Leveling a tandem axle trailer

jkidd

jkidd

Active member
So I bought a new tow vehicle and have been trying to get the trailer level with the new hitch. The old tow vehicle had Autoride suspension and the hitch height was lower so it just auto leveled. The new hitch needs a 5" rise and still doesn't quite level the trailer. At this level if I open the tailgate it will hit the ball latch on the trailer. At the back of the trailer I am 21" off the ground and at the front I am 19-3/4" off the ground. How level does everyone run their trailers? The trailer tows great at this position. I would like to move it to 4" so I don't hit the latch but I can live with 5". What does everyone think?
 
Jody, our "new" trailer is about 2" off level (from front to back of the trailer)--and we have towed it over 4,000 miles this summer. I carefully watched the tire pressures, tire temperatures (sensors on the valve stems constantly monitored in the RV, as well as the hub temperatures every two hours. There is no unusual wear on the tire tread, or different in running temperatures or pressures in the tires. So I have assumed that it is OK with that much out of level.
 
Interesting thread. I knew tandems were supposed to be level, but had no idea "how level." On my previous tow vehicle it just happened to come out perfectly level with a fairly run of the mill rise drawbar on my first try - beginner's luck! Then this spring I started towing with a new rig, and it was not quite level. Not knowing for sure how important it was, I erred on the side of caution and made sure it was pretty much exactly level (used a level on the frame plus measured from frame to level concrete). This time I used a combination of a typical "rise" drawbar and a special ball that has a built in 1" rise to the shank. Reason I went that way is that it worked better with the features on the back of the tow rig than a drawbar with more rise would have - it was an option I didn't know existed previously. Don't know if that would help your situation or not, but figured I'd mention it (there was one with a 2" rise also).
 
Bob that's good news is your new trailer a torsion axel ?


Ssobol I might consider a longer draw bar but adding 18" of length reduces the capacity by half and will put more stress on the receiver.
 
This is only conjecture (I like thinking about how things work), but I wonder if the temperatures of the tires and hubs would be a good indicator? I'm thinking that being off level puts a bit more load on one axle than the other, but if there is no extra heat maybe it's not too much? In other words, I'm trying to think what problem there could be that would *not* show itself as more heat. Maybe there is something though (and I have springs so don't know about how tandem/torsion would fare).
 
Sunbeam I could see where the longer ball could come in handy. The longer ball would allow me to adjust the hitch down but would have the same ball height. I would still have interference problem. Where your trailer has springs there is a pivot between the two axles that equalizes the load. On the torsion axle you don't have this. I guess the only way to know for sure would be to get weights on all four tires. Measuring the trailer at the front and back is going to be much more pronounced than getting the measurements right at the axle positions. My mind says I will have more load on the front wheels just don't know how much. Monitoring the tempratures is just a good practice to know your safe. My trailer has always wore one tire kind of funny off the inside edge. When I raise it up one inch it moved from the left rear to the right front.
 
jkidd":326jiz2h said:
Sunbeam I could see where the longer ball could come in handy. The longer ball would allow me to adjust the hitch down but would have the same ball height. I would still have interference problem.
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I kind of thought so, but I couldn't totally visualize your setup. It did work out nicely in my case, allowing me to get the trailer tongue up where I wanted it without the whole drawbar coming up.


jkidd":326jiz2h said:
Where your trailer has springs there is a pivot between the two axles that equalizes the load. On the torsion axle you don't have this.
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Ah, okay, I see. I've only had a single axle torsion trailer (camper not boat), and I thought there was something with tandem/torsion but couldn't remember what it was.
 
Sunbeam, you are correct. Too high and the rear tires will show inside edge wear. Too low and the front tires will show inside edge wear. ...at least that's what I experienced during the first couple of years towing 'Naknek.

Naknek's trailer was supplied with tandem bias-ply tires (not radials). As a result I noticed an increased amount of tire edge wear during the first five thousand miles of towing. At 5000 I swapped the tires and began searching for the cause. I checked with the manufacturer, and was told that ideally the trailer would be within 1/2" of level. I did the necessary measurements and got it pretty close. The manufacturer also HIGHLY recommended radial tires. (I asked "if it's so important, why don't you install radials initially?" Answer: "...it's a marketing-thing.")

I did the leveling and swap-to-radial tires at the same time, so I really don't know what was major 'fix, but it worked. My guess is that radial tires was the major factor, but getting the trailer as level as possible is still a good idea.

Jody - interesting issue with the hitch clearance. I can visualize the problem but don't see an easy work around. If you opt to go with an extended coupler it may not be a 'fatal issue. When I had the F350 the camper overhang required a 4' (yes, four FOOT) extender to reach from beneath the overhang. With lateral bracing on the extender it was Very solid and had no adverse impact on towing or handling.

Good luck

Best,
C&M*
*Overlooking the "Southern Ocean."
 
Casey":2jkl0s0x said:
Naknek's trailer was supplied with tandem bias-ply tires (not radials). The manufacturer also HIGHLY recommended radial tires. (I asked "if it's so important, why don't you install radials initially?"
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Ha, good one! Nothing like a snappy statement of the obvious (vs. thinking of the good replies later on.... :amgry)

While I didn't know how important it was to get the trailer perfectly level, I figured it couldn't hurt, and it wasn't difficult in my case, so I did. So far, so good (as always with trailers though, knock on galvanizing...)


Casey":2jkl0s0x said:
*Overlooking the "Southern Ocean."
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Ooooh, nifty! :thup
 
Jody, I have torsion axles. The tires are Trail America: Bias, Size: ST205/75D14 (F78-14) Load Range: C. PSI: 50 Load Capacity: 1,760 lbs. each. (I had just replaced the old trailer tires with radials. but a different size--and had to take what the trailer shop had it stock on the Friday night we did the exchange…)

I am running the current tires at 50 lbs, (measured with analogue dial gauge, confirmed by the pressure sensor) go up to about 55 lbs when running, temp is rarely more than 10 degrees over ambient.

I just measured the tread with a micrometer to give a more accurate picture: outer tread on spare: .229 in. outer tread on rt. front .195in, lft. front .201in. on rt rear .110 in and lft rear is .184, so the right rear is wearing significantly more than the other tires. The inner tread on all of the tires is worn less than outer, but I did not measure the inner. Currently the trailer is about 2" higher in the front, putting more load on the rear tires. Not sure why more on the right--than left--but have to assume it is either load, or minor misalignment of the axle (I did not measure that yet. I will weigh the trailer, but it will be without the boat, for registration. I have a number of other hitches at home, and we will be sure it is closer to level in the future.

On the 25 trailer, we went from bias to radial tires, and made sure the trailer was level (with bubble level, truck loaded--adjustable hitch, which was part of the equalizer bar package).
 
rogerbum":3odju3d6 said:
What is the new tow vehicle and how much drop in the rear do you see when you hook up the trailer?
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GMC 1500 355HP 9900lbs Tow
GMC001.jpg

It sits down on the overloads rear fender is about an inch higher than the front. It can all be solve by putting air bags on. I was just trying to avoid that.
 
thataway":1t0pj65m said:
Jody, I have torsion axles. The tires are Trail America: Bias, Size: ST205/75D14 (F78-14) Load Range: C. PSI: 50 Load Capacity: 1,760 lbs. each. (I had just replaced the old trailer tires with radials. but a different size--and had to take what the trailer shop had it stock on the Friday night we did the exchange…)

I am running the current tires at 50 lbs, (measured with analogue dial gauge, confirmed by the pressure sensor) go up to about 55 lbs when running, temp is rarely more than 10 degrees over ambient.

I just measured the tread with a micrometer to give a more accurate picture: outer tread on spare: .229 in. outer tread on rt. front .195in, lft. front .201in. on rt rear .110 in and lft rear is .184, so the right rear is wearing significantly more than the other tires. The inner tread on all of the tires is worn less than outer, but I did not measure the inner. Currently the trailer is about 2" higher in the front, putting more load on the rear tires. Not sure why more on the right--than left--but have to assume it is either load, or minor misalignment of the axle (I did not measure that yet. I will weigh the trailer, but it will be without the boat, for registration. I have a number of other hitches at home, and we will be sure it is closer to level in the future.

On the 25 trailer, we went from bias to radial tires, and made sure the trailer was level (with bubble level, truck loaded--adjustable hitch, which was part of the equalizer bar package).
Click to expand...

Thanks for all the details. I can see if I want it to be truly level that I will have to put air bags on it. That doesn't really bother me I was just trying to avoid it if I could. If I put the air bags on I can just set the rise to 3 inches and adjust the air to get me level. I know I see people that are towing out of level all the time and was just wondering what everyones experiences were if they did that.
 
Yes Jody, air bags or an extension. Some the 12 inch extensions, I've checked out say 5000 pounds & 500 pound tounge wt or 1/3 the rating of the hitch. If 12 inches would get the hitch in back of the tailgate that might work. I think it important to have the trailer as level as possible.

Good looking truck!!!

Jay
 
Some tailgates taper in thickness you might not need to go back past the end (top of the tailgate) in order to get the ball high enough.
 
Hunkydory":2kptzny8 said:
Yes Jody, air bags or an extension. Some the 12 inch extensions, I've checked out say 5000 pounds & 500 pound tounge wt or 1/3 the rating of the hitch. If 12 inches would get the hitch in back of the tailgate that might work. I think it important to have the trailer as level as possible.

Good looking truck!!!

Jay
Click to expand...
I meant to say 2/3 the hitch rating.
 
Since I got my "new to me" PACIFIC tandem, I have been working on the leveling thing. I measure the frame on level concrete, and also measure hub temps. I have gotten it to 3/4" low in front, measured where the "Y" joins the base "I" and it is 3/4" high at the end of the frame, measured at the end of the frame on the outside edge.

When I measure the temps on the hubs, the front hub temps are consistently higher than the rear. They are generally about 10 degrees higher front than rear axle. There has been some variation but rarely more than 15 degrees. The temps are usually within 10 - 20 of ambient temps, and were all replaced with new bearings about the same time the new tires went on.

The tires are not Marathons but the Les Schwab trailer tire, load range C radials and so far the wear appears to be pretty symmetrical. That I like.

I have not weighed it with separate axle weights but that sounds like a good idea. Thanks for bringing that up.

Harvey
SleepyC:moon

IMGP6704.thumb.jpg
 
I think it would be interesting to see how much difference there is. I would also like to know if a level trailer would even up the temps too. The brakes could mess with that a little.
 
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