Thank you for purchasing through links and ads on this site.
diglloyd Deal Finder...
Buy other stuff at
Up to 1527MB/s sustained performance
Organic Lab Tested Full Spectrum CBD
20% off with coupon code diglloyd20 at

100% organic non-GMO, no additives or preservatives.
Legal in all 50 states

Tire Circumference

Last updated 2012-02-25 - Send Feedback
Related: gear, Road Bikes

Most cycle computers have a means to enter tire circumference so as to obtain accurate speed and distance metrics.

The best way to check tire circumference is to sit on the bike and roll along next to a long measuring tape:

  • Point the tire valve at the “0” mark on the tape measure.
  • While keeping all your weight on the seat in a semi-normal riding position, maneuver the bike in a straight line along the tape.

After four (4) revolutions, I get the distance to the 1/2", then divide by 4 and convert to millimeters.

GPS-based systems don’t need tire circumference, but in my experience they are very inaccurate for riding where there are close-linked turns and/or heavy tree cover (e.g. mountain biking). I always prefer a bike computer that gives me speed and distance by a speed sensor; I have observed ridiculous errors with GPS, especially for speed (e.g. 3 mph instead of 8 mph!).

Make an Old Dog Run Like a Young Puppy
with an OWC SSD

SATA, USB3, Thunderbolt, internal upgrades and PCIe SSD options for Mac or PC.
View All OWC SSDs...


I measured these values on my road bike:

Veloflex Record tubular 700 X 22C @ 120 psi: 2098 mm
Schwalbe Ultremo ZX 700 X 28C @ 90 psi:      2124 mm

The difference is small at only 1.2% for the 700 X 22C vs the 700 X 28C, but that is 1.2 miles during a century, which becomes more and more significant if navigating turns denoted by a mileage mark. And if the turns are only 1/4 mile apart, even at the 25 mile mark, the error exceeds the gap between the turns! This can be very confusing in a city area with turns every 100 yards. So it is worth being accurate.

See also Nikon wishlist
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 6 hours unless noted. Certain deals may last longer.
$3199 SAVE $200 = 5.0% $99 FREE ITEMS Canon EOS R Mirrorless with 24-105mm in Cameras: Mirrorless
$1632 SAVE $700 = 28.0% $165 GIFT CARD LG C8PUA 55" Class HDR UHD Smart OLED TV in Electronics: Televisions
$3097 SAVE $200 = 6.0% $77 FREE ITEMS Nikon D850 DSLR in Cameras: DSLR
$1797 SAVE $200 = 10.0% Pentax K-1 Mark II DSLR in Cameras: DSLR
$998 SAVE $400 = 28.0% Sony a7 II Mirrorless in Cameras: Mirrorless
$1798 SAVE $200 = 10.0% Sony a7R II Mirrorless in Cameras: Mirrorless
$3998 SAVE $500 = 11.0% Sony a9 Mirrorless in Cameras: Mirrorless
$5987 SAVE $1839 = 23.0% ZEISS Loxia 5-Lens Bundle in Lenses: Mirrorless
$11594 SAVE $3157 = 21.0% ZEISS Otus ZF.2 3-Lens Bundle in Lenses: DSLR | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__