I have an 2012 SC 7.5, SRAM S80 front wheel, Renn 5-5-5 rear disc – Clinchers. I carry 2 tubes on me at all times. I currently run 80mm tubes with a valve extender for the S80’s. Cant run even a 60mm tube for the Renn. Im just curious as to what other people are doing? Maybe a 30mm with 60-80mm valve extender just for the front? this way i can carry the same size tube with me?