Day 16 of #30daysofbiking-A calibration ride

 A person from Wisconsin is in the Portland area house sitting and posted that she was interested in an afternoon bike ride and looking for a riding partner.  It sounded like a fun way to spend the afternoon and show an out-of-towner around.  We planned to ride Portland's 40 Mile Loop.  Alas, about mid-morning she sent a message that the bike she had borrowed wasn't going to work out and she regretfully wasn't going to be able to ride.  Unfortunately, I've only got one bike now, and couldn't offer an alternate.

It is still April, and I've committed to #30daysofbiking, so not riding was not an option for me.  I installed the new yellow tire on the front of the fixie, changing from a cheap yellow original equipment 700x38 soft rubber 60psi maximum tire that was prone to flats, to a cheap yellow 700x25 soft rubber 100 psi minimum tire that I hope will be a little more durable.

Along with the tire change I had to recalibrate my wired speedometer.  I figured I'd bring my Garmin 305 to calibrate against, and use the calculator function on my phone to determine the most appropriate wheel circumference to enter.

One thing nice about the 38 mm tire, it was dead on for calibration. The calibration setting is in full millimeters of circumference and one of those numbers was exactly what I needed.  I was not so lucky with the 25 mm tire. The circumference falls in between 2074 and 2075.  Actually, it calculates out to 2074.256.  So, it isn't going to be exact, but probably closer than most people's odometers.  I almost always run the Garmin anyway, but it's always nice to have redundancy as well as the ability to show multiple fields at once.

At any rate, with all the stopping, recalculating, resetting, and riding (re)peatedly I wasn't very fast, but I did get the 40 mile loop finished.  Even better, with a 30%-40% chance of rain predicted, I did not get wet!

...........road bike..........rollers........mtb.........lifecycle....total
Today.........39................0..............0...............0............39 Jan............710................0..............0...............0...........710
Feb........... 578...............0..............0...............0............578
March ...........701.............0..............0...............0............701
April..........483.................0..............0...............0..........483 Total..........2472...............0..............0...............0.........2472