5th airborne kingpin question

[bill maietta]

After much difficulty, my wife and I finally got our new kingpin installed. The kingpin itself ended up being about 5 inches closer to the ground so we had to lower the husky hitch to the bottom holes which gave us about 3-4 needed inches to be able to hook up. now with no adjustments to be had the Montana is a bit nose high, about a half bubble out of being level when hooked up. i know this will put some stress on the rear tires. Can anyone tell me if this is a problem and if so are there any ideas as to what can be done to help. The only thing I can think of is to have a trailer shop raise the rear of the trailer up somehow. By the way, the 5th airborne does tow much smoother than the stock one. Thanks in advance...Bill

[BB_TX]

I don't think "a half bubble" will be enough to be concerned about.
You might pick a spot at the rear of the 5er and measure from the frame to the ground. Then do the same at the very front. That will let you know just how much you are really out of level.

[JimF]

We did the same, hitch as low as possible, etc., run a little nose high. Let some air out of the air ride bags and got closer bujt not quite. Weighed the tires, even though it looks nose high the weight is right (within a few pounds tire to tire). Running it that way, will have to do.

[Msjan]

Did riding nose high cause any problems with your refrigerator.

[DarMar]

Wowsers, 5 inches more drop with the 5th airborne? I have been thinking a lot lately about a new king pin and that 5 inches could be a problem, I will have to look further. Are all makes of king pins that much of an adjustment? Bill, I see you have an 04 3400 ours is an 07 3400 and has I think the Lippert #1116 king pin.

[bill maietta]

quote:Originally posted by DarMar

Wowsers, 5 inches more drop with the 5th airborne? I have been thinking a lot lately about a new king pin and that 5 inches could be a problem, I will have to look further. Are all makes of king pins that much of an adjustment? Bill, I see you have an 04 3400 ours is an 07 3400 and has I think the Lippert #1116 king pin.

darwin, my kingpin was a fabex665. the model years could have made the difference or I bought my fiver used and perhaps the previous owner replaced it, not sure.

[clarkandsheila]

The ideal may be level when hooked up, both vehicles, but I sure don't see many that way.
Mine included.
I recently weighed my rig. On the way home the Hwy Dept. closes the scale on the weekend but leaves the scale active for us duffers.
Was able to weigh each axle separately and then go down one side, axle by axle. Even though my trailer rides a bit nose high the weight on the two trailer axles was within a few kilograms or about 10# of each other, same side to side.
I suspect, if the trailer is loaded properly the balance will be close enough that each axle carries close to the same weight unless your trailer is really nose high or you load very heavily.
Of course not everyone is going to be that lucky but this was my experience and I ws a bit concerned.

[JimF]

The rig being nose high did not affect the refer. With it moving down the road the motion keeps the coolant levels in balance. Of couse, when we stop we do level, more or less.

[Art-n-Marge]

This the second time today I've had to agree with Clarkandsheila. What are the odds.

Like Jim F, I ride nose high (but slightly) and run with the refrigerator on. I've been doing this for a year with no problems driving up and down hills. My weight differences are similar to clark, and in my case under the weight requirements by over a ton at the axles.

Here's some additional information that I hope someone can help me figure out the angle. The distance of the rig's main bottom framing (not the overhang) is 29' (it's another 7' to the king pin). The rear of the rig's ground to frame measurement is 4" lower than the front of the rig's ground to the frame measurement. The rear of the rig distance to the center of the rear axle is 11 ft. The front of the rig distance to the center of the front axle is 15'. The distance between the center of the axles is 3 ft. I don't know the degree of nose high but hopefully an MOC geometry expert can tell me what the degree of nose high I am. I don't know how much of a bubble that is, but I don't believe this is enough to worry about.

I do know that the higher the nose the more stress put on the rear axle and the suspension travel might be impacted if the nose is high enough and I don't know at what degree it's a concern since it's difficult to have every rig combination perfectly level. Yes, level would be nicest, but when is this a problem? If anyone knows better would you please explain and enlighten me? I am having a terrible time trying to find how to determine this and any help would be appreciated.

[BB_TX]

quote:Originally posted by Art-n-Marge

...........
Here's some additional information that I hope someone can help me figure out the angle. The distance of the rig's main bottom framing (not the overhang) is 29' (it's another 7' to the king pin). The rear of the rig's ground to frame measurement is 4" lower than the front of the rig's ground to the frame measurement. The rear of the rig distance to the center of the rear axle is 11 ft. The front of the rig distance to the center of the front axle is 15'. The distance between the center of the axles is 3 ft. I don't know the degree of nose high but hopefully an MOC geometry expert can tell me what the degree of nose high I am. I don't know how much of a bubble that is, but I don't believe this is enough to worry about.
..............

I think that is about 0.6 degrees. But it has been a long time since I worked trig problems.

[Art-n-Marge]

Hey, your guess is better than mine, but if it's only 6/10s of a degree, that's not bad, just a hair over 1/2 a degree. Thanks for that Bill. Maybe I'll get out my old geometry/trig book and figure it out. 4 inch height difference over 29 feet.

But Bill Maietta's 5 inch at the new pin.... wow that's a lot.

[bill maietta]

Art,
I thought 5 inches was a lot also. I didnt actually measure it but thats what it looked like. Im wondering if all those with extended kingpins that installed 5th airbornes had a similar experience. My rig is in storage so I havent had a chance to measure the distance from ground to frame front and rear. I will do that soon though.

[DonPd]

I also installed a airborne with the sidewinder turret and it did move my pin down about 5". I lowered the hitch in the TV and I am a little high in the front but it isn't as high as some I have seen going down the road. I don't think a little high will make much difference.

[Art-n-Marge]

Hi Bill,

Fortunately extending a hitch another 5 inches is why there are adjustment holes and hopefully this allows some recovery and gaining the distance to improve the ride is definitely worthwhile. I have not been successful in finding the metric that suggests how much of a rise is "okay". The best we can do for now, is to weigh your rig to ensure the weight is even all around the tires as much as possible, but that doesn't answer the question "how much off the level before the suspension is impacted"?

At least, our longer rigs allow that the rise to not be as bad. I have seen so many 5ers especially the shorter ones that are riding so high it almost looks like the front axles are in the air. That is definitely not good. I have also read in the past that a severe nose down is worse (I don't remember why), and I see that with TTs more than 5ers.

[Larry]

You might get both axles weighed seperatly and see how more you are carring on that rear axle.

[Art-n-Marge]

Yes, and side to side, too! To know the weight on each tire. Even if all tires are within their weight capacity, one tire carrying much more than the others will cause that tire to wear out much sooner than the others even if they look good.

If the tires weigh the same and there is a slope to your rig, then the suspension difference can affect a tire/axle wear (and weight distribution) and this is the part I don't understand. Tires are weighed at a standstill and without any suspension concern, but if you cannot travel level, how much of a slope is a okay until your suspension starts beating up the rig and you because it has some limited travel? This post is starting to become off-topic since it was originally about the 5th airborne kingpin causing a slope. I'll start a new one if I am able to locate how this works.

[mtheo]

I also have a 5th air borne and it did lower the pin a little. 2" maybe.
I also used the highest set of hole in the frame for the pin box, I did not use the same holes as was originally used. and lower the hitch in the TV one hole, about an inch.