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Trek Roscoe 8 build

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    Trek Roscoe 8 build

    Finished up a Roscoe 8 , size 19.5 2019 model. Wanted to give a few tips and hints to anyone trying modify a 27.5 plus bike there were a few unique challenges.

    The Chainline and front chainring were a big issue since the bottom bracket is 73mm and the chainstay goes very wide due to plus size tires. The bbs02 barely fit itself(I've heard the HD won't fit without spacers) the regular 44t chainring didn't stand a chance at fitting without running a huge amount of spacers that would basically negate any offset you gained.

    I opted for the mini 30T, chainline was terrible so I rearranged the rear cogs of the 12 speed NX. Moved gears 5,7,9,10 closest to the center and adjusted the derailer limit to turn it into a 8 speed. Basically first gear was where 5th gear used to be, helped the chainline immensly. Took it for a test and no skipping in first gear or anything, rode and shifted perfect. Here is a pic of the chainline on first gear.

    All in all, if you are willing to drop some of the higer geears, the Roscoe 8 can work just fine and still have crazy torque running in low gears with a 30t ring.

    Hey Luke I was just thinking myself to grab a roscoe and build up with a BBSHD. Wondering how you've been getting on with the bike now it's been a month or so since you finished it up?


    • Lukeonderko
      Lukeonderko commented
      Editing a comment
      Its going great, have about 300 miles on it now without any issues. absolutely zero skipping or anything, the 30T has some crazy torque, you can pop wheelies with it! A lot of the miles have been with a heavy backpack and on backcountry rock and dirt trails.

    Just finished my Trek Roscoe 7 2020 build, I’m running a lekkie 36t bling ring with the BBS02 750w 48v shark downtube battery, all come together beautifully, any questions just shoot


      I'm building a Gravity DeadEye 27Plus single speed with a Sturmey Archer RS-RK3 and Bafang mid-drive. The wheelset is still a week out, but everything else is here. My BBSHD arrived from Luna today, and I haven't cleared out the 63mm bottom bracket on the bike yet, but I have been eyeing the chainstays and hoping the stock 46t ring will fit without too much fiddling. I'll keep you posted.

      I also have an irrational and stupid hatred of downtube batteries, and frame bags, so I'm working on getting a custom 13s6p 30Q pack made that I'll fit in a box at the juncture of the top tube and seat tube that I can lock to the bike securely for commuting days. Maybe with a motion alarm.

      At any rate, thanks for the pics. I think the plus tires look 'right' and proportional for an ebike. Can't wait to start wrenching it together!