SEP 2018


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SEPTEMBER 2018 48 CompositesWorld FEATURE / Safe Cycling Booth #M49 bicycles in 2014 and 2015 in nine sections. ISO 4210 was "devel- oped in response to demand throughout the world, and the aim has been to ensure that bicycles manufactured in compliance with this International Standard will be as safe as is practically possible [editor's italics]. e scope has been limited to safety considerations and has specifically avoided standardization of components," according to ISO. Bike safety won't wait Given the market's growth projections, composite bicycles will certainly proliferate anywhere riders value high performance. Admired for their benefits in high-performance bikes, composites also must command careful attention from those who design and manufacture them. In time, standards and regulations will find their proper place, but this industry can't wait. Tools for design, testing and post-production evaluation of bikes that can keep their riders satisfied and safer are available, but bicycle builders must put them to use and support ongoing development of best practices. Donna Dawson is CW's (previously) retired senior writer emeritus, now residing and writing in Lindsay, CA, US, in the foothills of the Sierras. approach critical fracture levels, he points out. Further, "Static loads do not account for braking loads, which induce high fric- tional heat and induced loads on wheels and forks. And long- term service fatigue definitely needs to be considered, as well as vibration loads imposed over time on any composite components." "Sectioning [breaking] carbon fiber forks, which represent 82% of observed failures," says Beckwith, "often clearly shows significant leading and trailing edge porosity, voids and delamination incurred during the molding process." Standards and regulations Beckwith notes further that no legally binding structural safety stan- dards yet exist that address common rider load and environmental conditions (braking, impact loads, fatigue, vibration, material aging or degradation, material abrasion and wear) for high-performance composite bikes. Further, the existing ASTM D-30 test methods are not yet recognized by ASTM's F-08 Bicycle Committee. at said, the International Organization for Standardization (ISO, Zurich, Switzerland) published its ISO 4210 standard for Read this article online | Read more about this Rolo Bikes weight reduction effort in "Carbon fiber meets simulation in ultralight bike frame" |

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