68mm or 100mm Mid Drive for Scott Aspect 940?

[TrekElek]

Things have changed since my last post. My bike is now a Scott Aspect 940. My Trek Marlin 5 guy ghosted me. I ordered a BBSHD 68-73mm and was to be delivered today. My seller cancelled. My crank frame width is 73mm. Will a 100mm motor set work? I see mixed descriptions about the width. I am also concerned that there will not be enough threads for a 73mm frame.

 

[Chuy]

The 73mm bikes require longer bolts and 5mm spacers. I believe some kits supply the longer bolts but not the spacers - you end up using washers. The longer bolts are standard pitch M6, 15mm long; you can buy your own just make sure it is a 12.9 grade.

 

[TrekElek]

What about a 100mm motor kit? Is it the same as 73mm but fewer spacers? 100 mm kits are everywhere.

 

[Chuy]

I can’t say for sure, but I would think not. The 68/73 motor is for a bike with a 68mm wide BB. Put it on a 73mm bike and it is 5mm short, hence the need for spacers. A 100mm motor is going to be 27mm longer on a 73mm bike. It is going to be way too long. There are several install videos that address the 68 in a 73 install.
Here is a short video with the BBD02 but is same issue with the HD.

 

[TrekElek]

Thank you much. I now see that when the frame width was expanded to about 73 mm with two spacers added, there were also plenty of threads remaining on the motor drive component.

 

[Chuy]

The lock ring may not fit, is what some have said. You may also want to torque the lock nut to about 60 ft/lbs, instead of Bafang’s 30 or so. Mine came loose. I went with 60 and applied blue threadlocker. The other thing some have done is put a hose clamp around the motor and secure it with another clamp on the downtube.

 

[TrekElek]

Thanks. I plan to make a modified bracket with an ear that clamps to the down-tube.

 

[major masingil]

I have a BBSHD on a 73mm bottom bracket bike. I used a lekkie one-nut to mount the motor and it has held perfectly. I needed 3 spacers to push the motor out far enough to avoid the chainstay. I also used a 42t lekkie bling ring to help manage the issue. My best chainline is between 3rd and 7th gear on a 9-speed. If i remember correctly I did have to purchase longer bolts for that bracket you and chuy are talking about.

I like my set up. I still can use all my gears. The chain gets a little loud if I try to go full throttle in 1st gear. It works great to billy-goat me up a steep hill with no issues