15X12 for Zuma RX8 Vento Zip and most Minarelli design two stroke scooters including Yamamha Zuma.

15X12 is most common size for all two stroke 49cc scooters.

6 - 7 gram is best for street ridding from 6 for heavier people to 7 for lighter on stock machines modifed can go down to 5-5.5 race machines to 4 gram

DR PULLY SLIDING ROLLER WEIGHTS means better performance from your scooter period not matter what stage you are in upgrading your scooter. Simply add a lower gram weight and a Kelvar belt gets up up to speeed faster and smoother.

Dr Pully weights answer the question can I get more take off speed and get there quicker, yes you can with these sliding roller weigts with new sliders also.

Add the DR PULLY variator to complete upgrade. 151301 is in stock

Dr. Pulley Roller Weights The latest roller weights to hit the market and the most advanced weights available. These sliding rollers perform up to 20% better than standard round weights and last up to 18% longer with 22% less performance material loss. The weights have several unique features such as their composite material being nylon for faster performance. Made of unique tribological material SL-9T and SL-9TS (oilless PA46) Low friction coefficient / Low wear / High temperature resistance Aluminum compatible; No abrasive fibers (glass fiber or carbon fiber) Fastest Roller Weights available

These are being used in 150s 157QMJ and 50cc 139QMB Trans Variator get the DR Pully Variator for best results for 150s plus two stroke scooter such as Yamaha Zuma and Vento Zip and clones.

Dr. Pulley ---- UNIQUE Sliding Roller Weights

Traditionally, gear ratio is changed by the up-and-down rolling movement of the roller weights in the ramp of MDF;

Now the innovative Dr. Pulley Sliding Roller Weights “slide” up and down in the ramp of MDF to change the gear ratio. This unique “sliding movement” (Not rolling!!) provides exclusive advantages to make CVT perform excellently:

No abnormal wear will occur, even when Dr. Pulley Sliding Roller Weights work in the high gear position.