Tubeless tires are much, much better than the alternative, but that’s not to say they’re perfect. Sometimes, just getting a tubeless tire to hold air can be a challenge, and diagnosing the problem — let alone fixing it — can be frustrating. If you find yourself staring at a flat tire in the garage and muttering “why” over and over again, here are some tips for getting rolling again.
This article won’t cover mounting tubeless tires; we’ll assume the tire has been mounted successfully, but that it won’t hold air for more than a day or so.
No, we’re not celebrating yet, but this will get us closer to our goal by allowing us to zero in on the part that’s leaking.
Fill a spray bottle with water and some dish soap, or really any soap that forms bubbles. Next, inflate the tire to 30psi or so. Spray or just pour the soapy water all around the tire and rim, one section at a time. Note any places where air bubbles appear.
If there is a puncture in the tire itself that is leaking, this is generally an easy fix. Make sure you have plenty of sealant in the tire and move it around until the sealant pools at the puncture. Larger punctures may benefit from a tire plug.
With a sidewall leak, you’re usually better off replacing the tire. It might be possible to patch it, or if you’re really lucky, plug it, but in my experience sidewall repairs rarely last very long.
While rare, some tires have been known to absorb or even weep sealant. Tiny pores in the tire compound fill with sealant when it’s initially added, so you may need to add a bit more liquid to replace what’s been lost. If a tire still leaks through the tread or sidewall in multiple locations despite having good sealant coverage and no punctures, you may want to check with your local bike shop or tire manufacturer to see if the tire should be replaced.
Check to make sure the rim wall isn’t dented.
If it is, your tire won’t be able to seal. If you find your rim is slightly bent or dented, it might be possible to get things straightened out enough to hold air. According to Gerow, “a couple of small planks of wood, a vice, and a hammer will get you started.”
Even if the rim wall isn’t visibly dented or misshapen, there could be a small gap between the tire bead and the rim that’s leaking air. Make sure you have plenty of sealant in the tire, and hold it horizontally and tilted to allow the liquid to pool around the part of the rim where you saw the bubbles forming. Shake the wheel gently for a minute or so to let the sealant do its work.
In some cases, the tire-rim connection may not be tight due to buildup of old sealant. “Older tires can have a buildup of dry and hardened sealant at their bead that will create space between the rim and the rubber, causing air leaks,” says Gerow. “When mounting a tire that has already been mounted previously, be sure to remove as much dried sealant from the bead as possible.
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Sometimes a tire bead may not be fully seated in the rim. Try pumping the tire up to maximum pressure. The loud popping sound you’ll hear is the bead popping into place. If you didn’t hear that noise the first time you mounted the tire, chances are that is the issue.
After running through the checks above, try soaping the tire again and checking the same spot to see if the fix was a success.
In my experience a leaky valve is often the cause of air pressure losses over time. If the soapy water reveals bubbles at the valve, it’s time to investigate further.
Tubeless valve parts with a valve core remover tool (red, right).First, check the easy stuff: Is the core screwed in tightly? Is the inlet screw loose or bent? A dedicated valve core tool is helpful for proper tightening, and if your fingers aren’t getting the inlet plunger tight enough, needle nose pliers can do the job. Just make sure you don’t over tighten and break the valve, or get it so tight you can’t add air later.
If any part of the valve is bent or broken, don’t try to fix it; it’s time to replace it.
If soapy bubbles are forming around the base of the valve, it may not be attached to the rim properly. Most valves have a nut at the base that tightens the valve to the rim. Get this as tight as possible with your fingers, and if necessary give it a slight turn with a wrench. Just be sure to avoid tightening too much because you could damage your rim, especially if it’s carbon fiber, and you may need to be able to remove the nut on the trail in the case of a puncture.
Check the gasket at the base of the valve to ensure that it’s properly seated, and that it sits flush in the rim channel. Add a bit of plumber’s/PTFE tape to seal things if the gasket is particularly troublesome.Next, investigate the valve from the other end, which means taking the tire off the rim. Most valves have a soft rubber gasket that forms a seal around the valve hole in the rim, so check to make sure the valve is seated properly in the rim channel.
You can also add a bit of teflon tape around the base of the valve to seal things up.
Sometimes sealant can fill in small gaps around the valve. If you notice air leaking while on the trail, try rotating and shaking the tire so the liquid sealant can get to the valve.
If bubbles form around the spoke nipples, the good news is you’ve found your leak! The bad news is, there isn’t a quick fix. This generally means the rim needs to be re-taped, or at the very least the tape needs to be patched over. If the tape appears wrinkled, ripped, or punctured that’s probably what’s causing the leak. Tire levers can often puncture the tape while installing the bead, causing the tape to leak air through the rim.
There are many tutorials online for taping a tubeless rim, but in general, the idea is to get the rim as clean and as dry as possible before taping all the way around in one go. Be mindful of any gaps where air might be able to leak, keeping the tape flat and taut to avoid blisters or pockets.
Sometimes, tires can be sneaky leakers. Pump them up and they’ll stay rock solid in the garage for weeks, but as soon as you roll in the parking lot, or take a turn, they go soft. You soap ’em up, and there’s not a bubble in sight. In fact, this has happened to me a couple times in just the past few months.
This is usually due to a small cut that only opens up when there’s weight on the tire, or if the tire is pumped up to a higher pressure. In your garage, you can try to simulate the effect of riding by adding pressure above what you normally ride, or by deforming the tire with your hands and looking for air bubbles as the tire squirms.
Gerow notes, “Some tires need to be ridden immediately after setup in order to hold air properly. A new tire that won’t hold air in the garage might be good to go after a short romp on the trail.”
Once you find the sneaky leak, getting sealant to the right spot can do the trick, though a plug may work even better.
Ultimately, tubeless mountain bike tire systems are pretty straightforward and there are only so many spots where air can escape. Imagine that you’re the air inside the tire, and you’re looking for a way out. How would you do it? That’s exactly the mindset you need to solve this mystery.
Tubeless tires for MTB, cyclocross, gravel, and road bikes can leak for several reasons. While this is frustrating, the good news is that leaks are typically relatively simple and inexpensive to fix, and it won't take long to get back on the road or trail.
Let's take a look at some of the common causes of tubeless tire leaks and how to fix them:
Tubeless tire sealant is made with a liquid carrier. Over time, the liquid can dry up due to evaporation.
This is especially common in the American Southwest, where dry weather with low humidity is common. When you remove the tire, you might find the sealant is gone entirely, or has congealed into lumps some riders call "Stan's Boogers", named after the popular Stan's NoTubes sealant brand.
If your previously reliable tubeless tire used to hold air but doesn't any longer, it's possible the sealant is completely dried up. Another giveaway of dried-up sealant is a tire that "self-repaired" punctures from thorns initially, but later stopped. If a thorn punctured your tire, and the sealant failed to fix it, adding fresh sealant will usually resolve the issue.
There are two techniques to add new sealant. You can:
1. Break a section of the tire bead with your fingers or a tire lever, pulling back just enough bead to make it possible to pour in new sealant from a cup or funnel. When complete, put the tire bead back on and inflate. With a little luck, it will inflate with nothing more than a floor pump.
If a bigger section of tire bead was unseated, you might need to use an air compressor.
There's also a way to add sealant without breaking the bead. This method keeps the bead/rim interface intact, and increases the chance of re-inflating using a floor pump:
2. Use a sealant injector to push sealant through the presta valve. To use this technique, first remove the presta valve core with a valve core remover tool. Then use a sealant injector (it works like a syringe with a plunger) to draw up fresh sealant from the container and inject it through the valve. When complete, re-install the presta valve core and re-inflate your tire.
For the tire/rim interface to be airtight, the bead of the tire must be flush and fit snugly up against the matching hook bead pocket in the rim. Sometimes when you are attempting to mount a new tire on a used rim, the hook bead on the rim can have dried sealant, mud, or grit stuck on.
To fix this, remove the tire entirely, and drag a shop rag around the entire diameter of the hook bead, repeating this process on both sides of the rim. It should slide smoothly around without resistance. If you feel any bumps, investigate and make sure to remove them.
This issue can also affect used tires, which can have old, dried-up sealant stuck on the tire beads. As above, make sure to remove any old sealant so that the bead lies flat against the rim and then try remounting it.
Most bicycle rims have a hole drilled in the rim that allows the spoke nipple to be installed from the tire side. These holes allows air to escape and need to be completely covered for tubeless use.
New rims often come with tubeless tape already installed over the spoke holes for convenience, but it can shift under use. For example, if you had to use a tire lever to remove a tire, the tire lever can push the rim tape off-center, exposing the spoke holes.
Once the spoke holes are exposed, the system is no longer airtight and will leak.
Sometimes you can push it back into position to cover the spoke hole, but if the tape has split (usually due to age) or the adhesive no longer holds to the rim, it's time to replace the tape. Pull the old tape off completely and thoroughly clean the rim before installing new tape.
As with the spoke holes, the rim is also drilled to allow the tubeless valve to pass through. There is a rubber grommet or fitting on either side of the rim to create an airtight seal. Check the locknut on the valve to ensure it's snug (but don't over-tighten) and well-sealed.
If you suspect air is escaping from the valve hole, try letting all the air out of the tire, press down on the tire just above the valve, firmly push the valve toward the hub, then tighten the locknut to hold that adjustment.
Using the wrong valve can also create a poor fit with the rim.
There are a few common rim shapes in use and the valve needs to match. For example, the tubeless valves that come with some Shimano wheels have a unique shape that doesn't interchange with others.
To avoid this issue, use the valves that were originally included with your rim/wheel, or the specific valve recommended by the rim manufacturer.
If the previous 4 causes have been ruled out, look to the tire itself. Check the sidewall and tread for cuts. Tires damaged in this way can sometimes hold air in a workstand, but will leak once ridden because the rider's weight causes the tire casing to flex, widening the cut.
Small cuts can sometimes be booted from the inside if the rest of the tire looks OK and has tread life left. If not, it's probably time to replace the tire.
Back to blog Another season of changing shoes is approaching.
And you may remember that on one of the tires after the last winter/summer there is a jamb - a small bump. I don’t want to run to the store for the sake of one new tire. We understand. Or maybe it looks even better if repaired?
Yes, not every wheel that has met with a nail, rebar sticking out of the ground or a sharp stone on the road is considered damaged. Everything, of course, depends on the scale of the damage and its location on the tire itself. Some are easily repaired, while others are simply impossible to do - the tire can only be sent to the trash.
A bulge on a wheel, referred to by drivers as a bump or bulge, is the most common tire sidewall defect. It appears due to a collision with an obstacle or after falling into a pit, more often at high speed. The threads of the sidewall carcass are easily damaged by impact, and the tire at this point can no longer hold the load and air pressure - swelling appears. A small bump sooner or later turns into a big one, and driving with such a defect is dangerous - the wheel can shoot at any moment.
At high speed, this is fraught with loss of control, departure from the road and a rollover.
The quality of roads in Kazakhstan contributes to the appearance of bulges on tires
Some types of bulges are repairable, although this is a temporary measure. Not a single patch can restore the factory rigidity. Ideally, change the tire.
Special cord patches can extend the life of a tire with a herniation, even if the swelling has appeared on the tread. The sidewall is a different story. If the swelling appeared at a distance of more than 40 mm from the side, it can be repaired. If not, then the wheel needs to be replaced. Blisters on low profile tires are most often non-repairable.
For maximum safety when riding with a repaired bump, insert the tube. This is an inexpensive and reliable solution. On our market, you can find cameras made in China and Russia, the latter are slightly more expensive, but also of better quality.
The elimination of a side cut is a serious operation, therefore, as in the case of a bump, you will have to go to the professionals.
We need cord patches, fortunately in our time they are of different sizes and with a different number of layers. And if you do it wisely, then you can't do without special tools and vulcanization.
A cut, by the way, cannot be healed in all cases. If the gap is in the shoulder area of the tire, it is unlikely that anyone will undertake to repair it, since no guarantees can be given here. However, our Kulibins take on even the most difficult cases, cutting out parts of the sidewalls from the tires and even weaving the cord on their own.
Tire overhaul. We would not put such a wheel on ourselves
Low profile tires can be repaired, but more difficult. A tear in the sidewall is easier to seal on tires with a medium or high profile.
Sometimes a cut is confused with a pluck. This is when the outer layer of the sidewall caught on something sharp, a tear formed, but the frame itself remained intact. There is nothing wrong with that, although the drivers at the tire fitting company successfully repair the cut, for which they take it accordingly.
If a piece of rubber remains on the sidewall, then glue it with ordinary superglue (101st). If it came off, then it is better to cover it with raw rubber and vulcanize. Leaving the pluck bare is not recommended, because the tire carcass, often consisting of a metal cord, will quickly corrode.
In Europe, defective or used tires are perforated before being sent for scrap to prevent their resale and possible operation. But they don’t know that we have such holes on the sidewall patched once or twice
Cuts and hernias are not the only possible damage to the side of the tire. You can also spoil the side ring, in the process of changing shoes, for example. If it’s for garlic, then such a tire is already dangerous. Sooner or later, the tire pressure and the load in motion will start to squeeze the rubber off the rim - a wheel explosion can occur.
This ailment is repaired if the wire ring - the base - is intact.
There are no special technologies and materials to correct this particular problem, but most often craftsmen use a two-component composition for chemical (also called cold) vulcanization. After mixing, the mass is pressed into a fat-free damage. Compound manufacturers recommend waiting 72 hours before mounting a tire. Of course, our masters do not pay attention to this condition - they put the tire right away. And it’s good if the wheel is flat because of this at night in the parking lot, and not on the road.
If the side ring tears are barely noticeable, but the wheel still deflates, then you can use a special liquid - a bead seal designed to seal a tubeless tire.
These seals have been used in motorsport for some time. In particular, in the American Formula D Drift Series, drivers used compounds to keep the tire on the rim even with minimal tire pressure. Now they are banned.
Pay attention to the left rear wheel of the Nissan Silvia S13. Due to too low pressure, it was literally taken off the disk under load
Every schoolchild has faced this problem when patching the inner tube of his bike after hitting something sharp.
Repairing a car tire puncture with your own hands will also not be difficult even on the road. But for this you will need a pump (or compressor) and a universal tire repair kit with harnesses. All this is sold at any car market or gas station.
Repairing a tire on the side of the road with harnesses
The process is simple. If we are talking about the front wheels, then in most cases the wheel can not even be removed, it is enough to turn the steering wheel in the right direction, find the puncture site and carry out repairs. First, the hole is cleaned with a helical awl from the set. The tourniquet itself is smeared with glue and tucked into the eye of the awl, after which it is inserted into the tire hole. With a sharp movement, the tool is removed, and the tourniquet remains in place and clogs the hole. The tails are cut with a knife, but not at the root, it is recommended to leave about 20 mm. The tire is inflated and checked.
Sometimes a nail or self-tapping screw clogs the hole by itself, remaining in it.
If you see a hat in a tread, do not rush to pull it out. While the pressure is holding, move to vulcanize. And sometimes they drive with a screw in a tire for weeks.
Repair of a puncture at a tire shop
Punctures are also repaired with harnesses at a specialized service, although among professionals such repairs are not considered long-term. After a few months, the flagella dry out and can let air through. There are more advanced methods like cold and hot vulcanization. The latter is more reliable. In this case, the hole is sealed with an elastic patch, and the funnel from a foreign object is filled with a special compound. After that, a vulcanizer is put on the tire, it heats up the rubber and solders it.
In addition to the plaster, the puncture is also repaired with special cord fungi. Craftsmen process the puncture site: drill it and treat the surface with a tool to roughen it. Then the repair area is lubricated with glue (it is also called cement) and a fungus is introduced.
This is done from the inside of the tire. The cap of the fungus is rolled, and the excess legs are simply cut off from the outside.
Puncture repair with sealant
With the advent of tubeless wheels, and later run flat tires, many automakers began to abandon spare wheels. Instead, repair kits with compressors are supplied with the machines. A repair kit is essentially a bottle of pressurized sealant. Later, such spray cans began to appear on the shelves of ordinary car dealerships.
This method has not taken root in the CIS, because the condition of the roads makes it necessary to have at least a stowaway in the kit, but it can also be considered as a method of repair on the road.
The car must be jacked up and sealant must be pumped into the damaged wheel through the nipple. Next, you should spin the wheel, then pump it up, lower the car and drive a few hundred meters.
If the tire tightness has not been restored, repeat the procedure.
For commercial vehicles, cutting the tread with a special device (regrower) is a common thing. Moreover, such tire retreading is provided by the factory (marked REGROOVABLE on the sidewall) to increase the service life. But there are entrepreneurs who undertake to deepen the grooves in tires for passenger cars. But they are not intended for such an operation. Often used tires for sale are “refreshed” in this way. Be careful!
What is the threat?
The worst option is that the retreaded tire will shoot out on the road, as the master can damage the undertread layer when deepening the grooves. Such a tire will not be able to hold pressure at some point. There will be a boom! At best, the tire will indeed last a little longer, but is the game worth the candle? We think it's not worth it.
How is cutting done?
A regrower is used to cut the tread.
Roughly speaking, this is a large soldering iron with interchangeable tips of various shapes. It goes through rubber like a knife through butter.
If the tire is for passenger cars, then it is worth taking on a regrower only in one case - when part of the tread pattern was welded with "new" rubber during repair. This is where threading comes in handy in order to restore the grooves and symmetry of the tread.
Vehicle operation is prohibited if:
- tires have a residual tread height of less than 1.6 mm;
- tires have punctures, cuts, ruptures that expose the cord, as well as delamination of the carcass, delamination of the tread and sidewall;
- tires in size or load capacity do not match the car model;
- tires of various sizes, designs (radial, diagonal, chamber, tubeless), models, with different tread patterns, winter and summer, studded and non-studded, new and restored, are installed on one axle of the car;
- Tires retreaded according to the second repair class are installed on the front axle.
What is a second class repair?
This is the case when the carcass of the tire is restored after serious damage. A side cut (or tear) is a serious damage to the tire carcass.
A tube tire for a passenger car consists of a tire and a tube with a valve fitted with a cap or key cap.
The chamber is an annular closed rubber tube with a rubber-metal valve. It is made of elastic rubber and serves only to hold compressed air.
Chambers operate under severe conditions, experiencing alternating deformations at high temperatures. Therefore, rubber for cameras should be airtight, elastic, resistant to thermal aging, not change their physical and mechanical properties at different ambient temperatures.
The size of the chamber must strictly correspond to the size of the tire with which it is completed.
If we're talking about passenger car tires, tube tires are now a thing of the past. Foreign manufacturers have abandoned tubes, and now only tubeless tires are on the market. Cameras can be seen on domestic tire models, but not on all. Everything goes to the fact that cameras will soon become history.
A tubeless tire differs from a conventional one - it has a sealing layer 1.5...2.0 mm thick, which is vulcanized to its inner surface. It is made from a mixture of natural and synthetic rubbers with reduced gas permeability.
The tire beads are provided with a sealing rubber layer, which provides the necessary tightness in the area of the beads landing on the wheel rim shelves. This is facilitated by the special design of the tire beads, designed to increase the angle of inclination of the toe of the bead and the increased tightness of the beads on the landing shelves of the rim.
For tubeless tyres, plug-in rubber-metal valves (fig.
Advantages of tubeless tires:
The main advantages of tubeless tires compared to tube tires are:
Attention:
At the same time, the use of tubeless tires requires careful mounting and dismantling. Damage to the bead flanges, especially steel ones, can lead to depressurization of a tubeless tire. If a tire is damaged, it must be repaired by specialists using equipment designed for this purpose.
In case of loss of pressure, do not drive with a flat tire. this will destroy the hermetic layer.
The tube is not inserted into the tubeless tyre. At first glance, you increase the strength of the tire, in fact, an air cushion is formed between the chamber and the pressure layer, contributing to the destruction of the latter. If the load on the wheel is increased (for example: a sharp turn), the wheel may break.
There are complaints about tubeless tires due to weak sidewalls. I would like to say that this is not so. There are no perfect tires. The manufacturer seeks from the tire not only durability, but also comfort when driving. It is the softness of the sidewall that gives a feeling of smoothness in movement. Having made a rigid sidewall, we will be able to jump on curbs and sewer wells on our car; when driving on a flat and good road, we will feel uncomfortable.
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