Fits Fat Bike Wheels 20x4.
Why do you need a tube? An inflated inner tube provides structural support and suspension, while the outer tire provides grip and protects the more fragile tube. When putting scooter or motorbike tires on a fat ebike 20 x 4 rim, full pressure is recommended. A fully inflated tube helps push the tire against the rim and achieve a solid install.
Basic 20" x 4" Inner Tube Fat Bike Schrader Valve 20x4 Tube.
See a quick diy installation of a Shinko off road tire with an inner tube: