First Look: Terra Forma Evolution Hubs

Rus Kappius is bent on taking the mountain bike a step forward with his fresh take on bicycle transmissions

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

Tinkering. That’s how mountain biking was born and that’s part of what keeps it cool. These days fewer backyard engineers are bringing products to market, but those that are still push the envelope. One of them is Rus Kappius.

Kappius started road racing back in the 1970s. Since then he has won several national and state titles in mountain biking and cyclocross. He studied at the Colorado School of Mines and his background is in geophysical engineering. But his passion is, and has been since his teenage years (“a very long time ago…,” said Kappius), cycling. His love of bicycles has rubbed off on his son, Brady, who is an accomplished pro mountain biker racing this year for Clif Bar.

Why hubs?

Front hubs in any configuration will be available in limited quantities next year. Price for the front is $350. Rear hubs are currently in alpha testing and likely to be available late next year or 2013. Expect to pay $650 for a rear hub and $300 for a converted SRAM XX or Red gear cluster.

When you talk to Kappius his enthusiasm for his sport and the adventures he’s had thanks to it are apparent. That same energy led him into the world of hub production. During his years of mountain biking he happily pedaled along until one catastrophic mechanical failure left a friend stranded in the mountainous backcountry. His rear hub had failed.

“We were deep in the Colorado backcountry riding our mountain bikes. He had to walk for three hours to get out,” Kappius recalled. “I decided I needed to do something about the problem; what I consider the third most annoying problem in biking — hub reliability. First is flat tires, second is broken chains. I’ll leave those to problems to others to work on.”


The solution to the problem hit Kappius a few years ago when SRAM introduced its “hollow” cassette designs. Kappius said to himself, “that should be hub under there, not an air pocket!” From this eureka moment, Kappius came up with his design philosophy: “The number one priority of my hub design is to make it more reliable. Second is simpler, followed by lighter.”

Wider: Because Kappius is filling that void with hub, the bearings in the Evolution hub are much more widely spaced. This strengthens the entire structure of the wheel and is less tasking on the bearings themselves. In fact the oversized bearings in the Evolution hub are spaced 50 percent wider than in most current production offerings

Bigger: Everything is oversized on the Terra Forma Evolution hub. Kappius upped the size of not only on his hub’s bearings but also the size of the drive mechanism. Bigger bearings are stronger, easier to seal and last longer.

Kappius improved transmission reliability by making the engagement interface twice the diameter of standard cassette bodies. When you take apart the hub and inspect the pawls, springs and bearings and compare it to a normal hub, you see how bigger really can be better.

Faster: Kappius also saw that he could achieve all his reliability goals while making engagement quicker. A few companies like Industry Nine have started to realize the advantage of a super fast engagement. Currently the Terra Forma Evolution hub has 180-point engagement (Industry Nine has 120 point engagement).

I really noticed the quick engagement over technical terrain where I could pedal several half revolutions to keep my pedals from hitting rocks.

Lighter: Without the funding of a big R&D department Kappius already has his hub weights at 115 grams and 260 grams for front and rear 9 mm quick release hubs. A front 15mm thru-axle is 120 grams and a Lefty front is 110 grams.

Roadies listen up!

While Terra Forma Sports’ first hubs are for mountain bikes, the drive mechanism would fit inside an 11-23 cassette. And with the already low weight of the mountain rear hub (260 grams), a road version could be even lighter by lopping off the disk rotor mount.

The pair that I rode were working prototypes and Kappius is still working out some kinks. But the instant engagement and oversized mechanism is impressive.

Kappius machines SRAM XX cassettes for his hubs and the shifting is great, as you would expect. Some people have raised some concerns over the inability to throw on a readily available cassette, but the benefits of the Terra Forma hub far outweigh the inconvenience of cassette sourcing. And much like bottom bracket standards, what’s so bad about a hub and cassette being designed together, as a system, when that system is superior? Nothing.

On the trail the hubs have a great buzz when freewheeling. The instant engagement is fantastic and I noticed the improvement more than I thought I would. In technical terrain, the Evolution hubs are a clear advantage.

The front hub is very straightforward and Kappius has already produced a 15-millimeter thru-axle version and a prototype Lefty version.

Arguments aside

Rus Kappius is a mountain biker who wants to improve his riding experience. But unlike many who simply complain about a problem, he’s taken up the challenge of bettering it for all of us. The Terra Forma Evolution hubs are a step forward.

Normally I write on and on in favor of increased standardization in the cycling industry. But I’ve been won over by Kappius’ argument. It makes more sense for hubs to go this direction. Bottom brackets and headsets already have.

All arguments aside, Kappius simply wants to spend more time riding his bike and less time working on it. “Mostly I just want bikes to be better, and for us to look back and remember when hubs were on the short list of things that needed fixed on a bike. Past tense.”

Trending on Velo

An American in France

What’s it like to be an American cyclist living in France? Watch to get professional road cyclist Joe Dombrowski’s view.