SLiME Smart Tubes - a remedy for bicycle flats?


March 21, 2010

The regular-thickness SLiME self-sealing Smart Tube

The regular-thickness SLiME self-sealing Smart Tube

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If you’re a mountain biker, then you are no doubt aware of the increasing popularity of tubeless tires. For the uninitiated, these are tires that have no inner tubes, but that are instead partially filled with any one of various brands of slimy polymer goo. When the tire is punctured, some of the goo seeps out through the hole, and firms up upon contact with the air. They’re self-sealing tires, essentially. Because they don’t incorporate tubes, they also weigh somewhat less than a traditional tire/tube combo. On the downside, though, some brands are notoriously messy to install, and to keep airtight. They also don’t work with all types of rims. Well, if you like the self-sealing idea, but not the possible hassle of tubeless tires, there’s a product you might want to try: SLiME Smart Tubes - slime-filled inner tubes.

SLiME is one of the gooey products sold for use in tubeless tires, both bicycle and automotive. It consists of a non-toxic latex-based liquid carrier, which contains fibers and rubber particles that do the actual hole-plugging. With their Smart Tubes, they’ve simply pumped a modified version of the stuff into inner tubes, which you then install just like a regular tube. According to the company website, “Smart Tubes instantly seek out and seal punctures as they occur, preventing flats, repeatedly and continuously for up to two years.” They’re available in a variety of sizes for both mountain and road bikes, with either schrader or presta valves. They also come in lightweight, regular and Super Thick versions.

One question that immediately comes to mind with these things (Besides “Do they actually work?”) is one of weight. Obviously, because they combine both a tube and slime, keeping them light is going to be a bit of a challenge. Just how heavy are they? The SLiME website only gives the weight of the Lite tube, which is a claimed 219 grams for any of the mountain bike sizes - by comparison, a generic MTB tube weighs around 195 grams. That’s actually not much of a difference, although it would be good to know just how sturdy the Lite tubes are. At the other end of the scale, the Super Thick tube is five times thicker than the regular Smart Tube - no exact thickness is given, but one would assume they’re no featherweights.

But yes, do SLiME Smart Tubes actually work? A cursory Googling reveals mixed user reviews, although that’s usually the case with just about any product. We’re working on getting our mitts on some, so we can give you a first-hand review.

Watch this space...

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

ive used these for 2 years with no flats, regular tubes on the other hand...


The word on the street is that the slime doesn\'t work. What does work is Stan\'s No Tubes sealant. With tubes or tubeless, Stans will seal a surprisingly large cut in a tire or tube. I have even had good success with a concoction of my own before Stan\'s became available.


I\'ve used Slime in my mountain bike tires for more than 10 years now and love the stuff. I never flat out because the Slime is always there to seal the little punctures. This stuff is awesome and I\'m outfitting my wife\'s bike with these Slime tubes right now. Yes, the stuff does make the tube and wheel and rotating mass heavier but its worth it virtually never having to stop to change or patch a blown tube.


The idea seems viable, but... I cycled a fair amount of trips carrying baggage through Europe. I rarely had flat tyres, even some trips in excess of 2000 km went without a single flat. That was using kevlar reinforced tyres and regular (brand) tubes. The idea is that you should keep the tyre pressure at maximum so the tyre is hard enough to break or bend whatever causes punctures. And.. you will really be surprised at the reduction of roll resistance with hard tyres. Especially the mountainbike variety.


Just get the armoured tyres which work very well, they do the same job without all the extra potentialy environmentaly damaging rubber goo. Plus a puncture only takes ten minuits to fix once youve done it a few times you wont be afraid of getting one any more.


Got kids? Got neighbors that won\'t keep their puncture weeds (AKA goat heads) killed off? Put some Slime in their tubes or get the pre filled Slime tubes and you won\'t be wasting time and money fixing and replacing the kid\'s bike tubes.

\'Course the best fix is to get the kids to not ride through the weeds.

Facebook User

Use slime on my pushbike for approx 10yrs, the only time I have fixed a puncture since using slime I rode 10Kms home on a mostly deflated tyre[still got me home]when I pulled out the tube it had 7 holes in it one with the broken stick still in the tube [approx8-10mm thick]so whacked some patches all round shaking my head over the number of sealed punctures and rode to work in the morning.Brilliant stuff highly recommended.

Glenn Ryan

Slime tubes have been around for years. I know plenty of people who hate them, saying they don\'t work. Another good alternative is True Goo, which claims to work much better and faster than Slime. Quite a few good reviews of that. As for greenness and safety, ccording to its website:

\"True Goo Tire Sealant is non-toxic, non-flammable, non-reactive, non-irritating and environmentally friendly. When spilled, True Goo can be wiped up and True Goo is safe to be rinsed to a drain. True Goo should not be ingested.\"


True Goo should not be ingested? Well, I don\'t want it then! It\'s not totally totally GREEN! Don\'t you just love the \"green\" movement? In everything, moderation is the key!

Will, the tink

Has nobody sort of noticed that All of these Goo slime or other 'latexy' antileak compounds are coloured Green, is there a message.... Don't trust anything that has to be coloured green (especially fluoro-green to be Environmentally friendly....

Now they just need non toxic leak proof anti *[viral;retro-viral;bacteria;little squiggly thing] prophylactics...

BTW ,I have used stuff like this for over 15 years.. Not a Puncture to repair.. the tires only leak slowly if the bike isn't ridden for a few months, regular riding keeps it all firmed up... (Every brand had Proponents and opponents) AND it works in road bikes as well...

If anyone has ridden in England during hedge trimming season ,they will know the value of 'slime'. Hawthorn Kills tyres.

I use Slime in addition to Kevlar tire liners. Slime will instantly seal almost all leaks. But they need better instructions on use. You need to get the air valve at about the 11 O:clock position and walk away and wait fifteen minutes or so. If you use the type of pump that sits on the floor you will need to get the pump up on a milk crate or the hose may not reach. If you do not do this and wait as I remarked you may get an instant seal on the valve and it can be so bad that you canit get the core out at all. If you get a clogged valve you need to leave the valve stem in that same 11 O:clock position and with a pliar rip the valve right out of the tube. This way green goo will not spray out of the hole and bind to everything in sight. Jim Sadler

I have just cut up some strips of EVA foam about 4cm wide and used this to line the inside of my mountain bike tyre. After having about 3 flats in 1 week I wanted to try something without going down the slime or Kevlar liner route. The EVA was an unused weight training mat about 12mm thick. I was unable to re-fit the original 26” inner tube since some of the space inside the tyre has been lost. I have used a 24” inner tube (borrowed from my daughters wheel).

This has to be stretched a little to fit onto the rim, but it does not appear to be causing it any problems. The tyre was a little harder to fit back onto the rim, but still a one man job. I have completed a 5 mile ride on roads and canal tow paths (low speeds) and the tyre / inner tube has worked ok. No significant change felt in the steering. On my return I have inflated to 30 psi (was 20psi - too low) and will try another trip soon. I may also fit a slime inner tube, but a little put-off by reports of their 2 year life span and mess if / when they leak. Since EVA comes in various thickness I could add and extra 5mm if needed.

I am hoping the 12mm buffer will stop most of the thorns doing their worst!


EVA insert update:

I have added an extra layer of EVA to the front wheel since the first layer crushed down to 6mm approx. (Was 12mm) So I should now have 12mm of EVA again acting as a buffer.

I have fitted one layer of 12mm EVA into the rear tyre (will have crushed down to 6mm) and fitted a 24 inch Slime inner tube onto the 26” wheel.

I have completed about a 6-7 mile round trip down a canal tow-path with no problems. Still at low speed so I could not comment how the handling will have changed at higher speeds. The two layers of EVA weigh 160 grams approx.

It will be interesting (annoying) to see which tyre gets a puncture first.

Happy cycling people.


Don't know about their regular tires, but be very careful using the extra thick Slime tubes in a better quality tire. We bought 5 and just had the fourth fail in the same way.

Because the tube is finished smooth, they slowly move inside the tire as you ride, pulling the valve against the metal tire. In each case, they slowly pull the valve until you hit a bump or rock and then lose air very fast. It appears that their smooth rubber and a better quality tire's nylon lining don't create enough friction.

We survived three blowouts without issue, but I crashed at 20mph when #4 blew, resulting in cracked ribs and a cracked helmet.

If you choose to use these tubes, I strongly suggest that you add rubber cement to the tube before installing to give them friction -- or just use a better tube. It's not worth the pain.

Ed Klopfenstein
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