Safety, certification, and designing for durability
April 1st 2016
By Bob Forgrave
In the pre-mountain-bike era, when I was a teenage cyclist riding with reckless abandon on a Schwinn Varsity 10-speed self-modified for jumps and hard landings, a cautionary thought would occasionally enter my mind—-usually in mid-jump, far too late to do anything about it. “Can my bike handle this?”
Today, this question is far easier to answer for every mountain biker. Just look for the International Standards Organization certification. Over 7% of the entire population in the European Union cycles every day, so cycling is taken very seriously there. Focused on rider safety, the ISO introduced the ISO 4210 certification test for mountain bikes in 2014, and has subsequently updated it to this intense battery of tests:
- Falling mass: Hold a 50 lb steel weight a yard above the frame and drop it.
- Falling frame: Load the frame with 176 lbs of mass and tip it over . Onto an anvil.
- Fatigue/pedals: Apply 270 lbs of pedaling force 100,000 times.
- Fatigue/horizontal: Apply 270 lbs of horizontal force 50,000 times. It’s like standing on a lying-down bike (if you’re heavy enough).
- Fatigue/vertical: Apply 270 lbs of vertical force to the frame 50,000 times. That’s a lot of jumps!
If you can demonstrate all this without shearing, bending or cracking, you’ve earned EN 14766 certification. And CHANGE full-size folding bikes are the only folding bikes of any type, full-size or not, to achieve this reliability rating.
Here’s how this impressive rating is achieved. Look at any metal or wooden structure designed to maximize strength, from bridges to house gables to the Eiffel Tower, and you’ll see an abundance of triangles.
Over the past century, the triangle shape has also become the recognized method of ensuring the best strength/weight ratio for bike frames as well. Even with a gentle curve to accommodate the front wheel, forces in a CHANGE bike are split and reduced over two legs of a triangle—-both of which are smooth, with the two quick releases safely and ruggedly in the corners.
Compare this approach to a popular lower-end manufacturer of full-size folding bikes. Without a downtube to split the force, all impact from every bump, jump and weight shift goes through a beefed-up heavy bar—-that has a big hole drilled in it for the frame’s only quick-release fastening location. If there is going to be a bend, crack, or shearing issue, this is a likely place for it. You can probably get a cheaper Montague folding mountain bike, but is it a better long-term investment?