Clutch bell, different bearing options.
https://m.traxxas.com/products/search?keyword=Clutch+bell
Bearings
Tra 2728. Order from traxxas, hobbyshop, or online.
https://m.traxxas.com/products/parts/2728
Buy a traxxas clutchbell or the like, I think they are 5x7x2.5, one front and one back. Almost certain Hpi also uses needle bearings, as my 15fe has them.