cross-posted from: https://lemmy.ca/post/49655095

This is an Ultegra 11s chain after 1000km of wear from a 1500W mid-drive. Used to ride a Tangent back in 2016. T’was shredding till it went *clunk*.

  • Mac@mander.xyz
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    2 days ago

    Oh wow. I didn’t assume nylon gears!

    You need a better polymer with a higher glass transition temp.

    • Avid Amoeba@lemmy.caOP
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      2 days ago

      Haha, yeah. Nylon is great because it keeps the metal bits from wearing, allows them to be softer and lighter materials like alu, prevents shavings from spreading and grinding bits, and they’re quiet. But they lose strength at not too high temps. Beefier nylon gears can have enough strength even when softer. E.g. the helical gear of Bafang BBSHD which people regularly run 1kW through. Some people used to put Delrin (Teflon) gears in their motors, but I don’t think production motors have ever done that. These gears from the pic are tiny with small, helical, teeth. The front version of this motor is 1.8-1.9kg. Whenever you see a bike with a small hub, smaller than a typical disc rotor, front or rear, it almost certainly has similar sized gears. I also have a Shengyi with similar parameters to the G310 and it has almost identical design inside.