You need to measure the circumference. Start with your tube stem at 6:00 o'clock, and put a mark on the ground at that point. Roll your bike forward until your wheel has made one complete revolution, and then mark the ground again. Measure between marks. (conversion - Inches x 25.4 = mm).c9buff said:Hey guys,
Just got a cyclocomputer and want to input the tire size. The sidewall of my tire reads 700X26c. The instructions from Cateye say to enter the tire's circumference directly in increments of 1mm.
What number do I put in? Thanks in advance.
buff
c9buff said:Hey guys,
Just got a cyclocomputer and want to input the tire size. The sidewall of my tire reads 700X26c. The instructions from Cateye say to enter the tire's circumference directly in increments of 1mm.
What number do I put in? Thanks in advance.
buff
buckybux said:My Cat Eye instructions say to use either 212 or 213mm. However, this is only a estimate and a place to start. I then calibrate it on a rails to trails trail that still has the old RR milage markers, and check it over 10 miles. I have found the estmates to be off by over 10mm's.
Let's see. If you are able to adjust to the nearest mm, then at most you should be off by 0.5 mm. That is a 0.023% error. If the average is 2130 mm, and you are off by 0.5 mm, then over the course of a 100 mile ride, your error would be 124 feet. I think I could live with that.Insight Driver said:Do the rollout test as suggested, best done by actually sitting on the bike while someone helps you so that you get the true radius. The number you get will let you see if you want to round up or down to the nearest increment you enter into the computer. You see that you can't nail it exactly, your computer is granular, only allowing whole integer input. Such is life. You don't need any more accurate, do you?
Insight Driver said:Do the rollout test as suggested, best done by actually sitting on the bike while someone helps you so that you get the true radius.
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