Gear clamps to move the bigger rear sprocket for straighter chainline
https://electricbike.com/forum/forum/knowledge-base/motors-and-kits/bbshd/39170-how-to-rework-rear-sprockets-for-mid-drive-systems
Check out this nice video: How to rework rear sprockets for mid drive systems...
Nice tire: Surly Extra Terrestrial 26x2.5
Gearclamp used in this video http://www.gearclamp.com/
The cassette is a SunRace CSM98 bought on ebay
