Two weekends ago I had only my second climbing experience on routes that have been rated. Prior to that, all of my ascents have been free climbs on backcounty Adk slides which I merely assumed topped off at Class 4. Based on the rated routes I recently climbed, I now realize that some of these slide pitches have been low to mid Class 5. I also realize there is a big difference between a 5.4 friction and a 5.4 vertical climb (at least to me). So I was wondering for future reference, is there a basic set of rules for rating friction climbs?