1977 sportster front sprocket

[rider7816]

Hey guys,  I'm still fumbling around and been reading a lot where people have been saying the sportster front 21 tooth sprocket is good for cruising around the city maybe 55-60 mph. And if I want to lower the rpm's at highway speeds I should install the 22-23 tooth front sprocket.
I guess my question is, do I have to replace the chain as well to a different link count or is the standard 106 count used in all applications.
Oh yea, what's the difference between an oring style chain and non oring??

Thanks

Frank

[garyajaz]

22 tooth ok for light bike maybe some mods
23 too tall unless have some power

o-ring chain=this century...lol...better

new sprocket should get new chain anyway. 
count needed teeth.  may need an extra link