Millimeters per revolution of bike wheel?

ftbtef

New member
Joined
Oct 10, 2009
Messages
1
I have a 17.5 inch bike wheel, and I need to figure out the "distance in millimeters per one revolution of the bike wheel" for programming a bike computer, according to the manual. I am not sure how to go about this. I tried figuring out the circumference of the wheel in mm, but the number was too big (the manual includes lengths for 20"-27" wheels, and the number I got was way too big.) Any help?
 
ftbtef said:
I have a 17.5 inch bike wheel,...
Is that radius, or diameter, or circumference?

1 inch = 25.4 mm

Now ask your question again: doesn't make much sense the way it's worded;
a "manual" has nothing to do with math...unless used to set boundaries...
 
Since bike tire size is usually given as the diameter, I reckon we can assume your bike has a 17.5 inch diameter tire.

Therefore, it is \(\displaystyle 17.5{\pi}\approx 55\) inches in circumference. That is the distance in one revolution.

How many millimeters is that?. Multiply 55 by 25.4 and get about 1396.5 mm

Convert the 20 and 27 inch the same way. \(\displaystyle 25.4{\pi}D=\text{distance in one revolution in mm}\), where D is the diameter of the tire.
 
Top