Be careful of what you read out there because a lot of people just regurgitate incorrect or outright wrong info from others' posts who haven't actually done the work or even touched actual parts in question with their own hands.
Pre-gen wheel goes into swingarm that is 13mm narrower. To fit pre-gen wheel into wider new-gen swingarm, you have to make axle-spacers that's 6.5mm wider than before. Left-side spacer's easy to make.
Problem is adding 6.5mm to outside of caliper-bracket on right side.
It will no longer engage with tab on swingarm. Caliper will just swing around and around when you try to use rear brake. You can cut off tab on swingarm and weld on wider one to engage new position of caliper mount. Easier to just weld on bracket for front of torque-arm and use entire brake-assembly from pre-gen on new-gen swingarm. Will also match 10mm larger rotor on pre-gen wheel.
