Maybe your car's speedometer is off, and is saying slower than you're actually going? Wheel size can affect a car's speedometer just the same.

 

Yeah I thought that too haha but I'm now driving my dads Ford Focus and it's the same situation. My buddy destroyed my Mercedes when he hit a deer with it a month ago. This could all be in my head but I'll find out this spring with a GPS or something. Right now the bike is in pieces in my garage.