Plan on checking tubeless sealant every three to six months, and treat that as a ceiling rather than a promise. BikeRadar suggests topping up within that window, while Schwalbe says its Doc Blue sealant stays active for roughly 2000 km (about 1,240 miles) or 2 to 7 months. Heat, mileage and storage move the real number around, so the reliable method is to look inside the tire instead of counting days.
Why sealant needs attention at all
Sealant is a liquid latex mixture that plugs small holes as air tries to escape. It only works while it is still liquid. Schwalbe explains that aged sealant dries into a rubber film or separates into its component parts, and a film stuck to the tire wall cannot plug anything.
The intervals the sources give
| Source | What it says |
|---|---|
| BikeRadar | Top up every three to six months; take the tire off for a full inspection every 12 to 18 months. |
| Schwalbe (Doc Blue) | Active for about 2000 km or 2 to 7 months, varying with ambient temperature. |
The two ranges overlap and neither is a hard expiry date. BikeRadar notes that timelines can differ between sealants, and that climate, how often you ride and how the bike is stored all change how long sealant lasts. Check the label for your own product.
Check first, then decide
You do not need to add sealant on a schedule if the tire still has plenty. BikeRadar describes a simple dipstick check:
- Let the air out and remove the valve core with a core tool.
- Rotate the wheel so the valve sits at six o’clock and the sealant pools at the bottom.
- Slide a cable tie down through the valve like a dipstick. More than a centimeter (about 0.4 in) of sealant on it is considered fine.
- Refit the core and reinflate if the level is good.
If the dipstick comes back dry, plan a refresh. Many valves with removable cores let you inject new sealant through the stem with a syringe, which avoids breaking the bead.
The needle test
Schwalbe describes a functional test: pierce the tread with a needle and let the tire rotate. If the hole seals by itself, active sealant is present. If it does not, refill, and the new sealant will also close the test hole.
When to refresh sooner
- Before a race or a big tour. Schwalbe recommends checking and replacing the fluid beforehand, because a failed seal far from home costs more than a few milliliters of sealant.
- After hot weather. Schwalbe says the active period varies greatly with ambient temperature, so the interval can shift noticeably between a hot summer and a cool one.
- After a long idle spell. Schwalbe advises positioning the valve at the top point when a wheel is stored for a longer period, to avoid sticking.
- If a leak keeps returning. Schwalbe says a common cause of a tubeless setup not staying airtight is sealant that was not shaken sufficiently before filling, and that new, well-shaken sealant solves many problems. That makes fresh, well-shaken sealant a reasonable first fix.
Doing the full refresh
Once a year or so, take one side of the tire off. If the sealant is completely dry or congealed, BikeRadar says to clean the tire thoroughly, and dried sealant only adds weight. While it is open:
- Look over the casing for cuts. Sealant is meant for small punctures and, per Schwalbe, is not suitable for large defects such as cuts or bursts.
- Check the rim tape for wear and replace it if needed.
- Make sure the valve core moves freely, since sealant can clog it. Cores are cheap to replace.
- Shake the bottle well, then add the amount printed on it. BikeRadar notes the quantity depends on wheel size and tire width. As an example, Schwalbe lists 60 to 90 ml per tire for tires 23 to 60 mm wide.
Reseat the tire, spin and shake the wheel to coat the inside, then take a short ride so the sealant reaches every part of the casing. If the tire will not seat or keeps losing air, a shop can pressure-test it. Avoid CO2 cartridges for inflation on a sealant-filled tire: Schwalbe says CO2 has an unfavorable effect on its fluid.
Stop and get it looked at
Sealant is not a substitute for sound tires. Replace or have a professional assess a tire with a visible cut, bulge, exposed casing threads or a bead that will not seat. Do the same for a rim with a suspected crack or a leak you cannot trace. Do not ride on a tire you doubt.
Related on cycle99
If you are still deciding whether to go tubeless, read Why Tubeless Tires Are Worth the Switch. For the bigger picture, see How to Prevent Punctures, Tire Pressure, and Flat Tire? Here Is Exactly What to Do for when a plug fails mid-ride.
Sources
Last reviewed: October 2026.