Glueless tire patches are adhesive-based and are therefore not as effective as the standard ones which operate on the principle of rubber vulcanization.
Adhesives vs. Rubber Vulcanization
Adhesives/glues create bonding via mechanical and inter-molecular forces.
a. Mechanical Bonding
The surface of an object has a large number of irregularities and looks like “Swiss cheese” upon zooming.
The glue/adhesive penetrates the “cracks” and solidifies after drying. The result is a multitude of anchor points that connect the adhesive to the upper layer of the glued item. This mechanism reveals why glue sticks so well to the skin.
To increase the mechanical bond between two objects, glue manufacturers advise users to sand/roughen the surfaces before pressing the parts together to increase the number of cracks that glue can penetrate.
b. Chemical Bonding
Besides the mechanical bond, there’s also a chemical one based on covalent and Van der waals forces.
Covalent forces occur when two atoms share electrons.
Van der Waals forces (VWF) are distance-dependent intermolecular forces. Unlike covalent forces, they aren’t the result of electron sharing.
The engine behind VWF is the fluctuating polarization of particles.
Here’s how that works: Even when a molecule has a balanced charge (one side is positive, the other negative), the polarization still fluctuates ever so slightly.
When a particle is really close to another with the opposite charge, they attract each other.
Since the polarization shifts are small, VWF manifest only when the units are in great proximity to one another.
The rubber vulcanization that takes place when applying a standard inner tube patch provides a far stronger bond than “cold” adhesive solutions.
Standard patch kits come with a small tube of liquid which people often refer to simply as glue and rubber cement. However, the proper designation of the tube’s content is self-vulcanizing fluid – a form of rubber cement with an altered formula and qualities.
Here’s what happens when patching a tire via the classic method:
1. The punctured spot is covered with rubber cement/vulcanization fluid made of elastic polymers and volatile solvent keeping the mixture liquid.
2. Once applied, the rubber cement is left to dry for 5-10 minutes. During that time, the solvent penetrates the upper layer of the inner tube.
Consequently, the side of the rubber cement in contact with the tube reaches even deeper and bonds chemically to the inner tube.
After the solvent’s evaporation, the bond is solidified.
3. The exposed/upper side of the rubber cement/vulcanization fluid has free sulfur groups ready to connect to others.
4. The orange side of a standard patch undergoes special treatment and has free sulfurs ready to attach to others too.
When the patch is pressed against the puncture spot, the two pieces unite via disulfide bonds and form one single unit. The connection has great strength because it happens at a cellular level.
Regular adhesives cannot match the bond produced by vulcanization because they don’t alter the structures of both pieces to the same degree.
A vulcanized patch applied properly is strong enough to be considered part of the inner tube and can last a long time.
What Are The Advantages of Glueless Patches?
Glueless patches have two main advantages – they are faster and easier to use.
A glueless patch eliminates the need to apply rubber cement and wait for it to dry. All you have to do is sand the spot and put on the patch.
In consequence, a glueless patch theoretically saves about 5-10 minutes when fixing a puncture.
Another advantage of glueless patches is that they don’t require you to carry rubber cement and have a smaller profile.
Thus, if you want to reduce the volume of your spare kit, glueless patches will help you achieve that goal as they take very little space.
Glueless patches are also а good back-up if you were to run out of rubber cement due to a leak in the cement’s tube for example. For that reason, some people carry glueless patches in addition to their regular repair kit.
What Are The Downsides of Glueless Patches?
The downsides of glueless patches are:
Glueless patches tend to be more expensive than standard patches.
As already explained, glueless patches do not provide the strength of vulcanized patches.
3. Questionable reliability
Glueless patches often get mixed reviews. Some people say that they work just as well as the standard ones while others consider them a temporary solution at best.
(Personally, I’ve used a glueless patch only once about six months ago and it’s holding just fine.)
The likelihood of a glueless patch failure increases when the tires are inflated to high air pressure.
This dependence provides a hypothetical explanation as to why people are leaving chaotic feedback – glueless patches may be offering satisfactory performance when applied on low air pressure MTB tires while remaining inadequate for road tires which have to be inflated to a much greater PSI.
Tip: If you’ve just applied a glueless patch and count on it to return home, inflate the tire to its lowest air pressure rating to reduce the strain on the patch.
4. Questionable Time Savings
A glueless patch is definitely quicker, but if you fill the waiting period when using a standard patch with useful actions, the downtime will be minimal.
After applying rubber cement to the “injured spot”, I usually check the outer tire for external objects stuck in it and then reassemble my repair kit (multi-tool, spare tube, zip-ties…etc.) while leaving out only the patch that has to be applied and a tire lever.
Once the cement is dry, I apply the patch and mount the tire. This type of time management minimizes the losses and further negates the advantage that glueless tire patches offer.
Another way to eliminate the waiting time would be to simply replace the tube with a spare one and fix the puncture back at home. This method is even faster because you don’t have to search for the leak.
Of course, you will still have to go through the entire procedure back at home, but at least, you will be doing it in a less stressful environment.
5. Loss of Bonding Strength Over Time
With time adhesive loses its strength. If the patch has been sitting in your pocket for years, the chances of it failing are greater.
Standard patches, on the other hand, do not have that problem. As long as the patch is covered by foil, and the rubber cement tube is intact, the combo should work.
6. Lower Tolerance to Inflation and Deflation of the Tire
Some glueless patches work just fine at first but fail around the edges when the tire is deflated. This happens due to the weaker bond and the patch’s inability to keep up with the “shape-shifting” of the inner tube.
Frequently Asked Questions
If glueless tire patches use adhesive, why are they called “glueless”?
The term glueless indicates that the patch doesn’t require rubber cement/vulcanizing fluid.
The term is inaccurate because:
1) Glueless patches use glue.
2) Standard patches don’t use glue but vulcanization fluid.
Despite the inaccuracy, the term has been accepted.
Are there repair kits based on vulcanization that do no require waiting?
The company Rema Tip Top offers tire patches with SVS Vulcanizing fluid which does not necessitate waiting. You can put the patch directly on the punctured spot after applying the cement.
Is it Necessary To Carry a Secondary Spare Tube?
It’s good to have two spare inner tubes when going on a long trip, but for regular commuting, one tube in combination with tire patches is enough.
Why is My Bike Tube Patch Not Sticking?
There are four main reasons why a patch isn’t sticking;
The area of the tube that’s been repaired and the patch have to be clean. Impurities have a negative effect on bonding strength.
b. Insufficient coverage
The size of the applied rubber cement should be equal to or slightly bigger than the patch’s dimensions. If the coverage isn’t sufficient, the edges of the patch may peel off.
After applying the rubber cement, it’s necessary to wait 5-10 minutes before putting on the patch. If you don’t, the bond will be weak.
d. An “Unpatchable” Location
Not every puncture can be patched. If the hole is near the valve, it’s very difficult to make a patch stick. In that case, it’s necessary to replace the tube.
Can I Use Super-Glue To Fix a Puncture?
For better or worse, super glue isn’t a good solution to flats because it’s inflexible and brittle upon hardening. I have a dedicated post on the topic. You can read it here.
1. Glueless patches have their benefits (speed + small form factor), but they don’t provide the bonding strength of a standard patch using vulcanizing fluid.
2. Glueless patches are a temporary solution in most cases.
3. Glueless patches are more likely to be successful when applied on a tire with low air pressure.
4. Glueless patches are a bit expansive, but their size and simplicity make them a good back-up solution for times when there’s no rubber cement.