Posting mainly as reference for other drivers. About 1 week ago I had been driving over passes in HV mode and thought the engine sounded really loud. However after charging, driving around town in electric was still hearing it. Speed dependent but fairly prominent even at low speeds, sounding like a cheap motorcycle engine. Took it in today and found the cause was the front drivers side wheel bearing was bad. Car with 80k miles. I have driven all prior cars I have owned to around 250k miles and never had this issue. Reading on this forum and elsewhere looks like this is a fairly common problem for clarities and Honda really screwed up on this for our cars. So, if you hear a motorcycle engine sound in electric, that is probably your issue.