Life On The Bike

Life on the Bike

Welcome
Junior Gearing
Single Speed
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Life on the Bike

I started this site as a resource for juniors and parent/caregivers to make it easier to get started in competitive cycling.

Thank you for supporting junior cycling development. The effort here is to help parents and coaches get their kid into competitive cycling. Please provide comments about other areas of concern beyond junior gearing and the roll out.

There is also a calculator for single speed gear comparison. Let me know if you want any mods.

I am always open to helping junior development. Please contact me if you need assistance.

Clint

email me at sbclint

References

http://www.coloradocycling.org/juniors

Junior Gear Restrictions

The junior gear restriction is intended to help juniors learn to ride and race their bicycles more tactically. Gear restrictions limit the extent that an early developer can simply ride away from a group. This keeps the early developers in the pack, and therefore helps them develop their tactical skills in addition to their engines.

There are also physiological development benefits to juniors learning to "spin" their gears. Spinning at a higher rpm requires less torque than at a lower rpm for a rider going the same speed, so it is better for the rider's joints. Athletes need both muscular strength and cardiovascular conditioning to race well, and because there is more room to increase cardiovascular capacity than raw strength, it is natural to focus on a high-cadence pedalling style. One way to look at is that once riders approach and maintain a high level of muscular strength, the only way to go faster is to increase the ability to repeat an action more often. Spinning helps riders recruit more muscle systems to pedal faster and gain more propulsion.

Rollout

The rollout technique is simple. A rider puts his or her bike into the biggest gear ratio possible, using the largest chainring and the smallest gear on the cassette. Then, the bike is rolled backward to see how far one crank revolution will take it. The steps are simple.

Align the crank arm to point straight downward at a designated mark on the ground
Roll the bike backwards until the crank arm returns to the bottom
Confirm that the crank arm is stopped prior to second marker

Hint: Lifting the front wheel off the ground helps keep the rear wheel tracking straight, which improves the accuracy of the rollout measurement.

Remember

Officials may provide a courtesy rollout prior to a race, but the official rollout occurs after the race. This is to ensure that if a rider took a wheel during the race, his or her bike is still in compliance. It's important to remember that if a rider goes to the pit for a wheel during a race, he or she must specify the gear combination, as in "I need a 12 T cassette," or "I need a 14 T cassette."

In the United States, the rollout distance is specified as 26'-0" (7.93 m). Colorado juniors are fortunate to have a rollout rail made by Rocky Mounts for The Bicycle Racing Association of Colorado - The ACA that makes rollout fairly simple by keeping the wheel on a straight path. If you don't have access to a rollout rail, place a piece of tape at your zero mark and one 26'-0" away. Be sure to consistently use the leading edge of the pieces of tape as the official measurement marker. The width of a piece of tape (1" - 2"), if it is mistakenly included in the rollout measurement, can be the difference between passing and failing. Rolling along a straight edge or line will help to keep the wheel from wandering and improve accuracy.

Finding a Working Combination

Below is a tool to test some gear combinations easily. Playing around with some numbers will illustrate that the gear restriction seldom limits a rider's ability to race. This tool also provides a wheel odometer value in mm that you can use for your cyclometer. To reduce the potential for error introduced in the start/stop portion of the measurement, circumference is best measured through three rotations. The easiest way to do this is to lay out a tape measure on a flat surface to about 250 inches. Then, line up the leading edge of the rear wheel's valve stem at the zero mark with the bike facing backwards. Lift the front wheel to help the rear wheel run straight, and roll the rear wheel back three revolutions. Note the measurement in inches where the leading edge of the valve stem lands.

The best 650C looks to be the WickWerks 44 chainring with an 11-x cassette. I rolled out a Vittoria Rubino Pro 650C (23 mm) to 228-11/16" in 3 revolutions (228.7 ").

There are many combinations that work well for standard 700C setups using 23 mm or so tires (247.7 in in 3 revs). The USA Cycling rollout was standardized on a 52/14 combination, i.e., a 52T chainring and 14T small gear on the cassette, and many European countries use a more restrictive 52/15 and 52/16 setups. These ratios are 3.714 and 3.25, and they roll out to about 25.8 and 43.7 inches short of 26'.

Estimated Roll Out for a 23 mm Tire with a 2097 mm Circumference.
Chain Ring	Small Gear	Ratio	Estimated Rollout	rpm @ 27 mph
53	15	3.533	24.31 ft	97.7
46	13	3.538	24.35 ft	97.6
50	14	3.571	24.57 ft	96.7
40	11	3.636	25.02 ft	95.0
44	12	3.667	25.23 ft	94.2
52	14	3.714	25.55 ft	93.0
41	11	3.727	25.64 ft	92.7
45	12	3.75	25.80 ft	92.1

Play around with the rpm numbers to show yourself that gear restrictions actually have very little effect on a rider's ability to race at his or her best. Many years ago I had a great conversation with Norman Alvis about spinning. He made the comment that he would often wind up to 175 rpm for a sprint finish. Throw that number into the calculator before piping up too much about limitations.

Recommendation

A 12-x (e.g., 12-25) cassette is a common build. Salsa makes a 45 tooth chainring for both a standard 130 mm and compact 110 mm bolt pattern crankset. Therefore, a simple swap of the chainring is all that is needed to comply with junior gear restrictions. The Salsa rings do not have shifting ramps or pins, so riders must shift quickly to avoid shifting hesitation. An alternate suggestion is to use a 44 - 12 combination, since high quality 44 T chainrings are very readily available due to cyclocross demand. The 44/12 combination provides a 3.667 ratio Est. Roll out 25.23 ft and rpm @ 27 mph - 94.2 - see WickWerks for a 44 T chainring - they have a junior specific page WickWerks Junior Setup.

I am always open to helping junior development. Please contact me if you need assistance.
Clint
email at sbclint

References

http://www.coloradocycling.org/juniors

http://sheldonbrown.com/cyclecomputer-calibration.html

http://www.wickwerks.com/Products/JuniorRoadGears.html

http://sheldonbrown.com/harris/chainrings/110.html#rocket

Single Speed Gearing

The simplistic beauty of riding a single speed bicycle is awesome. The bike feels smooth.

Finding a Working Combination

Below is a tool to test some gear combinations easily. Playing around with some numbers will illustrate that the gear restriction seldom limits a rider's ability to race. This tool also provides a wheel odometer value in mm that you can use for your cyclometer. To reduce the potential for error introduced in the start/stop portion of the measurement, circumference is best measured through three rotations. The easiest way to do this is to lay out a tape measure on a flat surface to about 270 inches. Then, line up the leading edge of the rear wheel's valve stem at the zero mark with the bike facing backwards. Lift the front wheel to help the rear wheel run straight, and roll the rear wheel back three revolutions. Note the measurement in inches where the leading edge of the valve stem lands. The 256" listed here is a Vittoria XM Pro on Mavic Ksyrium Elite wheel, and for an urban number use 247.7".

There are many combinations that work well for standard 700C setups using 32 mm or so tires. An easy single conversion uses your existing 39T chainring and adding a 18T small cog replacement for the cassette.

Estimated Roll Out for the Vittoria XM Pro setup above.
Chain Ring	Small Gear	Ratio	Estimated Rollout	rpm @ 18 mph
39	19	2.053	14.6 ft	108.5
39	18	2.167	15.41 ft	102.8
40	18	2.222	15.80 ft	100.3
39	17	2.294	16.31 ft	97.1
40	17	2.353	16.73 ft	94.7

Recommendation

A 39 x 19 is fun, so that is where I currently ride.

I am always open to helping people have fun on a bike. Please contact me if you need assistance.
Clint
email me at sbclint

References

http://www.coloradocycling.org/juniors

http://sheldonbrown.com/cyclecomputer-calibration.html

http://www.wickwerks.com/Products/CycloCross.html

http://sheldonbrown.com/harris/chainrings/110.html#rocket

Contact Information

contact Clint at sbclint at bickmorefamily dot com

or (303)834-7093

or (720)421-4896