I have 700x38's. it lists a 700x32 and x28.. how do i figure out what to enter into the comp?

http://sheldonbrown.com/cyclecomputer-calibration.html At the end there are tips for dealing with cyclocomputers not listed.

Or if it doesn't help, please post some of the listed size/value pairs. (and/or model of cyclocomputer), so someone could figure out what they are and how to measure them.

Thanks for the link, used 2180.