These are Heavy-Duty tubes made specially for off-road and motocross! German made, these are the sturdiest, highest quality tubes on the market 3mm thick natural rubber construction helps resist pinch flats! Fits all Fat Bike Wheels 20x4. Great for Shinkos.

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: