06/14/2026
One of the most common questions I get about our portals or portals in general is “Can they survive at highway speeds?”.
I know portals are a foreign concept to a lot of people, but it’s clear that there’s a common belief that they can’t be used at high speeds. I can’t say for sure, but I have some theories on why people believe this.
The most common factory portal application is the Mercedes Unimog. They’re only capable of 55-65 mph. The early HMMWV’s (also equipped with portals) are also only capable of 55 mph. It seems like knowing that results in the correlation of portals = not rated for highway speeds. The reality is, the final drive gearing or lack of overdrive is the real reason the top speed is limited.
When the H1 Hummer was produced, the top speed was limited at 85 mph, meaning AM General felt confident that you could drive at that speed as long as you wanted.
Our portals use HMMWV based internals. The spindle bearings are comparable to a kingpin 60 or 14 Bolt (which spin 1:1). And the upper gear bearings are actually the same size as a 35 spline Ford 9” carrier bearing. Our upper gear is spinning 1.6 or 1.92 times faster than the wheel depending on the ratio. In racing applications, those bearings commonly see over 200 mph, which means over 2500 rpm. That’s well over twice the rpm they’d see in a portal application.
The only other moving parts in the portal are the two gears. If you’re concerned about that, the 5 gears and bearings inside your transfer case are spinning 4-5x faster than the parts in a portal, but no one is ever concerned about that being a problem.
We’ve had multiple customers racing Ultra4 with our portals, and Rod Hall put MANY thousands of miles on his factory back Hummer desert truck.
What are the other concerns that people have about using portals at high speeds? Let me know in the comments!
