From Team Associated:
These Factory Team Rear Hubs include inserts for adjusting the axle height of the RC8B3 and RC8B3e. The inserts give three settings to choose from. The lowest setting will make turns easier to drive through, though slower. The highest setting will make the buggy turn more quickly.
The kit universal axles will fit the #81077 Factory Team Rear Hubs with the addition of optional 8x16x5mm bearings #91564, which is a package of four bearings. The rear hub inserts are also sold separately as #81078.
#81077 – Factory Team Rear Hubs, aluminum, pr – MSRP $99.99
*Requires #91564 FT Bearings, 8x16x5 mm, non-flanged. See below.
#81078 – Factory Team Rear Hub Inserts, pr – MSRP $8.99