Does tubeless sealant mean an end to punctures?

Is it set and go with tubeless or is there more to think about?

When even the pro peloton is starting to come around to the advantages of a tubeless wheel setup you can be sure that, as a technology, it is sure to stick around. However, as many of us are starting to realise there is one aspect to going tubeless that probably has a far more important role to play than even the tyre and wheel itself.

We are of course talking about the tubeless sealant you need to add to complete the system. Tubeless tyres themselves are not a magic bullet for ridding yourself of dreaded punctures just on their own. It is actually this magic liquid that tends to be the real hero in preventing the P word from spoiling your ride.

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So what is it and how does it do this?

The best way to think of sealant is as the lifeblood of your tubeless system. Its primary job is to plug puncture causing holes by way of coagulation or, keeping the blood reference, by clotting. Forming a seal that will ensure the tyre remains airtight. The exact formula for a brand’s own sealant can be a closely guarded secret (just as with tyre rubber compounds) but effectively they can all be split into three types – those that contain latex rubber, those that utilise a synthetic alternative and those that make do without.

Latex based sealants are the most common, as natural latex rubber has very effective coagulating properties. Latex itself is actually an emulsion of extremely small rubber polymer particles in either water or a water-based ammonia solution. Most also have other non-active particulate in the suspension to act as a nucleus for the rubber to coagulate around (just like rain drops needs a speck of dust to form around), increasing the size of holes the sealant can fill.

The reason for this effectiveness as a sealant is that coagulation of the latex is activated by air. So when a tyre is punctured the dramatic release of air causes the liquid part of the sealant to evaporate, leaving behind the latex rubber particles to knit together and clog the hole.

Non-latex based sealants approach the prevention of punctures from a different direction. As it contains no ingredients that coagulate in the same way as latex it has to rely on a much thicker viscosity to plug any punctures.

Muc Off’s sealant supposedly lasts for more than six months.

So just pour it in and off you go?

Unfortunately due to the slightly unstable nature of all sealants it is not a fit and forget solution. Over time it will dry out and in the case of latex based sealants, will coagulate into a solid lump reducing effectiveness to almost zero. Every time you adjust tyre pressure you introduce air into the tyre accelerating the drying process. Outside air temperature will also have a dramatic impact on life expectancy, with effective operating times reduced as temperature goes up and for many, if the temperature drops below zero.

How to convert your wheels to tubeless: Are you doing it properly? 

For many sealants, this means that the life expectancy is shorter than you might realise and is the one aspect of a tubeless setup that can catch many riders out. Effeto Mariposa’s synthetic Caffélatex will last between one and four months, Stan’s No Tubes two to seven months, Muc-Off’s No Puncture Hassle lasts more than six months and Orange Seal between one and three months. Most other sealants will provide similar lifespans. One other rule of thumb is that the more effective a sealant is at plugging punctures the shorter it’s life span will most probably be. So in order to ensure effective puncture prevention using tubeless sealant you really need to check sealant levels probably more regularly than you currently do.


Milkit’s syringe lets you check sealant levels in your tyre and top them up if needed

How do I use it effectively?

Cycling Weekly sat down with founder and president of tubeless sealant producers Orange Seal, John Vargus to find out his top tips for maximising the efficiency of your sealant.

  1. Before you start it’s important that you shake the bottle of sealant enough to distribute the particulate evenly and ensure there is enough of it in the solution you will put in the tyre.
  2. Don’t just guess the amount of sealant to put in. Start by putting in the amount of sealant the manufacturer recommends. For Orange Seal it would be 2oz (57ml) of sealant for a typical 700x25c tyre. It should be enough to coat the inside surface of the tyre but not too much to add excess weight.
  3. Inflate the tyre to below your normal tyre pressure, around 70-80psi and ride the bike for a few minutes. This allows the pores in the rubber construction of the tyre to open effectively and enable the sealant to really coat the inside effectively.
  4. Then pump to your riding pressure. A tubeless setup should normally be 10-15% lower than the tyre pressure you use if running inner tubes.
  5. In the event of a puncture locate the source and rotate the wheel until it is at the lowest point to enable the sealant to begin the process of plugging the hole. Then rotate the wheel until the puncture is at the top. This will allow the air to get to the sealant and enable the sealant to begin coagulating and plugging the hole. If it still leaks air, repeat the process until it works.
  6. Sealant does dry out so it’s important to check your levels every couple of weeks and top up as necessary. If you do leave your bike unridden for any length of time it’s a good idea to unseat one side and check for any solid patches of sealant. Remove and refill.
  7. Finally, if you do get a puncture sealant alone cannot fix and you need to fit a tube you will probably get covered in sealant. A quick squirt with a waterbottle will help dilute it and prevent it from ruining your kit thanks to the water-based nature of most sealants.