Hindsight...yeah, yeah (trailer help needed)

[aka Larry]

As some of you know, I built my own 4'x7' utility trailer a few years ago. It was designed to haul my tires and tools to the track, but is used for hauling whatever I need.

The construction material was overkill (again hindsight is a cruel b*tch) as I used 2"x2x3/16" angle and 2"x2"x1/8" tube for the tongue. So right from the get-go its heavy, and when load, I think the tongue weight is just too much. How much is too much? Well I haven't actually weighed it to see what amount is actually on the tongue, but having to lift it on the ball when it's not lined up exactly is a *****, and it causes the car's suspension to sag quite a bit as well. IOW, as-is I don't think the trailer's axle is carrying enough of the load.

Take a look a the drawing below that shows the dimensions. Notice the two load numbers (stuff in the toolbox, and tire/wheels) as listed. These are approx, but rarely do I have any weight further back unless I'm hauling plywood, mulch, etc.

I'm considering removing the fenders and axle hangers and moving them forward to reduce the tongue weight, but I'm not sure how far. Obviously it will not tow well if I move the axle too far forward. Thoughts from the collective GJ wisdom?

 

[j p smith]

One of the rule of thumb suggestions for single axel trailers to move the axel back from center 1" for every foot of deck length, that looks like where you have you axel. Once you start moving the axel forward the trailer will not tow as well. You may notice that it will not track straight, almost like a vehicle that is toed out.

 

[aka Larry]

One of the rule of thumb suggestions for single axel trailers to move the axel back from center 1" for every foot of deck length...

That indeed was rule of thumb I found, and used. At the time, I anticipated a little more load on the rear portion, that has never really materialized.

I also read that the longer tongue I used (who's length was a WAG to be honest) causes it to have more tongue weight. So maybe I positioned the axle correctly, but made the tongue too long?

 

[lukedwag]

Rule of thumb only works for even load. Looks to me like your weight is all in the front of the trailer. Check your tongue weight loaded. Use the bathroom scale trick it works mint.

 

[Thumper68]

I know this might be a silly suggestion but why not just move the #200 of tires back in the trailer.

 

[vintagespeed1956]

shorten the tongue, the axle is in the right place.

 

[gte718p]

Trailer design looks good, I wouldn't mess with it.

Since it is a race trailer, I would break out the drill and make some speed holes to reduce weight and maybe move the tool box to the back.

 

[laser3kw]

Since it is a race trailer, I would break out the drill and make some speed holes to reduce weight and maybe move the tool box to the back.

no, no, no,
Carbon Fiber, then scale it, then decide there to put the tool box for best corner weights.

 

[racingtadpole]

Assuming you wish to keep the loaded configuration and largely only use it for the one purpose, scale it, and shift the axle to put around 10-15% of the gross mass on the ball. Keep in mind you need it to tow straight when its empty sometimes, so you may have to play around and compromise a bit to get it to work in both situations.

Edit:

If it helps you, my 7x5 utility trailer has 48" of drawbar and the axle is set at 44" from the front edge of the cargo deck. Different material and construction but unladen weight would be similar.
You have 91" hitch to centre of axle, mine has 92", you're on the money with axle location.
With those measurements in hand, I'd look at shifting the tyre rack back so its over the axle.

 

[koditten]

My guess is to center the axle. With that constant load, the rule of thumb won't apply.

I hate to tell you, but trial and error is going to be the right answer.

 

[APEowner]

I hate to tell you, but trial and error is going to be the right answer.

What? No. You want around 10% of the weight on the tongue. Do the math and move stuff around till it's right.

 

[1969]

I have built a number of trailers and I always us the 60/40 rule. Not saying its perfect, but it sure has worked very well for me.

 

[OccupantRJ]

Put a tongue jack on it and go on with your life. A tail heavy trailer pulls like ****. I have a 4x8 and often haul a ton or less on it. The tongue jack allows me to park the trailer loaded when I want, and when empty the jack allows me to skid the tongue around to line up with the ball. When I detach I lower the tongue a half inch so I can tell when the ball has reached it to hook up. I don't use a jack with a wheel as the skid keeps the trailer in place when parked.

 

[Bopbop]

A rule of thumb that I always used was to locate the axle about 6" to the rear of the center of the load weight or the 60 / 40 rule. Looking at you plan the axle may be a little far back for a typical utility trailer for hauling plywood, lawnmowers etc. However with the way that you show your load you are really tough heavy. I would leave the tool box where it is shown and relocate the tires over the axle. This would give you a tough weight of about 75 pounds since the axle will be carrying the load of the tires.
I would do I mach up and try towing it that way to see how it pulls. you may need to shift the tire location some for the best towing. When we use to race the dirt cars there was a few years where we had 2 different type of cars. On the trailer we had marked locations for the center of the tires to be located. Moving the car's location 6" either way would result in some bad trailer sway.
Good luck

 

[aka Larry]

Thanks for all the replies guys, I really appreciate it!

I don't want to relocate the toolbox because I need room for sheet goods on the back. The tire rack can (and is) removed often, and it can be relocated with no issues. I'm going to get some actually tongue weight numbers this weekend to see just how much I have.

I'll report back soon!

 

[bimmer1980]

If you really want to lower your tongue weight at the ball, without changing your load distribution, you need to lengthen the tongue, not shorten it.

Think about a wheel barrow and where you grip the handles.

Personally, I would just slide the tire rack back a few inches and see if that works better for you.

 

[icedevil]

+1 for the 60/40 split (axle centerline about 44.5" from the front of the cargo area). Since you have the toolbox permanently mounted, you may be able to get away with a 55/45 split (46"). Those arent huge numbers from what you have, but remember, you need to keep tongue weight on the tow vehicle, otherwise you'll be all over the road.

 

[TheEquineFencer]

Usually when I build a small bumper pull trailer, I make the tongue just long enough so when I turn it 90* it just clears the side of what I'm towing it with. That way when I loan it out to some "idiot" that backs it past 90* all I have to replace is the tongue when they bend it.

Personally, if I build a SA trailer for general use, meaning I'm "probably going to haul the world on it", I put the axle about 4-6 inches back from the center of the bed. That way when it's loaded to the gills, it doesn't have too much tongue weight. It might not be the right way to do it, but it seems to work OK for me. Dumping things off the back is pretty easy that way using the leverage from the tongue length .

FWIW, if you set two jack stands out in front of the trailer as it is now, take a string and go from one jack stand around the tires and back up to the other jack stand. Then move the jack stands until the string just does touches the tire on each side at the front of the sidewall of each tire. Measure from the string to the tongue near the ball. This will give you a good idea of the axle location in relation to the tongue.

 

[zak77]

I moved the axle for my landscape trailer because i wasnt happy with the tongue weight. Seems they used the standard 40/60 but with a load in it, way too much weight was being put on the tongue and it was a pain to move around even empty. I moved it about 8" forward so when empty 10% of the trailer's weight is still on the tongue so it tracks good. Now i can load it and put more or less weight on the axle as needed. My vote is to move the axle to where you need it, not where it should be per some standard.

 

[aka Larry]

FWIW, if you set two jack stands out in front of the trailer as it is now, take a string and go from one jack stand around the tires and back up to the other jack stand. Then move the jack stands until the string just does touches the tire on each side at the front of the sidewall of each tire. Measure from the string to the tongue near the ball. This will give you a good idea of the axle location in relation to the tongue.

For some reason I cannot picture this in my head. Can you draw it or explain it differently?

 

[TheEquineFencer]

For some reason I cannot picture this in my head. Can you draw it or explain it differently?

Click the pic then click it again to really enlarge it.

 

[TheEquineFencer]

There's actually a tool, a POGO Stick, that's made to go where the ball attaches that has a bubble level on it to measure to. That way if the tongue is off you can orient the axle to the actual mounting point it's towed from. I'd measure the top of the center of where the ball mounts when doing it myself.

Strings and a POGO Stick are what I used to use years ago to align axles for semi trailers. I'd get the front axle aligned, then adjust the rear axle torque arms to get the rear axle aligned with the front axle so it measure the same center to center of each axle.

 

[TheEquineFencer]

Click the pic then click it again to really enlarge it.

If the axle is out of line, the measurements will be way off from side to side.I hope this helps.

 

[Jeff Ivers]

Based on your drawing, you have, presently, far more than 60% of your weight on the hitch ball when the trailer is unloaded. You have placed the axle at 60% of the length, but you have more vertical bracing and the tongue all ahead of the axle line. Then you are loading it with 275 pounds or more all placed ahead of the axle line. Another factor, not previously mentioned is does your trailer sit level when hitched up? If not, you are further increasing the problem. Even on car hauling trailers, one should not exceed 500 pounds of weight on the ball. I would bet that you have more weight than that on your ball, when loaded as pictured. I suspect you need to move your axle about 8 inches forward.