Cyclometer Calibration

Because Odette and I were getting different distances on the same ride (like a 0.25 difference on a 30 mile ride) I finally rolled out several of the bike computers and compared them to the tables published by their manufacturers.

Bike
Tire
Rim
Width
Inches
MM
Spec- ialized
Veta
Filzer
Cateye
Jerry – touring Continental ultra 2000 700 c 28 83.5 2120 2134 2136 2136 2136
Jerry – mountain Serfas drifter 26 in 1.95 79.5 2019 2074 2055 2099 2050
Odette – touring Serfas barista 26 in 1.25 77.0 1956 1962 1953 1953
Odette – mountain Serfas drifter 26 in 1.5 78.5 1994 2010 1985 2030 2010
Will – touring Avocet cross 700 c 32 2249 2155 2155 2155
Will – mountain Specialized fat boy 26 in 1.25 1962 1953 1953
Tandem Avocet cross 700 c 32 83.5 2133 2249 2155 2155 2155

Most of the Specialized values are ones that were pre-programed into the computers and are described as reflecting the sizees of Specialized brand tires. The Sefas tires aren’t knobby – they have lightly indented tread – so it makes sense that they would be smaller than an ATB tire of the same size.

Here’s a link to Sheldon Brown’s cyclometer calibration page.