Picture of Slime Your Presta Valve Bicycle Tubes
Puncture vine (tribulus terrestris), also known as goat head thorns (The photo is from Google Images), is a big problem for bicyclists in several parts of the United States and also in a number of other parts of the world. It is certainly a problem in southwestern Idaho where I live. Even if there are no puncture vine plants in your immediate neighborhood, the thorns tend to blow into places where they did not grow. They have a knack for finding your bicycle tires. They are 100 percent effective at causing your tires to go flat.

Step 1: Slime

Picture of Slime
I have decided a sealant additive is my best choice. I use Slime, which is a brand trademark. My bicycle tubes use Presta valves, which are thinner than the more common Shrader valves found also on all automobile tires. It is easy to remove the valve core from a Shrader valve, add Slime to the tube, and replace the valve core. Presta valves have their broadest part inside the stem so that it is impossible to remove the core from the tube. 

Another Instructable slit the tube with a knife, inserted the Slime through the slit, and added a tire patch. The problem with that approach is that the least amount of Slime on the surface of the tube makes it impossible for a tire patch to stick. This Instructable will show you how to drop the valve core inside the tube and put it back in place after adding Slime to the tube. In the interest of disclosure, this basic procedure is described on the Slime website. I have illustrated it here with some things I learned by experience.

Slime coats the inside of your tire tube as your wheels roll. When there is a leak, the air moving through the leak draws some of the Slime into the hole and tiny shreds of rubber plug the hole. A tube with Slime added can last a very long time after a leak developed and sealed, even at pressures of 100 pounds per square inch.
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MarcoP410 months ago

This is a really cool idea, thanks. I always heard of removable presta cores, but didn't now they could be pushed "inside". Have you tried this with a lighter sealant such as Stan's? Also, do you feel any difference riding with a much heavier tube (now that it has 4 oz of slime inside?)

Phil B (author)  MarcoP410 months ago
I have not tried it with a lighter sealant. I did not notice any difference in ride quality. I always felt I needed to take extra weight off of myself before I worried about extra weight on the bike.

This is awesome! And works great.

Phil B (author)  heiko.langner.79611 months ago
I wish it were original with me. The idea actually comes from Slime. I simply thought I would demonstrate it for the benefit of those who had not seen it, and include a couple of perspectives from my own experience.

handy tip is using a bulldog clip to hold the valve stem in place the right way up before adding the slime. its easier to find and knock back through the valve before replacing the nut

Phil B (author)  trevthelegend61 year ago
Good idea.
freewso1 year ago
thank you
Phil B (author)  freewso1 year ago
You are welcome, but I stole the idea from Slime.
H88881 year ago
Slime works for some riding. If you are doing a lot of MTB in the desert, you will likely find yourself still limping home with tires going flat. At that point, consider tubeless systems. Basically these are Stan's Tubeless (expensive) and what is known as "ghetto tubeless" which is cheaper and also effective. Both may require an air compressor but they are pretty amazing once you get them set up. Google for details.
I hate sand spurs! I always step on them on the beach here in Lake Michigan in Chicago, but good thing you made this instructable because I've had to replace my bike tires countless times because of them! :)
Wow, that thorn looks evil! We have nasty things up here like devils club and the like, but that is more or less stationary. nasty
I wouldn't have thought that Devil's Club would pop a bike tire.
Phil B (author)  iminthebathroom4 years ago
I have not lived in Idaho all of my life. When we moved here, flat tires on bicycles were suddenly a problem until we got educated. If you do not have them in your part of Canada, be very happy. And, they are called goat head thorns or goat's head thorns because they do look like a goat's head when viewed at just the right angle.
The thorn in the picture we would call a "sand burr" in New Mexico. I have pulled a ton of them out of the dogs fur and my shoe laces.

Puncture vine is known locally as "Goat head" and the dry burrs bust into chunks with two spines each that really do look like a goat's head or a bull's head, which is what we called it in Colorado. The geometry of these is such that one of the two thorns always points straight up when they lay on the pavement.

Slime and Presta valves: It is worth using on 28mm or larger tires. I find that the slime won't seal the higher pressure needed for narrower tires. It will seal for 50mm or so, then break loose and spray for another 10meters, wash, rinse, repeat. Finally when my glasses have enough slime spots on them I will stop and patch it. I have had good luck with it in 28mm tires run at 80psi, so it might eventually keep the air in a narrow tire after enough air leaks out.

The slime does make the holes easy to find! Yes, you need to get it all off or the patch won't stick. I carry alcohol wipes in my tool kit for this purpose, and they are also good for cleaning grit out of road rash, and slime and gnat spots off my glasses.
freeza363 years ago
Those sand spurs are terrible in Kansas. When I was 10, I was on a spinning Merry Go Round at a playground, and I flew off inot a patch of these.
zomfibame3 years ago
ahhh, Sand Spurs, when I was a kid we moved to the South Carolina coast from up north... those things are miserable. bike tires would get destroyed within a few days..... then we discovered inner-tubes made of a dense foam-rubber. they were great, but they did weigh a good bit more than regular tires..... does the green foam make the bike noticeably heavier?
Phil B (author)  zomfibame3 years ago
I have never noticed extra weight from the Slime. I am sure it adds a few ounces. The purists who worry about every gram might be concerned, but there has always been extra weight on me that I needed to worry about first. Thank you for your comment.
vov35 Phil B3 years ago
I don't consider myself a purist, and I refuse to make weight saving changes that could be accomplished with a trip to the bathroom, but I don't like slime.

Slime has a tendency to settle when you're not riding and throws the wheel off balance until it distributes to the perimeter. This impacts control negatively, for example: I ride a road bike and try to only stop to rest at the tops of hills. This makes sense as far as preserving momentum goes, but with the addition of slime I'm given a choice of two problems. I'd either need to be on my brakes for the first few hundred meters, likely losing any benefit of stopping on a hill, or, alternatively, I can deal with an unstable ride and have to apply a lot of effort and concentration to keep the bike on the road and moving in a straight line as I hit 40mph.

Slime is wonderful on mountain bikes, though, where there is a high probability of punctures and a heavier tire makes the effect negligible. I use slime pre-filled presta tubes for my mountain bike.

Off to search for foam inner tubes for the roadie.
GENIUSMAXX4 years ago
Just a word of warning, the chemicals in the slime will cause the rubber to pull away from the metal in the valve stem (Schrader valve may be different). Giant used slime tubes in most of their bikes a few years ago and they are bad news, maybe a quick fix but trouble down the line. I work as a bicycle mechanic and we make it a habit to change them every time we see them.
Phil B (author)  GENIUSMAXX4 years ago
Thank you for the information. I usually get a couple of years, maybe more out of a tube with Slime in it before it develops a leak I cannot seal. On balance I get more life out of my tubes, even with Slime. Without the Slime the goats head thorns would consume too much of my time changing and patching flats, as well as forcing me to replace punctured tubes. I know Specialized makes an alternative to Slime and it is supposed to last much longer than Slime. I have not tried it. Again, thank you very much for your comment.
There are goat-head thorns all over in North Texas. We tried tire liners and heavy tubes, but Slime is the best. I even had to have the tires on my dog's stroller slimed after rolling through a patch in a park.
Phil B (author)  CatTrampoline4 years ago
I viewed your Instructable on keeping up your work-out routine by training together for an event with a pet, like a dog. I saw a photo of your dog's trailer to go behind your bicycle with its inflatable tires. Thank you for your comments.
sdavidson34 years ago
ouch the first picture looks painful
There is a tiny hook at the end of each spine, so they stick in and don't shake out. Since they are covered with those spines, you get stabbed when trying to remove them, too. They are murder on a dog's feet.
Phil B (author)  sdavidson34 years ago
They are painful. It is easy to puncture a finger or part of a foot with one of these thorns.
openidordie4 years ago

I have a observation;

why not just buy the tubes that slime offers, that already have slime and are
presta valved. Slime has been offering this for some time now... or maybe
you wanted a challenge... That's it. It is all about the challenge. ;)

Phil B (author)  openidordie4 years ago
I have seen the tubes pre-filled with Slime, but not in sizes that my bicycle uses. That is why I add slime to tubes. If pre-Slimed tubes are available in the sizes I use, they are not in local stores and I like the convenience of picking up a tube when I need it. I also keep some tubes for when I need a new one. If I were to buy the pre-Slimed tubers ahead like that, the Slime would probably be past its prime before I needed the tube.
Any bike shop using QBP (Quality Bicycle Products) as a distributor can get QBP's house-brand presta valve tubes which come with removable valve cores, which have wrench flats on the sides so you can access the wider part of the valve stem. I just use pliers to take mine apart, works great! It would be a lot less mess and time lost.
ajohnson84 years ago
tire liners, any good bike store will sell you a set, around $15, no more punctures.
Phil B (author)  ajohnson84 years ago
I tried tire liners. They caused more flats for me than they prevented me. See my response to joen below.
I don't have the exact brand name of the ones I have but they look a lot like these:


(mine are orange and black)

You buy the size you need and don't have to cut anything so there would be no rubbing through, I put a set in my slicks years ago and have had no issues what so ever. Before the liners I have punctures all the time.

Hope that helps.
Phil B (author)  ajohnson84 years ago
Thank you. It appears they still have ends that overlap. That is what caused trouble for me.
pfred24 years ago
When a buddy of mine owned a gas station and broke down a flat car tire and found Slime in it he'd put it back together give it back to the customer and tell them that he was sorry but there was nothing he could do for them besides sell them a new tire. In other words if he saw Slime he'd refuse to repair the tire. He did the best tire patching I ever saw too. He'd never just plug a tire. Take away from this what you will but he was a great mechanic and his opinion was less than stellar of the product.

He never described in detail exactly what the problem was but from what I have divined I think the Slime made it impossible for him to get a patch to apply correctly. I could tell by his expression and demeanor that Slime was a touchy subject with him and I never pressed him on it.

Personally I use thorn proof tubes. They're not totally impervious but they work pretty good. Thorn proof tubes do have a couple of downsides like they are so thick they can be hard to mount and they're so heavy they're well, just heavy!

But this is about avoiding flats right?
Phil B (author)  pfred24 years ago
This is not really about avoiding flats. If it were I would have written a lot about where puncture vine thorns are found and not found, as well as how to eradicate them. It is really about how to get a sealant into a Presta valve tube and restore the valve.

I linked an Instructable in which the author intentionally slit a new tube so he could insert Slime. Then he patched the slit he made. There I noted that the least bit of Slime on the outside surface of the tube will keep a patch from adhering. That is probably the objection your friend who services tires has to Slime. If a tube filled with Slime does break open, especially inside a tire and rim, it is a mess. Fortunately, Slime is water soluble and it does clean up, but your tire feels like Will Smith and Tommy Lee Jones in "Men in Black."
pfred2 Phil B4 years ago
I have a Presta to Shraeder adapter for my one bike with Presta stems I wonder if that'd work? Not that I'd ever use Slime but I'm just wondering.
Phil B (author)  pfred24 years ago
I am not sure if the adapters are called Shrader to Presta or Presta to Shrader adpaters. The interior diameter fits the Presta valve. The exterior is threaded for any tire fixture that accepts a Shrader valve. I expect what you have is what is needed.
I know that automotive slime can destroy a car tire if it is used wrong, and in emergencies, it is almost always used wrong. This might be what you buddy constantly sees, and hates the product for, or at least wants to avoid being blamed for the tire's destruction.

After the automotive slime is put in the tire, the tire needs to be spun at high speeds to use centrifugal force to repair the tire, something done via driving the car. Since most people use slime when they have a tire blowout, they are not in a position to drive on their tire, so they just dump slime in their car. All the slime settles to the bottom of the tire.

What happens then is that there is the tire becomes imbalanced, with a weight on one side of the tire, the tire will never run correctly again. (A car tire is tubeless and wide, the slime will just pool in the bottom of the time). You will feel the car "thump" as you drive. The only way to fix it is to pull the tire completely off the rim and scrape out all the slime by hand.
Yeah to patch a tire you have to break it down anyways so that wasn't it. But he only had one set price for patching a tire, not a different price for patching a tire someone put Slime in. I guess he figured if he tried to have different prices people would think he was ripping them off. So he just didn't do it. But he still had to take the tire off the car, break it down on the machine, see the Slime, put the tire back on the rim, on the car and get nothing for doing all of that. he'd ask people if they put Slime into their tires but most played, or actually were dumb about it.

He probably even had to clean Slime off his tire machine afterward too. So I understand why it ticked him off.
joen4 years ago
I don't know if you have it where you live or not but here in Phoenix we have Bull heads and other sticky things that can give you a flat in a hurry. I found that heavy duty tubes in combination with a plastic thorn shield that goes around the parimiter of the tube between the tube and the tread of the tire can give you excelent protection from flat producing stickers. The ones I used outlasted 3 sets of tires and two bicycles! My bicycle was stolen so they may still be going strong. Check with your bicycle shop about this.
Phil B (author)  joen4 years ago
Heavy duty or puncture resistant tubes are generally helpful. I have not used them. My thin tires make it difficult enough to wrestle the tube into the tire and onto the rim. The extra thickness of the heavy duty tube would only make it even more difficult.

I did use the tire liners you mention. The ends often need to be feathered or the ends, themselves can rub through the tube and cause a flat. I had that happen a couple of times and stopped using them because of that problem, even though I had feathered the ends. My aim with this Instructable was to describe how it is possible to get tire sealant into a Presta valve tube, so that is why I did not mention tire liners.
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