Tyre liners for 20x4.0, 26x4.0 inch wheel, Fat tire bikes.
Kevlar Plus Size Bike Tire | Black Friday Deal 30% OFF - Hycline
20x4 Fat Tire High-Performance - (2-Pack) Designed to Improve Speed & Minimizes Drag on Hard-Pack or Paved Terrain, Honeycomb Tread for Virtually Zero Rolling Resistance, Ultimate Speed & Traction - Walmart.com