Ah, okay. You were right the first time.
Remove the 608 bearing and install a 6900-2RS (or 6900ZZ) bearing in its place.
It will fit, they are both 22.00mm outside diameter.
You may need to coerce it.
Sometimes I install it in the wheel with the proper spacer — then use the axle nut on the truck to press the bearing into the pulley. Sometimes that works.
Otherwise, set a pinball in the center hole of the bearing, and tap the ball gently with a hammer maybe?
EDIT:
sorry i guess i should be clear. I was able to install the new bearings into the pulleys. But the pulley gear is hitting the motor mount… Looks like i need a spacer in between the hanger and pulley/bearing. I was hoping it’s a direct fit with just a bearing replacement.
ok…this is a noob mistake LOL.
i did this without installing the wheels, but once i put the wheel into the pulley, the 8mm bearing on the wheel sits on the 10mm step on the truck, effectively spacers out the pulley.
@3DServisas
Would the mini ECO V2 work on normal trucks like FB275 or only FB320? Seems like the hanger profile is the same.
I need a summer drivetrain with higher ratio than 1/3, I’m overheating every motor I try 
Can confirm, it will work. I have a 275/ECO V2 setup, just laying there. Waiting for a battery sucks. 
Public Service Announcement:
Remember Maytech redoing 6396 motor mounting to fit our usual mounting pattern? The motors have 5, M3x6mm bolts holding the entire stator to the motor faceplate.
Is this new mounting solution too weak? Yes. This is what happens from torque and vibration:
All 5 bolts get sheared off. Subsequently you will lose motor wires in the process because the motor will be able to do a 360 degree twist.
Maytech has already been warned about this!
Solution? Use a chamfer bit on the original 4 M4 bolt holes. Chamfer the holes, use proper bolts: 5 M3x8mm class 12.9, 4 M4x10mm class 10.9 countersunk. Make sure to use at least green loctite on the bolts!
Fix this to save your motors, board and health.
Since there’s a choice between Rockstar and Superstar, I guess the bolt pattern is different.
I have 3DS 3.75 wheels I want to use with them. Do you know if they are MBS or Trampa bolt pattern?
Maybe I don’t need that adapter plate at all? The wheels have the smaller pattern for mini SS geardrives. Hard to tell from pictures. 
I believe its trampa bolt pattern
Any updates on FB320s? 
The wheels you just posted a picture of are only for SS-Mini Gear Drives.
Will your normal 3.75 hubs work on the ECO V2? Or is it Trampa hubs only?
Separately sold 3.75" hubs are 1:1 with SUPERSTAR Hub bolt pattern.
SOLID… is the word here…these will never break… probably will do well as a hockey puck too
Can confirm maytech now added this solution to all their 6396 motors.
Do you or anyone else know if this issue is relevant for their 6880 motors as well?
There are no issues with the mounting of 6880 motors. I am using them myself 
Looks good to me 
Did that happen due to those retaining bolts shearing off?
