im confused...mine says 5503 on my rear tire, and theres not 55 weeks in the year....maybe im looking at the wrong number...but theres only two 4-digit numbers, and the other one is 2913, which wouldnt make sense either....on my front tire, it says [1992] in brackets, but i dont think thats a date stamp...my bikes a 97 lol, not sure what that number is i googled date stamp, and found something similar on my bike, it says NA72403 ... maybe it would be 24th week of 03? and my front tire is BPH 4501...but idk if im looking at the right stuff lol