Hi guys gonna renew my chain and sprocket on my nc21
which do you consider best o ring or x heavy duty
Cheers

I've got plain chains on me my bikes, just spray it everytime i get back from a trundle. Think xring chains are supposed to cause less drag, but never tried one.
Cheers
Ian

X-Ring aren't worth the premium over O-Ring, it's a marketing gimmick. They claim longevity but even using DID stuff I've not noticed any real benefit worthy of the investment. If you look after your O-Ring properly, it should last 20k miles or more.