I have a Quarq, it is a Sram S975 172.5 53/39. I purchased this on March 29, 2010 and rode it till August 25, 2010 when I went back to school. The cranks have about 2000 miles on them and have worked perfectly. All of my cranks have a protective film over them (crankskins) to make sure they do not get too scuffed up. If you have questions please ask. My asking price is $1250 (you cover paypal fees) + shipping.