Rear suspension mods needed for Hawk Shell on 3/4 ton truck?

[Stringer]

Hello,

I'll be picking up a new Hawk shell soon.

I drive a 3/4 ton Chevy Silverado. Aside from maybe getting E-rated tires, is there a clear need to make any upgrades to the rear suspension? I've read about torklifts, sumo springs, air bags, etc, and wondered how necessary all of it is for a 3/4 ton. My plan is to keep my load as light as possible. I'll delete the rear seats and the tailgate.

I will likely be off pavement a bit here and there, but I'm not planning on rock crawling or getting into anything too crazy.

However, I do have a 5x10 cargo trailer that I plan to tow occasionally. That, at most, would have a dual sport motorcycle in it, but most of the time it will likely just have random camping gear and bicycles in it.

With this in mind, what say you, experienced campers of WTW? Do I need to beef up my rear suspension, and if so, what's the best way to go about it? If I need it, I'd ideally love something that is as simple and minimalist as possible (I don't love the idea of needing a compressor for airbags and needing to make adjustments to them regularly - I think I'd rather have a "set it and forget it" type of solution back there, even if it means a stiffer ride). Also, for what it's worth, I plan to have the camper on the truck full time, so I'm not worried about how the truck would ride unladen.

Many thanks!

 

[Wandering Sagebrush]

My 2¢ worth. Measure and record front and rear truck height (ground to top of wheel well opening) before the camper is on. Measure again when camper is installed. If you believe it makes the rear squat too much, decide which method you want. Since your camper will be on all the time, I believe a modified spring pack might be your best option. Consult a reputable suspension shop.

 

[Beach]

You should be ok, if you don't carry an excessive amount of gear in the camper and the trailer tongue weight isn't heavy. Get E rated tires and good H.D. shocks to start with. Install the camper and all gear and drive it, get the rig weighed, then decide if any mods are needed.

 

[RC Pilot Jim]

My 2.5 cents worth (inflation)
The 3/4 ton truck is the ultimate in hauling trucking. Back in the day (1986) we had a 2,500 pound Lance camper sitting on our 3/4 ton 1977 Chev Silverado 454 V8, Turbo 400 trans, 3.74 rear gear - 4 door that also towed a 18 foot ski boat on stock rear suspension. plus 4 passengers and it got fairly decent gas mileage (8-10mpg) for the weight . Course gas was $1.25 per gallon

What needs a spring upgrade is half and quarter ton trucks like below.
My old semi - improved 2012 Eagle shell with the awning weighed 1,300 pounds dry.

Food, water, firewood, chairs misc , beer for one person, for one week in the desert weighed another 350 ponds.
Occasionally I also towed a 1987 Suzucki Samurai.

The tow vehicle is/was a 2012 Tacoma 4 liter V6 4WD.with 3.74 rear gear (towing pkg) . Lots of low end torque Camper was mounted full time. My local suspension shop changed out the springs for those that supported 1800 pounds.

Camper bolted down full time for 8.5 years and 67,000 miles with no problems. Mileage 12.5-16. 14.5 with Suzucki.
You will have no problems with a Hawk shell on a3/4 ton truck with stock suspension

 

[jdavis]

I have my Hawk on a 2500 Ram. The truck feels good when I'm driving with the camper on. I have an aftermarket sway bar and air bags. I don't put much air at all in the bags because the camper only squats the backend about an inch.

Before I had a Palomino that was quite a bit heavier. That camper made the truck sway and feel a little unsafe.

 

[ckent323]

Put your camper on with all your gear and try it first. Load range E tires strongly recommended.

If the truck rear sits too low or you don't like the ride then I concur with the approach suggested by Wandering Sagebrush. Also be sure to check the spacing when fully loaded between the axle and the frame hard stop. I suggest a minimum of 2" clearance. Make sure the rear end when the truck is loaded is not lower than the front end as that can lead to handling and sway issues.

Both Deaver Suspension (Santa Ana, CA) and Alcan Spring (Grand Junction, CO) have good reputations.

The stock springs on my 1993 Dodge W250 3/4 ton were just too darn stiff and the front springs only had about 3/4" travel before the axle hit the rubber stop on the frame. The truck had a tendency to bottom out and give a hard jolt on large bumps (even speed bumps).

I had new front and rear springs 2" taller than stock made and installed by Deaver Suspension. Also new Bilstein 5125 shocks.

The truck now has a much better ride. The springs are a bit softer which leads to a bit more sway than the original stiff springs so I ordered a Hellwig anti-sway bar for the back. I am awaiting the delivery of the sway bar and I expect it will minimize the little bit of roll when going around corners that the softer springs caused.

I have never used air bags but I get off road enough and have read enough issues with air bag leaks that I decided against them. I would not want to deal with a deflated airbag on some dirt track 100 miles from pavement and help. I know some folks love them.

 

[ntsqd]

'96 CTD 2500, with the then 6.5' Phoenix in it sat level and the overloads were not in contact. Took a pretty good bump to make them make contact. I ran that combo on Load Range D tires for ~50k miles of dirt and pavement. In more than a couple ways I wish that I had that combo still.

The current Chucara XL weighs quite a bit more and the overloads are in contact. Load Range E's this time around.

 

[camper rich]

I have a Dodge 2500 SB with a Grandby on it and pull a 4 x 6 offroad trailer. I have made several Baja trips with a fair amount of off road. I was going to get heavier springs or airbags but my spring dealer talked me into Timbrens which replace the factory jounce stops and are half the price of airbags, plus, they are solid rubber and don't leak. Easy to install yourself and you put them on and forget them like you mentioned. I liked mine so much I added a set to the front also. They also help with the sway.

 

[Lighthawk]

I've moved to a RAM 3500 and our loaded Hawk gave 1" of squat after I added a RC 2.5" spacer to the front springs.
I did this to give room for 35" tires to increase our overall ground clearance.

I ended up adding Timber Grove airbags to put us back on an even keel. I tried rubber stops but they were too harsh on rough terrain when they would contact the axel. The bags modulate sway both in compression and extension.
In any case, measure for level so your ride is balanced.

 

[Stringer]

Thanks to all of you for great advice!

I'll keep the load light, make those measurements, get the camper on, and see how things sit - then go from there.

Excited to get out there. Thanks everyone.

 

[rubberlegs]

If your state allows, weigh your truck before and after the camper is installed at a weigh station. Weigh each axle with the trailer. Then decide with this information and the change in height someone else mentioned.

 

[ckent323]

Stringer, et. al,

Rubberlegs, your suggestion is good. Knowing the weight of each axle is useful particularly if trying to decide on suspension changes.


Before I talked to Deaver Springs I took my truck - with camper on, full fuel tank, full water tank all my camping gear and Wendie in the passenger seat, to a local public scale and got weights for front axle, rear axle and the whole truck. I then measured the height of the front and rear fender wells off of the ground (on a flat surface). Finally I measured the distance from top of the axle to the bottom of the frame bumper stops for front and rear axle.

I provided that information to Deaver along with my description of the ride going over bumps and around corners. Jeff Crosby (the owner of Deaver Suspension) used all that info to build custom spring packs for both the front and rear. He suggested raising the truck 2" to get better axle to frame bumper stop clearance (to increase suspension travel). He also had me measure the original springs and provide that information as well - see the proper way to do that in a FAQ here: https://deaverspring.com/faqs/

I actually had Deaver ship the springs to the local Truck shop that usually works on my truck and the local shop installed them. The local shop also measured for new shocks because the new springs are 2" taller than the originals. Getting accurate shock compressed and extended lengths are important. We also had to talk about valving of the shocks. The valving controls how fast the shock rebounds. My mechanic (also does suspension) advised on the appropriate valving selection. The Bilstein shock model I chose had two standard valving configurations for the lengths I needed. Custom valving is of course available but I was not prepared to get into that.

It turned out that the rear spring height after install was too low. I had to drive it that way for awhile and the sway was bad. The truck rolled too much when cornering. I contacted Deaver and explained the issue with rolling. Jeff said he apparently made a mistake designing the rear spring pack and recommended just bringing the truck there to let them make it right. I made an appointment to bring the truck down and they removed, rebuilt and reinstalled the rear spring pack in an afternoon (no charge of course). Jeff said that if I have any additional issues just call make an appointment and bring it back in and they will make it right. He said that the softer springs will still give a bit more roll on cornering than the original stiff springs and suggested adding a rear sway bar if it is more than I am comfortable with.

After driving the truck a few hundred miles on combination of freeway and around town I decided to order a Hellweg sway bar for the rear. I am also going to order a 2" drop Pittman arm as the angles on the original Pittman arm are a bit more than optimal.

I am happy with the new Deaver springs and I recommend Deaver.

All that written, I was a suspension novice going into this. I have learned a lot. I strongly recommend going to a suspension shop that is familiar with 4x4 light trucks, particularly on whatever make and model you have, and discuss options before jumping into any suspension modifications. As with most modifications there can be unforeseen consequences to a change which may lead to a succession of changes.

Side note: The Deaver shop is a step back in time. It is in a former blacksmithing shop. The overhead belt pulleys and shafts for equipment are still in place and there is one belt drive drill press still in use. The company was founded in 1892 by blacksmith Frank Deaver and made Buggy Springs and transitioned into motor vehicle springs. They have been in that building since the 1920's when they moved from the first shop that was across the street (now an apartment complex) and the company has been owned by 4 successive generations of the same family.

I hope some of this info is useful.

Craig

 

[ntsqd]

Some truck stops have private scales and I've found those to be more agreeable in dealing with non OTR trucks.

A footnote, Craig, that 2" drop pitman arm is going to work the lower bushing in the steering box a bit harder. If they are offered for your truck I'd look into the bolt-on support bearing kits that place a bearing below the pitman arm by using a custom nut.

 

[ckent323]

ntsqd,

Thanks I'll look into that.

However, I'm not sure I understand the issue. Presently the hole in the Pittman arm (9) is not orthogonal to the bushing bolt (13,15) on the drag link (14). Although, the bushing itself is cone shaped so that centers it up. It seems to me this puts an uneven load on the drag link bushing at the Pittman arm and also at the drag link steering arm bolt and bushing (12) (note: my drag link is solid not adjustable).

Since the cone shaped bushings are compliant doesn't that minimize any load on the steering box (7) spline, whose relationship is held orthogonal because of the shaft and spline? It seems to me this is a wear issue on the drag link bushings and may effect the steering a little because of the angles of the bushing bolt to the Pittman arm. I am no expert on this so I'm not sure I understand the interactions of all these parts and what happens when things are changed.

In my research on lifting these trucks (1993 Dodge Ram W250) I read that when these trucks are raised 4" or 6" a dropped Pittman arm is required (for example, Skyjacker makes 2", 4" and 6" drop Pittman arms for this truck model to go with their various lift kits). That written I did not see any requirement to replace the stock Pittman arm for a 2" lift only that it was suggested.

Writing this up which is making me think more about this, I realize one thing I have not done (and will do) is to check to see if the drag link is still parallel to the ground or if it is at an angle to the ground. If it is still parallel with the stock Pittman arm then a drop Pittman arm is probably not the right thing to do (that would probably make it not parallel to the ground).

The following diagram shows my steering linkage.

 

[ntsqd]

OH! I assumed that those trucks were like their 2wd cousins and the second+ gen CTD's with a drag link that crosses the chassis CL. There may not be such a kit made given the drag link being parallel to the chassis CL. The issue is that even though you haven't increased the center to center length of the lever, it is now working in a plane that is 2" lower than the lower sector shaft bushing was designed for. If that seal at the bottom of the box starts to leak it more than likely is because the bushing is starting to wear. You may or may not notice the subtle lack of steering I/O loss.

Anyway, OP, I think that you'll find the existing springs are more than up to the task. I'm assuming that your Silverado is fairly late model in which case the rear springs under it are THE spring to use in a LOT of rock crawlers (after removing a leaf or three). They're a very good design that rides well.

Once the Chucara XL had been in our truck for a while I noticed that the rear springs were sagging. Worse they were sagging at an angle due to the poor location of the pair of 2GC batteries (as far the right rear is is possible). Not long ago I had our local 4WD Specialist replace those springs with new, OEM type springs. He wanted them ordered for the max load capacity offered, so in effect he put 1 ton rear springs under the truck, and then tuned them (by selectively removing leaves) to sit level with the camper in the truck. My point being that if they do sag that you likely have an OEM spring type option as well. Delivered these OEM type replacement pair of springs cost about what one Deaver spring costs. Not to say that Deaver's are not worth their price because they are. (I have a set of Deaver's under the FSB that I wouldn't trade for any stock spring.) Just that there may be lower cost, reasonable quality options. I believe that the springs that I bought for our camper came from General Spring.