Do You Really Need 1-Ton Axles?
Not All Axles Are Created Equal
One of the most common questions we get is "What's the biggest tire I can run on my Dana 44 front axle?" At the risk of being a wet blanket, our answer is "It depends."
Beyond tire size, factors such as gearing, horsepower, vehicle weight, and intended use have a huge bearing on whether your axle will survive or not. Additionally, an "axle" is made up of several components that vary in strength. Those 35-spline chromoly axleshafts won't do you much good if the pinion gear breaks before it can transfer power to the shafts. As a rule, bigger is better when it comes to everything from the ring-and-pinion to the axletubes to the wheel bolt pattern. Note though that you lose ground clearance as you add a larger ring gear, so you might need to run bigger tires to regain ground clearance, and that can negate some of the strength gains you get from bigger axles.
The lighter your vehicle is and the less horsepower it has, the more likely a smaller axle will live under your vehicle. Gearing is more complicated, as too tall an overall gearing means you must use momentum and can shock load parts, but lower gearing from the transmission and transfer case puts more torque into the axle. Automatic transmissions generally can cushion the rest of the drivetrain, including axles, through the slip in the torque converter. Ring-and-pinions tend to be damaged by shock loads from things such as hopping and jumping. Axleshafts tend to succumb to torque, twisting until they fail.
Ring-and-pinions larger in diameter are stronger as a result of more contact area through tooth engagement (the same reason an axleshaft with more splines is stronger than the same diameter axleshaft with fewer). That larger ring gear also allows for a bigger carrier, which is in turn stronger as well.
All of this is not to discount tire size as a factor. Certainly, a larger tire places more leverage and stress on the axle assembly and, in particular, the axleshafts. The weight of tires (and wheels) can vary widely as well, and should be taken into consideration when comparing products. For example, 37-inch-tall tires vary all the way from 68 pounds for all-terrains with two-ply sidewalls up to a whopping 94 pounds for the heaviest, Load Range E mud-terrain. Similarly, we have seen 17-inch wheels vary from 22 pounds all the way up to 37 pounds, and those are both non-beadlock aluminum wheels. A lighter tire and wheel combination will not only be easier on your axles but also provide improved braking and acceleration. Things get complicated on a vehicle used off-road though, since a tire that is too light might be more susceptible to punctures than a tire with heavier construction.
Axle Survival Factors
Axle Components & Considerations
Ring-and-pinion: Diameter, hypoid gear angle, high pinion or low pinion
Carrier: Drop-in locker, full replacement case
Axleshafts: Material, spline count, diameter
Axletubes: Diameter, thickness, trusses
Housing ends: Full float or semi float (rear)
Hubs: Hubs or drive slugs, bolts or studs to attach
Yoke/flange: Size, straps or U-bolts
U-joints: Diameter, material