Sealant - how long does it really last??

In my case, i put on a new tire 1 year ago (700c-28mm), with 35-40ml sealant, and half a year ago, i top up another 25ml through the valve hole. Yesterday i remove the tire, and realized there is around 60ml sealant still there.

According to any sealent instructions seems sealant will be complete dry after 6-9 month.

Have been tubeless user for 2 entire years, now all my 3 bikes (commuter, road, TT) in tubeless and i will never go back to clench and tubular. Those i ride 5000km/year and those i ride 500km/year, seem the same, it's just still there, seems the same amount after 6-9 month.

But seems i never encounter sealant to be complete dry out in any of my tire, i'd be rather it really dry so i only need to top up every half year. In this case I will need to consider to try to empty all the old sealant in tires before top-up, incase the old sealant to be lose effectiveness after half year.

I don't worry about my commuter, it spent 2 rear and 1 front tire every year, but

Considering i only ride around 500km of my TT bike every year, if i put in 30ml at the beginning, then 20 ml every half year, after 2 years there should be too much fluid inside...

Any experience?

 

How long sealant lasts depends on a few factors.

The type of sealant makes the most difference. The white-ish water/latex-based sealants like Stan's tend to dry up more quickly than the glycol-based sealants (orange or green). That said, Stan's works really well and it's what I use.

The weather you ride in makes a significant difference, with hot and dry conditions resulting in shorter sealant life.

The permeability of tires varies, with "tubeless ready" tires that require sealant allowing more evaporation than true UST tubeless tires (which work without sealant, though you should still use it for flat protection).

I imagine that how much you ride is bound to affect sealant life, but I haven't seen any real data on that.

On my own bikes, I typically only use 1/3 - 1/2 of the recommended amount of sealant for a given type of tire. This is plenty for them to seal properly, and some of the manufacturer's recommendations are just way too much (they're in the business of selling sealant, after all). Depending on the bike, I add more sealant every 3-6 months to make up for what dries out. I've heard that glycol-based sealants last longer, but I haven't had enough experience with them to say for certain. Either way, adding sealant is no big deal, as long as your valve stems have removable cores.

 

According to various tests I've seen on the internet Stans seals the best; so knowing that Stans recommends redoing the sealant once every 3 to 4 mos, I wouldn't go past 4 mos. For some reason all sealants last the longest in cold seasons but don't last as long in hot seasons, so probably every 3 mos in a warmer climate and 4 months in a colder climate.

I have no experience with these kinds of sealant, just what I've read over the years on the internet from users, so if someone else has better advice then go for it...please!

 

There are lots of factors, as I mentioned above. Another one is the pressure of the tires. The sealant in my fat bike tires lasts quite a while, probably because at single-digit pressures, there's very little air loss over time and little air is added from ride to ride. The less air exchange, the less evaporation of the liquid in the sealant. Although I should probably stick to some kind of schedule, the truth is that I generally add sealant when I can't remember the last time I did it.

 

Thanks for the reply. I am using Stans regular and realized it's still far less dried than the instruction. all my 3 bikes are road bike with 700c and 25-28mm tires, 60-80psi.
i wrote this because i was maintaining all my 6 tires all seems keep the same amount of sealant after 6-12 month of use, some only 500km in 1 year span while others rides 3000km in 6 month.
Now i realize if i put less sealant in will solve all my problems, and all the instructions 30ml for a road tire and top up every 6 month, i can do 20ml in the begining and 15ml every top up, i will never need to worry too much sealant in the tire anymore.
Thanks a lot.

 

For road tires that size, your plan seems good. I'm glad I could help.