Hi! I own two EBC bikes a C model and a S model. Though I bought them both at the same time a year ago, do to multiple surgeries for my wife and I, they've been sitting unused in our garage until this week. Here's the problem. The S model has a normal electric bike whir. However, the C model is very loud when using the thumb throttle, and is getting louder with each ride. It's like a loud screeching sound. For example, today I was riding in our neighborhood and watched a lady working in her yard at least a hundred feet away from me jump, swing around, and shoot me a dirty look as I came around the corner and was pushing the thumb throttle. Any ideas or diy things I can check myself or should I call EBC for advice? Other than this issue which can surely be fixed I can't say enough good things about these bikes. The ride is phenomenal.