General Cycling Discussion - Anyone know the 35c setting for the Scwhinn bike computer
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I have a Specialized Vienna 2 with 700x35c (35-622) Nimbus tires. I bought a cheap Scwhinn bike computer ($10 one) and the manual lists these settings:
26.6" (700x25C) - 2124
26.8" (700x28C) - 2136
27" (700x32C) - 2155
Scwhinn must have gotten tired of providing useful information at that point, because no setting is provided for 700x35c. I looked around on the internet at other manuals for other bike computers, and while the settings above are consistently the same for all of those tire sizes, some manuals suggest 2164 for the 35c and other suggest 2175 for the 35c. Anyone know which it is for the Scwhinn?
Use the "group F" column. Note the column represents the circumference of the tire in millimeters, which is why the numbers aren't exactly the same in your schwinn chart as sheldon's chart, because it's both a very precise scale and not all tires with the same rated size are the same size.
Being a few mm off won't make much difference at all.
If you really care enough, you can do what he describes as a "rollout test" (described on that page as well) to calibrate your computer to the exact width of your tire, not that of a 'typical' 35c tire. Note that with tire deflection and as you lose air, this number still won't be exact. Live with it.
04-25-09, 08:40 AM
why not roll it out? Just takes minute: Put the bike on a smooth surface with the tire valve at bottom dead center, roll the bike straight ahead one full revolution of the wheel until the valve's at BDC again and measure in millimeters (2.54/inch). There's your setting. It's most accurate if you sit on the bike when you roll it forward.
04-25-09, 10:31 AM
...and measure in millimeters (2.54/inch). 25.4 to the inch.
Thanks, I'll use the number from the Sheldon Brown site. It's about right in the middle of the other two I've seen, sounds like it'll be close enough...
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