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Chainring question: 2015 Xtracycle Edge Runner w/BBSHD Mid-Drive 1000W conversion

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    Chainring question: 2015 Xtracycle Edge Runner w/BBSHD Mid-Drive 1000W conversion

    Hey folks,

    I converted my wife's Xtracycle to an e-bike last year using a kit that I got in a trade from a friend who works for a non-profit out of chicago. It was my first buildout, and I actually wrote about the experience for The Verge. Very fun time, but mistakes were made.

    The big one is the chainring right now. I used the one that came with the kit — a Luna 30T mighty mini that's very cool looking, but my wife absolutely hates the thing. She's not into spinning and wants to pull more chain for each pedal stroke. Being inexperienced, I don't know everything I need to consider, here. After the build experience that I wrote up, we paid a friend to install a 9-speed cassette on the back (I don't recall the specific range, but I want to say it's a 10T – 48T or thereabouts).

    So, my question is this: for the Edge Runner specifically, do I need to make sure I'm keeping to the original 8mm offset of the tiny 30T chainring? I think it might actually be a little much, as it was pretty difficult to get it to properly shift into the highest gear. Or can I go shallower? She's a strong cyclist, so I think she'll be just fine with a 38T chainring, but it doesn't seem like I have a lot of options there when it comes to keeping 8mm offset.

    Typically 'we' want as much offset as possible. Most of the time the issue is the chain stay which is the horizontal frame bar. Newer frame designs that are designed around 1x's and for wider tires don't leave much of a recess for the ring before kicking out for wider tire clearance. The BBS gearbox is usually about the size of a 1x ring so that take up the space of the original ring which means the new chain ring has to go out further which often times means the chain line is worse and you may not be able to get to the lower(bigger) gears. My bikes I have like 1mm of clearance between the teeth and the chainstay.

    Her bike having a super long wheelbase and not especially wide tires I would not expect there to really be any issues. If the 30t has been fine maybe going with a BCD spider that uses 'regular' chain rings would be a decent way to go and give you more options.