Black Ox Sealant is a new bike tire sealant designed to work for mountain, road and gravel bikes (even in inner tubes for basically any bike). Its secret sauce is a mix of different length carbon fibers blended into the latex-based sealant.

And those fibers are chopped in house to control the lengths, then blended with other materials to create a sealant that uses both physical and chemical properties to plug holes up to 9mm in diameter. To test it, they shot the spinning tire with a rifle:

They also tested it with three different screwdrivers puncturing the tire, ripped out at once, with surprisingly little air pressure lost:

black ox sealants carbon fibers plugging a puncture hole in a mountain bike tire

Carbon fibers help fill a puncture hole to clog it up, helping the sealant coagulate to plug the leak.

It’s made in Oxford, North Carolina, using technologies and materials borrowed from their parent company, which makes products for the aerospace industry. It’s good down to 20ºF (-6ºC), with a cold-weather formula planned for later this year. They say it’s compatible with other brand sealants and Cush Core inserts.

Retail is $5.99 for a 4oz bottle, $17.99 for 16oz, and $28.99 for 32oz. They recommend about 2oz for a 700×40 gravel tire, moving all the way up to about 10oz for a 29×3.8″ tire. So, probably best to get the bigger bottles.

BlackOxSealant.com

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ZZ
ZZ
1 year ago

They’re not big on environmental quality, are they?

SK
SK
1 year ago

No discussion of the environmental or health impacts of carbon micro fibers?

Nicholas
Nicholas
1 year ago

How long do the small carbon fibre pieces take to break down naturally in the environment?

John
John
1 year ago
Reply to  Nicholas

Is this really a serious queston? The worst thing you contribute to the environment is the carbon fiber hairs that may or may not escape the tire in the event of a puncture? Exactly how many punctures a month do you expect to have?

retro_slouch
1 year ago
Reply to  Nicholas

It never will. Carbon fibers are essentially just carbon graphite, and will not decompose. Carbon composite bike frames and components are particularly tricky since they contain strong resins and adhesives that make it trickier and more expensive to recycle. 99% of sealants are already non-biodegradable and are not very nice for plants and animals to consume, thanks to oils, rubbers, and other nasty stuff. This is a latex-based sealant, and so we’re getting a few real nasty bits together into a not very friendly cocktail.

The bike industry has never focused on sustainable practices, and there is no good option for a nice air-holding solution as far as I know. The closest match would be the biodegradable Effeto Mariposo sealant that was posted here recently, but this is likely very resource-intensive to make, as it uses olive pits. (They are likely able to get pits from food processing factories though, which reduces impact.)

OFfCourse
OFfCourse
1 year ago
Reply to  Nicholas

Carbon does not break down. But this would be an absolute minimal amount put onto the trail.

fatcamper
1 year ago
Reply to  Nicholas

I thought the same thing about this having a negative environmental impact. It’d be cool if they could source recycled fibers.

Jeff
Jeff
1 year ago
Reply to  Nicholas

the increase in CO2 production from your elevated breathing rate during said exercise that caused the puncture is probably far worse for the environment. So you should be sure to hold your breath during the entirety of your ride.

TIm
TIm
1 year ago

Why do so many companies think “testing” their product with a firearm is somehow impressive? If I’m in the market for a bulletproof vest, yes I want to see the demo where the test dummy is unharmed after getting shot close range, with a high caliber armor piercing round. If I’m in the market for tire sealant, I’m much more impressed with a rock stabbed into the sidewall at low speed that doesn’t cause a total flat.

blahnblahblah
blahnblahblah
1 year ago

the USs 5+ billions tons of carbon a year has an impact this however will not

b
b
1 year ago

There’s a simple solution to the environmental problem. Don’t buy the product.

Jon Hinman
Jon Hinman
1 year ago
Reply to  b

Yep, go back to driving a car, and replacing/disposing of wearable parts that each have more of a carbon footprint than a whole bicycle.

Artie
Artie
1 year ago

I am simply amazed how haters can down play such an awesome ground breaking product. Carbon is in everything including us. Using a rifle to demonstrate how effective this product is genius. Nothing can be more destructive to a pressurized tire than a bullet hitting the side wall. Hi how would pass through likely causing it to expand. Leaving a larger exit hole. These people are obviously jealous but I am amazed. So my question is how soon will it be available for cars and trucks and how can I become a part of the sales and distribution? Because this is huge. Congratulations on this product. Eagerly wanting to help bring it to the masses.

Andrew
Andrew
1 year ago

What could be more american than thinking of a reason to use a gun to sell tire sealant?

dan
dan
1 year ago

Screw driver test. Sounded like the tire was sloshing with sealant. Would anyone really want to ride with that much?

Jeff
Jeff
1 year ago

I just want to see this 29 x 3.8″ tire. And the bike that it will fit in.

Seraph
Seraph
1 year ago

I like that the video showing it seal on a spinning tire has a major cut in the edit, basically not showing the actual point in time where it seals the tire. So basically we have a video that claims to show the sealant filling a .22 hole but never actually shows us just that.

Primoz
Primoz
1 year ago
Reply to  Seraph

Did you not notice the edit/splice in the vid where they could have easily changed wheels!? Lol

Gone Bike'n
1 year ago

Wow, there is some weird organized negative “enviromental” campaign against this product. The couple of ounces contained within a tire will have zero impact. Carbon by it’s nature is inert. These posts are totally bogus. I haven’t used this product, but it looks promising.

Chris
Chris
1 year ago

i think your going to need a lot of valve cores…

Jim E
Jim E
1 year ago

Wouldn’t cat hair mixed with Stan’s do the same thing? The fibers seem about the same size.

Morgan
Morgan
1 year ago

Just wait till you have to run your hands through the inside of the tire when you have to throw a tube in. You’re going to get carbon slivers like crazy doing that.

TheKaiser
TheKaiser
1 year ago
Reply to  Morgan

Aside from the other environmentally based objections, this is actually a really good point you bring up. Anyone who has worked in hand’s on carbon manufacture or repair for an extended has experienced this issue. I’d wondered about the internal risks of of breathing in fibers spraying from a punctured tire, but hadn’t thought about external risks to the skin.

Randal Bladel
Randal Bladel
1 year ago
Reply to  Morgan

Naked carbon fiber, without a a hard epoxy resin, are quite soft. You will not get a carbon fiber sliver from them. I think they are softer than fiberglass fibers I have worked with, Nor will you be subjected to “sprayed” carbon fiber, as it will be coated with the latex solution.

Fakebling
Fakebling
1 year ago

are all the bizarre eco warrior comments from the same IP address? or maybe some rival company, weird.

Collin S
Collin S
1 year ago

Most tire sealants are biodegradable despite what Captain No above claims. Bike Radar did an article on it and I know that it has been reported here in Ask a stupid question with stans

https://www.bikeradar.com/features/tubeless-sealant-environmental-impact/

Nick
Nick
1 year ago

They test it like that because it’s fun. Have a sense of fun. Besides, we finally have sealant that is perfect for hunting season on those days we forgot to wear orange.

briannystrom
briannystrom
1 year ago

I have nothing against the product per se, but their recommendations for how much to use are insane! Ten ounces in a 29×3.8 tire? I wouldn’t use that much in a car tire, let alone ANY bike tire.

M.
M.
1 year ago

Awkward moment when you want to buy the big bottle at your local bike shop:
“Do you have big back ox”?