Mine only has one size - 650b x 37mm. But I am going to run 33mm tires.
Don't know if it is that much of a big deal to not be dead-on, but was wondering if anyone knows off hand of any computers that have more 650b sizes to select from.
I see also that I can measure the tire and input that. I guess I will try that but was wundrin' if anyone's has 650b inputs.