Tubeless bike tires: setup, sealant and hookless rims

The evidence here is moderate: real tests, but not many of them. 19 sources, listed at the end.

What the tests say

Speed. Bicycle Rolling Resistance (BRR) tested a Continental GP5000 S TR at 100 psi, 28.8 km/h and 42.5 kg load¹:

Across eight gravel tires, tubeless averaged 19.3 W vs 23.2 W with butyl tubes at “low” pressure. At “extra low” pressure, the gap grew to 5.1 W per tire². Sealant costs a little: on a 25mm tire, 40ml added about 0.6–0.8 W, and BRR estimates about 1 W per pair at 36 km/h with 30ml³.

Hookless limits (as of Oct 2026). ETRTO’s hookless pressure figures are recommendations, not a legal limit. TOUR words it as “5 bar is recommended as the upper limit” for tires up to 29mm, “unless tyres or rims have a lower pressure limit”⁵. Schwalbe lists these maximum pressures on hookless rims:

• 25–29mm tires: 5 bar
• 30–34mm tires: 4.5 bar
• 35–39mm tires: 4 bar

Schwalbe says only its tires marked TLE/TLR may be used on hookless rims, and that if the rim or wheel maker’s stated maximum is lower than the tire’s, the lower figure applies⁴. TOUR’s summary of the ETRTO minimum tire widths:

• internal rim width up to 21mm: 25mm tire minimum
• 22–24mm: 28mm minimum
• 25mm: 29mm minimum, a 2023 ETRTO change that no longer permits 28mm tires on 25mm rims⁵

That 2023 change is disputed. TOUR notes it contradicts earlier Enve and Zipp announcements, and Schwalbe still considers its 2022 recommendations safe⁵. ENVE says its own 27c and 29c tires are designed and tested for 25mm internal rims, and that its rims state maximum pressures in the rim channel that exceed ETRTO’s⁶. When in doubt, follow the more conservative of the tire, rim and ETRTO figures.

The ISO blow-off test requires a tire to hold 110% of maximum pressure for five minutes. ENVE calls this inadequate and requires 165% (120 psi for a 28mm tire) before approving a tire⁶. In TOUR’s bounce tests all combinations passed at normal pressure. The one failure, a Zipp 303/Vittoria Corsa Pro 28 pairing, popped off only at 10 bar, double the nominal pressure, with mounting fluid⁵. Hooked vs hookless made no measurable rolling-resistance difference: across the three rims BRR tested (one hookless), the largest gap was 0.29 W, and the largest hooked-vs-hookless gap was 0.25 W, within test error⁷. These limits come from manufacturer documents and press reports of the ETRTO standard, which isn’t free to read.

Pro racing. After tire-separation incidents in early 2024, the UCI reminded teams of ISO 5775-2:2021 and 5775-1:2023, asked teams, riders and commissaires to report any incident involving hookless rims with tubeless tires, and asked SafeR, its road-safety body, to study the issue⁸⁹¹⁶. BikeRadar’s article (updated Aug 2026) reports no ban¹⁰; road.cc’s July 2026 coverage also describes hookless as a minority choice at the 2026 Tour¹⁷. In Feb 2024 the riders’ union, the CPA, said through its president Adam Hansen that it is “100 per cent against hookless rims”¹⁸. BikeRadar reports only 3 of 23 men’s WorldTour teams used hookless rims at the 2025 Tour¹⁰.

Sealant. Latex-based tubeless sealants seal by drying in the hole, which is also why they dry out inside the tire. Glycol-based tube sealants can last the life of a tube¹¹. Typical guidance is 30–60ml per wheel, topped up every 2–12 months (more often in low humidity), plus a yearly clean-out of dried residue¹¹. Stan’s (via Lennard Zinn) is reported to say its sealant stays liquid for 2–6 months depending on temperature and relative humidity¹². One retailer lists Stan’s Race Day as liquid for “2 to 7 months”, with top-ups every 3–6 months¹⁹.

Desert angle. In a Singletracks test through a hot summer in desert and mountain terrain, Orange Seal’s regular formula had nearly dried in both tires after about three months, while its Endurance formula was still fairly fresh at 10 weeks¹³. SILCA’s sealant, which it describes as a hybrid of natural and synthetic latex, claims 6+ months. road.cc found it stayed fluid about five months but failed to seal two small punctures¹⁴. Independent latex-vs-synthetic comparisons are scarce.

Burps and failures. Hookless rims rely on bead fit and air pressure. In BRR’s insert test, a 40mm gravel tire without an insert failed at 9 psi, running on the rim edges. With an insert it completed the test¹⁵. Nobody has published controlled data on how often burps happen.

The numbers

• ETRTO-recommended hookless maximum pressure: 5 bar/72.5 psi (25–29mm), 4.5 bar (30–34mm), 4 bar (35–39mm), as of Oct 2026; a lower rim or tire maximum overrides it⁴⁵
• A 25mm internal rim: ETRTO has recommended at least a 29mm tire since a 2023 change, though ENVE tests 27c tires on it⁵⁶
• ISO blow-off test: 110% of maximum pressure for 5 minutes; ENVE tests to 165%⁶
• Gravel tubeless vs butyl tubes: −3.9 W per tire at low pressure, −5.1 W at extra low²
• 30ml of sealant costs about +1 W per pair at 36 km/h³
• Stan’s: sealant stays liquid 2–6 months depending on temperature and humidity (as quoted; a retailer lists 2–7 months for Race Day)¹²¹⁹
• Hooked vs hookless rolling resistance: at most 0.25 W apart (0.29 W across all three rims tested), within test error⁷

Myths and disagreements

• “The UCI banned hookless.” Not as of BikeRadar’s Aug 2026 update. The UCI reminded teams of the rules and asked for incident reports¹⁰¹⁶.
• “Hookless is faster.” BRR found no rolling-resistance difference⁷. Claimed benefits are about manufacturing and weight, not speed.
• “Sealant lasts all season.” Manufacturer guidance starts at 2 months, and less in dry heat¹¹¹²¹³.
• Disagreement: is the safety margin enough? ENVE and TOUR’s consulted experts call the 110% ISO test inadequate, and the CPA’s president said in 2024 it is “100 per cent against hookless rims”. Manufacturers say properly paired systems are safe⁵⁶¹⁸.

Setting up and living with tubeless

• On hookless rims, check the rim’s stated maximum pressure and the wheel maker’s tire compatibility list. Respect whichever limit is lowest, including the tire’s and ETRTO’s⁴⁵⁶.
• Use about 30ml for road tires and more for gravel and MTB, within the 30–60ml-per-wheel range³¹¹.
• In Phoenix summers, check sealant about monthly, by shaking the wheel or pulling the valve core. That’s a practical reading of Stan’s guidance and the desert test¹²¹³. Clear out dried residue at least once a year¹¹.
• Carry a plug kit and a spare tube. Sealant won’t close every cut¹⁴.

Sources