These are the best Roller Bearings for your Vespa PX150 or Genuine Stella. The Clutch side Bearing has Carbonitrided inner ring and oversize balls. Special high-speed precision bearings, reinforced for increased load and heavy applications, with oversize balls, carbonitrided inner rings, steel and polyamide cages. The co-operation of Malossi technicians with the company SKF allowed to obtain an important technical result for the fine-tuning of high-quality racing engines. The main differences to other bearings produced by SKF for scooter motors are the larger diameter bearing rollers and the partially carbon-nitrated inner ring. These features lead to a smoother running motor, especially noticeable at high revs. High revving motors can fail prematurely due to excessive heat expansion of standard grade bearings. Vespa PX150 Genuine Stella 2T