Class 3 and Class 4- 5 Comparisons

Class 3 one ton or Class 5-6 two ton? One class wins acceleration, the other wins braking

Ram (Dodge), GM and Ford One Ton Dually’s


Freightliner, Peterbilt and International

By H. Kent Sundling

With a one ton dually now rated to tow over 20,000 lb trailers, the difference between empty and fully loaded truck can be 4 inches difference in truck squat. That means trouble to the driveline and pinion angle which causes vibration, axle wrap and U-joint popping.

Then there’s braking, though one ton dually’s from the big three have improved their braking ability, they still aren’t great with big trailers. In the tests  and reviews I do with trucks, we run trucks on a race track with and without trailer brakes. Without trailer brakes, you’d be shocked at how far and long a new one ton dually diesel takes to stop without trailer brakes. It’s hundreds of feet at 60 mph.

Then take a class 5 or 6 conversion truck like the Freightliner M2 or Pete 335 and do the same thing with the trucks air brakes and engine brake and it will make you smile. And with air bag suspensions, they don’t squat when loaded.

Engine brakes are the same in over-the-road semi-trucks, which are dramatically more powerful than an exhaust brake in a one ton diesel.

Each new model pickup truck year has an increase in towing capacity. What is the limit? Truck manufactures don’t know, they work off demand. The new SAE trailer towing standards that start in 2013 will help, but at some point with 20,000 lb plus trailers, you are going to need a heavy truck with big brakes.

The term medium duty truck covers a lot of territory. It use to refer more to 2-ton trucks. Since 1998 the 1-½ ton trucks are coming back. In the “Forties and Fifties” a 1-½ ton truck was a common size. By the “Sixties” farmers needed more capacity and the 2-tons took over the market of medium duty truck. Now you see more and more big rigs on the farms that have all grown to match economics of size. The market for pickup trucks has once again become competitive. Bigger diesel power created bigger trailers and so on.

A one-ton use to be as big as a pickup grew up to. With trailers growing over 15,000 #’s truck manufactures have brought back the 1 ½ ton’s with the Ford F450-550, GM HD cab and chassis, and Dodge 4500-5500. With the growing trailers it’s so important to get the numbers in line for the maximum capacity of your truck.

You need to know the GVWR (Gross Vehicle Weight Rating) of the truck and the trailer. You need to know the GCWR (Gross Combination Weight Rating,) what the two together weigh. You need to know each GAWR (Gross Axle Weight Rating.) and you need to know the tongue weight of your trailer whether the tongue is a ball or mini-fifth wheel in the bed or a receiver hitch drawbar. Most folks don’t know that most of the tongue weight of a gooseneck or bumper pull trailer is on the rear axle, so the Rear Gross Axle Weight Rating is especially important.

Starting in 2011, the big three raised the GCWR from 26,000 lbs to 30,000 lbs on 1 ton dually pickup trucks. GM quit making C4500-7500. So they need to rate their 3500 high enough to compete. But Ram and Ford aren’t going to just set in the sidelines.

Now the other category of medium duty trucks, the 2-tons. I have worn out my share of trucks. No I really mean I wore them out! When I was done with them they were worth about $20 a ton for scrap metal. The springs were arced the wrong way, the box was gone, and you couldn’t tell what color the engine was from the oil dripping off it. But by then I could replace the starter, alternator, u-joints or clutch with my eyes closed.

Being a rancher/farmer meant my truck had to pay for itself with use. Being overloaded most of the time is what got the job done. I hauled livestock, hay, wool, tractors, balers, backhoes, buildings, trees and whatever “kind of fit” the trailer. I was overweight, over width, and under trucked. No not me, the truck!

After I replaced another set of u-joints in the drive shaft, I thought maybe I’m working my 1-ton dually too much. It had 300,000 miles on it and my Korean replacement door from the last time I jackknifed the trailer, was leaking so much air I couldn’t hear the weather report on the AM radio. So time for my next workhorse. I saw an ad for some furniture van body 2-ton trucks. They had 90,000 miles on them so they were already broke-in. My neighbor and I each bought one. Mine was a C65 Chevy. I took the 18 ft. van body off, leaving a flatbed and added a recessed gooseneck ball to the rear of the rear axle.

I pulled a 32 ft. flatbed triple axle trailer with it and had 12 feet to haul cargo behind the cab in front of the gooseneck. That was the most reliable truck I ever pulled with. It had a 366 cu gas engine and a 5-speed manual transmission with an electric 2-speed Eaton axle. I loved that truck and couldn’t hurt it. Ten gears, I was in heaven! If even rode nice. I couldn’t tell it was loaded, it had low axle ratios and would pull anything 70 MPH. Tires cost more but they also lasted longer. The most expensive repair I did to the truck was replace the king pins in the front axle. The next 100,000 miles were all trailer miles. So I do like bigger trucks with bigger brakes, trannies, axles and springs.

In the above picture you can see how much taller the M2 Freightliner is than the one ton’s, with more glass for visibility and a larger wheel cut for out turning some one tons. On dirt roads, a big truck can take more caution with the front axles as wide as the outside dual. This can make the truck steer toward the ditch on a soft road shoulder. One ton pickup trucks front axle is inside and matches it’s inside dual wheel.

In Freightliner M2, better visibility so you can see more deer in the mountains, air seat, 50 degree wheel cut, turns like a one ton This M2 Freightliner conversion makes hooking to a gooseneck easy, no worry about hitting the bed rails I helped where their “Hurt Locker” truck comparison, 3 new one ton dually’s towing 20,000 lbs Downhill is the dangerous side, stopping power is what separates 1 ton and 2 ton trucks, exhaust brakes on the new diesels help
Summit Hauler Super Singles Wide Base Low Profile tires handle better than duals 2013 Ford F350 Sterling (deceased) same as Ram (Dodge) 4500 is competition for Ford’s F450 We tow in the Rocky Mountains often for our truck comparisons

If you also decide you pull too much weight for a 1-ton, (Ford F350, Dodge 3500, GM 3500,) now the next decision is between new and used. One of the nice things about a used big truck, (two-ton or 26,000 GVWR) is they can last like an “Eveready Battery Bunny.” If you go out to farm country, you can find the old “Over The Road” rigs that are 30 years old plus still hauling corn or hay. Some trailer dealers also sell big trucks even conversions that are classified as an RV. The rental businesses like U-haul, Hertz or Penske sell thousands of used 2-ton trucks a year. Penske is friendly with GM so a lot of these used van trucks can be found at new GMC franchises. Hertz is friendly with Ford but also sell there own trucks and used cars. Several of the 2-ton used trucks that U-haul, Hertz and Penske would have will have the a low profile kit with just 16 in. tires, so they won’t be any harder to climb up into than a 1-ton. Some of them will even have Allison automatics, and a few diesels. I think my truck came from Mayflower originally. It had a hydraulic lift, which I used a couple of years and then took off. So check out a few of the big moving companies also.

One ton dually pickup trucks win the battle with speed and acceleration. The larger cab and chassis trucks on certain models will have less horse power and torque with the same diesel engines than 3/4 and 1 ton diesels. Manufactures consider pickup trucks to be loaded 10 % of the time and let the engineers have their fun competing with other brands for top power. Cab & chassis trucks on the other hand are designed to be loaded 90% of the time and are made for a longer life cycle.

The two ton trucks can have larger diesels and more towing power, but aren’t designed for racing but for more controlled slower lift offs. But with large air brakes, engine brakes and weight, win the contest for stopping a trailer.

Most of the 2-ton trucks will have 6 to 10 gears in the manual transmission or 5 or 6 speeds with an automatic transmission. These trucks are made to be loaded all the time. My 2-ton gave me the least amount of trouble hauling loads and pulling trailers. It’s also nice to have a heavy truck pulling the trailer. It gives you more control when you brake going down hill keeps the trailer behind you instead of trying to pass you. And if you were to loose your trailer brakes, these big trucks with their extra weight and size of their brakes, will stop you better than a 1-ton, (Ford F350, Dodge 3500, GM 3500.)

If you choose a new big truck, (2-ton, medium duty) choices range from Ford F650, F750 to Freightliner M2, International 4700, Peterbuilt T-330 and Kenworth T-300. And with the big boys you can get engine or exhaust brakes, crew cabs, any diesel engine you want, more gears, air ride and air seat. Yes air seat! The diesels in these medium duty trucks are very powerful, with a whole other realm of torque reaching over 1000 ft.#’s. Now the biggest down side is the cost. So it’s a bigger decision. And they have a better resale value. You are also looking at a truck designed for one million miles plus instead of a target of 300,000 miles for a good pickup truck diesel.

Another consideration is drivers license. I had a Class A drivers license in Colorado, which would let me drive anything in the old days. Now I have an CDL for multiple trailers. But the one ton dually pickups starting in 2011 model year have a GCWR of 30,000 lbs, so a CDL maybe needed for both. Unless you’re disguised as a RV.

This is a gray area for the whole country. Pickup trucks pulling trailers and big trucks pulling gooseneck trailers seems to confuse the DOT, (Department of Transportation.) I know some people who get tickets because they are over 26,000 GVWR (Gross Vehicle Weight Rating) and don’t have a CDL and log books and I know people who have never been pulled over with rigs that look totally commercial. Even with national CDL’s you would think there is some kind of constant rule but several states law enforcement seems to not know what to do. 10 years ago in Colorado when I pulled everyday, I never stopped in a port with a loaded trailer even when I hauled large round bales 12’ wide. But when I went threw Nebraska even with a stock trailer, I had to stop at the ports. Now the portable ports in Colorado would stop everybody. The one thing the DOT does agree on is RV’s. Pull a fifth-wheel RV or a horse trailer with Living Quarters and don’t make money hauling your horses to a roping jackpot and you may not require a CDL or logbook unless you are in an Eastern state that makes their own rules.

Another problem with a big truck and a short wheelbase and a single rear axle is the bounce. Some people ad 1000 lbs weight to the rear frame so when not pulling a trailer it will bounce less. A nice heavy flat bed will help. If you always are hooked to a trailer it won’t be a problem. My truck had a 18’ flatbed, so I did use it without the trailer to haul things. It worked well for me but not everyone wants that long of a rig with a trailer.

When GM made 4500/5500, they came with exhaust brake, low axle ratios and Allison Automatic. All useful on mountain grades. GM has dropped out of the medium duty market. Picture left, on mountain grades, exhaust brake takes the fear out of the fast side of the mountain.


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