The roller comes with a friction drive which helps transfer power from the engine to the rear wheel. The power is transferred from the 38 or a 49cc engine to the bike’s rear wheel. The drive rollers promise strength and hardness. The larger the drive roller, the better it is as it gives the bike a great speed. The installation of the friction roller is easy and quick, so you can get these replaced easily.
It is solid piece with a keyway shaft and then hollow in the center. It looks like it would be a good friction drive roller. That wouldn’t eat up tires like mine does. My friction drive roller it’s completely different. It is One solid machined piece of metal. Witch is totally on me, bikeberry sent the right piece I ordered. But they don’t really give a good description about some of the parts. I guess that older Versions of the friction drive roller are like mine. And this one won’t work! So before you ordering one, take yours out.
If U ride, U will need this! If U are putting on the miles U will need to replace this roller but its an easy job, just don't do it on the lawn )