JRA with the Angry Asian: Tire brands should tell us how much sealant to use

Tire brands seem content to defer to sealant companies, but no one knows tires better than the companies that made them.

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There’s all sorts of information on bike tire sidewalls these days: Minimum and maximum pressure, rotating direction, bead type, casing type, rubber durometer, and on and on. Some of that is just for marketing and branding, but a lot of it is provided for more practical reasons. However, with tubeless tires becoming increasingly popular — and with more companies pushing the format — why are consumers still left to mostly fend for themselves when it comes to figuring out how much sealant to use?

I swap a lot of tubeless tires, and the tires span a wide range of sizes and widths that include nearly every possible variant between 700×25 mm and 26×4.6″. As a result, I admittedly might get a little more annoyed than most about how often I have to figure out much sealant to use in a particular tire: 30 mL here, 50 mL there, maybe several hundred mL elsewhere. 

Most of the time, the amount of sealant required is dependent on the tire size, but as many of you already know, it also varies a lot on the tire model. 

For example, something with a super supple and porous casing like from Rene Herse or Challenge might require more sealant than usual. On the other hand, I’ve found tires from Goodyear and American Classic require much less to stay reliably airtight. My fat bike tires? Those gobble up a whopping 200 mL each.

Yes, this hot stamp is already pretty darn busy. But I think there’s still one piece of information missing.

While the tires change from day to day, one thing remains the same: the fact I need to look up, or at least verify, how much sealant I should ideally be using. But even that isn’t as straightforward as it should be since most sealant brands are frustratingly vague about how much of their product to use. 

Take Stan’s NoTubes, for example. Without question, NoTubes is the most widely used sealant brand on the market, yet here’s what you’ll find on the company’s FAQ page:

“For a XC 29er tire (2.0-2.2”), we recommend 3-4 ounces (89-118 mL) of sealant as a starting point. The amount of sealant can be adjusted based on the volume of the tire. More sealant can also be added if a tire is particularly porous and difficult to seal. For road and cyclocross tires, we recommend 2 ounces (60 mL).”

So for a 700×25 mm road tire, the answer is 60 mL. A UCI-legal ‘cross tire? 60 mL. A 45 mm-wide gravel tire? Uh, apparently also 60 mL. And what if you’re running a 27.5×2.6″? Or a 650×42 mm? Your guess is as good as mine.

Orange Seal’s FAQ isn’t much better. It says to use “1-2 oz for 23–28c; 3 oz for 27.5; 4 oz for 29ers; and 6-8 oz for 3.0-5.0.”

Note there’s nothing listed for gravel tires, there’s a single recommendation for seemingly all 27.5″ and 29″ setups (2.0″? 2.6″?), diameter categories with no widths paired with them, and width categories with no associated diameters.

And Continental? There’s nothing I could find in text form, but this came from a video manual for its RevoSealant: “For a 2.0 or 2.1″ tire, squeeze 80-100 mL of Conti RevoSealant into the tire. For a 2.2 or 2.3″ tire, the amount squeezed into the tire should be 100-120 mL. And for one 2.4 or 2.5″, 120-150 mL.”

Uh, what about road tires? Gravel tires?  And no mention of tire diameter?

I think you see my point here.

From where I sit, it’s the tire brands that should have the best information on how much sealant should be used for their tires. They know what the actual casing surface area is for a given model, as well as how porous a particular casing may be. And yet almost none of the tire brands I spoke with provide that information to their consumers.

“As a tire brand, we can’t guarantee the quality and sealing effectiveness of a competitor’s sealant,” said WTB PR and product marketing manager Clayton Wangbichler. “Therefore, we can’t in good conscience tell somebody how much of a competitor’s sealant will be sufficient. I’ve used some sealants where an average amount of sealant works just fine, whereas others seem to require an ocean of sealant within the tire in order for me to feel confident in its ability to seal a puncture. Some sealant doesn’t seem to work at all, regardless of whether there is 2 oz or 20 oz of sealant in the tire. Other sealants are incredibly thick and therefore require more volume to fully coat the inside of the tire.”

“A tire is part of a system where only one component may be ours,” explained Goodyear president Luke Musselman. “Riders today can choose from a wide range of sealants available on the market, each of which may have different recommended volumes for a given tire size. Given that, we would point to the sealant manufacturer to provide the recommended volumes of their products for best results.”

Goodyear provides a lot of good information on its tires, in particular with respect to what rim widths are associated with each printed tire size. But in my opinion, there could still be more, especially when it comes to tubeless. Photo: Goodyear.

“Safe filling amounts are a feature of the sealant and need to be unambiguous,” said Specialized’s director of tires and tubes, Wolf Vorm Walde. “Different sealants may require different amounts. A tire brand cannot foresee what type of sealant riders fill into their tires. The sealant is a part of the wheel assembly. Mounting instructions have to come with any part of the assembly itself, especially when it is an alternative part as in tubeless ready tires.”

Does any of this seem a little silly to anyone else besides me?

Even NoTubes implies that its own somewhat broad guidelines are the result of variations in tire casings and dimensions.

“We keep thinking about trying to match specific tire width and diameter with sealant amount recommendations, but tire volumes and casing styles seem to vary so much that it’s tough to rely on that entirely — one of those cases where being too specific may be worse than offering general guidelines,” said Chris Currie, who handles brand and marketing for NoTubes. “We usually recommend 2 oz for road tires and 4 oz for 29″ mountain tires as a broad guideline. Personally, I use 2 oz in my 40 mm gravel tires and 4 oz in my 29×2.5″ Maxxis tires. I’ve had some tires (even the same brand) that seemed to be more porous and required a bit more initial sealant, though.”

It shouldn’t be this hard. 

I agree that different sealants work differently, and that they may require somewhat different amounts for optimum performance. But in reality, most of them aren’t that different in terms of how much you need to use.

I agree that there’s a fair bit of variation in how much sealant is needed for a reliably airtight setup, but in my experience, the major variable isn’t the brand of sealant you’ve got in your hand, but rather the size and porosity of the tire. 

I also agree that some sealants are better than others (and some, like Finish Line’s thankfully discontinued first attempt, are positively awful). But most tire brands with their own sealants already recommend against using anything else, so I’m not sure why they have to further hedge by accommodating the lowest common denominator.

And yes, the tire is only one part of the whole tubeless equation. But it’s also the one that has the most influence on how much sealant should be used. “The sealant is a part of the wheel assembly”? Inner rim width might alter the total air volume, yes, but when you consider the main function of sealant is to plug up the interface between the tire and rim, and the casing itself, I hope you’ll agree that rim width really doesn’t matter here.

The one notable exception I found to all of this is Bontrager, which lists on the product page of every tubeless-compatible tire it sells a precise recommended sealant amount. A 700×25 mm R3 Hard-Case Lite gets 35 mL. The 28 mm version? 40 mL. And Bontrager recommends exactly 45 mL for the 32 mm size. And on the sealant side, Effetto Mariposa has a pleasantly precise online guide.

Wondering how much sealant to put into your Bontrager SE6 Team Issue TLR mountain bike tire? It’s right there, plain as day. Bravo, Trek. Bravo. Photo: Trek Bicycle Corporation.

I get it. Although every one of the tire brands mentioned here makes its own sealant, none of them can guarantee that everyone will actually use that specific sealant. But in caving to that uncertainty, it seems that no one wants to be on the hook if a consumer doesn’t end up having a good experience with their product.

But that just seems like a cop-out. 

Sure, the chances are good that someone will use something other than Bontrager sealant in their Bontrager tire. But the company’s verbiage is clear that Bontrager sealant is what’s recommended, and those volume specs at least provide users with a decent starting point. That person might end up having to add a little more if they live in a dry climate, or if their preferred brand of sealant just isn’t as efficient at plugging porosities in the casing. But isn’t that better than leaving people to guess?

Why should I be the one to learn on my own that my WTB gravel tires work best with slightly more of a higher-viscosity sealant than others? Can’t WTB tell me that since they presumably know their own tires best?

Perhaps there’s a little bit of light at the end of the tunnel, though.

When I suggested it, Bontrager marketing manager Alex Applegate sounded genuinely interested in the idea of printing these sealant recommendations right on the tire casing. After all, the company has already done the hard work of determining the proper sealant amounts for each of its tubeless-compatible tires, so how much more would be required to just put that number right on the tire’s hot patch?

“That is a great idea!,” Applegate said. “We are going to look into it.”

For sure, it’d be a design challenge to figure out how and where to incorporate a sealant volume recommendation directly on a tubeless tire. But it still seems like a worthwhile endeavor.

And Vittoria? “I hear you,” said the company’s senior vice president of product development, Ken Avery. “I think there is certainly room to innovate on this topic.”

“Well, [the idea of labeling tires with recommended sealant amounts] has been discussed, but they always end up deferring to rider preference and to the sealant companies,” said Schwalbe North America brand manager Nathan Forbes. “The proponents of doing it say it would help simplify life for consumers. The people against say that it varies greatly depending on your type of riding and the type of sealant that you use.” 

I’ll be the first to admit that tubeless bicycle tires are still far from perfect, especially for gravel and road. But now that legitimate tubeless rim standards have been established that tire brands can reliably design around, many of the problems we’ve been dealing with to date should progressively get better (and they already are). 

It’s pretty obvious that tubeless is where the industry is headed across all performance categories. But given how many times the industry has shot itself in the foot on the topic — and how much it clearly wants tubeless to be widely adopted —  shouldn’t tire companies want to make this as easy as possible for people?

JRA is an acronym well-known to bike shop employees, usually applied to customers submitting warranty claims that are clearly invalid (“I was just riding along when my top tube dented!“). It’s in part an homage to James Huang’s long tenure as a shop mechanic, but also the title we’ve given to the collection of random musings that are regularly published here on CyclingTips. Most — but not all — of them are tech-related, but either way, they reflect what’s been on his mind and what he’s been thinking about when he’s just riding along. Follow the link for other JRA posts.

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