The pair managed to hold off the peloton by two minutes and seven seconds in a stage earmarked for the sprinters. Carpenter now also leads the race.
"It wasn't really my intention to get in the breakaway today because the course wasn't super suitable for it, or it didn't look like it, but then I got in there with Ruben and we just rode conservatively at first," Carpenter said.
"We were given too big of a time gap, which just made our day pretty easy."
Several attacks and breakaways ultimately failed due to the attrition caused by the hard work of Cannondale and the category three climb early on. Then came the affects of climbing Boulder mountain and the altitude.
The duo slipped away and led the race for 110 kilometres, their advantage still at five minutes and 20 seconds with 30 kilometres to race.