Being in the rumor business here, occasionally we stir up a few bees nests. Some of hearsay surrounding the Continental belt drive system introduced at Eurobike did just that, which included a rumor that Gates Carbon Belt Drive was considering Aramid to replace the carbon. We’ve heard from several folks with hands on experience that if handled improperly -mainly if its crimped or folded to severely- the Gates system can weaken and snap. We haven’t experienced this since our only test bikes with the Gates system have come prebuilt. That said, Gates has replied that they are absolutely not considering Aramid. Here are the combined comments from Todd Sellden, director of Gates Carbon Drive Systems, and their PR agent:
It is incorrect to say that Gates is considering using Aramid.
Gates used Aramid 30 years ago in a similar industrial belt. A decade ago Gates phased out Aramid and introduced its patented carbon fiber tensile cord technology for industrial belts because it provides superior power density. The years of R&D that Gates has with carbon tensile cord in industrial belt applications made carbon fiber the most sensible and durable material for bicycling, which is why Gates made carbon fiber the backbone of the Carbon Drive. Unlike industrial belts that are being marketed for bicycling applications, Gates Carbon Drive is the result of years of R&D on a bike-market-specific application and it is truly the premium product in the bicycle marketplace—and the only system designed from the ground up with bicycling in mind.
Regarding tooth size: Gates experimented with various tooth profiles (from 8mm to 14mm) before the launch of Carbon Drive. Gates found the larger teeth required larger sprocket sizes that are heavy and impractical for bicycling applications, where weight is a major consideration. The 11mm tooth size on Carbon Drive was chosen specifically because Gates found it to be the best combination of light weight and strength.