AXLE TUBESUpdated 2 months ago

Axle Tube Diameter and Wall Thickness

Let’s start with the basics. An axle tube’s strength is largely defined by two key factors:

• Outside Diameter (OD)
• Wall Thickness

Larger outside diameters significantly increase resistance to bending. Meanwhile, thicker walls increase resistance to denting and torsional flex. Together, they determine the axle tube’s overall rigidity, load-handling, and abuse tolerance.

Here’s a general comparison of typical axle tube dimensions:

Axle Tube Strength and Bending Resistance

Tube strength is exponential in relation to OD. That means a slight increase in diameter gives us a huge jump in resistance to bending. To illustrate:

So, when you go from a factory Dana 44 to a Dynatrac ProRock 60, you're not just getting stronger shafts and gears—you’re multiplying tube strength several times over.

This becomes critical when:

• You’re running oversize tires (37”+)
• You’ve got increased track width
• You’re hitting high-speed desert whoops
• You’re absorbing rock impacts at odd angles
• You’re hauling heavy loads or towing

Dynatrac Variable Tube Thickness: Why and How We Do It

One of the most unique features we offer in our ProRock XD60, and 80 axles is variable tube thickness. Here’s what that means:

• Near the differential housing, we run thicker wall tubing—up to 0.500”—where leverage forces are the highest.
• Closer to the outer knuckles or bearing ends, we taper to 0.375” wall, reducing unsprung weight without sacrificing strength where it's needed.

How It’s Made:

We start with DOM (Drawn Over Mandrel) or SRA (Seamless Rolled Alloy) steel tubing and then CNC-machine the transition areas. In some cases, we sleeve or internal reinforce high-load zones, depending on application.

This method allows us to optimize strength-to-weight ratio, putting strength only where it’s needed most. It’s smarter than just throwing a heavy 0.5" tube across the whole length, which creates unnecessary weight.

Real-World Example

Let’s compare a common build:
 A Jeep JK running 40” tires, off-road loaded weight 6,000 lbs.

• OEM Dana 44: 2.5" OD x 0.25" wall → vulnerable to bending under rock pressure, especially if long-arm or high-steer suspension applies leverage further from the housing.
• Dynatrac ProRock 60: 3.75" OD x 0.375–0.500” wall (variable) → up to 4–5x the bending strength, without a massive weight penalty.

OEM vs Dynatrac: Axle Tube Size Overview