Mountain Biking 101: DIY Tubeless Tire Sealant

While there are still occasional detractors, lots of people are running tubeless setups these days, and most tire and rim manufacturers are building products with tubeless use in mind. With the exception of UST, pretty much all of these options still require the use of sealant, and there are a bunch of good options on the market.

Despite the presence of a slew of perfectly suitable sealant alternatives, I’ve started mixing up my own. Why? Because it’s considerably cheaper, and it’s pretty easy. I swap tires around often enough that I tend to go through a lot of sealant, so cost savings are appreciated. By mixing my own sealant, I get good results for less than half the price of Stan’s.

I find that tires sealed up with this recipe will generally stay sealed for a full season in the northwest, although people in hotter and drier places might need to re-up more often. In terms of getting the tire to seal, I don’t notice a significant difference between this recipe and any of the commercially available brands. In terms of stopping leaks once they start, I’d say the best commercial brands are a bit better than my homebrew, but I’ve had good luck with it sealing up small holes.

Credit Where Credit is Due

Now, before I go any further, I need to give credit for this recipe: my concoction is a very minor variation on “Wade’s Secret Sauce,” as described in this thread on MTBR. That lengthy thread has a lot of information in it, and lots of people have come up with their own variations. And, since this is the internet, there’s plenty of disagreement about what variation works best, including discussions of the best glitter size, propylene glycol vs ethylene glycol, different variations of slime, adding shredded tire, etc.

So don’t take this as the final word on homebrew sealant – if you want to learn more, read through that thread. But if you’re not interested in dealing with that, here’s what I’ve done that’s worked well for me.

1)     16 oz Latex Mold Builder – $17.99 ($10.79 after discount)

This is the key ingredient, and the only one that’s a little tricky to find. I use the “Castin Craft” brand, which I get from Michael’s craft store. Tip: Michael’s pretty much always has a single item 40% off coupon available on their website. Also, when buying, make sure the latex hasn’t dried out.

2)     16 oz. Glycol Based Antifreeze – About $7 for a gallon.

Propylene glycol is the less poisonous option, but functionally, ethylene glycol will work fine. You can get this pretty much anywhere that sells car stuff.

3)     16 oz. Automotive Slime – $14 for 32 oz

Slime makes a tubeless sealant that works on its own in tubeless tires, but for this recipe, you want the cheap automotive stuff. You can get this at auto parts stores, Walmart, etc. I bought mine on Amazon.

4)     32 oz. Water – $free.

Just regular ol’ tap water.

5)     1 oz. Glitter – $4 for a lot of it

Many people in the original MTBR thread will argue against glitter, but I’ve had decent luck with it. Glitter comes in sizes – after some experimentation, I use the larger size (also purchased from Michaels). Since the glitter will inevitably get all over the place, I like to use black – it’s slightly less noticeable.

The glitter seems to help clog up small punctures in the tire. The downsides are that it can lead to premature clumping of the sealant, and it can theoretically interfere with getting a good tight fit in the bead seat. I haven’t run into either of these issues, but that comes with the caveat that 1) I swap tires pretty often, so I’m a bit less prone to the clumping issues that can happen over time, and 2) I’m primarily using rims that have a “bead hook” where getting a tight bead seal is pretty easy.

The Process

No need to play Julia Child here; you just kinda mix the stuff together. If you’re an ounce over or under on any of the proportions, it’s not really going to matter.

Some lessons learned:

-You’re probably going to make a minor mess. Dress accordingly, and do this is in the garage, not the kitchen.

-A gallon milk jug works well as your receptacle. It’ll be about ⅔ full when you’re done.

-You’re going to want a funnel or some sort of means of pouring the stuff into the milk jug. The latex in particular is lumpy and disinclined to pour nicely. I like to measure out the water and the antifreeze in the latex container, which helps to wash the last bit of latex out of there.

-When mixing, I usually fashion some sort of mixing apparatus to stick into a drill. On my last batch, this was a piece of cardboard duct taped to a spoke. The end goal: mix everything up really well.

-The consistency when finished should be fairly runny, with some lumpy stuff in it. Kind of like a thin-ish green milkshake.

-Since a milk jug is convenient for storage but slightly less convenient for actual use, I transfer a bit of the concoction into an old Stan’s Sealant bottle, which is handy for squirting sealant into the tires.

-Like most other sealants, it’ll separate over time – make sure to shake it up before use.

Potential Recipe Tweaks

Like I noted above, this recipe has worked well for me so I haven’t done a ton of experimenting with it. That said, there are lots and lots of tweaks that people have tried, so if you’re feeling ambitious or this recipe isn’t working out for you, a variation might be worth a shot.

A good number of the variations focus on different chunky stuff in the mix to aid with clogging holes. Particularly in areas with a lot of thorns this can be crucial. Adding shredded bits of a tire seems to be popular, but making this is a bit of a hassle and the automotive Slime already includes some rubber bits. Many people have also recommended black pepper (as in the seasoning) and / or cornmeal. If you’re concerned about glitter’s downsides, these could be excellent (and probably cheaper) substitutes.

Some people add ammonia, which should help a bit with keeping the latex from prematurely clumping up. I haven’t had many problems with this, so I haven’t bothered with it.

There are also some recipes that use xantham gum. The general consensus here seems to be that exact quantities matter a bit more, so I’d call this an “advanced” recipe. But if you’re looking for maximum sealant performance, or if you just like tinkering with this sort of thing, this is worth further investigation.