Need help with a truck/camper suspension upgrade

[drewactual]

Bilstein offers a 5100 series as well as a 4600 series. There is some talk elsewhere that the 4600 series is for heavy loads like a truck camper and the 5100 series is for lifted trucks going offroad. Comments?

Just checked on my rims and they are rated to 3600 pounds.

4600 are called heavy duty, and they're fine shocks for road use... the 5100 series are usually extended shocks and the valving is often specific to vehicle (which I believe to be a gimmick, as they've zero clue how you use your truck)... most of them are functional and will be for a long while, but some fail out of the box... to add to that, the plating leaves something to be desired, too, and they can look pretty bad after a short while... I have 5100's on my rig... I've had 4600's or 5100's on every rig I've ran... but I won't anymore. from bilstein I may run a 5150, but since I'd be dropping that much I'd likely go ahead and step up to FoxRacing...

The FoxRacing and their direct competitors are hardly comparable to the monotube body shocks at all, they are so much different in ride quality, fit & finish...

you look to have taken the time to do your rig right.. and it shows... I wouldn't fall for the bilsteins... they are living off of reputation from era's long past.

 

[1stDeuce]

I'll kinda second what Drewactual says... While I am running 4600's on my truck, and they do fairly well, I have a set of XJ 5100's that are HORRIBLY stiff, and yet I have experience with the 3-4" lift TJ 5100's that ride amazingly well... What exact vehicle they "tuned" on makes a HUGE difference. My guess is the TJ was running fairly reasonable spring rates for it's weight, so the shock only does damping duty on a well tuned suspension, as it should. When they did XJ tuning, I suspect the XJ was a good bit over weight for it's spring rates, so the shock damping was much stiffer to compensate. Therefore 5100's are a crap shoot in my experience.

I will say that the vehicle weight and spring rates for 4600 series shocks are not likely to differ much over applications, so tuning should always be fairly reasonable. And there's a "with camper" version of the rear 4600's that might work OK in this case, particularly if an appropriate leave pack is used.

As for custom springs, I still think you're fine with a local place, but I've used Eaton Detroit Spring in MI before. They did pretty good work for me, but that was 15 years ago...

Good luck!!

 

[rrliljedahl]

I am too far down this path to change vehicles.

Would it be cheaper to convert this gmc 3500 4wd to a dually or to do a 19.5 wheel/tire conversion?

Just a ballpark figure.

 

[IdaSHO]

Rear axle and bed swap would cost you peanuts compared to a 19.5 conversion.

Its rarely cheaper to do a 19.5 conversion than practically anything. :Wow1:

LOTS of coin wrapped up in such a conversion. The DIY way with used parts is still a $4k+ venture.
Kits available online run about$3k, then you have to have tires fitted at $300+ each plus mount and balance.

That said, once you go 19.5, the tire life and stability when loaded is MUCH better than what youve got now.

 

[Seabass]

We run an 08' F-450 on the farm. It has factory 19.5's and its amazing how well it can handle a load. You know, I bet you could source a used dually rear axel and them buy a pair of steel rims and put a set of super singles on it. They would be "G" rated. There's a company that sells a custom wheel that would allow the truck to track properly with an inset wheel on that dually rear end. Then the bed wouldn't have to be changed. The tires and wheels would still carry a fair ticket but.....with a real good set of springs, the heavier dually rear end, and super single tires, that truck would be as heavy and capable as it would ever be. I'm not totally convinced the frame will ever really give trouble. It will....or it won't. I'll try to remember what company was selling those wheels. They are often used on 450's and the likes for people that don't want a dually any more. I had a dodge dually for several years and I seriously considered a set of those wheels because a dual wheeled truck sucks in the mud. Ultimately I sold the truck and bought my OBS ford.

 

[IdaSHO]

Super singles is an option, but not one I wold entertain unless he did the swap front and rear.

Otherwise there is a need for always carrying two spare. Just more weight.

A dually rear end is going to be the cheapest alternative, and can be done with 100% OE components

I'm not totally convinced the frame will ever really give trouble. It will....or it won't.

IMO it totally depends on how the front of the pivoting frame was set up.

He is carrying a LOT of weight on those two locations.

 

[pappawheely]

IMO it totally depends on how the front of the pivoting frame was set up.

He is carrying a LOT of weight on those two locations.

I would question the strength of the aluminum structure before the truck's frame. Is this the same truck that went to a questionable builder and had to be revised? I apologize if it is not.

 

[IdaSHO]

You know.... I had to do some digging but you are absolutely correct.

Same truck.

But after digging up these previously posted photos, I'm more worried about the chassis than anything any more :Wow1:

Im having trouble really sorting out how it is attached, but one thing is clear, the mounts look to be attached (welded, bolted, ??) to the webbing of the frame and not the top.

Regardless of attachment method, it doesn't look good... That's a LOT of leverage on that frame.

I have a new question about the front mounts on my pivot suspension.
They are 2x4 aluminum box tubing but with no sleeves or bushings holding the grade 8 bolt.
Is that a problem?
View attachment 267416
View attachment 267417

 

[Buliwyf]

Is it possible to score some used 550/5500 or 350/3500 DRW wheels and apply them to his stock axles? The front axles would need some sort of hub replacement, right? I'm not a GM guy so.....

Most of the Ford Superduty upgrades I do are based n take off parts found on Ebay from chumbs turning their tucks into pathetic brodozers. Plenty of nice factory wheels. I avoid aftermarket wheels, they're either $$$$$ or weak. My tuck is an XL, so a set of Lariat or Platinum wheels really sets it off nicely.

 

[rrliljedahl]

Yes, this is the build where I successfully sued my original fabricator for never finishing my flatbed build.
http://www.expeditionportal.com/for...int-suspension-question?highlight=Rrliljedahl

I recovered my monies and moved on to another fabricator who with the advice of this forum finished my build.

I am not an engineer but will try to show what was done to my truck.



Original bed was removed.


Rear pivot was welded in.



After advice from forum members, my new fabricator sleeved the rear pivot and added bushings. He also reinforced the aluminum frame at the pivot point




Front upright tacked to the outside of the truck rails.
Yes it is cantilevered.

Front upright welded to truck frame with wooden block to support the aluminum bed.




After advice from the forum, my new fabricator welded a steel beam in horizontally between the two uprights and added gussets for reinforcement. I also added 1 inch HDPE instead of those small wood blocks in between the aluminum bed and the reinforced uprights.




Number 9 FNL bolts used to hold the aluminum frame to the front uprights.
In retrospect, I probably should have had these sleeved through the box tubing.

Now I will be the first to admit that I have been snake bit on this project from the start. It has taken me 2 years and 3 months from the time I purchased this truck until I had a completed camper. My marriage has suffered because my wife advised me to abandon the project right after I sued my first fabricator. I had a "dream" of a truck camper I could take off pavement but I could not afford a an EarthRoamer or a TigerRV. I now have the camper attached to my truck but the camper weight is 1000 pounds over the prebuilt estimate. I am simply trying to make the best of a difficult situation.

I am having 8000 pound rear leaf springs installed to handle the 7000 pounds of rear axle load.

I have ordered Fox 2.5 shocks with external reservoirs to hopefully help tame the camper rolling from side to side.

I now must address my 16 inch rims that have a load rating of 3600 pounds as my rear tires are carrying 3500 pounds on a CAT scale. I do not know what "factor of safety" was engineered into the rims when they were rated.

Some say my truck will never handle this camper. Others say just take it off pavement now and enjoy it after all the effort and monies I have put into it.

I am simply trying to do what is reasonable by asking for your collective advice in this most difficult situation.

 

[pappawheely]

Don't worry, everyone who goes the custom route has a steep learning curve. That's why this site is great; where else would you get the knowledge and experience that is here.

 

[pugslyyy]

Looks like you've made a lot of progress with the rig, congrats!

I have Deaver springs on my Fuso, but you will have more options than I did so may not need the full custom.

As others have said, I would get rid of the overload springs and go with a single leaf stack. Airbags are great for adjusting between different loads (we have them on our truck for when we haul a trailer with it) but not what you want to depend on for the standard load.

 

[topher800]

I finally have decent internet so I have edited my original post and added pics.

I am interested in recommendations as to leaf spring and shock upgrades.

Springs: I added an extra leaf, any spring shop can do that (cost me about $750). If you have an overload pack, get rid of it and get a custom main pack (or the GM pack you mentioned). I used Denver Spring (Denver CO) as they do a lot of utility trucks, they requested truck fully loaded and it came back sitting perfectly level. As other's have noted, upgrade the fronts. See if Chevy/GM has a front spring for snowplow trucks.

Shocks: I went with Fox Factory (adjustable and with reservoirs) 2.0 front and 2.5 rear. I had the rears custom valved for the axle weight by Fox. Other options exist (King, Fox, Sway-away, OME, etc). Interestingly, Denver Spring recommended Monroe shocks...but I hadn't told them I wanted to sustain 50mph over 30 miles of washboards with no fade.

Tires: I upgraded to a load E with a 4180lb rating per tire (Toyo OpenCountry A/T II 285/75R18). Don't skimp on tires, good to be 25% under capacity, unless you are all pavement.

I have a 2011 RAM 2500, GVWR is 9600# and 6010# GAWR Rear (sum of stock tires). My worst case weigh-in was 5140 front, 6420 rear, 11560 total (that was 3700# payload). Usually I am 300-400 lbs less.

 

[redthies]

I am simply trying to do what is reasonable by asking for your collective advice in this most difficult situation.

I think your remedy of a heavier (weight appropriate) custom leaf pack is the simplest solution to your issue. Hopefully you found a supplier who will be willing to add an extra leaf or two if you still feel you need it.

If you find some stronger wheels in 18", Toyo MTs are rated at 4079 lbs each in either a 295/70-18 or 285/75-18. The 295s are slightly shorter and fatter which might help with stability ever so slightly. You could get to 4289 lbs per tire if you went to a 37x13.50-17, but a Toyo has it listed at 37.0" tall and 14.6" wide!! That's a LOT of tire!

Your situation isn't ideal, but as long as you continue to think things through, and keep an eye out for stress on the chassis etc, you should be fine.

 

[Jeep]

Another product we sometimes use for heavily loaded trucks are Timbren rubber springs. They replace the bumpstop, kind of look like an air bag, have a little bit of travel. One thing they do very very well is stabilize the chassis, get rid of the sway. They are not connected to the axle so they don't inhibit down travel, and there is pretty much no risk of damaging them. They ride fine when there is a load on them, not so great empty but in my opinion they beat "add on airbags" hands down. On top of the handling benefit, is the benefit of having a very progressive bumpstop, you will never bottom out "hard". If this were my truck, I'd upgrade the springs to the point of handling the load properly, throw a good set of shocks in, and a set of Timbrens. Lots of good advice on tires above.