Readers & Their Rides: Chris Killer’s All-Mountain Bike


Chris Killer’s All-Mountain Bike

Regular readers might remember Chris Killer from when we featured the electric tandem he built so that he and his non-cycling wife could ride together (EBA, October 2019). The unique, home-built bike worked perfectly, and the two still ride it together. Well, apparently, there was more to come.


Given that Chris has a PhD in creativity and innovation in engineering design and a master’s degree in mechanical engineering, it’s safe to say that he knows a thing or two about making things that work. He also rides a mix of traditional and electric bikes. Four years ago his Bionicon (a German bike known for user-adjustable geometry) was stolen. He’d yearned for another, but they’re not easy to come by here in the U.S. 

One of the first upgrades he made was adding these SPD downhill-style platform pedals.

He then bought a Diamondback frame and built it into a bike with the goal of getting a motor from Revel Propulsion. Chris says that company is run by Paul Daniel, who makes the motors, and quips that he seems to only sell them for one day a year, and he sells out. 

“In climbing mode, this bike’s geometry can be positioned in a radical 78-degree seat angle, which puts your weight nice and forward, so you’re not going to wheelie on the steep climbs.”

Here Chris shows just how forgiving the descent setup is.


While he was waiting for the next release of those motors, a friend was selling a 2015 Bionicon EVO, and Chris jumped at it. He says the parts aren’t necessarily high end, but he doesn’t need a lot of carbon fiber or other weight-saving parts since the bike is an e-bike. In the end, with the Revel motor and 250-Wh bottle-style battery, the bike ended up weighing just 43 pounds, which was nearly 10 pounds lighter than many off-the rack e-MTBs. 

To handle the extra controls, he had to use an extension on the dropper-post lever to clear the Bionicon valve-release button.

The way the geometry changes with the Bionicon system is that both the Xfusion fork and the Magura rear shock have extra travel, and by pressing a button, it allows a glissando change between a more forward climbing mode and a more relaxed descending setup. 

As with many home builds, Chris uses an EggRider display. The ergonomics aren’t great, so Chris 3D-printed that blue cover to help keep him from accidentally hitting the wrong button.

As Chris explains, “In climbing mode, this bike’s geometry can be positioned in a radical 78-degree seat angle, which puts your weight nice and forward, so you’re not going to wheelie on the steep climbs. When descending, you can alter the head angle to around 64 degrees to help put the rider’s weight well behind the front wheel. 

Currently, Chris has a 170mm-travel OneUp dropper post, but he’s looking for a 200mm version.
The Revel motor and 250-Wh battery sit low and close together on the frame.
For the rear shock, there’s an additional chamber at the top that allows for the geometrical adjustment.

Chris says that he most often rides the bike in level 1 just to overcome the bike’s extra weight. In fact, he says if there was a .5 mode, he’d prefer to ride in that. Even with that small level of assist, he usually goes on four-hour rides with significant climbs, carrying a spare battery. The Revel system provides some resistance even when off, so as he says, riding home with no battery power is not fun.

As close as it is to its final build, the bike remains a work in progress for a while. We can hardly wait to see where Chris’ unique design vision ends up!

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