The pdf document below is an excellent Introduction to Racing by Matt Winston, published in the Go-Ride magazine.
This article is aimed at Youth riders, and has information for the rider and their helpers and parents – what to expect at your first race, how to prepare for it, hints and tips, rider categories explained and more.
In the document Matt suggests a 46 chain ring with various smallest sprocket sizes for each Youth category. It very much depends on your bike and whether you want to spend money on specific chainrings and rear cassettes, or make do with your bike as it is. More serious racers will use specific combinations. A 46 chainring may require a compact chainset. Smaller chainrings can be used with a wider range 10 speed cassette (locked out as required). NOTE: the 46×14 combination for Youth A NEARLY ALWAYS rolls back in excess of 6.93m, unless you have THIN tyres and its a COOL temperature.
For Youth A riders racing in Europe, a 52 chainring with a 16up cassette will be required. This is recommended for the UK for Youth A. For TRACK racing, 49×15 is generally used by Youth A riders. These combinations are generally within the 4.93m rollback with tyres in general use, and on hot days – BUT DO CHECK.
For Youth B riders 48 chainring with a 16up cassette works. For track 48×16.
There is some variability with measuring rollback at events, it depends on the technique and how accurate measuring lines are setup. Attempting to get within a centimetre of the limit nearly always leads to a rollback failure especially if gearchecks are done by experienced commissaires. The temperature does make a difference.
If you are new to cycle racing, look out for our orange CSP kit, and our experienced members will help you. Better still, tell someone you are going and they can help you when you get there.