I am tounge light, and I get sway, at 35 mph. I intend on moving the axles back 6" or more to rectify this, but don't want to do it but once. How do I determine how far to move the axles?

I too have build trailers from mobile home frames and found the balance point of the empty trailer be at the front shackle bolt. Once the trailer was totally built I turned it upside down and set it on a round post. Set the axles/wheels on it and moved everything until it balanced. Been hauling put to 4 tons for years on it.

Figure out some way to weigh the tongue. Then load it up, see what the tongue weight is in present configuration. Then put an I beam or log crossways under the trailer, and jack up the log at various positions fore and aft, and see what the tongue weight does. I'm thinking you want at least 300# on the tongue, but not sure.

Or the lazy man's way- just don't load the trailer all the way to the back when hauling hay. You could stair-step it up, so you get more weight on the tongue.

I think you need at least 10% to 15% of your weight on the tongue. If it still sways then what about adding a stabilizer bar ?
Personally I'd sell it and find a gooseneck ! You will love the way they pull and how much better you can jockey one around in close quarters.

Standard trailer axles are usually set at 60%. That would put the center at 9'6". If you pull it with a heavy truck up to 70% works ok for bumper trailers. For hay 60% +/- is going to be about the best over all.

(quoted from post at 15:13:44 10/02/14) I have a 8' x 16' trailer, that I built 14 years ago, from a mobile home frame. It has always worked well for hauling tractors and machinery, but I generly watch the truck bed, and tires, to determine tounge weight, and move the load accordingly. It pulls down the road well at 55 empty, and I do need the tounge jack, to hook it to the truck. Life has been good with it , till I started hauling small square bales on it. With a perfect cube shaped load,(128 bales), that is 20 to a layer, and 5 high, and 8 down the center, to tie it. With that load, I am tounge light, and I get sway, at 35 mph. I intend on moving the axles back 6" or more to rectify this, but don't want to do it but once. How do I determine how far to move the axles?

Click to expand...

have measured a lot of 16' bumper pull trailers & find that different builders use all kinds of set back. 12", 16", 18" 24" and on and on. My 24" was waaayyy too bumper heavy with an evenly distributed load, so I changed it to 13" set back and now it works/trails great. I say 70% (3 ft-2in) is faaarr too great....my experience & opinion. 60% (19.2 inches) useable, but not to my personal liking. But, in the end, it is what suits each application.

Rather than moving the axels why not add an axel to the back of the trailer? MH axels are cheep and there every ware it seams and it would easer to add one than to move 2 and would cure the sway problem. Just an idea. Bandit

I have built several trailers and I use the 60/40 rule 60% in front of the center of the axles 40% behind always works for me.
Ypop

How hard would it be to modify traile, Add length to the front or shorten rear?

I was told the rule of thumb for 16 ft trailer would be center of the two axles will be half 16 = 8 ft and then back 1 inch per foot 1x16=16 So center of two axles will be 16 inches back from the center 8 ft. I have a 20 ft implement trailer and a 10 ft dump trailer. Both factory built, both follow the rule of thumb.

That said, you could cut 16 inches off back of trailer or add inches to the front of trailer, instead of moving axles. Or adjust center of gravity of load to put proper weight on hitch.

One day while eathing breakfast, I had a tail gate party. I got the 3 biggest men there, combined weight close to 900# to sit on my tail gate while I measured the distance between top of rear wheel and inside of fender. So when I load any trailer, I look for a 5/8 to 3/4 inch compression on rear springs. That seems to be the sweet spot for my trailers. So where the axles aren't really isn't that important, adjust the load to put weight on rear tires. Different story when trailer is empty. Trailer will bounce like a basketball. It will feel like trailer is kicking the rear of truck.

I didn't come in, and see the post's until 5:30 pac time, so I have been back out with a tape measure. 8' 3" seems to be the center of my bed, not counting the 3' 4" tounge, which holds the breakaway battery, and tounge jack. The total bed length is 16' 6", which surprised me by 6". I haven't used a tape on the bed in 14 years, since I built it. Another thing that surprised me, was that the center of the two axels, measured in at 8' 2", which explains the sway problem. It seems the tounge with battery, and tounge jack, is the only weight, that is on the hitch, and I definitely have to move the axles back. It shouldn't be so bad, with the trailer upside down. Now I have to get this done, before the winter rains start. Thanks for all the input guys!

The rule of thumb only applies to trailer bed, not hitch. Go to a trailer sales place and measure new trailers. Like I said, both my trailers are made with the rule.

So your axles are actually slightly ahead of center, that would explain your problems. Lol. Some quick advice as you procede, be VERY careful if you cut your old suspension off the frame rails. Those rails don't have much material and you can easily damage them when you cut off the hangers. Any damage to such a light frame could cause trouble. I would suggest buying a new suspension kit and just trimming down the existing ones to get them out of your way. That will also leave the front ones intact to measure from to make sure you keep straight and aligned. If you buy a complete kit you will also get new equalizers and bolts and bushings giving you a nice new suspension, and you can torch off the old bolts and save dealing with rusty nuts. If you need a supplier for parts I use Redneck Trailer Parts, they are about the best price around and will ship UPS.

Have you tried stacking it differently to simulate moving the axles? Say with ten fewer bales at the back or move five bales at a time from the back to the front? That will give you an idea how it will handle after you do move the axles.

Myself, I would leave the trailer as-is and just stack it differently, or maybe build a small platform on the tongue to carry a few bales further forward.

Good luck.

Jon! This particular trailer, has a 3/4"x 2 1/4" flat bar welded under the light 10" I beam frame. This piece stops 18" from either end of the I beam. The shackle hangers are welded to the 3/4" flat bar. The old shackle hangers, are 1/4" flat bar bent in a u, or channel shape. fabricating new hangers , will be similar with what I done weekly at the Boeing Co, and thanks to Harbor freight, I have the bender for this, and can stack drill the hangers, before bending. HF drill press.

Sounds like you have it under control then. Good luck on the repair.