How much sealant to add, and how to tell it's dried out

This page gives the dose for your tire's width and how to tell whether the sealant already in it has dried out, using the figures each sealant maker publishes for its own product.

The short answer

Sealant has a working life, not an indefinite one. It slowly evaporates and turns into rubbery lumps or a dry, flaky skin inside the tire, and once most of it is gone the tire stops sealing new punctures on its own — a small thorn or a bit of wire that would normally seal itself instead leaves the tire soft. Both the dose and the interval come from the sealant's own maker, for that specific product, matched to the tire's actual width. Schwalbe publishes 60-90 ml per tire for tires 23-60 millimeters wide and 90-120 ml for 62-100 millimeters wide, active for around 2,000 km or 2 to 7 months, whichever comes first, with hot weather pushing the working life toward the short end of that range. Stan's, Muc-Off and other sealant makers publish their own, different numbers for their own sealants — the table below has each one's figures side by side, sourced to that maker's own page, so the first thing to check is which sealant is actually in the tire, not just the tire's width.

Dose and interval, from each maker's own page

These three are examples, not the full list of sealants in use. Orange Seal is another widely used brand; its own product page for the Endurance formula describes it as lasting two to three times longer between top-offs than Orange Seal's Regular sealant, but unlike Schwalbe, Stan's and Muc-Off it doesn't publish an exact milliliter or day figure on that page, so there's no specific Orange Seal number to add to the table above. Within a single brand the product line changes the number too: Stan's lists a lower dose for its Rolled Gold sealant than for Original or Race Day at the same tire size. If the sealant in the tire isn't one of the products above, look on that product's own page, or at the fill line printed on the bottle, before assuming any figure here applies.

What dried-out sealant looks like

Sealant that has been sitting in a tire for months tends to show up, when the tire is opened, as small rubbery lumps or dried strands with only a little liquid left, rather than a smooth pool of fluid — Road Bike Rider's own article on checking tire sealant, written by Jim Langley, describes exactly this after opening tires that had gone unchecked for a long stretch. Stan's own guidance adds a related, practical reason not to let that happen: sealant from its Race formula, if left to dry out fully inside the tire, can stiffen the tire's casing enough to affect how the tire rides, which is itself a reason to check on a schedule rather than wait for a puncture that won't seal.

Checking the level without breaking the bead

Most dedicated tubeless valves use a Presta-style core that unscrews from inside the valve stem, and a small valve-core tool — Park Tool's VC-1 is one, sold for exactly this — removes it so the stem opens straight into the tire without touching the tire bead at all. Park Tool's own product page notes one thing to confirm first: not every Presta valve core is actually removable, so check the valve on the wheel before relying on this method. With the core out:

1. Pass a stiff wire, a spare spoke, or a zip tie a short way into the stem and pull it back out. Sealant that comes back wet means there's still liquid inside; sealant that comes back dry or in clumps means it's time to add more.
2. If the tire needs more, add sealant straight through the open valve stem with a syringe or squeeze bottle, then reinstall the core and pump the tire back up to riding pressure.

If the valve core isn't removable, there's still a way to check without pulling the tire fully off the rim: Road Bike Rider's own guide describes letting the air out, squeezing the tire's sides toward the middle of the rim to slacken the bead, then working about six inches of one side off the rim near the valve with tire levers and turning that section down to look inside before reseating the tire and re-inflating it.

What sealant does not fix

Sealant is built for the small punctures a tire picks up while rolling — a thorn, a piece of wire, a sliver of glass. Schwalbe's own guidance is direct about where that stops: only with more serious damage, such as a larger cut or a snakebite-style pinch flat, does the sealant not help. That's a matter of the size and type of the damage, not the amount of sealant in the tire, so adding more sealant to a cut it already can't close on its own won't change the outcome. A cut too big for the sealant to close on its own needs a plug or a patch from outside the tire, and a cut too big for a plug needs a tube.

Rim tape and the valve nut

Two smaller parts of the same setup affect how well the sealant stays where it belongs. Schwalbe's guidance is that one layer of rim tape is usually enough, with a second layer worth adding specifically on rims that have a small shoulder diameter, for easier inflation.

On the valve, Schwalbe's own FAQ is more relaxed than a lot of setup advice suggests: the rim nut isn't required to ride the tire. Where it does earn its place is during a sealant check like the one above — with the tire soft and the pressure low, an unsecured valve stem can drop down into the rim well, which turns a two-minute check into a longer one, not because the seal fails but because the valve is now sitting inside the rim instead of standing up through it.

Get the tire's actual width first

Every dose figure above is keyed to the tire's real width, not the wheel's marketing name or a rounded number from memory. That width is printed on the tire itself as an ISO/ETRTO size, and this site's page on tire and rim numbers covers where to find that marking and what it means. If the wheel is a new hookless one, the tire choice and the pressure ceiling are a separate check from sealant dose — see hookless rim tire and pressure limits for that before adding sealant to a tire that shouldn't be mounted on the rim in the first place.

Check it on your own equipment

These take you to the manufacturers and standards bodies the page draws on, so you can look up your exact model.

• Manufacturer specification
  Schwalbe's tubeless technology FAQ (opens in a new tab)Fill quantities by tire width in ml for Doc Blue sealant, the service-life figure, and what the sealant can and can't seal. — www.schwalbe.com
• Manufacturer specification
  Stan's NoTubes sealant-amount chart (opens in a new tab)ml/oz dosage listed tire-size by tire-size for Stan's Original, Race Day and Rolled Gold sealants. — stans.com
• Official support page
  Stan's NoTubes Sealant Support page (opens in a new tab)Stan's own service-life range (2-6 months) and the factors that shorten or extend it, plus the quarterly-check recommendation. — stans.com
• Manufacturer specification
  Muc-Off MTB Tubeless Sealant product page (opens in a new tab)Muc-Off's own dose-by-tire-size chart and its six-month lifespan claim, with the heat caveat. — us.muc-off.com