Sub frame for 5er to clear edge of bed.....

[jelag]

So I have a new to me, 2013 2WD, 3500 Laramie Longhorn.... its a great truck, low mileage and it has never towed...

The bed is 37" off the ground and the bed rail is now too high for my 5er... I've got to mate the two together to get an idea of what size of rectangle tubing to use... to get the correct lift... at this point I'm going to see what the squat will be on the truck... about 2,700 lbs tongue weight...

I want the 5er to be as close to level going down the road as possible... so that I have close to equal weight on the axles...

My thoughts are 3/16" wall tubing... 2x4, 2x5, or 2x6 based on my needs... I'm thinking of using 2 pieces, 10 ft long to weld along the frame hanging new hangers on the tubing..... to correctly space the axles..... I'm just guessing that the extra length over what I've read... (7 ft) would add some stability.... I'm also thinking of welding a piece of 1/8" thick, x 6" wide strap between the frame and the tube to allow space to screw both the aluminum skirt from the outside of the trailer... and the plastic sheet that covers the bottom of the trailer... thus allowing the new sub frame to extend down...

I would also reinforce the hangers... and assume I might have to look for a 4 step, step for the RV instead of the 3 step, step that's now on the coach...

Any or all thoughts would be appreciated... if you've done this,,,, or thinking of this.. please chime in....

Jim

 

[Dieselnerd]

I recently had my trailer fitted with a new independent suspension with disc brakes and also lifted. They used 2 X 6 inch square tubing and mounted the suspension brackets on the tubing. This was done by a custom trailer builder and they do a lot of 5th wheel lifts. This is the second one I've had lifted this way and I'm happy with it.

Here is a picture I just took. They used about 5 feet of tubing on each side.

 

[jelag]

Ron.... is that what it took to get the trailer level and high enough for the bed on your truck... my 2013 Laramie 3500 2WD has a bed that sits 37 1/2 off the ground when it sits empty.... my first thoughts was maybe 4 or 5.... but some measurements today... leads more towards the 5 or 6" lift.... what did you do about your steps...

Thanks for your thoughts

 

[Killer223]

can you role the axles over on the trailer, most are springs under axle, i moved mine to spring over. was perfect.

 

[Dieselnerd]

My trailer was lifted a total of 3 inches.

My DRW with it's high load capacity just touches the overload springs with the 3200# hitch weight. My previous SRW 3500 sagged enough that the trailer was level.

The reason for the 2 x 6 inch tubing is the torsion suspension axles sit 3 inches lower than the old spring suspension did.

With the 3 inch lift, my triple steps still work fine and my rear Jacks reach too.

 

[rynosback]

Jim,
Not sure where you live. I have a 15 Ram 3500 4x2 and had two inch risers added to my MS when I ordered it. Everyone said that I would be fine, but it did not add up. So I did it thinking better to have more bed rail clearance and make sure that I was towing level. I would go to Moryde as they are a first class operation and do excellent work.

 

[jelag]

I believe in the torsion bar style axle... however this RV is now 10 years old and lots of miles... the old truck is sold, the new truck is getting ready to tow.... and we need this RV to go another 12 months before we replace it... so we're not going to spend the money now for new axles... however I'm skilled enough and have the proper tools to put in my own step frame... hopefully you can see that from my first post... what I'm trying to do is get feedback from those who have done this in the past... and maybe catch a step or two that I might not have thought of.... I'm now guessing 4" or 5"... the supplier who will supply the tube has both in stock...

 

[CBari]

Jim, you might try hooking the trailer up on flat level ground and then using two bottle jack on each side of trailer between the axles and lift till trailer is level. Once there place wood blocks equal to the distance you moved the trailer up under the tires and set the trailer back down to load the suspension and double check your height and level of the trailer. Measure twice cut once you know. Extra work this way but takes the guess work out of it.

 

[ScottLewis]

Most definitely determine the bed height with the load on it. When I bought my '06 I was sure I'd have to have a sub-frame for the RV built. Even got them to reduce the price of the truck because of it. The '06 was nearly 5" taller than the '98 2WD it replaced. When I hooked up the RV, the bed dropped nearly enough to level the RV.

 

[Deleted member 995608]

My vote goes towards the sub frame over a spring over conversion. For what the dealer charged us for a spring over, just a few more dollars would have gotten a sub frame from reputable trailer builder and kept the springs below the axle.

 

[surfbeetle]

I too have this issue with my new truck. I have found this https://www.trailerblocks.com/collections/4000lb-to-7000lb-axle-kits but I'm not sure if that's the way I want to go. The spindles on my axles are higher up than the centerline of the axle. I was considering swapping the axles to straight axles to gain the height.