For racing in the USA, from the USCF rulebook: 1M6. Junior Gears. Road 17-18: 7.93 meters (26\u201f)(52x14) 15-16: " 13-14: " 10-12: " Track 17-18: Unrestricted 15-16: 6.78 meters (22'3")(48x15) 13-14: 6.36 meters (20'10.5")(48x16) 10-12: 6.00 meters (19\u201f8")(48x17) The gear limit for a rider is determined by the age of the rider and the discipline, and applies in all events in that discipline
Since the kid will be nine on Dec 31, 2011 his racing age is 9 and is eligible for Youth only (<10 yr old) races. But you might as well use the restrictions for 10 year olds - 6.00 meters rollout (distance travelled with one turn of the crank) on the track. The gear figures above assume a 700x23 tire, so you'll need to adjust the noted 48x17 accordingly. The USCF rule book used to give the figure in gear inches as well, = 98 gear inches, so 6.00 meters ~ 74 gear inches. So don't go over that limit and you'll be good.
Jim Carter Class C referee and the rollout go-to at the Sunny King Crits every year. Mountain Brook, Alabama United States of America
________________________________ From: sean flores <seaneee175@gmail.com> To: classicrendezvous@bikelist.org Sent: Wed, January 5, 2011 2:31:39 PM Subject: [CR] Gearing Advice for Junior Track
Hey all.
I'm building up a junior Starnord track bike for a friends son. It's come time to decide the gearing and would love some input. Especially from those of you who have/are coaches.
He's a pretty tough kit. Pretty strong, but rides mostly BMX. He's 8 going on 9.
Wheels are 24", with 150mm cranks. Rear hub is double fixed. My initial thoughts were a 42 up front with a 12t and a 15t which would give 84/67 gear inches respectively. Then I reconsidered with a 40t up front for more flexibility, sticking with a 12t and then a 16t which would result in 80/60 options. The 60 gear inch ratio would be the "get used to a fixed wheel" ratio.
Initially it will be used with a front brake to get him used to the idea with the end goal of getting him in a club or program locally.
Would love to hear any thoughts before I go on the hunt for a ring.
I know this is somewhat off topic, but hey, the bike is on topic and there is a great wealth of knowledge on this subject here.
Sean Flores San Francisco, CA USA _______________________________________________
The maximum chaingear ratio for Junior riders is based on age and discipline. Blocked gears will be allowed, except in National Championships. All tests for compliance shall be done using the "roll-out method." There is no restriction for cyclocross or MTB races. For road and track the limits are: 54