McGrath won the women's Deschutes Brewery Awberry Butte Circuit Race in 2:10:05, averaging almost 24 mph over 52 miles for the ValueAct Capital Cycling Team.
McGrath finished 12th overall - 4:13 behind winner Evelyn Stevens of Webcor Builders - and was followed closely by fellow Durangoan Marisa Asplund in 13th, racing for DFT p/b Treads.
Durango's Carmen McNellis and Amy Dombroski took 30th and 53rd overall, respectively.
Colby, racing for Colavita Sutter Home, finished Stage 6 in 3:11:31, four seconds ahead of runner-up Taylor Shelden. Colby went an average of 26 mph over the 83-mile stage and finished 16th in the overall standings, 6:41 behind Rock Racing's Oscar Sevilla Rivera.
Astana's Levi Leipheimer was unable to defend his 2008 win while racing in the Tour de France, where he teamed to help winner Alberto Contador and third-place Lance Armstrong before breaking his wrist and bowing out.
Floyd Landis, stripped of his 2006 Tour de France win because of doping violations, took 75th in the BMC Classic.
heraldsports@durangoherald.com