2 Pack 18x8.50/9.50-8 Inner Tubes, High Duty 18x6.50-8, 18x7.50-8, 18x8.50-8, 18x9.50-8, 20x8-8, 20x10-8 Universal Fit Tire Tube with TR13 Straight Valve Stem (18x8.50/9.50-8)

What It Is

This is a 2-pack of heavy-duty inner tubes designed to replace worn or punctured tubes in riding mowers, zero-turn mowers, and garden tractors. They fit a range of common tire sizes, making them a universal option for lawn and turf equipment.

Fitment & Compatibility

Before buying, verify your tire’s sidewall markings. These tubes fit sizes: 18x8.50-8, 18x6.50-8, 18x7.50-8, 18x9.50-8, 20x8-8, and 20x10-8. They also cover the 18x8.50/9.50-8 size. The TR13 straight valve stem (approx. 1.5" long) is standard for most lawn mower wheels. Check that your rim has a 0.453" valve hole—common on steel wheels. If you have a larger valve hole (e.g., for a tubeless tire), you may need a rubber grommet. Not for use on cars or high-speed trailers.

Key Things to Know

• Quality: Heavy-duty rubber, but some users report slightly thinner sidewalls than OEM tubes. Fine for typical lawn use, not for heavy commercial loads.
• Installation: Moderate difficulty. You’ll need tire irons and a bead breaker. Lubricate the tube with soapy water to avoid pinching between rim and tire.
• Gotcha: The TR13 stem is straight—if your wheel has a bent or angled valve hole (common on some zero-turns), this stem may not align properly. Measure your old stem angle first.
• Dual pack value: Two tubes for under $18 is cheaper than most single OEM replacements, but check that both tubes are defect-free before mounting.

Should You Buy It

Buy this if you need a budget-friendly, universal replacement for a standard lawn tractor or zero-turn mower with a straight valve stem and one of the listed tire sizes. Avoid it if you require exact OEM thickness for heavy commercial use or have an angled valve stem—look for a specific brand match instead.