Old 10-22-13, 07:40 PM
  #24  
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 31,491

Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!

Mentioned: 32 Post(s)
Tagged: 0 Thread(s)
Quoted: 1141 Post(s)
Likes: 0
Liked 20 Times in 19 Posts
A fairly good approximation to the rolling circumference of a bike tire is to assume the tire has a circular cross section. If the named width is correct the circumference can be calculated by (rim diameter+(2* tire width))* Pi

For a 700-32 the estimate is (622+(2*32)* 3.14159... = 2155 mm or about 99.2% of your current value. Realistically a lot of "32" tires are a bit smaller so a true roll-out measurement is still the most accurate method.
HillRider is offline