Males Watts per Kilogram (W/kg)Fair From 2.23 to 2.78Untrained Less than 2.23Females Watts per Kilogram (W/kg)Superior 4.30 and greaterExcellent From 3.33 to 4.29Good From 2.36 to 3.32Fair From 1.90 to 2.35Untrained Less than 1.90FTP ratings are based on research by Hunter Allen and AndrewCoggan, PhD, Training and Racing with a Power Meter(Boulder, CO: VeloPress, 2010).Heart Rate Zone CalculationsZone % ofMaximumHeart RatePerceived Exertion Benefits1 50–60% Relaxed, easy pace,rhythmic breathingBeginning-levelaerobic training,reduces stress2 60–70% Comfortable pace,slightly deeperbreathing, conversationpossibleBasic cardiovasculartraining, goodrecovery pace3 70–80% Moderate pace, moredifficult to holdconversationImproved aerobiccapacity, optimalcardiovascular training4 80–90% Fast pace and a bituncomfortable, breathingforcefulImproved anaerobiccapacity andthreshold, improvedspeed5 90–100% Sprinting pace,unsustainable for longperiod of time, laboredbreathingAnaerobic andmuscular endurance,increased powerWheel Size and CircumferenceYour speed sensor automatically detects your wheel size. Ifnecessary, you can manually enter your wheel circumference inthe speed sensor settings.The tire size is marked on both sides of the tire. This is not acomprehensive list. You can also measure the circumference ofyour wheel or use one of the calculators available on theinternet.Tire Size Wheel Circumference (mm)20 × 1.75 151520 × 1-3/8 161522 × 1-3/8 177022 × 1-1/2 178524 × 1 175324 × 3/4 Tubular 178524 × 1-1/8 179524 × 1.75 189024 × 1-1/4 190524 × 2.00 192524 × 2.125 196526 × 7/8 192026 × 1-1.0 191326 × 1 195226 × 1.25 195326 × 1-1/8 197026 × 1.40 2005Tire Size Wheel Circumference (mm)26 × 1.50 201026 × 1.75 202326 × 1.95 205026 × 2.00 205526 × 1-3/8 206826 × 2.10 206826 × 2.125 207026 × 2.35 208326 × 1-1/2 210026 × 3.00 217027 × 1 214527 × 1-1/8 215527 × 1-1/4 216127 × 1-3/8 216929 x 2.1 228829 x 2.2 229829 x 2.3 2326650 x 20C 1938650 x 23C 1944650 × 35A 2090650 × 38B 2105650 × 38A 2125700 × 18C 2070700 × 19C 2080700 × 20C 2086700 × 23C 2096700 × 25C 2105700C Tubular 2130700 × 28C 2136700 × 30C 2146700 × 32C 2155700 × 35C 2168700 × 38C 2180700 × 40C 2200700 × 44C 2235700 × 45C 2242700 × 47C 2268Appendix 23