Facebook LinkedIn Twitter RSS

Designed for speed and quality, Bethlehem company’s monoskis to be used in Paralympics

By ,
Tyler Walker, two-time Paralympian, on a monoski made by DynAccess in Bethlehem.
PHOTO/BRYAN MYSS Tyler Walker, two-time Paralympian, on a monoski made by DynAccess in Bethlehem.

When the 2018 Winter Paralympic Games start March 8 in Pyeongchang, South Korea, several alpine skiers will be shredding the slopes using monoskis made by a startup in Bethlehem.


Watching from the sidelines and ready to assist with a bag of tools, if necessary, will be Channy Tokura, president and owner of DynAccess Ltd., and her husband, Joachim Grenestedt, a Lehigh University professor of mechanical engineering who designed the monoskis.

Except DynAccess’ sleek, highly engineered, high-speed skis never break, a fact that has caught the attention of professional and recreational skiers who are paraplegics or amputees and who use adaptive skis.

Tyler Walker, a member of the U.S. alpine ski team, Stephani Victor, an American who will ski with the Swiss alpine ski team, and Arly Velasquez, of the Mexican alpine ski team, will be competing in Pyeongchang on DynAccess monoskis.

“DynAccess builds the best adaptive skiing products I have ever used,” Walker said in an email.

Chris Devlin-Young, a four-time Paralympic medalist and World Cup and X Games champion who is now retired, was a high-profile early adopter of DynAccess monoskis, which helped give the Bethlehem startup visibility.

“I have been skiing for 25 years and I have used and broken almost every product available,” Walker said. “The engineering and craftsmanship that goes into DynAccess products is such that whether or not I’m going to break something is never something I have to worry about.”

If anything, the one thing Walker said he has to worry about is “how fast I want to go because the equipment won’t be holding me back.”


Founded in 2011, DynAccess was born out of Grenestedt’s desire about three years earlier to help one of his students who became paralyzed after a mountain-biking accident.

Grenestedt, an avid skier, encouraged his student to try adaptive skiing and accompanied him to a program in upstate New York.

Grenestedt was dismayed at the condition of the monoskis.

“This program had a number of monoskis, and I think half of them were broken. I thought, this is ridiculous. There is no reason they should be broken at all,” he said.


So, Grenestedt set about making a better monoski for his student.

It was a natural fit for the engineer, who has a penchant for designing high-speed vehicles, including airplanes, cars and boats, and who has even piloted some of them.

Grenestedt designed and drove a streamlined motorcycle, known as a streamliner, in which he broke a land speed record in 2009 in the Bonneville Salt Flats in Utah. The streamliner is in the America on Wheels Museum in Allentown.

At Lehigh University’s Composites Laboratory, where Grenestedt is director, he designed and fabricated that first monoski for his student with the help of Bill Maroun, one of his technicians.


They use a number of small local companies to make component parts for the monoskis, but it was Grenestedt’s reverence for speed and machines that led him to seek the expertise of Penske Racing Shocks based in Reading to collaborate on a custom-made shock absorber for his monoskis. Penske is renowned for making shock absorbers for some of the fastest racing cars in the world.

“They make the best shock absorbers on the market, hands down,” Grenestedt said.

The shock absorber is a critical component in the monoski, particularly when the skiers don’t have legs to absorb the force when they hit bumps.

The shock absorber “decides how the rider feels the ground, how the ski keeps contact with snow,” he said.


Grenestedt met frequently with the Penske team and would have long discussions on how to build a shock absorber for his monoski prototypes. Sometimes he would leave with a prototype and return with feedback from the skiers about its performance.

Out of those discussions and test runs, they developed the Penske Pro Air, an 18 inch-to-20 inch long aluminum shock absorber that is used exclusively in DynAccess monoskis.

“It’s been a really cool co-development,” said Jim Arentz, technical director at Penske Racing Shocks. “I think DynAccess chose us because we could respond to their request really quickly and come up with a custom solution that suited them best.

“They were requiring a pretty specific list of criteria that had to be met to be make it successful.”


Penske’s work with DynAccess has been the first time it’s been involved in building a technology that’s so integrated with the functioning of the human body, where “man and machine are combined as one,” Arentz said.

“I’d say 99 percent of what we do, there’s a tire involved, where there’s a car or a motorcycle that is helping to isolate some of the inputs from the road or terrain to the driver that doesn’t go directly into the person,” he said.

“This is such a direct connection.”


Sometimes the adjustments are small, but the skiers feel it in a way that someone riding in a car or all-terrain vehicle would not, Arentz said.

“They are feeling it in their bodies immediately,” he said.

The team at Penske also designed a manual lock on some DynAccess models so the monoski stays in position when the skier rides the chair lift.


Tokura has been working to get DynAccess’ monoskis in wider use among adaptive skiers of all levels, not just elite athletes.

She and Grenestedt are hands-on and travel frequently to demonstrate their products – DynAccess has four models of monoskis – in workshops and trade shows and to be out in the field with new and potential clients, including programs for disabled veterans.

“Since the market is very small, we try to demonstrate and ski with the potential and existing customers to make sure the product is working well and introduce them on the market so people can test ride it,” Tokura said.

“Once they purchase them, we also try to ski with them. We can’t find any other company that is doing that.”


Tokura has received two $15,000 technology transfer grants from the Southside Bethlehem Keystone Improvement board for startup costs and to market the company’s latest model, the Hydra.

“We ski with a lot of the top U.S. athletes. They are to some degree guinea pigs for us when trying our new technology,” Grenestedt said.

“We listen to them a lot, get input from them and build different equipment and try different things on them, like sleds that move in a different way.”


The company often tests a new component for a year on the racing circuit before it’s put in its final product.

While other manufacturers also make their monoskis from the same material DynAccess uses, chromoly steel, a strong but lightweight alloy, the biggest difference is in the design.

“It’s like the difference between a Ferrari and a Fiat,” Grenestedt said.

“It’s high quality in every respect.”

Also Popular on LVB

Write to the Editorial Department at editorial@lvb.com

Leave a Comment


Please note: All comments will be reviewed and may take up to 24 hours to appear on the site.

Post Comment
View Comment Policy