The motor is getting older. <grin>
Don't know, but I've had some hills, typically in the heat of the summer, where I'd swear I was riding in sticky tar or something that made my bike seem to drag up a hill. Road surface seemed fine and smooth and didn't seem sticky. So I never found out and just imagined it was just a combination of many little things that added up to a perception I had that I could never even see in the data I collected.
Though that's not to say something isn't amiss in your particular instance. But instead of grasping at all sorts of imagined solutions that might involve significant costs, just wait until it becomes very evident what the reason is.
Welcome to BF!
Trek Edmonds = Trek Émonda ?
Last edited by Iride01; 04-22-22 at 10:07 AM.