Can anyone else with a Radrunner Plus tell me if their bike has a fairly noisy motor? Mine sounds like a small sewing machine. It's not unpleasant, but I'd prefer my bike to be much quieter. I've had mine for a few months now and my husband recently bought a Rad City and his bike is completely silent. I wrote to Radrunner and got a complicated response about tensioning spokes or making a derailleur adjustment all of which make my brain hurt. I don't want to muck around with this or spend money at a bike shop if this is normal and just the way the Radrunner Plus sounds. thanks!