Old 03-29-20, 09:48 AM
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bpcyclist
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Fairly Loud Scraping Sound When Out Of Saddle

Few days ago doing hill repeats, began hearing a rather loud scraping sound only when out of the saddle only with left crank from the 730 or so position to the maybe 615 or so position. Loudest on 1st revolution, quieter on 2nd, quieter still on 3rd, then, after 4 or 5, it is gone, even if putting out maximum power--all out of the saddle. Sounds quite similar to the sound of a rim brake with metal shards hitting a brake track--very scrapy sounding. Quite loud on that 1st rev. Happens in all gears, though I am running 1x10 right now as FD cable snapped. Chain not hitting FD cage, plenty of room on both sides in all gears. Chainrings not rubbing against anything. Now, staying in-saddle and starting from standstill and applying max possible power canno0t reproduce sound, no matter how hard I push in any gear. Only happens when really stepping on that left crank at teh 730 to 615 positions. Did the little BB stability test with the cranks in the 3 and 9 positions--totally no movement, no motion, nothing.

Bike is a 2018 BMC SLR02, Ultegra/105, well-maintained. New chain/new cassette recently. Lubed up and clean. Had to order a Shimano crank removal tool and it has not arrived from Japan yet, so have not had a good look inside. Pedals recently removed, cleaned up, greased, reinstalled. No issues apparent doing that.

Thoughts? Obviously, it is concerning, given that it really does sound like something is scraping against something else.All LBS's closed here, pretty much. Just wondering if there is anything I can do in the mean time. Bike and BB probably have about, maybe, oh, only 6000 or so miles. Thanks a million!!!!
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