winstonw wrote:In another thread, it was mentioned Australian grades can be matched to US categories, which are guided by FTP watts/kg.
I think C grade was accepted as 3-3.5watts/kg.
No, they are not.
What determines your category level in the USA (and many other countries) are your race results and points accumulated from racing.
When you first start racing, you are required to start as a Cat 5, race and earn enough starts/places to gather the points needed to be upgrade to Cat 4. Then the process repeats. For Cat 5, you get points for finishing, and part of the process of earning points at that level is simply gaining racing experience before you are permitted to race in the higher categories. Naturally, Cat 5 have people of widely varying levels of fitness, plus those that are simply not fit enough to race at higher categories.
From Cat 4 and up, then you actually need to start gathering points based on results in order to earn your category upgrade. This is typically done in geographical divisions, e.g. NorCal (northern California) or State boundaries, sometimes several states combined. As a result, due to the variance in racing numbers / depth of fields, even this does not end up producing equality across the country. A Cat 3 in one division may be at Cat 2 standard elsewhere but if they travelled to another division, they would still have to race Cat 3 (and they may well clean up). If they stayed there, eventually they would accumulate enough points to be upgraded.
Power outputs are not and never will be used as a grading mechanism. All the W/kg numbers refer to is the typical power of riders that race in those categories, but it's quite a wide band. e.g. in some districts, you won't win a hilly Cat 3 road race without an hour power of ~5W/kg.
If you want to know what grade you should be racing in Australia (and you are not sure), then just go race. If you win by a country mile, then smile for the after race photo, take your $20 envelope, brag to your significant other all night simultaneously explaining why you need those new deep section carbon wheels, and turn up next week in the next grade up. If however you get dropped pretty quickly, then drop down a grade.
Lather, rinse, repeat. Simple really.