We know, there’s no such thing as a stupid question. But there are some questions you might not want to ask your local shop or riding buddies. AASQ is our weekly series where we get to the bottom of your questions – serious or otherwise. Hit the link at the bottom of the post to submit your own question!

If you’ve had a tubeless tire filled with sealant sitting in your garage long enough, you’ve probably seen it. Some mysterious liquid seeping through the sidewall. Is it bad? Do you need to replace your tire? Replace the sealant? Those are all extremely valid questions and ones that we hoped to find the answer to. Now, thanks to insight from Stan’s No Tubes we have the answer to that, and a bunch of other sealant related questions. Still have more questions about tubeless, tires, sealant, or otherwise? Drop us a line with the link below!

Why is there liquid seeping through the sidewalls of my tire after having it sit for awhile, or long after adding the initial sealant? Is it bad? What should I do to avoid/fix it? Does it matter what sealant or tire is used in this case?

Stan’s No Tubes: This starts with the fact that tires, even modern tubeless or tubeless ready, are not perfectly air tight. The liquid you can see seeping through sidewalls or occasionally old puncture sites is generally one or more of the ingredients used as a preservative or “longevity enhancer.” For the majority of sealants currently on the market, that ingredient is often some form of glycol or glycerine (clear liquids, oily in nature) as they typically blend well with natural or synthetic latex and are hygroscopic in nature. As the latex or coagulant begins to dry, the remaining elements continue to find tiny pores or imperfections in the tires that leads to the seeping look.

Basically no, it’s not bad and won’t hurt anything. It’s not a great look we’ll admit, and we are continuously looking at our own formulations as well as those of the competition. In the end we have a few goals – first, sealant has to seal, bottom line, second, we are looking to balance longevity with puncture protection. Sealant that doesn’t have decent longevity and user friendly characteristics is a painful product to work with and if you don’t have good puncture protection, see point 1.

You’ll find, if you haven’t already, that many sealants on the market exhibit some type of seeping just as you’ll find that some tire makers or some types of tire construction are more or less susceptible.

Can I mix sealants together? If not, what’s the best way to clean out a tire before adding a new, different sealant?

Stan’s No Tubes: No, sealants should not be mixed together. You likely won’t relive your elementary school volcano science project, but you will likely degrade the efficacy of the sealant in a big way.

Cleaning tires is easier said than done in most cases. If you wanted to make a go of it then I’d turn the tire inside out, let the current sealant dry over a couple of days then give it a good scrub with soapy water and a stiff bristle (nylon or similar) scrub brush.

Do tires have a certain shelf life once sealant is added? Or can they simply be refilled with sealant until the tread is worn down or the casing is destroyed?

Stan’s No Tubes: No, tires do not have a shelf life from a sealant standpoint. Short of the worn tread or damaged casing mentioned, dry rot might be the only time based constraint but applies whether sealant or tubes are used.

What causes Stan’s boogers or Urchins? Should they be removed from the tire?

Stan’s No Tubes: Oh man, of all the things we’ve brought to tubeless, Stan’s biggest contributions might be the terms “booger” and “burp.” We all have come to understand the meaning but not the most graceful terms to explain tubeless to the masses.

Essentially what happens when the booger, urchin, coral, Stanimal, etc has formed is the sealant has started to dry or some other debris has found its way inside. That first dried bit or piece of leaf or loam that got in the tire basically tumbles around, snowballing, until you’ve created a prize in the Cracker Jack.

Yes, you want to remove the alien from the mix when you spot (or hear) them. We’d also recommend topping off your sealant at that time as some of the latex (in our case) has been consumed in the creation process.

What is the best practice for installing sealant in a brand new tire, and then keeping it maintained in the long run? I.e. how often should you check it, refill it, etc.

Stan’s No Tubes: There are several options for sealant installation. One is to leave the last few inches of the last tire bead open when mounting the tire, then simply pour in the recommended amount by the manufacturer. Some sealants, our standard formula for example, also have the option of being injected with a syringe or small bottle attached to the valve with the valve core removed. Exercise caution here as some sealants, like our Race formula, should not be injected through the valve, with or without the valve core in place as it may clog the valve or strain out important particulates.

Longevity is always a tough question to answer as there are many factors to consider. How permeable is the tire casing? How much sealant was originally installed? What is the storage environment from a heat/humidity standpoint? How often is the bike ridden? There are some wild claims made about sealant longevity from some manufacturers, and the old adage of “if it’s too good to be true…” should definitely be considered.

It’s not just longevity that’s important, but efficacy (see Rollers of Death video above – don’t try this at home!). Just because the sealant may still be wet inside the tire doesn’t mean it can flow to or seal a puncture.  For us, if you can hear the sealant sloshing around inside the tire and don’t find drastic pressure loss between uses, then you’re in good shape. Otherwise, it’s time to top off. A good practice is to open a tire bead and take a peek every 8 weeks, but we see our sealant often lasting 3-6 months in average conditions.

When it comes to getting the most out of your tire sealant, are there any tips or tricks that Stan’s would suggest?

Stan’s No Tubes: First and foremost is to give the bottle a good shake prior to installation. Basically you can’t shake it too much. The other is to do the wheel slosh in a quiet area every so often or open the bead for a quick look in the 8-10 week range.

For road tubeless use, the 2oz bottle ensures a perfectly measured mix of liquid sealant to sealing crystals and the little bottle is nearly infinitely refillable for your mountain bike needs.


Got a question of your own?  Click here to use the AASQ form, or find the link under the Contact menu header up top anytime a question pops into your mind! 


  1. Eli on

    For a road rider with maybe one flat a year tubeless seems like lots of work. (I have never tried tubeless) Guessing leaving wheels in a hot trunk of a car would make the sealant degrade faster?

    If sealant in the tire only lasts 3-6 months how long does it last in the container?

    Do you have to clean out the old sealent each time you refill even if you stay with the same brand/type? Cleaning the tires as you say may seem easy but that is multiple days with no use of your bike unless you have other tires to use.

    • Mike Franke on

      If your tires and wheels are tubeless compatible already, it’s not a difficult conversion at all, and it’s well worth it. Even if it’s not compatible, and you use a Stan’s retrofit kit, it’s really not much harder than replacing tubes, only you will just to it the one time, then maintain the sealant.

      It’s absolutely not a lot of work.

      I keep my bike in my Element most all of the week during my workday, and I’m in Central Florida, where vehicle interiors get “pretty hot”, and I’ve not noticed any significant degradation of the formula.

      No, you don’t have to clean the old sealant out each time you refill, unless you end up with Stanimals inside, which has never happened to me. The only time you really need to clean the setup is if you change formulas, and the easy solution there is to just pick one sealant brand and stick with it.

      I’ve used both Stan’s and Orange Seal Endurance with excellent results. I suspect all sealants are pretty good, in general, so don’t stress about converting. Trust me, you’ll be glad you did.

  2. Greg Simmons on

    I think the jury is out on Road tubeless as the benefits (at least for me) are far less transparent. However, on MTB, tubeless allows much lower air pressures for better traction. On road, the traction is less important so and I am not convinced some high volume tires wouldn’t do the same thing. I have tried it on road and MTB and love it on MTB and hate it on Road. Maybe gravel, but roadies will 23-28cc tires would be better served with wider rims and 28cc high volume tires.

    On MTB you are much more likely to puncture your tube than on road, so if you changed your tires 4 times with tubes over 2 weeks, you would appreciate tubeless. It allows you to keep riding and deal with the puncture later versus tubes dealing with it as it happens.

    Agree on the cleanup being a pain, but I do it once a spring/summer season with a pressure washer.

    • Greg Simmons on

      And anyone that tells you they are doing it for weight savings is crazy…its all about running the lowest pressure for the best traction and getting the byproduct of not having to deal with flats as they happen.

      • Mike on

        One of my bikes is a fatbike and I went with tubeless on it especially for the weight savings. 😛

        But for my XC and trail bikes it’s all about safety, traction and rolling ressistance.

  3. Bmx on

    Been on tubeless 2 years on a road bike. Around 150 miles per week commute 2 punctures . 1 was a nasty snake bite in the tyre that dented the rim and the second was a 3mm gash in the tyre that sort of sealed but was later made good with a plug. In my opinion tubless road is no brainer riding through glass a general nasty london roads. I use orange seal endurance and top up every 4 months. Its available in bulk from Amazon as i use it on my plus sized mountain bike i tend to use alot of it.

  4. Bruce Miller on

    This is about an overlooked safety benefit of going road tubeless, I have been riding road tubeless in Seattle since about the time Stan’s came up with the road tubeless conversion, 10 years-ish I think but basically a long time. Seattle area streets are NOT particularly pristine or well maintained – no goatheads but glass and other debris, etc.

    In all of that time I have had 3 flats that required roadside repair. Each of those flats came from a piece of glass or metal that I did not see that cut my tire so badly that it would not seal completely, and had to be lined with a spare tube I carry, inflated to low pressure to get home.

    Here is the safety part – each of those 3 flats deflated the tire slowly as the Stan’s tried to seal the gash. In each case, I was able to some to a safe rolling stop and maintain bike control. When rode with tubes and would get the occasional flat the tire would flat immediately and the tire wobbled on the rim as I slowed down. While I never crashed because of a flat, I never enjoyed the task of riding on a flatted tire until I could stop safely. That is one of the reasons that I understand that pros continue to use tubulars for racing; they (the tublars) typically flat slowly with punctures and allow a safe rolling stop.

    I think that going road tubeless has a number of benefits (and some hassles) but I know that if i get a cut in a tire on a high speed turn, my tire is not coming off the rim and I am going to have an easy stop. That peace of mind makes it worth it for me.

  5. Justin on

    What about the fact that Stan’s sealant prematurely corrodes aluminum spoke nipples? Funny, I don’t see that mentioned on their website…

    • Ricky Bobby on

      If you have sealant on your spoke nipples, you’re doing it wrong.
      It’s been my experience that I never end up with sealant on the wrong side of the strip. I’ve found that Stan’s attacked my Panaracer tires, but I didn’t experience that with other tire brands.

      I switched to orange seal anyway, I like the longevity better and finds that it seals slightly better.

  6. mrbuddypepper712 on

    Been using Stans in numerous mountain tires for years without problems.Recently I bought a pair of Vittoria Zero tires for my crossbike.All 4 side walls had so many leaks that I would lose 20+lbs over night.I added a total of 4.5oz and rode 70+miles over 2 wks.They would not seal.I exchanged them with Panaracer GravelKings.Same problem with both tires.Sealant bubbled out of many holes overnight.Yes ,the tires and tubes say tubeless compat.I painted the insides of the GK’S with industrial contact cement.Each tire got several coats.The leaks would not stop.The valves do not leak and neither does the rim tape.I shook the hell out of the Stans container each time I added more.The seller can not explain.I use 75psi in the GK’s and 60psi in the Terrenos. I put tubes back in.What’s up?

    • Zach Overholt on

      Color is one indicator, but it can be hard to tell if it’s dried, or if it’s one of the many different sealants that are white. If you’re unsure, you can just clean out the tires to the best of your ability and add your new sealant of choice. Should be fine, especially if the tires are used since they’ll be due for replacement in the near future.


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