Advice please
I had my first rear tire flat (hub motor). I decided to fix it myself (I have repaired tons of QR flats but no axle nut flats). I didn't realize I should loosen the nuts but leave them on the axle, so in removing the wheel I was not positive if I might have lost washers or spacers. I know, my bad. Since I was having a heck of a time remounting the wheel into the dropouts I decided to call the Mobile Bike folks I've used before to do it and show me any tips or tricks they have. My illness affects my muscles and I have to figure out different ways to do things. Anyway, they came and mounted the wheel. He said there were no other spacers or washers needed and I didn't lose any. Fast forward I have been riding 2 days now and there is the slightest grinding noise from the front der when I pedal and after I ride a while the chain just moves on its own to one side of the big chain ring cog or the other! The left shifter is kind of a like a friction shifter, with dashes instead of just a "1, 2, 3" marking. When I see the chain start to go, and feel it in my feet, I am shifting back one or two dashes to get it back centered on the chain. The trike did NOT do this before the flat repair; it rode perfectly and was silent. Any idea what causes it to shift itself off the big cog up front all by itself? Any fix ideas? TIA.