Introduction: Slime Your Presta Valve Bicycle Tubes

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.

Step 2: Remove the Nut

Picture of Remove the Nut

Use a pair of pliers to remove the nut from the thin threaded visible portion of the valve. The threads may have been crimped a little to prevent the nut coming off accidentally. Save the nut because you will be putting it back onto this thin stud.

Step 3: Drop the Valve Core Into the Tube

Picture of Drop the Valve Core Into the Tube

It sounds like the worst thing you could do, but allow the valve core to fall into the tube. Blow on the end of the valve stem a little to inflate the tube enough that the valve core can fall into the tube. If the valve core sticks in the valve stem, push the core out of the stem with a finish nail.

Step 4: Prepare to Pump in the Slime

Picture of Prepare to Pump in the Slime

Be sure to buy Slime designed for bicycles. The shreds of rubber suspended in the green solution are finer than those in Slime for automobile tires or for motorcycle tires. Slime comes with a clear plastic tube for connecting the bottle to the tire valve stem. It is sized for a Shrader valve. Use a brass Shrader to Presta converter. See the yellow text boxes. 

Attach the clear plastic tube to the bottle of Slime. Screw the brass converter onto the stem of the Presta valve tire tube. Connect the clear plastic tube from the Slime bottle to the brass converter. 

Step 5: How Much to Add

Picture of How Much to Add

My tires are 700mm x 23mm. That is almost 27 inches in diameter and just under 1 inch in width. Four ounces of Slime is about right for my tires. The Slime bottle has markings in four ounce increments. Although difficult to see in the photo, you can see a slight difference in color that indicates where the level is inside the bottle. Squeeze the bottle to pump Slime into the tube. You may need to manipulate the tube to allow the Slime to pass beyond folds and crimps in the tube. You may also need to twist the bottle cap open half of a turn and allow air back into the bottle. When finished, remove the Slime bottle, the clear plastic tube, and the brass converter. Rinse the clear plastic tube so it is free of all Slime residue.

Step 6: Find the Valve Core

Picture of Find the Valve Core

The valve core is easy to locate inside the tube. It has probably settled into the lowest part of the tube. Pinch along the length of the tube until you feel the valve core. You may be able to make it fall back toward the valve stem, but then you will need to locate it again. (Second photo) You will need to move it along part of the way "inch worm"-style. (Third photo) This means you pinch the tube against the end of the valve core more distant from the stem. Then pinch and push some of the tube in front of the other end of the valve and grasp the front end of the valve. Release the pinch at the rear. Pinch where the rear of the valve is now.

Step 7: Tip and Push the Valve Into Place

Picture of Tip and Push the Valve Into Place

It sounds terribly difficult, but is actually quite easy to tip the thin end of the valve core into the valve stem. Then push it into the stem as far as you can.

Step 8: Put the Nut Back in Place

Picture of Put the Nut Back in Place

You will probably need to tap the top of the valve stem to get the core to present its threaded end. You may need to use a knife point to pull it out of the stem. Often I can simply shake and tap on the stem until the end of the core presents itself. Pull the threaded end of the valve out as far as possible. Catch and hold it with a fingernail. Twist the nut back onto the valve core's threaded end. 

If the valve does not seal and hold air pressure, loosen the nut and push a few drops of water into the valve stem to wash away any shreds of rubber that might be blocking the valve. Give the water an assist by pushing and pulling the valve core back and forth in the valve stem. Or, press on the core so a significant amount of air escapes from the tire. That usually blows away whatever kept it from sealing. Then fill the tire with air to the desired pressure.

In my experience, the combination of Slime and a tire tube is not forever. After a couple of years the tubes often develop a slit or another leak that the Slime cannot seal. I do not try to save the Slime in the old tube, but discard both the tube and the Slime. Slime has a limited useful life, anyway.

One morning I was seven miles from home on my 14 mile bicycle route. Some puncture vines had blown their way into the middle of my lane. Normally, I would simply have ridden around them, but there was an oncoming automobile and I went right through the puncture vine. I stopped and picked numerous goat head thorns out of my two tires. My tires looked like a teenager with acne. There were green dots of Slime coming up out of my tires everywhere. But, my tires sealed and I rode home with no flat tires and plenty of tire pressure. I continued to ride on those tubes for quite a long, long time.  


dasilvarsa (author)2017-09-22

There is a much simpler way of doing this.

Wait until you have your first puncture on that tube.

Or Create a hole in the tube opposite the valve if you don't want to wait for a puncture.

Find the puncture hole

Enlarge the hole to about 3 to 5 mm in diameter using a very sharp knife or scissors.

Insert the slime into the tube through the enlarged puncture hole in the tube.

Repair the hole with a patch.

Pump up tire.

Ride into the sunset.

Phil B (author)dasilvarsa2017-09-25

I believe I mentioned I was forced to ride through quite a few goats heads and I had green spots all over my tires where Slime oozed out. If that had been my first punctures, I could never have latched them all and would have had a 7 mile walk back home. But, my tires sealed and I rode home with no inconvenience. Also, in my experience Slime always gets onto the outside of the tire so that a patch will not stick. If it works for you, that is great. It has never worked for me.

iminthebathroom (author)2011-06-11

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


freeza36 (author)iminthebathroom2012-08-05

I wouldn't have thought that Devil's Club would pop a bike tire.

Phil B (author)iminthebathroom2011-06-11

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.

gumby_kevbo (author)Phil B2011-09-01

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.

melonmark (author)2016-04-21

Awesome - thanks so much! I found that you don't need a presta-schrader valve adapter when doing this. Just skip the connector tube and stick the nozzle of the slime bottle right on the presta valve. It fits perfectly - just just have to tip the connection off occaisionaly as you fill to let some air back into the bottle. If you aren't running tubeless and you live somewhere with goatheads, slime is key. They don't make tubes big enough for my current tire size, so sliming my tubes myself was needed.

Phil B (author)melonmark2016-04-22


Evenmoregarlic (author)2015-09-30

Excellent tip, thank you. I found the first tube a bit "fiddly", but after that, plain sailing.

MarcoP4 (author)2014-10-09

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)MarcoP42014-10-10

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.

heiko.langner.796 (author)2014-09-12

This is awesome! And works great.

Phil B (author)heiko.langner.7962014-09-12

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.

trevthelegend6 (author)2014-06-04

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)trevthelegend62014-06-05

Good idea.

freewso (author)2014-01-02

thank you

Phil B (author)freewso2014-01-02

You are welcome, but I stole the idea from Slime.

H8888 (author)2013-12-07

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.

TheHumanWhiz (author)2013-08-31

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! :)

freeza36 (author)2012-08-05

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.

zomfibame (author)2012-03-16

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)zomfibame2012-03-17

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 (author)Phil B2012-07-02

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.

GENIUSMAXX (author)2011-08-05

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)GENIUSMAXX2011-08-05

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.

CatTrampoline (author)2011-07-28

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)CatTrampoline2011-07-28

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.

sdavidson3 (author)2011-06-25

ouch the first picture looks painful

CatTrampoline (author)sdavidson32011-07-28

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)sdavidson32011-06-25

They are painful. It is easy to puncture a finger or part of a foot with one of these thorns.

openidordie (author)2011-06-26


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)openidordie2011-06-27

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.

yaman.cool63 (author)2011-06-24

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.

ajohnson8 (author)2011-06-21

tire liners, any good bike store will sell you a set, around $15, no more punctures.

Phil B (author)ajohnson82011-06-22

I tried tire liners. They caused more flats for me than they prevented me. See my response to joen below.

ajohnson8 (author)Phil B2011-06-23

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)ajohnson82011-06-24

Thank you. It appears they still have ends that overlap. That is what caused trouble for me.

pfred2 (author)2011-06-12

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)pfred22011-06-13

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 (author)Phil B2011-06-13

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)pfred22011-06-13

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.

vigothecarpathian (author)pfred22011-06-13

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.

pfred2 (author)vigothecarpathian2011-06-13

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.

joen (author)2011-06-12

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)joen2011-06-13

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.

joen (author)Phil B2011-06-13

I was using heavy duty tubes and liners in dirt bike tires which are about an inch and a half wide or so. If your tires are narrower than that then my idea won't work as well.

Dr Qui (author)2011-06-13

Excellent instructable.

I will pass this on to a few of my racing bike cycling friends who have been wanting to use slime but where not able to because of the presta valves.

In Ireland the problem usually come from the thorns of the blackthorn in late summer when the roadside hedges get cut by flail mowers and the thorns are scattered everywhere, I have Kevlar lined tires on my bike and I still manage to pick up thorns.

Phil B (author)Dr Qui2011-06-13

Thank you.

bengel1 (author)2011-06-12

I am a bike mechanic and this brand of slime has never really worked to well on any bike I've used and it actually doesn't last to long. Plus it tends to be heavy and if your tire slips off the bead and blows and flings slime every where. Now that I'm running tubeless I prefer to use Stan's instead. It's easier and, lighter, lasts longer, works better and can be used in tubes or tubeless tires. I'd give it a try.

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Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying ... More »
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