I've been using non o-ring chains now for 3 seasons with great results. I can't feel more power but If there is any truth to belts being more efficient then a non oring has got to be more efficient then an o-ring chain.
I did a test last year with a brand new rk o ring in the chain case and a brand new rk non o-ring on the main chain. Sprayed the non o-ring with chain wax once in a while. After a season the o-ring chain actually stretched more than the non. $25 chain vs an $80 chain. I'd call that free horsepower.
I did a test last year with a brand new rk o ring in the chain case and a brand new rk non o-ring on the main chain. Sprayed the non o-ring with chain wax once in a while. After a season the o-ring chain actually stretched more than the non. $25 chain vs an $80 chain. I'd call that free horsepower.