Transforming a 2500HD into a 3500HD

Suspension Upgrades for a Chevy 2500HD

Michael King's Northstar Laredo and Ram 2500HD - Truck Camper AdventureAlready own a three-quarter-ton pickup truck and can’t afford to buy a one-ton truck to haul a truck camper? Then you’ll want to take a look at this article by reader Michael King. Michael lays out the strategy and approach he used to upgrade his Chevy 2500’s suspension to haul a Northstar Laredo SC truck camper.

Truck Camper Adventure’s recent article concerning the limited payload of the Chevy 2500HD is spot on. The F-350/3500 series pickup truck is the preferred platform to haul a hard-side truck camper. I own a 2015 2500HD crew cab with the 6.0L gas engine with single rear wheels (SRW). In this article, I’ll discuss how my needs changed after switching from a Four Wheel Camper (FWC) Granby pop-up to a Northstar Laredo hard-side. Full disclosure, I’m slightly over my truck’s payload rating and I’m okay.

I’m a big guy (6 feet 5 inches). After years in the corporate world, I was finally on my own. Starting a business you want to save every nickel, and I was tired of flying, so I decided to use my truck camper as a mobile office. There are quicker ways to get to your customers, but not with the flexibility that a truck camper provides. I found my FWC shell via Craigslist, a farmer needed cash for an almond shaker. A deal was struck and a few modifications later, I had my mobile office.

The Grandby’s weight was 1,100 pounds, so there were no issues with the truck’s payload, but after a year of use, the excellent FWC showed its limitations as a mobile office. During cold weather (9 degrees), I would release latches, leave the top down, crawl in, set the thermostat at 58 degrees and call it a night. In the morning, I would push up the top, make coffee and oatmeal, and get ready for the days’ drive. I got good at configuring the interior for sleep, shower, or a mobile office, but there was a down side. While driving on more than one occasion the rig didn’t “feel right,” then noted to my embarrassment that I forgotten to lower the roof. Moving to a hard-side was more a convenience due to the time it took to raise and lower the roof at rest stops. Doing this two to three times in a day, over a month on the road gets old quick. Hard-side campers don’t have that problem and are great in that everything has its place. It was time for a change. Based on Mello Mike’s review of his Northstar Laredo, I decided to upgrade to a Laredo in October 2016. I did the deep dive into the needs of my rolling man cave and learned about my truck’s Gross Vehicle Weight Rating (GVWR), axle ratings, and payload.

king3 - Truck Camper Adventure
My first truck camper, a FWC Grandby pop-up.

Through research, learned the payload of my Chevy 2500HD was limited for the new task and had to decide if getting another truck was necessary or if it was possible to continue using it. After working the math, I chose to keep it after noting the numerous aftermarket options. The payloads of a Chevy 2500HD and a 3500HD are 3,140 pounds and 4,080 pounds, respectively, and investigated why there was a difference between the two trucks. It came down to three things: rims, tires and springs.

First, a look at the rims and tires. The Chevy 3500HD rides on 18-inch rims while my Chevy 2500HD WT has 17-inch rims. Tires are rated different as well. My tires are LT245/75/17 load range E 121/118R, while the 3500HD has LT265/70/18, load range E 124/121 tires. The key is the load range number, this tells you how much weight each tire can support. Size 245 tires support 3,195 pounds, while 265 tires support 3,525 pounds—the 330 pound per tire difference gets the additional 1,320 pounds of payload of the 3500HD. I’ll save everyone time and say there are no 245/75/17 tires with a 124/121 rating. Only one tire in 17-inch rims will get you 3,700 pounds and that is a Nitro Tire Dura Grappler LT285/70R17 E 126. Note, tire height and width are different and should you elect to put them on your truck your speedometer should be reprogrammed. Chevy will do this for $220, but only with stock tire sizes. The 285’s could be large enough to change speed odometer settings to think it’s 18-inch rims.

Next up, the leaf springs. A 2500HD has five leaf springs, four mains and one overload positioned under the mains with no bump stops. The 3500HD has seven springs. Four mains, one overload under the mains and two overloads above with bump stops. Chevrolet, uses the same frame for both trucks and upgrades springs, rims and tires to increase payload capacity of its 3500HD. One could add springs to the suspension ($700) and/or upgrade to higher load rated tires and rims ($1,000 to $1,500). Ebay has good prices on 18-inch rims. If you can afford it, getting these can easily upgrade a 2500HD to a 3500HD.

As for my new Northstar Laredo truck camper, the dry weight of the camper is 2,066 pounds. With a full water tank, loaded refrigerator, electric jacks removed (saves 128 pounds), two batteries, a roof rack, awning, and an entry ladder, I’m at approximately 2,430 pounds. Thirty six gallons of fuel, add another 222 pounds. Another 60 pounds for food, clothing and kitchen ware brings the weight up to approximately 2,712 pounds. Add airbags, Torklift tie downs, a rear sway bar, and plywood sheet to get camper sides above the side rails, as well as tools, and a Honda generator. Fifty pounds of metal for a generator mount/crash bumper and myself, the scale reads 9,742 pounds. This is only 242 pounds over the 9,500 pound GVWR of my truck and a number I can live with.

In order to handle this extra weight, I added a few modifications including rear sway bar, fabricating a pair of bumper stops to engage bottom over-load springs sooner, and installing a set of airbags. According to the GVWR sticker in the driver door frame, the maximum GAWR axle weights are 4,400 pounds front and 6,200 pounds rear. According to the scales, my axle weights are 4,320 front and 5,420 rear for a total of 9,740 pounds, these weights are well below the axle ratings. Keep in mind my tires support 3,195 pounds at 80 psi each and are well within load range specifications. I can report abrupt lane changes at 60 mph with no problems. The truck has no sway and maintains control driving Interstate 10-40-80 cross winds.

While most trucks are registered as commercial vehicles, no special licensing is needed to operate a truck camper. Enforcement is reserved for trucks operating commercially. However, if an officer observes an unsafe operation, i.e. sagging or excessive sway, you’ll get pulled over in a heartbeat. Note, I drive no faster than 65 mph and usually at 60 mph even when the speed limit is 75. Mindful that you’re controlling 5 tons, dealing with cross winds can be tricky and you may need to make an emergency maneuver. A slower driving speed gives you time to react, reduces stopping distances, and saves on fuel.

Michael King's Northstar Laredo and Ram 2500HD - Truck Camper Adventure
My new Northstar Laredo hard-side.

I really like my NorthStar Laredo/Chevy 2500 combination. It makes a good mobile office without having to pay $100 a night for a hotel room, plus I can cook my food and enjoy “flyover” country. The savings for my business are pretty significant. I can stay on the road for 50 days and spend only $1,800. The 6.0L gas engine allows additional payload over the Duramax diesel, and combined with 4.10 rear end, is a respectable tow/haul combination. The grade assist transmission, if set correctly, holds mpg almost as good as an Allison transmission. The gas mileage is pretty good, too. Driving below 2,000 RPMs and no wind, the mpg for my rig, hand calculated is 12.5 to 13. On back roads, 13-14 mpg is normal and considering cost per mile basis, it’s hard to beat the gas motor.

In closing, if you want a hard-side truck camper, buy a one-ton truck. You’ll pay a bit more, but the extra cost is worth it in that you won’t have to modify the suspension or have to buy bigger tires. However, if you already own a Chevy 2500HD, it’s possible to safely haul a hard-side camper if it’s not too heavy and if you make certain suspension modifications to the truck.

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About Mike K 2 Articles
Michael is a Florida native, California transplant, and outdoors enthusiast. He served 13 years in the U.S. Marines, working on aircraft and as a Combat Engineer Officer specializing in building bridges. Michael now owns his own packline business and uses his Northstar Laredo truck camper as a mobile office to meet prospective clients and to check on current customers. In his off time, Michael enjoys beach and mountain-lake camping with his wife and kids and exploring "flyover" country in his Northstar Laredo. His hobbies include wood and metal fabrication, cycling, and fishing.

6 Comments

  1. can you share the part numbers you used for this conversion? I’m looking into doing this on my truck, exact same body style.

    • Look at the load rating on tires. Purchase ones having a 4000+ load rating as well.
      Note: I purchase the Coopers with that rating with better sidewall. Gained 1 mpg per gallon but lost pulling capability. Coopers (285’s) lowered my ratio from 4:10 to 3.74. Everything is a compromise when Truck Camping.

      Now have 230K miles on my truck with an Arctic Fox 811. One heavy TC

  2. Rims, tires, and springs. Mike I cannot address Chevy, but I will address Ford…its more than rims tires and springs. It’s the rear axle, that is what determines the load capacity. The rims and tires and springs are all a part of the support and operational package that works in tandem with the rear axle. Now it could be the Chevy 2500 uses a 3500 rated axle, I dunno, might be something to look into and making an axle swap is not hard, junkyard and a couple of hours of your time.

    That said, I discovered years ago that the difference in price for the same-same truck except a F 250, vs an F 350, is measured more in hundreds of dollars rather than thousands.

    Given that I personally have found even the F 350 sorely lacking in MY performance and safety envelope. Now I don’t run light or small TC’s. My Arctic Fox 1150 is an F 350 Dually class IMO. But wait, there is more: I add a Big Wig rear sway bar, Rancho RS 9000 XL adjustable shocks and Tork Lift Stable load Upper Stable Loads. Now the performance and safety envelope has been expanded to the point I feel comfortable.

    When you toss a TC into the bed of a truck you have added more weight and you have raised the center of gravity. The number one thing you can do for the CoG issue is bigger sway bars. I run the Big Wig and I have experimented with running it on the front also. I would say for the Rear BIG WIG don’t leave home without it. Add the front and the truck will go around corners like a rocket ship on rails at a big cost in ride comfort.

    My personal views are most likely different. My driving for most of my almost 60 years behind the wheel has been in short wheelbase high-performance cars, I have never owned a sedan in my life. Also as an engineer (retired), I want to keep my family safe and as you add a TC to the mix you are correct there are mods that should be made to ensure increased safety. Generally, most who add payload to their trucks only do so to meet a short term need from point A to B. But a TC can sit in the bed for months as we travel and our use factor needs to be considered in mods we make.

    Thank you for your article on the Chevy, I would never have thought it was that close on them. Albeit I grew up with Chevy ranch trucks and the weight we put on and behind was nothing short of amazing.

  3. It is good to see that some people do the research and realize that many trucks are tye same even though they have different badges and ratings. I have been in the auto repair business over 50 years and still do restoration and repair in my home shop. I compared Dodge 3rd generation trucks in addition to the Cheverolet . 2500 vs 3500 they have the same axles front and rear , same brakes, same frame, even the same wheels when comparing SRW. They have different spring options, and when they show different ratings on the axles it is because they rate them as an assembly. Changing the correct parts can give you the same performing truck.

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