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How to Thorn-Proof Your Bike

By Bob Forgrave
President, Flatbike

It’s a sunny day, you’ve got the time off, your bike is calling you…and it’s got a flat tire. And the bike pump is … somewhere. If this has ever kept you from getting out on a bike, then here’s exactly what you need. Here, on one comprehensive page, are five ways to thorn-proof your bike, from the simple to the hilariously expensive…


A few weeks ago, I got a call from Randy, a private pilot who likes to fly his CHANGE folding mountain bike into remote places for exciting adventures in his private plane. He wanted tips on how to avoid thorn flats.

How remote? And what kind of vegetation are we talking about?

thorn bush

Cacti in West Texas can have some awfully long thorns…

Those are some serious spikes. And West Texas cacti aren’t the only problems. Blackberries, devil’s club, goathead thorns, ‘wait a minute’ vines…nearly all parts of the country have some species that are unfriendly to inflated tires.

Basically, if you know you’re headed into thorn country, there are five different ways to address the issue of puncture flats.

1. What you already have, just tougher.

Tires and inner tubes come in thicker, thorn-resistant versions, which are tougher for thorns or broken glass to puncture. Why don’t all bikes come like this? Because extra rubber results in extra weight. How much do you want to free yourself from flats?

Using a set of these in the 80’s, I once went over 2,000 miles between flats; when I finally got one, it was from a thumbtack inserted in the sidewall at a bike rack. Even the best intentions won’t stop everything…

The Specialized Armadillo tire series has different levels of rubber thickness, with more thickness protecting more, but also offering a bit stiffer ride. The Continental Gatorskin, on the other hand inserts a layer of Kevlar clear around the tire to protect against anything–perhaps even sidewall thumbtacks.

Armadillo tire

Kevlar: If it can stop bullets, it can stop thorns.

You can also protect against thorns at the inner tube level. But thicker tubes are becoming harder to find in recent years.

tube box

Kenda owns a large portion of the thorn-resistant tube market.

FLATBIKE ASSESSMENT: Good, easy plan. We include Continental Gatorskin flat-resistant tires standard on our Flatbike Century folding road bike.

2. Self-healing tires that aren’t science fiction.

The idea is simple. A small amount of liquefied goo stays inside your tire. When you get a puncture and the air starts leaking out, the goo rushes to the opening and clogs it.

In practice, this often works, especially if the hole is small enough, the hole is on the bottom of the tire, and the self-sealing compound in your tire is recent enough to be still liquid.

dried slime

Otherwise, you end up with this inside your tires (The “tire coral”, not the money).

If you go with this approach, you probably want a tubeless tire, because there’s simply no way to change the liquid inside an inner tube. Notable self-sealing solutions are Slime and Stan’s. The website MBAction has a great review of these and other sealant solutions, with the wonderful testing warning, ‘All tires were harmed during the testing process.’

FLATBIKE ASSESSMENT: Wait & see. Some folks swear by the tire sealant approach, and we’re interested to hear from you. But a tubeless tire works best with a compatible rim. Useful extra aids are a bucket of soap water, a sponge, and an air compressor. And after that, we wonder if the time previously spent fixing flats on the road is simply transferred to garage maintenance, installing and removing old filler.

3. A solid choice for narrower tires?

For a while, before my thorn-resistant tires, I rode a 1980’s technology, solid rubber tire. Potholes were memorable on my spine, but traction was good and I never got a flat.

On the surface, an update to this approach sounds appealing. Flat tires are the #1 maintenance issue bringing customers into many bike shops.

That said, compressed-air tires distribute a shock across the entire rim, while solid tires distribute stress only locally. And some bike shops charge a premium for replacing a solid tire. Has advanced technology made a difference?

With today’s advanced polymers, there are more options and better options than ever. One example is the Tannus Airless Tire. Made of closed-cell polymer foam, it is reportedly as light as most tire/tube combos, good for over 5,000 miles and comes in 12 stylish colors. Tannus even claims equivalent rolling resistance to inflated tires.

solid tire

No more flats. Ever.

During Bike Expo NY 2018, a Tannus rep offered to put a set of Tannus airless tires on a CHANGE 702 folding commuter bike, which I then rode in the 40-mile Five Borough Tour, plus another 20 riding to and from the event.

After a 60-mile day, I must say that the difference between the solid rubber tires of the 1980’s and the carefully calibrated polymer tires today could not be more stark. Even a cobblestone road was possible at 15 mph–still not fun on narrow tires, but the choice of tire composition was never in question after the first few wheel rotations.

cobblestone ride

Among the joys of that 10-mile pre-ride was a surprise section on this road. It felt just like a regular air tire!

FLATBIKE ASSESSMENT: Airless tires will remain more difficult to install/uninstall than inflated tires. But not by much, with the right tool. And it’s a one-time deal.

Last we’ve heard, there’s also about a 5% loss in rolling efficiency. If you keep your tires fully inflated all the time, pumping up for every ride, these aren’t for you. But if you often go weeks between fill-ups, adding 20 lbs or more when you fill up, then you’re going to experience an increase in rolling efficiency. We’ll continue to explore this area as it matures.

4. Like solid tires, but not.

We got this tip from a reader–thanks, Donny–and it has developed into a brilliant idea that’s worth a category all its own. But first, let’s take a step back and look at what riders (road and MTB) actually do with their tires.

Road riders have a preferred pressure that must be maintained over time for maximum efficiency. They rack up many miles on pavement that may occasionally have a pothole, broken bottle, or goathead thorn. Under low pressure, ‘pinch flats’ may also occur, without any obstacle in the way.

goathead thorns

Goathead thorns: Nasty stuff.

MTB riders, on the other hand, vary their terrain–one day dirt trails, another day lots of bumps and big jagged rocks–so their tire pressure varies accordingly. The rockier the terrain, the more pliable you want your tire to avoid punctures and increase grip. Broken glass isn’t usually an issue, but goathead thorns and cactus thorns are worse.

So while an airless tire might make sense for a road bike rider, it would take away the ability for MTB riders to adjust pressure for different terrain. Enter a new category: the tire liner.

tire liner

A tire liner goes between your tire and innertube, protecting against puncture.

A tire liner can be inexpensive. The one shown here from Mr Tuffy is just ten bucks, with a 70% satisfaction rating. Folks have ridden over 1000 miles with it, and even ‘successfully’ run over broken glass. (And “Ed” in the comments has an even cheaper solution that may be more reliable.)

But it’s still not flat-proof. And you can create your own flats, both from semi-inflated tires (pinch flats) and from having your rim liner slide to the side and rough edges puncture your inner tube (anyone have a name for that?). And tire liners are no match for goathead thorns.

Now here’s where it gets really interesting. Suppose you took the inflated tire idea, and the foam solid tire idea, and the liner idea, and melded them together into a single product that inflated but was thick enough for goathead thorns?

Tannus Armour

Tannus Armour: an MTB-focused liner that’s finally designed for goathead thorns.

The Tannus Armour is a special type of liner–the red part–with 15 mm of the Tannus solid-tire material under the tread of the tire, and 2mm on the sides. It’s like having most of the advantages of an airless tire, plus the ability to adjust pressure to your terrain.

Tannus Artmour with nail

Normally, this is a ride-ending disaster. Not with Tannus Armour.

Even in the worst case scenario, with a random goathead thorn doing a stealth insertion from the side that goes through tire, 2 mm liner, and inner tube, giving you a flat…you still have 15 mm of solid tire to ride back on, protecting your rim from rock damage.

FLATBIKE ASSESSMENT: We cannot pass this up. We are now offering Tannus Armour at Flatbike, both separately and as an add-on to our our full-size folding mountain bikes. We now offer Tannus Armour for 20″, 26″, and 27.5″ wheels.


5. And now for something completely different…

What if price were no object, and you could just optimize for the ride on your own wheel? This is the idea behind the Energy Return Wheel.

According to company literature, not only does this completely flat-proof option perform as well as a standard mountain bike wheel, but it outperforms a standard wheel, particularly on uphills. Available for the low, low price of just $2,699 from EnergyReturnWheel.com.

FLATBIKE ASSESSMENT: Hmmm. That’s…different. Can we still afford the rest of the bike? And do we have to clean the insides of the tires after a ride?

Overall, that’s five different ways to solve the flat-tire problem. Which one works best for you?

See you on the trails!

Bob Forgrave's Signature

full-size folding MTB

Bob Forgrave is president of Flatbike, an
ecommerce company offering full-size folding bikes
and kits to make any bike take up half the space.




  1. That’s a freaking joke, right?!! You meant $26.99 a wheel…

    1. Bob Forgrave says:

      It sure seemed like that to us! I imagine there are lots of R&D dollars to pay off, but that’s more than most folks spend on a whole bike, so what would you put it on?

      And this is a MTB wheel, so you’re going to be spending a lot of time hosing mud out of the inside crevices of your “tire”.

    2. jesse says:

      yes I live in southern California do you know of any bike shops that sells tanus tires and install especially in Riverside and orange counties or even orange county sanbernadino county

      1. Bob Forgrave says:

        Jesse, we don’t know about installation elsewhere in the country, but in the Pacific NW, we are selling inserts and evaluating selling the solid tires. Most any local shop should be able to handle installation.

        In our experience, installation is roughly equivalent to changing three tires. But then you’re done with the whole problem of punctures.

  2. Donny says:

    No mention of tire liners? Who’s paid you off? -Donny in Goat Head Central

    1. Bob Forgrave says:

      Hi, Donny. Goat Head thorns are the worst…except maybe Devil’s Club!

      You are absolutely right about tire liners being a useful addition to this listing. We’d never heard of them until after the article; now it seems this product category is worth a blog of its own. Do you have experience with them there in Goat Head Central?


      1. Jonathan Wykoff says:

        I’ve run tire liners since the late ’80’s. While they’re not completely flat proof, they do reduce the number of flats significantly… and I’ve had my tires looking like a studded ice tire after running through a patch of goatheads. I’ve also had the tire liners cause a flat. Bought cheap ones years ago. After about a year in the tire, the liner cracked and gnawed a hole in the tube. They are a great option for the budget rider, and very simple to install. Definitely a must for kids bikes!

        1. Bob Forgrave says:

          This is great to know, Jonathan, and something to consider adding to our upcoming bikes. Do you have a favorite manufacturer of tire liner?


        2. Bob Forgrave says:

          Jonathan, we’re ramping up now to have Tannus tire liners in stock by mid-November, for installation on all CHANGE 612 and CHANGE 812 folding mountain bikes. No answer yet for the rugged hybrids, but we’re working on it!

  3. Jessica says:

    Love the new look on the blog! Great post, really informative.

    1. Bob Forgrave says:

      Thanks, Jessica! We’ve been looking forward to this improvement for a long time. And…interesting side-note on this topic…we’re moving closer to a bike introduction this fall with Tannus airless tires standard. Just need to get some testing miles in first!

      1. Zach says:

        That would be awesome! I’d love to avoid pinch-flats with a ride like that on a potholed, curb-filled DFW commute. Thanks for this post–it’s the clearest and most informative I’ve run across so far!

        1. Bob Forgrave says:

          Zach, this high-quality, low-maintenance, completely flat-proof bike is now a real thing. Tannus airless tires, shock seatpost, 1 x 11 Shimano gearing…the works. I’ve been riding it this Winter in Seattle, in rain and over speed bumps, and it’s done well. Here’s a write-up on it.

          We’re now looking for early adopters who might want to try a bike like this in other cities. Interested?

          1. Dan Ruzicka says:

            Goat head thorns in my area. La Quinta/Palm Springs CA.

            Yes, how do I?

          2. Bob Forgrave says:

            Dan, we’re amazed at how many parts of the country have goathead thorns. For tires 2″ and over, we recommend Tannus Armour inserts. We’re restocking now on these and will soon have them for fat tire bikes with tires over 3″ wide.

            Under 2″, we’re looking at several options. Armour may work at 1.5″; we’re testing it out. And with road tires, Tannus offers airless tires in different PSI equivalents. We’re experimenting with the 28mm 110psi combination shortly. What are your needs?

  4. Antonio Evans says:

    I need a tubeless tire for my 26 inch rear tire.

    1. Bob Forgrave says:

      JensenUSA is having a sale on 26-in tubeless tires (https://www.jensonusa.com/bike-tp/26-inch-tubeless-tire). There’s no difference between a front & rear tire. But you’ll need a tubeless-specific rim to accept a tubeless tire.

    2. Carlos Alejandro says:

      While it looks somewhat stylish, I would tend to say it would take time for the buyer consumer to get used to the look and appearance. With that being said, I would tend to believe it would cause wind drag while riding your bike!

      1. Bob Forgrave says:

        Change does take time…if at all. Regarding wind, maybe the reason they introduced this for MTB instead of road bikes is precisely because of the increased wind resistance!


    I live in goathead country. With an innertube liner and some liquid puncture sealant I have zero problems.

    1. Bob Forgrave says:

      That’s quite an accomplishment; goathead thorns are legendary! For now, we’re focused on a highly-rated liner (Tannus Armour), but if flats are still an issue in goathead country, we may recommend puncture sealant as well. Thanks for the feedback, Scott!

      1. Chuck says:

        Bob, you mentioned Tannus Armour will have fat tire (20″ x 4″ is my tires) options in the near future. Later this year or next year? I live in Austin, TX, and will try regular liners with sealant but will keep an eye out for your products if I still run into issues. Thanks, Chuck

        1. Bob Forgrave says:

          Hi, Chuck. I just checked, and Tannus offers Armour for 11 widths of 20″ tires, but not 4″. Currently they go up only to 2.5″, so a long way from fat bikes. In fact, they have only one size Armour for fat bikes, and that’s 26″ x 4-4.8″wheels (what we carry).

          I’m a bit concerned about the regular liner + sealant combo approach. The whole premise of sealant is that it moves freely to the hole. If you’ve got a standard liner in the way, or a liner + inner tube inside the liner both in the way, then sealant effectiveness is reduced. So I’d go with EITHER the tube + standard liner approach or the sealant–not both.

  6. Paul says:

    I would used the Bell solid rubber inner tube but it’s size only fits 1.75 to 1.95 and I ride a motorize bike 25 to 35 MPH I like 2.25 width need all the rubber I can pay down on the road I ride rural areas that are miles from any resources and sometimes taking 200 + mile trips.
    The solid rubber tires I know are pass down from generations from Grandpa to son to Grandson to great grandson now that is a dependable tire 70+ years instead of the demonstration stick a thumb tack in one sticks several pocket knives no flat. About changing the tire at bike shop there damn stupid you don’t cut the solid inner tube you cut the warn tire down the center comes right off no problem.
    Anyone got a link to solid rubber tires with a size 26″ X 2.25″ I would be happy to have.

    1. Bob Forgrave says:

      Having personally ridden one of those old-style tires for 2000 miles, I know how rugged they can be. I also know how firm they were; I remember feeling pothole collisions in my neck!

      Modern materials have increased not only the distance possible (4,000+ miles) but also, thankfully, the ride comfort. Tannus has a variety of solid road tires, but as you note, nothing more than about 1.4″ wide. The reason is one you’re not as susceptible to on a motorized bike–weight. Even the lightest polymer weighs more than air. At some tire size, it’s too much of a difference.

      The compromise is the Tannus Armour inserts, which are in 26″ x 2-2.5″. The combine a wrap-around protective liner with an innertube that can have whatever psi in them. Some downhill MTB riders take them down to 15psi. Road riders probably more. The point is, pumping up your tubes becomes a “sometimes” thing rather than a routine thing. And if you still get a flat, you can ride it that way to safety with no harm to the rim. We’ve got stock on Tannus Armor–including this size–as of yesterday.

  7. steeba says:

    …would be nice to see some 20 x4″ tires (solid ?) and others coming out soon.

    1. Bob Forgrave says:

      Yes, but honestly, I don’t see it happening soon. For narrow tires, a solid tire can weigh less than tube + tire. For mid-range tires (up to 2.5″), an insert can allow you to run a thinner tire with no performance loss–same weight. But at 4″, any solid tire or insert is going to weigh more.

      It’s possible that a Tannus Armor insert for a smaller tire on a larger diameter wheel could be cut and placed inside a 20×4″ tire, but I have no idea about the effectiveness of that. Definitely off the beaten path.

  8. Cold Rider says:

    I made over 3K Km using a liner. NO FLAT , and often found glass shard ,cable staple and even once a metal screw . IDK about other solution but IMHO a good quality liner that is the widest you can get is worth every cent . before your buy one look the reviews about it and Ride Safe for ….. until you need to change your tires ,Cheers

    1. Bob Forgrave says:

      I agree. Pound-for pound, there’s nothing better than a good liner. That’s why we offer the Tannus Armour inserts for MTB use, on our folding MTBs or for anyone to buy from Flatbike. See https://flatbike.com/product/armour-tire-inserts/

  9. Brody White says:

    I have a mongoose BMAX. It has 20″x 4 1/4″ size tires on front and back. Absolutely love the bike, it’s my daily driver. But I go through inner tubes, at least one every two months. I even think I have a motocross bike inner tubes in it now. Thinking well they’ve got to be a little tougher, than a bicycle brand. And just cause I had them and they actually kinda fit. But i guess what its coming up on spring and my back tire is flat. Its hard enough just trying to find a place that either has them or that can order them. And I most always ride on the road. Maybe some grass. But bumps, pot holes, ledges, and curbs. Are the only “hazards” I really put it through. Only thing I can think of would be replacing the rim liner. Maybe and a second layer. And I like that idea of a tube liner, but I doubt I can find one for that wide of a size tire. Any thoughts or ideas?

    1. Bob Forgrave says:

      Great question, Brody. First, yes, 4+” wide tires get us into “fat tire” territory, beyond where Armour inserts apply (up to 3″). So let’s work the problem another way.

      You’re getting chronic flats on a bike that you love, and that’s hugely frustrating. Something–probably the same something–is causing all the flats. Before we get into some common causes, do one thing. Pump up one of your leaking tubes and hold it under water in a sink or bathtub, turning it until you see the stream of bubbles.

      Now one of these below will apply:
      1) Leaking from the inside of the tube. Spoke heads or a sharp tube liner. This is when you create your own flats from something sharp on your rim. Tube liners are super-cheap and worth replacing. If you can’t find one your size, wrap electrical tape around the rim enough times to cover all the spoke heads with double thickness.
      2) Leaking from the outside of the tube. A persistent object. With tire off, put your thumbs together inside your tire and run them all the way around the inside until you come to the thorn/tack/glass that keeps giving you flats. Remove it.
      3) Leaking from the side of the tube. A pinch flat, between underinflated tube and rim. Keep your tires pumped.
      4) Leaking from the valve. Loose valve stem. Tighten it.
      5) Leaking everywhere. Old tube that no longer holds air. Replace it.

      That’s all I’ve got. Let us know what works, OK?

      1. Ed Carmen says:

        I ride with 700×23 cheap tires with the wire bead cut off inside of my 700×25 tires on my road bike. Very few flats, slightly harder to change but worth the extra time between flats. Not concerned about extra weight on leisure century rides.

        1. Bob Forgrave says:

          Brilliant, Ed. It’s hard to imagine a tire liner that’s tougher than a 3-ply tire itself. And old 23mm tires are easy to get for free. Thanks for sharing here!


          1. Erik says:

            Umm.. where can I find them (for free…)?

          2. Bob Forgrave says:

            Your local bike shop may be tossing out completely worn tires for cutting up & inserting. Not exactly a high-tech, high-speed solution, but it’s at least free…

        2. JC says:

          Love this.

        3. Chuck Keranen says:

          I read as many of these comments as I could….
          I have been running WTB 26x 2.25 TRAIL BOSS tires OVER the original bald cruiser bike tires 2.125 with no issues. If the pressure is below 20psi you can tell… otherwise I’m good !

          1. Bob Forgrave says:

            Thanks for sharing! You’re in good company. Tires-over-tires are getting a lot of votes as the absolute cheapest solution. So…here’s a low pressure limitation, beyond which this approach feels wonky. Is there also a speed limitation, as the wheels spin faster and amplify any wobble? I think I remember someone mentioning that…

        4. Anthony says:

          What’s the best tool to cut the wire beads from around both sides of old tires? Jig saw maybe…?

          1. Bob Forgrave says:

            Ah . . . this is for putting an old tire (or part of one) inside another tire for added flat protection. Cutting through the wire bead is easy–any wire cutters. The next part is what’s tricky: (1) cutting the rest of the tire down evenly, so that you have the same amount of material on both sides, with no wobble, and (2) cutting smoothly, so you don’t leave any points or burrs that can create your own internal flat risk. A jigsaw should help with fast, even cuts, but I’m not sure about whether the resulting cut surface would be abrasion-free…

    2. Danny says:

      Hey, I have a fat tire bike 20″x 4″. Had trouble with thorns and other items. I got tired of it so I took my old outside tire, cut off the sides, fit in my new tire then I put a Tuffy liner, then tube. Vuala! NO MORE PUNCTURES!

      1. Bob Forgrave says:

        A liner and another tire inside your tire is an aggressive way to go. But it gets the job done!

  10. Johnny blade says:

    So here in Southern California the homeless who live at a river full of goatheads do this: take a treadbare worn down tire, use a knife to remove any remaining side tread ( rendering the tire essentially smooth) and cut away the metal bead on both sides, then use the old tire as a tire liner…you can purposely smash beer bottles on asphalt and the tubes are unbothered….side note, if you wear spandex to minimize drag from wind… But say you ride for exercise…you probably just like wearing spandex…if you want exercise wear jeans and a heavy backpack on gravel riding an $80 Walmart bike….for years.

    1. Bob Forgrave says:

      Brilliant re-use of a spent tire. This is definitely the ultimate low-cost solution! As for performance at speed–not a homeless concern–I’m tempted to try this sometime to test the effect of tire deflection.

      The old tire and new tire likely have the same circumference, yet one is going inside the other. For an example of what happens when two adjoining surfaces have a size mismatch, consider your fingers after a long time in the water. The skin’s outer layer expands, yet is fixed in place, so it buckles into a prune shape. Here, the inner layer is too big for its location, so it buckles into the inner tube. Maybe not an issue, maybe it is. But I’m interested to see if anyone doing this experiences an uneven tire with a shimmy at speed.

      Where this solution is GREAT is on a long, slow bikepacking trip where you’re unprepared for the local thorns. Stop in at any bike ship, ask for used throwaway tires in your size (when you buy a new set of tubes), install them this way, and you’re back to traveling with far fewer cares.

      1. Ray says:

        I did not experience any issue from using an old road tire as a liner inside my mtb tires. I ride 26×2.125 dirt trail tires, however I had already considered that issue prior to using the idea so I cut about 3/8″ from the liner tire and used rubber cement to glue the liner tire to the inside of my tire. There was a small (1/4″+/-) so I had to cut a small sliver off the piece I had originally cut out and glue it into the gap. I made sure there were no edges anywhere that could cause a self inflicted puncture and I also cut an old inner tube in half sideways, cut some pieces from the inner part with the valve stem on it and threw that part away. Now I have the outer half (tread up and sides) between my lined tire and my new inner tube. I also have cut pieces of old inner tubes and Christy’s 10mil house wrap tape for rim liners. I did the same thing with the inner tube that I did with the tire liner tire, cut a little out so there wouldn’t be excess from the reduction in diameter compensation for length.
        Before this elaborate system though, I was just taking tan painter’s masking tape 2″ and putting 6 layers around the inside of the new tire making sure to get it nice and smooth to avoid any potential for tube abrasion. It worked pretty well I didn’t get any punctures and I’m in Colorado foothills territory (goathead and cactus plus broken glass and lots of nails/tacks/screws from construction workers not cleaning their trucks/trailers or securing their hardware loads) but I wanted to experiment with this new system I have now for a more “permanent” solution.

        1. Bob Forgrave says:

          Congrats, Ray! That sounds like a lot of work. But goathead thorns are the ultimate test. Did this increase the weight a lot? I know there’s a 27 x 2.1″ Tannus Armour that is a light, spongy form–thorns might get in, but they can’t penetrate all the way to the tube.

  11. mattack says:

    Now down to the low low price of $1749 for the energy return wheel! (just the current price shown on the site 6/12/20).

    Found this site googling “solid bike tire”. (Have yet another flat on my cheap bike I’m riding during the pandemic since I can’t go to the fitness center.)

    1. Bob Forgrave says:

      Oooh! Now this wheel is down to the cost of one of our folding mountain bikes. Now if it would just fall another grand…

      Thanks for your interest in solid bike tires. We’ve been selling Armour inserts, but are about to investigate solid tires too. Rolling resistance is easy to measure—distance rolled vs. pneumatic tire down the same hill—but we haven’t yet figured out how to quantify vibration and ride comfort in an equally low-tech way. We’re open to ideas!

  12. Megan Alder says:

    I love that you wrote this article about bicycles and how to get the best accessories and needed things to avoid a flat tire. My husband has a bike which wheel is broken and he has to fix it so we want to look for an expert. I will start looking for a bicycle repair to make sure it’s taken care of, and we’ll make sure we follow your advice in the future.

    1. Bob Forgrave says:

      Glad to help, Megan.

  13. Andrew Arroyo says:

    Great article, thanks!

    I wonder if we could slit the inside center of a flat tube and sheath it over a new one as a inexpensive tire liner, and also ward , off shifting rim strip causing flats, that we could dub inbread or inside job flats!

    1. Bob Forgrave says:

      Good thinking, Andrew. But even then, you’d have a thickness of just two tubes, easily overcome by goathead thorns. Some folks have had success with the similar method of inserting an entire tire this way, after trimming off the wire beads. The ultimate cheap solution for casual, thorn-proof, low-speed riding…

  14. Terry Peterson says:

    All this sounds good BUT, is there a tire made that is much thicker for the novice rider?

    1. Bob Forgrave says:

      Based on the “novice” concern, I’m assuming this question is actually about tire width, not tire thickness. A common width for all-terrain bikes (good for roads and trails) is 40mm, or 1.5 inches. It’s the width we have on our full-size folding rugged hybrid, which is popular among folks returning to cycling after years away.

      A wider tire won’t be any less susceptible to thorns and glass flats, but it’s more forgiving of non-regular tire pumping. If it’s low, it’s just a little slower, usually not at risk of a pinch flat.

  15. Terry Peterson says:

    Terry again, I would like to know of a thicker tire to stop thorns from penetrating the tire and entering the tube. Thanks

    1. Bob Forgrave says:

      Ah. You did mean thicker, Terry. Actually, the value isn’t in how thick (and heavy) the rubber is, but in a layered approach. Continental Gatorskin, which we put on our road bikes for flat protection, has a layer of Kevlar. That should handle nearly all thorns.

  16. lu says:

    26 * 4 tires and nothing works. Have tired MR TUFFY even two at a time and the goat heads just laugh. I have to repair the tube at least twice a week riding 5-10 miles a day for required health rideing

    1. Bob Forgrave says:

      Goathead thorns go through anything. So thickness is key. These thorns go into Armour inserts also…but don’t come out the other side, keeping your tube safe.

  17. Gerrit Kellerman says:

    I did road cycling many years ago, and we took a bicycle spoke, flattened the ends and bent the spoke in almost a U shape to the profile of the tyre. Both ends were then held in place by the brake shoes on the caliper.
    You would bend the spoke so that it just cleared the tyre and sat about 0.5mm above it.
    In theory most thorns don’t puncture the tyre the first time you roll over it, but as you continue to ride the continuous rolling eventually makes the thorn penetrate the tyre.
    The spoke pulled it out before it could go around for a second time. You would still be riding and just hear a ping sound as it hits the spoke.

    As added protection on my training bike which had 700c x 28mm tyres on, we used to take old 700c x 18mm tyres and cut the steel beading off. Then we inserted these into the bigger tyres (with great difficulty) to give another layer of protection. And for a training bike the heavier wheels was good additional exercise.

    1. Bob Forgrave says:

      This is a brilliant insight about a “thorn scraper”, Gerrit. Thanks for sharing! I’ve never heard of this, but we did have a customer who put 27.5″ wheels on a frame designed for 26″ wheels, with only about 1mm of clearance, which seemed awfully tight. He mentioned the pings. Now I see the benefit!

      And your comment about inserting de-beaded tires inside other tires is interesting as others have mentioned it. This is apparently a more widespread phenomenon than I’d realized. Great to have the additional details for others about how it’s done!

      1. Gerrit Kellerman says:

        Hi Bob,
        I don’t know if you can see me email adres from the comments section. If you can send me a a mail. I found some old photos showing what we did that I can send to you

  18. Harry says:

    On a Fat Tire Facebook page someone suggested Green Slime. Any comments?

    1. Bob Forgrave says:

      Slime is a commonly used option. The problems are also common. With a fat tire, you need more slime than usual sloshing around in your tire, so there’s a weight issue. And because you’re tubeless, you’ll need a certain amount of tire pressure so your tire doesn’t separate and “burp” slime out. FInally, if all goes well, you’ll still need to pull your tire yearly to clean out all the dried slime.

      So… yes, it’s common, but at Flatbike we don’t recommend it.

    2. Danny says:

      It’s good with Tortilla chips, that’s about all

  19. Thomas Holden says:

    I was getting a flat on my car fixed and I noticed a pile of old truck/construction machine inner tubes behind the shop. Asked the guy how much for one and he said just take it, they’re trash to him. I cut it into strips 1.5″ to use as a liner between the tube and tire on a 26″ MTB. The rubber is 1/8″ thick and I used two layers, putting a dab of super glue every six inches or so to hold it in place until I got the tube inflated. Haven’t had a flat on that bike in over a thousand miles.

    1. Bob Forgrave says:

      An interesting approach! A truck inner tube is likely to be thicker than a car inner tube, while having none of the unevenness of an internally-mounted tire strip. Good find!

  20. Mark Lerch says:

    Cacti have spines. Not thorns.

    1. Bob Forgrave says:

      Thanks. I didn’t know the difference–and neither did my bike tire–so I just looked this up. Botanically, thorns are modified branches. Spines (like on a cactus) are modified leaves. Good to know!

      In related breaking news, you can also spine-proof your bike…

  21. Fred says:

    Your comment about Kevlar: If it can stop bullets, it can stop thorns. is incorrect. Kevlar is a fabric, thorns can separate the fibers and penetrate, this is why an arrow can kill someone wearing a Kevlar vest unless it’s stab rated, and kevlar in tires are not stab rated.

    Notice in this article that a sewing machine needle can penetrate the fibers easily, thus it stands to reason that they used that a thorn can penetrate Kevlar.

    Having lived in the Mojave Desert of California where goat heads roam freely, I can tell you I got at between 1 to 2 flats a ride on average, and I used Kevlar belted tires, I also tried Slime Sealant and that was a joke for high pressure road tires, once you inflate to about 70 psi the slime would just blow out of the tire and the tire was flat again. Even tried Slime in a thorn resistant tube to no avail. Goat heads even penetrated Mr. Tuffy liners! while the liners did reduce the flat frequency to about 2 a week it didn’t stop them. Only when I switched to Specialized Armadillo All Condition tires did I no longer get flats, in fact I didn’t get a flat for about 15,000 miles, and when I did finally get a flat it was due to a Specialized Armadillo tire being worn down to where the cords were showing.

    Thank God I moved away from that area but I do miss riding up into the mountains.

    Once I got out of Goat Head country I started using Panaracer Flataway liner which is a Kevlar liner, I think those worked pretty good but the other day I got a tire wire that penetrated both a Specialized Roubaix Pro tire with a Endurant belt and a Blackbelt liner which both is nothing but Kevlar wound with nylon and the other belt is not described but as a tightly woven fabric.

    What I am wondering is if cloth rim tape or old handlebar tape could be used as a tire liner? Sticky tape like Duct tape is not strong enough to stop much but what about black Gorilla tape? Anyone tried any of that stuff? I have a couple of old handlebar tape, I may try that and see what happens, it is a bit thicker then a liner but it is softer so maybe there might be some comfort in the ride? I do have an idea, I could take a tack and try penetrating that stuff which I have all of it I mentioned, and see which is the toughest to penetrate, not sure how accurate that test would be vs stopping something from penetrating a tube once inside a tire.

    1. Bob Forgrave says:

      Good to know about Kevlar. Maybe its bulletproof reputation is stronger than its protection?

      Also great feedback about slime not working above 70 psi, and the effectiveness of Specialized Armadillo All Condition tires.

      If you’re looking for a tire liner, here is the consolidated feedback front lots of Flatbike customers.
      * Adding an extra tire, with the bead cut off, inside your tire is completely thorn-proof, if a little wonky at high speeds.
      * Thin liners like Mr Tuffy help a little, but thorns still get through, so you still get flats.
      * Thick Tannus Armour inserts successfully stop punctures from becoming flats, even for goathead thorns.

  22. Jim Brown says:

    Haven’t had flat after cutting the bead off 700x23c tire and installing it inside my 700x28c tire. I’m not racing with it just tired of flats during the rainy season here in Philippines. One week I had 4 flats on rear tire all nails and sharp metal. My fix above is in week 4 now.

    1. daniel58 says:

      I love the creative rational idea of using an internal tire tread, which is about 85% of the tire tread width; with both the tire wire bead and non tread tire sidewalls completely cut away.

      Now that definitely helps to cut down on the internal tire tread weight to a much more practical critical lower tire tread weight amount.

      Now one can also utilize some walmart athleticworks exercise foam mat material which is made out of NBR foam(nitro butadiene rubber) or also called neoprene closed cell rubber foam;

      now it comes in 24 inch width by 72 inch length dimensions that one can easily and readily cut to suit one’s application and the thickness of the neoprene foam is 10mm or nearly half an inch in thickness;

      now one can simply layer a section of this NBR neoprene foam between the tire casing and the internal tire tread to further help to isolate one’s internal tire’s tube; so that any potential puncturing agent such as even a goat head thorn would have to go through the 10mm(about 3/8 inch) of NBR neoprene foam as well as the section of internal tire tread also as well;

      now one can also additionally incorporate and utilize a 120 mesh 304 stainless steel mesh which has a hole size aperture of 0.125mm between hole diameters;

      which would provide a very tough armor like additional layer of goathead thorn tire puncture protection also as well, that would act like a nearly impenetrable stainless steel mesh tire armor shielding belt;

      now this stainless steel mesh belt would be placed directly under the tire casing to help potentially directly deflect any potential goathead thorns so that they would be forced to be deflected in a parallel sideways non-vertical orientation tire non-penetrating parallel direction to the stainless steel mesh tire armor shielding belt;

      now even if portion of the sharp goat head thorn actually makes it partially through the stainless steel mesh tire armor shielding belt;

      it would still have to make its way through the 3/8 inch NBR neoprene foam layer and then also the internal tire tread section also as well;

      now the chances of the goat head thorn actually making it through the stainless steel mesh tire armor shielding belt layer, and then also the 3/8 inch NBR neoprene foam layer belt and then also the internal tire tread section belt; would be almost impossible to penetrate all three of these total combined designated goat head thorn resistant tire puncture tire layers;

      now the big additional bonus here is that the two additional tire puncture layers of the stainless steel mesh layer and the neoprene foam layer would also not add much more additional weight to the tire puncture triple protection layering system but would in fact add a much more comprehensive and significant amount of goat head thorn tire puncture protection liner.

      1. Bob Forgrave says:

        Thanks for a really thoughtful analysis, Daniel. I think you have a future in tire design!

        It seems like this could be a great low-cost solution, given enough time investment.

        In the meantime, at Flatbike we’ll keep focusing on Tannus Armour liners as the antiflat solution with the lowest overall time investment.

  23. Bruno John says:

    Steps to fix a flat bike tire without tools: a useful guide you should know: The first step to fixing a tool-free bicycle tire is to separate the tire from the bicycle wheel. When you repair a flat bike tire, it is crucial to remove the tire bead by crouching down and placing the wheel in front of your knees. You have to pull the tire together with the tube towards the direction of your body. Apply pressure to your thumbs that are placed on the rim, so you can easily pull the tire from it. Then, inflate it by opening the Presta valve and blowing air into the tube until you are confident there’s enough air inside. Ensure that the tube is in the right shape so you can put it back into the tire easily.

    1. Bob Forgrave says:

      Useful info. Sometimes, though, the tire is tight enough, or the the fingers not strong enough, that tire levers are necessary. At times I’ve used up to 3 of them on a particularly tight tire!

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