Welcome to the new Junior Velo gear chart. I believe it is a huge improvement over the original. Changes appear almost instantly. You can change the highlighting to reflect US, Australian, or road racing rules. You can add and remove as many cogs and rings as you like. Enjoy.
- The chart reflects USCF and Australian rules as of 2006. The UCI specifies only the 7.93 meter road gear limit for juniors.
- Some typical rolling diameters are shown below. For more accurate results, use actual measurements from your own wheels and tires.
Tire size Effective diameter 700c x 23mm 26.57 in 675 mm 700c x 20mm 26.26 in 667 mm 650c x 23mm 24.57 in 624 mm
- You may add cogs or chainrings one at a time, in a list (14,19), or using a range (44-46).
- The chart will save your choices between visits, as long as you are on the same computer and browser. This doesn’t work if cookies are disabled.
- Internet Explorer users will find that some controls don’t respond right away. Try using “tab” rather than “enter” after entering a number, or clicking somewhere else after using a control. Even better, get Firefox.
- Gear Inches - Chainring teeth/cog teeth * 27 inches. This is traditional, but does not reflect any actual dimension of the bike.
- Exact Inches - Similar to Gear Inches, but using the actual rolling diameter of the wheel in inches.
- Rollout - How far the bike rolls in one revolution of the pedals.
- Speed - What we want more of.
- Cadence - Revolutions of the pedals per second.
- Effective diameter - How far the wheel rolls in one revolution, divided by Pi. This take tire flex into account better than measuring the wheel with a ruler. Also called Effective diameter.