Grinding on left side when off the saddle? Please help!
I have a 2011 Cervelo P4 with a Zipp VumaChrono crankset and Dura Ace Di2. When I stand to climb hills, and power down on the left pedal, a grating and grinding noise emits near the crankset. Sounds like metal on metal, but not sure. I've taken it to my mechanic for a tuneup but he didn't fix it.
When I brought it back, I told him to test it on a hill but he responded there are no hills near the shop! Is there a way to simulate a hill? Shouldn't my mechanic know how to do this???
Any tips would be appreciated.