Rollo said:Hi guys,
I'm 17 years old and therfore am in the under nineteen category. I'm competing in my first age group race this weekend and have just found out that i need to ride restricted hears. I hear that there is a screw in the rear derailuer that i can adjust to block off gears to save me from having to purchase a new cluster.
If anyone can give me anymore information on how to do this, what screw, how much to adjust and if it is something i can do myself or something i will need to get a mechanic to do?
Any help would be fantastic!!
Thanx Rollo
The following is a snipped bit from ontariocycling.orgsch youth racing.phpOpen ↗:
Assuming that it is a regulation race this is pretty much a typical explanation from what I have seen on UCI regs. Alas, I am more than a few decades past the cutoff for Juniors so no personal experience. 🙄
[font=Arial]2.2.024 For Junior Men and Junior Women, the authorized maximum chain gear ratio is 7.93 metres. [/font]
[b][size=1][font=Arial]What does this mean?[/b]
[/font][/size][font=Arial]When the bike is in the largest gear (big ring on the front, smallest gear on the back) it must travel less then 7.93 m when the pedals are turned exactly one full circle.This is tested by doing what is called a “roll-out”.At the race, the commissaire will shift your bike into the largest gear available (biggest front, smallest back), and then roll it backwards watching one pedal.When the pedal goes around exactly one time, the distance will be marked.If it is more than 7.93 meters the bike will be illegal, and you will not be able to ride.At the end of the race the same check will be done, and if your bike fails, you will be disqualified.[/font]
[b][font=Arial][size=1]So how do I comply?[/b]
[/size][/font][font=Arial]The best way to insure that you bike will pass the test is to make sure that your “big ring” has 52 teeth, and that your smallest rear gear is 14 teeth.This combination is by far the most commonly used and will be very convenient if you need help with a flat or require other mechanical support during a race. These are standard parts that are readily available from your local bike shop, and should be provided at no extra cost on a new bike.[/font]
[font=Arial]The other way to pass the test is to “block out” some of the gears on the back.If you have a 52 tooth "big ring" on the front you must block off all gears smaller that 14 on the back.If you have a 53 tooth "big ring" you must block off all gears smaller than 15. The best way to do this is to adjust the limit screw on your rear derailleur to prevent the use of the smaller gears.Some commisaires may also require you to make the illegal gears unusable by wrapping them with tape and/or cable ties. Remember that your bike will be checked after the race – if the adjustments slip during the race, or if you get a spare wheel that has different gearing you could be disqualified.[/font]
