Hundreds if not thousands of motorized bicycles are out there using the kit supplied sprocket attachment method. Many have accrued high milage without a problem. Installed and maintained correctly the so called 'rag joint' rubber sandwich method will suffice for most riders. Key words here are "installed/maintained correctly"
That being said you'll get lots of responses from builders who rely on the 'clam shell' style of clamp around adapters as well as bolt on methods such as using a disc brake rotor that bolts to the sprocket and hub.
True, the kit supplied adapter has some drawbacks and requires careful installation to perform correctly without damage to the spokes but it has been done many times and those who use them seem satisfied with the results.
Like many aspects of this hobby you'll find several ways to do things and it will be up to you to choose which way to go. Do a little research and reading using the search feature at the top of this page. Type in Keyword, 'sprocket adapter'. Good luck.
Tom
