Depending on the width of the tire either the 26"/ 700C or the 29" setting will work. Start with the smaller setting first and if you are unable to close the clamp around the wheel then move up to the 29" setting. Typically wider tires will use the larger setting.
If you have further questions please contact us here, or by phone at 888-925-4621 during business hours.
If this answer didn't address your needs, let us know what we can do to improve it.