Understanding width of tires Saw two different tires. One marked 700c 38mm 40 622 measured 1.25 " wide.Other tire ,same markings but with addition of marking, one and five eighths x one and a half,measured 1.5" wide. If both 38mm wide why quarter inch difference in width?
Tire sizing can be very confusing.  The late, great Sheldon Brown has written a web page that does a magnificent job of answering your question.