Maxxis Tube Extra Heavy Duty 80/90/100-21 TR4 (CSV)

Meet the Maxxis Tube Extra Heavy Duty 80/90/100-21 TR4 (CSV) — a purpose-built inner tube designed for 21-inch dirt and dual-sport wheels. Built to withstand rugged trails, aggressive riding, and long days in the saddle, this tube keeps your front end predictable when the terrain gets rough and the pace increases.

Why this tube stands out

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  Extra-heavy-duty construction with a robust butyl formulation that resists pinch flats and slow-air loss on harsh off-road surfaces.
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  Precisely sized for 21-inch rims compatible with 80/90-21, 90/90-21, and 100/90-21 tire combinations, so you get a reliable, snug fit that seats cleanly on installation.
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  TR4 (CSV) design aligns with modern 21-inch rims to promote secure bead seating, stable air pressure, and dependable performance under load.
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  Reinforced valve area and sturdy shoulder construction to resist impact and bending during tall jumps, rocky descents, and aggressive cornering.
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  Consistent air retention minimizes downtime on the trail, helping you focus on riding rather than tire maintenance.
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  Real-world durability built for enduro, off-road, and adventure riders who push their bikes through hot, dusty, and muddy conditions.

Ideal for who and when

This inner tube is tailor-made for riders with 21-inch front wheels who value reliability over rough terrain. It’s a strong choice for enduro events, long-distance trail rides, desert runs, and daily-teardown adventurers who don’t want to worry about punctures or air leaks after a tough climb or rock garden.

Use cases and practical benefits

• maintain steady grip by keeping tire shape under lower pressures for better feel and control on loose surfaces.
• dependable performance on mixed-terrain routes where flats are more likely.
• fewer interruptions due to deflation, so you can ride longer between top-ups.

Tips for best results

• Inspect the tube for defects before mounting, and align the valve stem with the rim’s valve hole to ensure a clean seating.
• Pair with a compatible rim tape and proper rim width to optimize bead seating and prevent pinch flats during hard landings.
• Inflate to the rider and tire manufacturer’s recommended range after mounting, then recheck after a short ride to confirm even seating.

The Maxxis Tube Extra Heavy Duty 80/90/100-21 TR4 (CSV) is a thoughtful upgrade for riders who demand durability, dependable air retention, and consistent performance from their 21-inch front tires. When the ride gets tough, this tube keeps you moving with confidence.