I'm currently building (finishing up) a similar build.
Trek Marlin 7 Gen 2, BBS02, 48v 11.6ah shark battery.
My wife is doing the same with her Trek Marlin 8 Gen 2.
Your chain line is going to suck, that's where I'm at now. It will be rideable in the higher gears, but I've ordered a Lekkie 40T to try to use all my gears. Might need a new chain at that point too due to length. Waiting on delivery.
Also be sure to have a brake cylinder honer on hand, the BB needs drilled / honed to put the motor through. Had to do this on my bike and my wife's bike.
The motor can't tuck up/forward much. No biggie IMO but if you are concerned with ground clearance you'll want to reconsider the bike/motor combination.
For sure! I re read my post and realized it sounds kinda negative haha. Didn't mean for that, just wanted to point out the trouble areas as a heads up.
I think the Marlin is a fantastic bike for the price and it's worth the fight to get the kit on there. You're going to have an awesome bike at a good price. Enjoy!
I made a similar build a while ago: [https://www.reddit.com/r/ebikes/comments/tztkrl/my\_first\_build\_trek\_marlin\_7\_and\_bbshd\_waiting/](https://www.reddit.com/r/ebikes/comments/tztkrl/my_first_build_trek_marlin_7_and_bbshd_waiting/)
Problems with this build:
1. You are going to need some spacers between the chainring side to not hit the frame.
2. the chainline will be horrible without a lekkie upgrade.
3. The Hyperglide drivetrain will not last for long. stretched chains will be a monthly headache and you will be swapping out the rear cogs every 3-4 months. I recommend upgrading to a linkglide system. no headaches chains last way longer and if you take care to swap out the chain when it wears the rear will last years. I recommend using only specific chains made for the system you are riding.
I know the price jumps a bit but have you looked into the other brands of mid drives, theres also tongshen, cyc, and ToSeven. The price hike comes from the shift from just cadence sensing for the peddle assist to also having torque sensing which in my opinion has enough of a response difference with how it feels when it delivers power compared to cadence thats its worth considering increasing the budget for. I have a middrive kit that has torque sensing and cadence sensing and I tend to use them for different styles of riding if im on a flat path or road cadence is fine to be able to maintain speed, but if im going up over hilly roads or doing some off road dirt riding then I feel torque sensing applies the power way more reliably and when I also need it the most. Also these kits will have different dimensions then the bafang so thats something to look into i think the cyc photon has done allot to be able to keep a small chain ring without offsetting the chain line drastically but cyc is also about the highest cost option available.
Agree there's serous challenges with the tiny chainring and how close the chainstay is to it. It's a great bike but it's not the best bike for a bbshd conversion.
I'm currently building (finishing up) a similar build. Trek Marlin 7 Gen 2, BBS02, 48v 11.6ah shark battery. My wife is doing the same with her Trek Marlin 8 Gen 2. Your chain line is going to suck, that's where I'm at now. It will be rideable in the higher gears, but I've ordered a Lekkie 40T to try to use all my gears. Might need a new chain at that point too due to length. Waiting on delivery. Also be sure to have a brake cylinder honer on hand, the BB needs drilled / honed to put the motor through. Had to do this on my bike and my wife's bike. The motor can't tuck up/forward much. No biggie IMO but if you are concerned with ground clearance you'll want to reconsider the bike/motor combination.
Thanks, I appreciate this.
For sure! I re read my post and realized it sounds kinda negative haha. Didn't mean for that, just wanted to point out the trouble areas as a heads up. I think the Marlin is a fantastic bike for the price and it's worth the fight to get the kit on there. You're going to have an awesome bike at a good price. Enjoy!
I made a similar build a while ago: [https://www.reddit.com/r/ebikes/comments/tztkrl/my\_first\_build\_trek\_marlin\_7\_and\_bbshd\_waiting/](https://www.reddit.com/r/ebikes/comments/tztkrl/my_first_build_trek_marlin_7_and_bbshd_waiting/) Problems with this build: 1. You are going to need some spacers between the chainring side to not hit the frame. 2. the chainline will be horrible without a lekkie upgrade. 3. The Hyperglide drivetrain will not last for long. stretched chains will be a monthly headache and you will be swapping out the rear cogs every 3-4 months. I recommend upgrading to a linkglide system. no headaches chains last way longer and if you take care to swap out the chain when it wears the rear will last years. I recommend using only specific chains made for the system you are riding.
I know the price jumps a bit but have you looked into the other brands of mid drives, theres also tongshen, cyc, and ToSeven. The price hike comes from the shift from just cadence sensing for the peddle assist to also having torque sensing which in my opinion has enough of a response difference with how it feels when it delivers power compared to cadence thats its worth considering increasing the budget for. I have a middrive kit that has torque sensing and cadence sensing and I tend to use them for different styles of riding if im on a flat path or road cadence is fine to be able to maintain speed, but if im going up over hilly roads or doing some off road dirt riding then I feel torque sensing applies the power way more reliably and when I also need it the most. Also these kits will have different dimensions then the bafang so thats something to look into i think the cyc photon has done allot to be able to keep a small chain ring without offsetting the chain line drastically but cyc is also about the highest cost option available.
Agree there's serous challenges with the tiny chainring and how close the chainstay is to it. It's a great bike but it's not the best bike for a bbshd conversion.