Tolerance buildup

Ok, my $.025 (inlation adjusted!)

His method is not bad at all, just that the accuracy numbers are really bogus.

To start with, he used a 30' tape measure and measured to .010" That is about as good as you can get using scibed lines on plates with dicom spray. Measuring on the ground with rubber tires, I would be more comfortable with 1/8" or 1/4" or 10 to 20 times less accurate.

Next hit is the fact that the tape measure has some inaccuracy from National Bureau of Standards. They are good but I'd figure another 1/8" in 30'

Net: I'd expect that this method would be good for around .1% or .2% error with good attention to detail and road bikes with high pressure tires.

Cheeers!!

Doug G> Please comment on accuracies reported in this article on calibrating a bicycle

(Nice answer from Roy J)

Which is why I use a dressmaker's tape around the tire, enter it, and forget it.

Thanks.

Yours,

Doug Goncz (at aol dot com) Replikon Research, Seven Corners, VA

Doug Goncz wrote: (Nice answer from Roy J) Which is why I use a dressmaker's tape around the tire, enter it, and forget it. ^^^^^^^^^^^^^ I agree. And, even assuming that all those impressive measures (pun accidental) to gain great accuracy are valid, what are you going to do with the bicycle, use it as a surveying instrument? After a ride, I usually say, "Well, I rode about so many miles today."

Rather than fumbling with a tape measure around the tire, I find that two chalk marks on the sidewalk one wheel revolution apart are easier. And if you area real accuracy freak, make it ten revolutions, and use a steel tape measure. (Be sure to take the temperature of the tape measure, and use standard tension on it.) :-)

After a ride I usually say, "Whew. I made it. How about a Coke?"

Yeah, that's the method in the book. Optical sensor detects tire valve passing fixed point and fires paint ball gun.I just took the wheel out, ONCE, measured it, and that was it.

I have one and I think it's in decimal feet. For a really small tire, in inch units, you'd make twelve revolutions and convert feet to inches.

Q: What is the most significant difference between a rectal thermometer, a basal ovulation thermometer, and a fever thermometer.

A: The taste!

To read about my senior project at ODU, Go to Google Groups and enter dgoncz along with any or some of these words: ultracapacitor electric bicycle motor generator fluorescent energy display

Buy a GPS and mount it on the handlebars. Download track to computer with G7to or, if you use (UGH!) Windoze, G7toWin. You get track, times and distances.

Ted