Equipment

Steel Tape (30 m/100 ft or longer)

Thermometer

Spring Balance (minimum of 50 N or 5 kg or 11 lb)

Jones Counter (or Jones-Oerth, or Jones-Oerth-Lacroix [JOL])

Mallet or Hammer

Mag Nails (or PK Nails, or Concrete Nails)

Washers

Paint

Bike

Duct Tape

Pen/Pencil

Calculator

Calibration Course Calculations

300 m or longer

Temperature at start of measurement

Temperature at finish of measurement

Average Temperature

Coefficient of linear expansion/contraction of steel is

0.0000116 m

m oC

Temp. Coeff. = 1 - (0.0000116 X {Average Temperature - 20oC})

eg. If Temperature was 5oC at start of measurement and 8oC at finish and if the first measurement was 300 m and the second measurement was 300.04 m.

Temp. Coeff. = 1 + (0.0000116 {6.5oC - 20oC})

= 1 + (- 0.0001566)

= 0.9998434

Actual Length	= Average Distance x Temperature Coefficient

= 300.02 m x 0.9998434

= 299.97301 m

Therefore add 2.7 cm to make the calibration course 300 m

Pre-Calibration Ride	Covent Garden 8 km

948450	951901	955352	958802.5

945000	948450	951901	955352

3450	3451	3451	3450.5

Average	3450.625 counts x 1000 m/km x 1.001	= 11513.585 counts/km

300 m

First Ride	Change in Counts	Distance (Working Constant)

Finish	022000	0	0

7 km	033514	11514	1.00004 km

6 km	045027	23027	1.99999

5 km	056541	34541	3.0000

4 km	068054	46054	4.0000

3 km	079557	57557	4.9991

2 km	091062	69062	5.9983

1 km	102563	80563	6.9972

start	114062.5	92062.5	7.9960

Measure a second time and calculate distance again. Distances should be within 0.8%.

Measure calibration course a second time.

Calculate post calibration constant.

Average pre & post calibration constant = Constant of the Day

Divide the # of counts for the first measurement by the Constant of the Day. Repeat for the second measurement. Distance is the smaller of the two distances. Add or subtract to make the distance 8 km. Hammer in a Mag nail or PK nail at the Start, finish, and turnaround.

Bernie Conway