Forum Discussion

MTBob's avatar
MTBob
Explorer
May 30, 2013

Lifting My Rear End - Rev 2

This post is a continuation of my earlier post relating to inserting spacer blocks between my upper spring pack and lower overload spring.
see: http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26944326/srt/pa/pging/1/page/1.cfm
As a follow-up to my earlier posting, I traveled about 800 miles with the initial 1/2" puck inserts as shown in the previous post. And, just like someone mentioned, YUP, because I didn't have them bolted onto the overload spring, I lost one. I was going over some extremely rough roads east of Glacier Park, MT - really, really rough frost heaves and broken surfaces.
So, when I returned I replaced all the bolts with stainless and drilled & tapped them for a 5/16 securing bolt. I applied medium grade loctite to the 5/16" bolt as a shake proof restraint. I also added an additional 3/8" plastic insert to the puck, giving it 7/8" overall puck height. This is about the same spacing when the camper is not mounted on the truck.
Here's how the puck set up looks now:

After talking to an suspension shop and an alignment shop, they both pointed out another problem resulting from my previously sagging rear end. The front tires have abnormal wear on the outside edge, indicating the camber is improperly adjusted. This is apparently caused by the truck not being level, after only 20,000 miles.

To determine if the truck is level, I'm now measuring the height of the wheel well to the ground, front and rear. With these 7/8" insert pucks the truck is within a 1/4" of level, with about 15 psi +/- in the air bags. That puts the truck suspension strongly in the overload spring and it has raised the rear end significantly. Unfortunately, I don't have a before & after measurement of how much lift I got with the puck inserts. But, I do know that the truck rear end is about 4 - 6" higher.
So, I'll run the rig set up like this for a while and see how it works.
By the way, the High Density Polyethylene (HDPE) plastic seems to be holding up very well. However, Interstate Plastic in Boise recommends Ulta High Molecular Weight (UHMW) plastic for this application. They say the HDPE can crack at temperatures below freezing and that UHMW is a tougher material. If I see problems with the HDPE pucks I'll change over to UHMW material.
Bob

14 Replies

  • Several TCers have installed front hitches on their trucks, and then use a hitch mounted carrier, and put heavy items up there, like generators, extra fuel cans, extra water containers, that sort of thing.
  • Whoa, no jokes about the wife making good ballast! haha
    Made that mistake once when we were surfing behind the boat! Never again, she can sit where she wants!
    Yes obviously cant move the camper forward. You can try to get as much heavy stuff forward in the camper, of course putting stuff in the overhead will stress it out and make you more top heavy.
    Do you carry a generator or anything heavy on a rear hitch rack?
    Could put a front hitch on and load up heavy items off the front bumper.
    Is the truck a long bed? How long is the camper?
    I know my setup would do the same thing on a IFS truck.
    Does your DMax already have a leveling kit,(leveling keys)? Those throw off the camber if not re-aligned.
    You may actually have some positive camber already before loading up the back of the truck. Might not all be due to the camper weight.
  • Grit dog wrote:

    IMO only thing that will cure your tire wear issue is to get more weight forward on the truck so that the front axle is seeing close to normal weight.

    How would you recommend that I move weight forward? The camper is flush with the front of the truck box. Other than mounting my DW as a hood ornament, I can't see a way of increasing the front end load.
    Suggestions?
    Bob
  • Good info!
    I need to do something similar to mine. Just wish the overload spring had a hole in it like the chevies. Need to get a little more creative on how to secure them. Kevlar duct tape?? haha

    Regarding your front tires, I believe it was not primarily becasue your truck wasn't level (rear sagging), but because you have enough weight on the back to unload the front suspension. Leveling the truck's ride height will not do much towards transferring weight forward.
    Solid axle trucks dont have this issue becasue the camber does not change with position of thesuspension where it does with an IFS.
    If you re-set camber to account for the loaded condition you'd have negative camber when unloaded and wear out the insides of the itres instead when empty.
    Example: My setup is heavy in the back. CG of the camper is behind the rear wheels by about 8", combined with the trailer tongue weight, even though my bags level the truck up, steering is still light. In the 2000mi maiden voyage with the camper last week I had zero noticable front tire wear (solid front axle) and took about 10k miles off the back tires. Of course my tires arent ideal for heavy loads either. They have the capacity, 3950lbs/ea, but being siped mudders they wear rather quickly under heavy load.
    IMO only thing that will cure your tire wear issue is to get more weight forward on the truck so that the front axle is seeing close to normal weight.