Honestly, the last thing you have to worry about it whether your rim cement changes rolling resistance on the tires. Some triathlon geeks have gotten everyone stirred up about rim cement and its effect on rolling resistance. Get in a warm-up paceline at 28 mph and you'll be worrying about all kinds of things (heart, lungs, legs, etc.) and not your rim cement. If you're worrying about rim cement, it's about whether your tire is staying on your rim. Period.