I have a bike tire that is really tight and difficult to mount to my bike's wheel. I discovered this device when googling for advice and decided to make my own model rather than buy one since it's really simple. It allows you to lever the rubber over the lip of the rim without putting plastic between the rim and the tire.

See this video for how to use this bike tire jack device:

This video was also very helpful and taught me a few tricks I didn't know when mounting a difficult bike tire: 

Components:
1x: bike tire jack - arm
1x: bike tire jack - handle
1x: m4 screw ~25mm long
1x: m4 nut

Print instructions

Printer Brand: Prusa i3 mk3s

Supports: Yes

Resolution: 0.2

Infill: 30+%

Filament: AmazonBasics PETG Black

Since the components need to be pretty strong, I printed at 40% infill with 4 external perimeters. I'd suggest doing something similar.