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Tubeless

A wheel and tire setup without an inner tube, using a sealed rim and tubeless-ready tire with liquid sealant.

Published January 1, 2025

Definition

A tubeless tire system eliminates the inner tube from a wheel and tire assembly, instead relying on an airtight rim bed, a tubeless-compatible tire, a sealed valve stem, and liquid latex sealant to hold air and automatically seal small punctures.

How It Works

In a traditional clincher setup, a rubber inner tube inside the tire holds air pressure. In a tubeless setup, the tire bead seats directly against the rim, creating an airtight seal. Liquid sealant inside the tire is distributed across the inner surface by rotation and centrifugal force, sealing spoke holes, minor porosity in the casing, and small punctures as they occur.1

When a thorn or sharp object punctures the tire, air pressure forces sealant into the hole where it coagulates and seals the puncture — often so quickly the rider doesn't notice. Punctures up to approximately 6mm can typically be sealed this way depending on sealant type and location.

Advantages

  • Fewer flat tires: Sealant handles most small punctures automatically
  • Pinch flat elimination: Without a tube, there is no tube to pinch between tire and rim on impacts, allowing lower tire pressures
  • Lower tire pressure: Riders can run 2–6 PSI lower than tubed setups for the same protection, improving traction and compliance2
  • Slight weight savings: Eliminates the inner tube, though sealant offsets some of this

Disadvantages

  • Initial setup complexity: Requires tubeless-specific rim tape, valve stems, and compatible tires; seating the bead can require a compressor or high-volume pump
  • Sealant maintenance: Sealant dries out and loses effectiveness over time — typically within 60–90 days depending on climate and sealant type3
  • Large punctures still require a tube or plug: Holes too large for sealant to seal require a plug or inner tube to get home

Required Components

  1. Tubeless-ready rim — sealed rim bed, no exposed spoke holes
  2. Rim tape — seals spoke holes; must be tubeless-specific and correctly applied
  3. Tubeless valve — replaces the tube's valve stem, seals into the rim bed
  4. Tubeless-compatible tire — labeled TLR, TR, or Tubeless Ready; has a stiffer bead and lower-porosity casing
  5. Sealant — 60–120ml per tire depending on tire volume

Sealant Maintenance

Sealant should be checked and refreshed every 60–90 days on average, though this varies by brand and riding climate. Dried sealant loses all sealing properties and can be heard rattling inside the tire as a ball of dried latex.3

Recommended Pressures

Running tubeless allows lower pressures than tubed setups. Common starting ranges:4

Discipline Front Rear
XC MTB 20–26 PSI 22–28 PSI
Trail/Enduro 18–24 PSI 20–26 PSI

See Also

References

Footnotes

  1. Mountain Bike Action, "Everything You Need to Know About Mountain Bike Tire Sealant" https://mbaction.com/everything-you-need-to-know-about-mountain-bike-tire-sealant/ ↩

  2. Muc-Off, "How and When to Add Tubeless Sealant" https://muc-off.com/blogs/how-to-hub/how-to-use-muc-off-no-puncture-hassle-tubeless-sealant ↩

  3. Mountain Bike Action, "How to Refresh Your Tubeless Tire Sealant" https://mbaction.com/how-to-refresh-your-tubeless-tire-sealant-in-five-easy-steps/ ↩ ↩2

  4. BikeSize, "Tubeless Tire Setup & Sealant Top-Up" https://bike-size.com/articles/tubeless-tire-setup-guide ↩