Road Course Measurement Bulletin Board    Forums  Hop To Forum Categories  Course Measurement  Hop To Forums  General Course Measurement Topics    NEW 25-M CALIBRATION COMPETITIVE WITH PRESSURE MONITORING
Go
New
Find
Notify
Tools
Reply
  
NEW 25-M CALIBRATION COMPETITIVE WITH PRESSURE MONITORING
 Login/Join 
Picture of Neville
posted
I have just shown that the calibration factor determined with the new 25-m course method differs from that on a home 400-m course with later temperature correction by pressure monitoring by only negative 0.008%. Since it only took a total of 5-10 min to do the calibration on the temporary 25-m course, this means that the new method is quite competitive.

At the start of a certification, I calibrated on my home 400-m course:
Temp: 70 deg
Tire press: 600 kPa
Whole rev: 191
Spoke intervals out of 32: 15.3, 15.7,15.1, and 15.4 (ave, 15.375)
Calibration factor: 1.001(191+15.375/32) /0.4 = 479.18 rev/km

After bicycling 20 miles over 75 min to the race course, temperature had risen to 80 deg and tire pressure to 612 kPa. Based on a pressure coefficient of negative 0.1333 rev/km/10 kPa, the new calibration factor was 479.18 - 0.16 = 479.02 rev/km. The uncorrected factor differed by plus 0.033%.

I decided to compare the factor obtained from the new 25-m method. There was no painted line at the side of the road, so I used the distinct line of a concrete gutter. (Mark Neal seems to have tested the method on something similar.) I did all measurements in the same direction, since the gutter sloped towards the curb and I felt most comfortable guiding the bicycle with my left foot on the upside of the slope.
Whole rev: 11
Spoke intervals: 30.8, 30.8, 30.9, and 30.7 (ave, 30.8)
Calibration factor: 1.001(11+30.8/32)/0.025 = 478.98 rev/km (negative 0.008% from pressure monitoring)

Thus the new method compares very well with pressure monitoring on a home 400-m course and much better than the conventional use of a home course.
 
Posts: 304 | Registered: 01 November 2004Reply With QuoteReport This Post
  Powered by Social Strata  
 

    Road Course Measurement Bulletin Board    Forums  Hop To Forum Categories  Course Measurement  Hop To Forums  General Course Measurement Topics    NEW 25-M CALIBRATION COMPETITIVE WITH PRESSURE MONITORING