Over the hill on an electric bicycle

Neal at NTS Works in Santa Cruz built up a prototype Fat Free electric assist bicycle for me to try over the next few days. Of course I took it straight from assembly to a 32 mile ride with 2000 feet of elevation over the Santa Cruz Mountains without so much as a shakedown ride.

NTS Works Fat Free electric assist bicycle

The Fat Free is meant to be a utility A-to-B bike for transportation. Because NTS Works is based in the Santa Cruz Mountains, designer Neal Saiki engineers his bikes to be especially well-suited for use in hilly terrain.

Neal’s no slouch — this guy led the engineering team who created the world’s first human powered helicopter at Cal Poly SLO in 1989. He worked as an aeronautical engineer at NASA for a while before returning to the coast to design bikes for Santa Cruz Bicycles. In 2006, Neal founded Zero Motorcycles, a highly regarded manufacturer of electric motorcycles for dirt and street use.

Neal knows manufacturing and design, he knows battery technology, and he knows electric motors. Beginning last year, he began applying this knowledge to the design of electric assist cargo bikes. The “Fat Free” electric commuter and utility bike is his latest design.

NTS builds the Fat Free around a custom-designed 5.5 lb aluminum frame. Motor and battery are mounted low and near the center of the bike for superior handling.

NTS Fat Free frame 5.5 lbs

The 350 watt mid-mount motor provides three user-selectable levels of assist when the rider pedals, with NuVinci’s n360 continuously variable transmission hub providing 360% gear range.

The motor is powered by NTS Works Mini 48 Bicycle Battery, which yields 419 watt-hours of energy. NTS Works claims 50 km of real world range, which they define as “with some cargo and some hills.”

It turns out the distance from my home to my office is a hair over 50 km, with 2000 feet worth of hills in between. Electric bicycle range claims never live up to reality, so Wednesday morning I set out to test this claim. The illustration below shows the elevation profile of this ride, with speed on the Fat Free (in orange) compared against speed on my road bike (blue). The bottom graph shows Strava’s “power estimate,” which is calculated based on speed, road gradient, and weight.

Scotts Valley to Santa Clara bike ride graph elevation speed power

I obviously made it to the office, and in about the same time it takes for me to do it on my speedy road bicycle. The Bafang controller showed plenty of juice left on the battery, too, so I’d say the battery exceeded my expectations.

For this long ride I think I still prefer my road bike, but I believe this is a decent test of the Fat Free’s capabilities and endurance. If I can bike through heavy mist up and over the Santa Cruz Mountains, then this bike can certainly handle a cross-town commute.

How does it ride?

I live at the top of a hill where I have to grunt out a few hundred watts just to get home every evening. An electric assist bike flattens hills like this and removes terrain as a barrier to cycling.

The Fat Free is clearly meant for utilitarian use, but the midmount motor means you have plenty of torque available for hills and fast starts from the red light if you desire. I compare the feel of this bike with the Stromer ST1 or Specialized Turbo. Stromer and Specialized designed their bikes for get-up-and-go performance, but the Fat Free approaches the performance and pure fun factor of those better known brands at a fraction of the price. NTS expects to retail these bikes for US$2,600.

This bike will be available for sale beginning September 2014. If you’d like a test ride, I’ll have this bike through Sunday. Ping me so we can arrange something. You can find me at Diridon Station on Thursday morning, and I’m at the north end of Santa Clara (near Great America) all day Thursday. Not sure where I’ll be Friday. Saturday and Sunday is tight but we can still work something out.

NTS Works has an amazing amount of information about this bike online.


  1. Is the Fat Free in production? The link to more information above is broken and there’s no contact information to be found on NTS’s websites. It seems like a great design and I’m in the market in this price range right now (October 2015)

  2. Thanks for letting me know. So many players in the market now. I can understand staying out of the fray.

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