New answers tagged drivetrain
The NuVinci® N360 is a continuous variable transmission that is roller based. It is marketed and used mainly on hybrid and low maintenance city bikes. They must have had some market success as they have been around since 2006. I recall seeing them at Interbike around that time. More info in the internal structure
There have been designs, but cyclists tend to be picky about increases in weight or losses in efficiency. Bicycles do not have the problems of large spinning masses or rough clutching at low speed, and we seem to do OK with discrete steps in the gear ratio.
Last year I found my girlfriend an older Takara (classic steel frame) with shimano SIS components, and it worked fine. Yes, the components were flimsy, junky, and jumped on certain gears, but it got the job done until we could upgrade it. The next year we purchased a Trek 600 (aluminum frame) with all shimano 600 components and stripped it. We then ...
If its a low quality bike, you're probably best off just selling it and buying a decent bike to begin with -- there are good used road bikes for reasonably low prices. The first problem is that cheap road bikes likely don't even have cassette+freehub systems -- they have freewheels. High quality freewheels aren't cheap, and you do need a freewheel remover ...
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