Mountain Biking Gets a Boost from Generative Design
Michael Alba posted on June 10, 2019 |
Rurok Industries is a startup aiming to build better mountain racing bikes. (Image courtesy of Rurok Industries.)
Rurok Industries is a startup aiming to build better mountain racing bikes. (Image courtesy of Rurok Industries.)

Mechanical engineer PJ Tolentino loves biking on the many mountainous trails in his native Philippines. These trails are tough, with steep climbs, even steeper descents and nary a level surface. As demanding as these trails are on the rider, they’re just as demanding on the bike, and Tolentino was unsatisfied with the available gear. He and his cycling companions found that even the best bikes on the market could be improved, and Tolentino thought they could do better.

“That was our simple idea, the thought that maybe we could make a better bike,” he said. “After much consideration, we pulled the trigger. We then sold all our bikes just to fund the development of our first product.”

That product was a bike frame called the Cordillera (the name is a Spanish term for a system of mountain ranges and pays homage to the cordilleras of the Philippines).

The Cordillera

All-mountain riding is the biking equivalent of downhill skiing but often without the benefit of a chairlift to the top of the mountain. You have to grind up to the summit. It was during the arduous journey up the mountain that Tolentino, an all-around mountain biking expert, saw what could be improved. In off-road conditions, a shock absorbing suspension system is necessary if you want to go fast and be stable. However, this comes with the trade-off of absorbing the rider’s pedaling power. Whether climbing or descending, you want your energy to be translated to speed, now wasted in the shock absorbers.

The Rurok Cordillera in action. (Image courtesy of Rurok Industries.)
The Rurok Cordillera in action. (Image courtesy of Rurok Industries.)

Balancing his full-time job as an engineer at a semiconductor company, Tolentino and his friends began designing a unique suspension mechanism that would form the core component of the Cordillera. The design works to keep constant a parameter called anti-squat.

“Think of squat as the tendency of a car to pitch backwards when you step on the accelerator,” Tolentino explained. “We can design suspension systems to produce an opposing force, called anti-squat, to prevent that from happening. Producing the right among of anti-squat is tricky as it is determined by a lot of parameters such as instant center, center of gravity, and chain line angle. Our goal with our suspension system was to generate a constant amount of anti-squat, even as all those parameters change all throughout the movement of the suspension.”

Tolentino took the suspension design and incorporated it into the Cordillera bike frame. With the frame, all-mountain bikers could maintain efficiency whether climbing on smooth ground or with suspension movement during technical rocky terrain. Tolentino and his friends also designed the Cordillera to have a specific geometry which they felt worked best for them after testing several prototype iterations.

The Kanlaon

Cyclists soon began to take notice of the Cordillera, and Tolentino and his team decided it was time to officially form a company for their bike frames. They called the company Rurok Industries, named after the Filipino word for “peak.” Rurok soon set to work on a second bike frame, the Rurok Kanlaon (the highest peak on the island of Negros, Philippines).

(Image courtesy of Rurok Industries.)
(Image courtesy of Rurok Industries.)

It was in the early stages of developing the Kanlaon that Rurok was approached by a partner that would elevate their design capabilities. Software provider Siemens had taken note of Rurok and offered the company a role in its Solid Edge for Startups program, which provided Rurok with free access to the Solid Edge suite of CAD tools. While the Cordillera was designed with the help of years of biking intuition, the Kanlaon had the extra advantage of Solid Edge’s modeling and analysis tools.

“We saved a lot of development time and money being able to develop products digitally,” Tolentino said.

The Kanlaon was designed with a special mechanism that allows riders to adjust the geometry of their bike to suit their preferences. Some riders want a long, low bike that’s stable when going fast. Others prefer a short, nimble bike that’s good for playing around. Rurok called this switching mechanism Play&Slay Mode. The biggest design challenge was ensuring that the switching mechanism could accommodate all of the bike’s components, and the Solid Edge analysis tools helped Rurok overcome that challenge.

The Halcon

After the Kanlaon, Rurok wasted no time setting to work on its third bike, the Halcon (Halcon is the toughest mountain in the Philippines—do you see the pattern here?). While the Kanlaon was more of bike for having fun, Rurok wanted the Halcon to be a serious performance Enduro bike. In all-mountain fashion, Enduro racing sees cyclists compete to bike up and down demanding mountainous trails in the shortest possible time (cyclists are not typically timed on the uphill stages, though uphill endurance is a crucial aspect of the sport).

The design of the Halcon was particularly aided by Solid Edge, as Tolentino and the Rurok team used Solid Edge generative design to run topology optimization on components of the bike’s structure.

“The highlight of this third product is optimization,” Tolentino remarked.

Topology optimization is an algorithm that strategically adjusts the geometry of a part to make it as light as possible while retaining its structural properties. It works by running several iterations of a finite element analysis, with each iteration removing elements that have low impact on the part’s structural integrity. This algorithm can achieve huge weight savings. After being topology optimized, the mass of a part can be reduced by 50 percent or more. Since biking is a sport where every gram matters, Solid Edge’s generative design was crucial in optimizing the performance of the Halcon.

Topology optimization of one of the Halcon’s linkages. (Image courtesy of Rurok Industries.)
Topology optimization of one of the Halcon’s linkages. (Image courtesy of Rurok Industries.)

Rurok used generative design for four of the Halcon’s linkage components, specifying the target factor of safety and letting Solid Edge optimize the shape.

“Generative is our own personal design engineer,” Tolentino explained. “It enables us to make parts that are stronger, lighter, easier, and better than how we could have ever designed it.”

Rurok employed a similar approach when optimizing the design of the Halcon’s new suspension layout. “We changed our suspension design philosophy from the Cordillera to the Halcon,” Tolentino said. “We have added drivetrain cog sizes a parameter during optimization. This decision meant that conventional kinematic analysis techniques would be too slow. We had to develop a special software running a ‘Parametric Optimization’ code to achieve our design goals.”

Rurok has been testing their designs with their own Rurok Factory Racing Team, which competes in Enduro races throughout the Philippines. The Halcon, which is currently in preproduction, is expected to be on the market later this year.

Factory Rider Kimi Grande testing the Halcon. (Image courtesy of Rurok Industries.)
Factory Rider Kimi Grande testing the Halcon. (Image courtesy of Rurok Industries.)

Tolentino and the rest of the Rurok team have poured their passion for biking into their products, motivated not just to grow their company, but to improve their own biking performance.

“We believe that bikes need to move forward and progress, just as the rider does,” said Tolentino. “That’s why we do it.”

To learn more about Solid Edge and its generative design capabilities, its startup program, or to download a free trial, visit the Siemens website.



Siemens has sponsored this post. All opinions are mine.  --Michael Alba


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