Q: Who is AxleTech International Motorsports?

A: AIM is the motorsports group of AxleTech International, a global manufacturer of axles, transfer cases, brakes and related driveline components for military and specialty vehicle markets. AxleTech International is the former off-highway division of Rockwell International. Please see the History link on the main menu to learn more about AxleTech. AIM was established to bring AxleTech’s unique and extensive experience in off-highway axles to off-road motorsports enthusiasts.  

Q: Why a portal conversion system for Dana 60 axles?

A: As we surveyed what was available in the market we found that there was a strong desire for portal axles but all the current options required removal and replacement of existing axles. Wheeling is expensive enough as it is without having to completely re-engineer your axle and suspension installation. So we designed a product that will allow you to keep your current axles in place and increase their capability.

Q: Will the conversion system mount to any Dana 60 axle?

A: Our first version of the portal conversion system is designed for a kingpin Dana 60 axle and rear rigid Dana 60 axles. We strongly recommend the use of a high strength inner “C” such as those offered by Crane, Reid Racing (Dedenbear), and Solid Axle. We are investigating balljoint Dana 60 front axles.

Q: Is the portal conversion system available for other axles?

A: We targeted the Dana 60 axle initially because of its popularity but we designed our portal system to be flexible in application. To go from one axle to another we change out the adapter knuckle – the portal box and brake remain the same. We are working on new applications including the GM 14 bolt, Dana 44, Toyota, and Land Rover. Experienced axle builders can adapt our portal wheel end to any axle with the use of an aftermarket Dana 60 inner “C” and the appropriate axle shaft changes.

Q: What was the design methodology for the portal conversion?

A: We selected a target vehicle weight (6000 lbs), engine torque (500 ft-lb), gearing and tire size to guide the design of the case, gearing, and attachment knuckles. Target life for gears and bearings is 10,000 hours before failure. Target loading for the wheel end follows our normal combat vehicle design guidelines of 5g (5 times normal axle loading - 1g static + 4g dynamic). Target vehicle speeds ranged from crawl speed up a 60% grade to 80 mph. Finite element analysis (ABAQUS software) and gearing/bearing performance simulation (ROMAX software) were used extensively throughout the design process.

Our overriding concern was an easy interface to the axle. We retained the standard Dana 60 yoke / u-joint and kingpin mounting interfaces. This approach allows you to take advantage of existing upgrades that have been developed over time.

Q: What type of materials do you use for the portal conversion?

A: The case and cover are made from ductile (nodular) iron. The input shaft is made from 4340 steel. The output shaft is made from 4140 steel. Gearing is made from 8620 steel. All components are heat treated. Gearing, input shafts, and output shafts are case carburized per our normal practice.
 

Q: How heavy is your portal wheel end?

A: Our portal wheel end adds approximately 75 lbs per corner versus the standard Dana 60 wheel end configuration. These wheel ends were designed to be bombproof so the extra mass provides massive strength and durability. The extra mass is very close to the ground level thus acting as a countermeasure to the change in vehicle CG from 5” of lift.
 

Q: What type of lubricant is required? 

A: API GL-5 80W90 gear oil is suitable for our wheel ends.
 

Q: What size wheels will fit your portal wheel end?

A: Our portal conversion was designed around a 16.5 inch diameter HMMWV wheel. Any wheel 17 inches in diameter or larger should fit without difficulty. Please check the installation diagram on the Portal page for the minimum inner wheel diameter requirements. We recommend a minimum of 5 inches of backspacing with more backspacing being better.
 

Q: You use straight gears. What about the noise?

A: Helical gears are indeed quieter but bring another set of design challenges for dealing with thrust loads. Our design rationale (to be proven with test data) is that the gears are running in a bath of GL5 90 weight gear oil, enclosed by a solid nodular iron case and enclosed in a large wheel / tire assembly. Any gearing noise that does radiate from the wheel end is going to be competing with engine noise, exhaust noise, and tire noise. Stay tuned for test results, though.

Q: Holy Scrub Radius, Batman! How much scrub is there on these things?

A: All portal wheel ends suffer from the same problem – the presence of a gear case between the steering axis and the wheel mounting surface. The remedy is the use of wheels with deep backspacing. Our portal wheel end was designed around a HMMWV double beadlock wheel with 7 inches of backspacing. If you are running a 3.5 inch backspace wheel on a Dana 60 then using a 7 inch backspace wheel on our portal wheel end will get your scrub radius and track very close to where it was originally.

Q: What about CTIS?

A: We offer a CTIS-compatible version of our portal conversion system using components already proven in numerous commercial and military applications.