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Vapor Propulsion Labs propels Bosch in North America

Published November 1, 2023
Living off the radar in the Rockies, VPL co-founder Zack Krapfl and his team are driving Bosch e-bike integrations in North America


A version of this article ran in the October issue of BRAIN. 

By Paul Tolme

PORTLAND, Ore. (BRAIN) — Of all the concept bikes shown here at the MADE framebuilder show, in August, the full-titanium triple tandem “Sch:Long” from Schwift Cycles was likely the most expensive — and downright bonkers — electric bike on display. 

A 10-foot-long titanium triple tandem with three Bosch batteries, 150-plus miles of range, a Bosch Cargo Line Speed motor, four Gates Carbon Drive belts, a Rohloff E-14 electronic shifting hub, and couplers that allow it to be disassembled and stored in a suitcase for travel, the Sch:Long was priced at $100,000.

But it wasn’t really for sale. the Sch:Long is the latest mad science project from Vapor Propulsion Labs and its demonstration brand, Schwift, which fabricates one-off prototypes with irreverent names to show the eye-popping possibilities for Bosch integrations. 

The Sch:Long. Bob Huff Photo

Vapor Propulsion Labs, or VPL for short, is the North American distribution and engineering partner for Bosch e-bike Systems. In addition to Bosch, VPL offers a growing list of advanced drivetrain and e-bike components including Supernova lighting, 3x3 internal gear hubs, and Pinion gearboxes. 

Founded in 2019 by longtime collaborators and Bosch integration specialists Zach Krapfl and Forrest Yelverton, VPL is based in Paonia, Colorado, where it occupies a 7,500-square-foot carbon-negative warehouse and fabrication studio. 

VPL has operated largely off-the-radar since its founding, with a bare-bones website at But the company is now stepping into the spotlight with appearances at MADE, and at the Cycle-Con expo, and following a recent Bosch press release announcing the North American distribution partnership.

In addition to the two founders, VPL’s team includes four former Gates Corporation employees (including Krapfl) who worked together in the Gates Carbon Drive bicycle division of Gates. Frank Scurlock oversees business development for VPL following a 30-plus year bike industry career that included stints at Gates, Rockshox, and as a co-owner of Spot Brand, Maverick, and Juliana, among others. 

Marc Seemann oversees sales and service for Pinion in North America, working remotely from Iowa. And former Gates supply chain manager Aaron Goldschmidt handles logistics and operations. Yelverton oversees engineering while Krapfl specializes in assembly and integrations. VPL also works with skilled contractors including legendary titanium welder Nelby Varoqua, the “chief hot fuser,” and industrial designer Erik Eagleman.

VPL strives to be a one-stop-shop for brands seeking to create a new Bosch e-bike, offering a full suite of services including design, engineering, and prototyping, with a goal of bringing that new model from concept through to production. 

“If they need engineering, we can help with that. If they need industrial design, we can assist with that,” Krapfl says. “We have fabricator chops. We understand exactly what is required engineering-wise to create a frame, whether it’s one or a million. We can get them to a prototype, and then it transitions to a production bill of materials.” 

From a new OEM perspective, going into production on a new Bosch e-bike can be overwhelming without skilled guidance. To streamline the process, VPL created an automated BOM (Bill of Materials) Generator that enables a customer to go step-by-step through the entire Bosch product line without having to pick and choose parts numbers from a vast spreadsheet. 

“It’s a logic-based system where if you choose this motor, you use this kind of battery, and this battery is mounted to the frame in this way, and the lights are integrated in this way. The BOM Generator spits out the bill of materials, and then populates it with all the pricing.”

VPL’s clients include small custom framebuilders like those at MADE as well as established North American brands including DeVinci, Niner, Vaast, Batch, Terra Trike, Catrike, Co-Motion, and Crestline, among others.

For customers looking to manufacture in Asia, VPL also helps OEMs with production and assembly thanks to its partnership with Willing in Taiwan. “Willing has a huge amount of experience with Bosch. We’ve worked with them for 25 years and we have a very close relationship. Willing is our go-to, but if OEs have their own relationships we don’t try to steer them away. What’s most important for us is to make our customers successful.”

VPL took over as the Bosch distributorship in 2022 following the collapse of previous North American distributor Saris. Krapfl, whose history with Bosch dates to 2009, helped Bosch identify Saris as a distribution partner while he was working for Gates. “In retrospect, it wasn’t the greatest fit,” he says. “Bosch was never a focus for them.”

Claudia Wasko, vice president and general manager of Bosch eBike Systems North America, called Krapfl "undoubtedly one of the foremost e-bike experts in North America."

"He has broad experience with transportation electrification and a deep understanding of bicycle design and manufacturing," Wasko said, adding, "He’s also intimately familiar with the Bosch eBike system and, along with Forrest Yelverton — while they were both at Cannondale — collaborated with us on our earliest e-bike prototypes back in 2009. These innovations ultimately evolved into what is now the Bosch eBike system of durable, high-performing mid-drive motors for pedal-assist e-bikes."

After leaving Gates to start VPL, and subsequently winning the Bosch distribution, Krapfl and his team fleshed out VPL’s lineup of complimentary products. With a resume dating back to Schwinn in the 1980s, Krapfl is a thinking person’s bike nerd who wants to help drive electrification in North America. 

Krapfl tries to live a low-carbon lifestyle due to his concerns about the climate crisis. VPL’s Paonia facility is carbon negative, Krapfl says, thanks to a 48-kilowatt solar array that generates 700 percent of the building’s electricity needs and feeds excess electrons back into the grid. The solar array is in addition to a ground source heating system, a biomass heat system, and an anaerobic digester that produces methane used in the facility.

Why Paonia? 

“It’s beautiful,” Krapfl says. “There are no traffic lights for 40 miles. You can ride around with prototypes and nobody knows what they are. There are no paparazzi.”

If you visit Paonia, keep your eyes peeled for a tall, bearded man with his wife and daughter pedaling the most pimped-out triple tandem you’ve ever seen. The Sch:Long is Krapfl’s family station wagon.

The VPL team at MADE. Bob Huff Photo
Topics associated with this article: Electric bike

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