5th wheel lifting

[historybuff]

Originally Posted by DaveSchwartz

They don't (have any user-adjustability, that is).

Here's some research I did when this topic came up last year.

The start angle is set by the way the square hole is cut on the axle-end of the spindle arm and then its permanently welded on. The start angle is indicated by the axle part number so you could buy new axles with a different start angle.

The lift kit that Dexter sells is probably by far the better option.

Thanks for this link. I see the picture of the lift kit under the trailer. that looks simple enough. just looks like it adds 2 bolts and a plate to the existing axle mount.

[drstimpy]

4" doesn't seem like much on a 31' 5th wheel. Can you even tell visually that is isn't level? Seems like a major project for mostly theoretical gain. Be sure to know your new height for clearance. Isn't a raised trailer going to also be more of a sail and have a higher center of gravity? Just curious.


Some must watch while others must sleep

[historybuff]

Originally Posted by drstimpy

4" doesn't seem like much on a 31' 5th wheel. Can you even tell visually that is isn't level? Seems like a major project for mostly theoretical gain. Be sure to know your new height for clearance. Isn't a raised trailer going to also be more of a sail and have a higher center of gravity? Just curious.

Actually my concern isn't the levelness of the 5er, its the clearance at the bed rails. Getting it a little more level is only an added bonus. I need to get another 2" clearance so by raising the frame 3-1/2 inches and raising the hitch 2", theoretically I should have gained 2" inches of clearance at the rails and the front of the 5er will have only gained 2" inch height. The rear will have gained the bulk of the lift, about 5-1/2 inches.
Do my calculations make sense?

[MikeInRaleigh]

On mine, you can definitely see that it is off level. My main concern was overloading the rear axle, as the torsion axles are not load distributing like the ones hung on springs. After doing some calculations to estimate the extra load on the rear axle, I took the camper to a scale and verified that calculations were very close. The result was still within the maximum of the axle and the tires, but just to be safe, I upgraded to Load Range D tires. So I now have almost 1000 lbs. of margin on the tires.

[historybuff]

Originally Posted by drstimpy

4" doesn't seem like much on a 31' 5th wheel. Can you even tell visually that is isn't level?

Actually it wasn't me that said 4"out of level. I am more like 14" out of level. I will be installing the hitch this week and hooking up to take measurements. I had done this last year when I hooked the truck up for the first time but no longer have the measurments. Since then I have only traveled a couple hundred miles with it.

[MikeInRaleigh]

If you are 14" out of level, you are probably heavily overloaded on the rear axle. On my 8280 and F350, here are some measurements: Unloaded rail height = 57.8 inches, 8280 level height = 58.5 ", tailgate clearance 6.5". spring settling 1.5", yielding about 4" out of level front of the trailer to the axles. Loaded front axle weight =3260 lbs, rear axle weight =3820. Since the 8280 is rear kitchen, some of the weight difference could be from the trailer configuration. The axle rating is 4000 Lbs., and now with the load range D tires I recently installed, the tires are rated at 4900 lb per axle. If you are measuring the level from front to back, you would get a bigger number than mine, which is front to the axles. Mine would probably be more like 6 or 7 inches front to back, still a lot less than your 14". Looking at the specs, the 8281 has much more pin weight than the 8280, implying less axle weight, so if you can get a little more level, you may be ok on axle weight. Best to take it to a scale once you optimize the hitch and rail clearance and get the facts.

[historybuff]

MikeinRaleigh, My trailer compairs to yours in height. I just measured nose at 56-3/4, level but I am measuring from gravel which can be +or- a bit. My truck sits at 60" exactly unloaded at the tailgate. So the nose of mine would have to come up 11-1/4 inchs to have 6 inches of clearance. It would probably settle back down 3 inches. I measure front and back from the moulging strip that runs full length. right now it is 29-1/2 front and 29-7/8 on the back. So I am more like 16 inches out. I will know more tomorrow when i hook up.
When I started this thread I didn't realize how much I needed to change something.

[historybuff]

All is well, I guess. Just finished installing hitch and hooking up. 7" out of level front to back, that relates to 4 degrees on the level bubble. Truck squat is 1-3/4 ". Found rail clearance to be 6 inches on the mark. I don't know why I got such differant measurements last summer. I will remeasure about 100 miles into our first trip this year after everything has settled in. I guess the black top in the parking lot last year may have had a dip I didn't see. I plan to purchase new tires in the fall so I will go to load range "D" at that time, or before if necessary. Thanks for the feedback. I learned a lot. HAPPY RV'ING

[historybuff]

I emailed Forest River, they asked for pictures of my rig hooked up so I sent them a couple. They responded that it looked fine. They thought I would have no problems. I see no downside of having the load range "D" tires. So in the fall thats the route I will go. Until then, see ya on the hiway. Thanks for the help and the learning session.

[MikeInRaleigh]

Just finished a 350 mile tow each way last week, and measured tire temps at each stop. The rear tires consistently ran about 20 degrees hotter than the front. Also, the sunny side ran about 10 degrees hotter than the shady side. With the ambient of about 59 degrees, the fronts were running about 79 and the rear about 100. The pavement in the parking lot was also about 80. I never checked this kind of thing when I was pulling level with my Chevy 1500, so I don't know how much is due to out of level vs. just having the rear kitchen floor plan, where much of the load is behind the rear axle. Funny how your perspective changes. When I was pulling with the 1500, I was about 500 lbs. over the rated payload, so I put as much stuff as possible behind the rear axle to take load off the pin. Now with the F350, I am about 1500 lbs. under payload, so I move as much heavy stuff under the bed, in the basement, and in the truck!

[historybuff]

Originally Posted by MikeInRaleigh

Just finished a 350 mile tow each way last week, and measured tire temps at each stop. The rear tires consistently ran about 20 degrees hotter than the front. Also, the sunny side ran about 10 degrees hotter than the shady side. With the ambient of about 59 degrees, the fronts were running about 79 and the rear about 100. The pavement in the parking lot was also about 80. I never checked this kind of thing when I was pulling level with my Chevy 1500

I have always carrried a digital temp gun but never remember much differance in the tires. I usually just checked hub temps at fuel stops. Good idea to check tires, we get 100+ temps and the tire tempuature could really spike.

[MikeInRaleigh]

Checking at every rest stop paid off for me last fall. I apparently lost a grease seal, and the hub ran dry. The bearings had disintegrated and the wheel was at a noticeable angle. The repair shop couldn't get the race off and I had to have the axle replaced. I hate to think what would have happened had I not stopped at the rest stop.

[historybuff]

I'll be checking more carefully from this point on.