from Rookie’s keyboard,
Hello, friends
Today, I am going to talk about a topic concerning many rookies, namely glueless tire patches(or GTPs for short).
The strongest quality of GTPs is that they can be applied to the damaged spot right away – a very attractive property because it eliminates the need to mess with rubber cement (something rookies aren’t so good at).
But it comes at a price – GTPs are adhesive-based and therefore not as effective as the classic patches operating on the principle of rubber vulcanization.
Rubber Vulcanization > Adhesion
Adhesives or simply glues make the bonding of two elements possible via mechanical and intermolecular forces.
Here’s how that happens:
Surfaces have irregularities that look like “Swiss cheese” under a microscope.
The glue enters those “cracks” and becomes solid upon drying. The outcome is a great number of anchor points connecting the adhesive to the upper layer of the glued item(s).
This mechanism explains why glue adheres so effectively to the skin.
To enhance the adhesion between two objects, glue manufacturers recommend sanding or roughening the surfaces before joining the parts to increase the sections that the glue can penetrate.
Meanwhile, standard tire patches operate on the principle of chemical bonding.
Chemical bonding is based on covalent and Van der Waals forces (VWF). Covalent forces occur when two atoms share electrons.
VWF are distance-dependent intermolecular forces. Unlike covalent forces, they aren’t the result of electron sharing. VWFs are the result of the fluctuating polarization of particles.
Even when a molecule is balanced(one side is positive, the other negative), its polarization still fluctuates ever so slightly.
When a particle is very close to another with the opposite charge, they attract each other.
VWFs manifest only when the units are in great proximity to one another.
Rubber Vulcanization
The rubber vulcanization process that normally happens with standard patches results in a stronger bond.
Standard patch kits come with a liquid known as rubber cement. The longer and more accurate name of that substance is self-vulcanizing fluid – a form of rubber cement with an alternative formula.
Below you will find the sequence that takes place when patching a tire using the traditional method:
1. The punctured area is covered with rubber cement containing elastic polymers and a volatile solvent to keep the mixture in liquid form.
2. After application, the rubber cement needs 5-10 minutes to dry. During this time, the solvent will penetrate the upper layer of the inner tube.
The inner tube area and the rubber cement on it bond chemically. Once the solvent has evaporated, the bond is solidified.
3. The exposed/upper layer of the rubber cement contains 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 punctured spot, the two pieces unite via disulfide bonds and form one single unit. This connection is very strong because it occurs 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 properly applied vulcanized patch is strong enough to be considered part of the inner tube and can last a long time.
The Pros of GTPs
Glueless patches have two major advantages – they are quicker and easier to use.
A glueless patch doesn’t require rubber cement and there’s no need to wait. You just sand the spot and install the patch.
Theoretically, a GTP will save about 5-10 minutes and some energy when fixing a puncture.
Another super minor pro of GTPs is that they don’t require you to carry rubber cement, and the whole kit takes close to no space.
I always carry a few glueless patches as a form of backup if I run out of rubber cement.
The Negatives of GTPs
1. Price
Glueless patches are more expensive than standard patches, but let’s be realm fellas – some of you are spending more on coffee and cigarettes already.
2. Toughness
As I already explained in detail, GTPs are weaker as they are based on a mechanical bond.
3. Less Reliable at High PSI
The greater the PSI, the greater the stress on the patch.
For that reason, GTPs have a more satisfactory performance when applied on low-air pressure MTB/commuter tires.
However, if you have road or hybrid tires pumped to a rock level of firmness, the chances of the patch failing are higher.
For that reason, if you are using the patch to get back home after a nasty puncture in the middle of the night, pump the tire to the lowest air pressure setting and start pedaling.
4. The Time Savings Don’t Matter All That Much
A glueless patch is quicker, but does it matter?
If you use the downtime for useful actions, you lose nothing.
After applying rubber cement, I usually check the tire for external objects stuck in it. Then, I pack my repair kit. I only leave the patch that will be applied and one tire lever.
After the cement is dry, I put it on the cut and assemble the tire.
This strategic time management greatly negates the advantage that glueless tire patches offer.
And of course, you always have the option to put on a new inner tube and fix the injured one at home where you will be calmer and also safer.
5. The Bonding Strength Gets Progressively Weaker
Over time adhesives lose power. The longer the patch sits in your pocket, the more likely it is to fail when used.
Regular patches do not have an expiration date. If the patch is covered by foil, and the rubber cement tube is intact, it will work even if bought 5 years ago.
6. Frequent Inflation and Deflation Can Damage the Patch
Some GTPs are fine at first but fail around the edges when the tire is deflated. Why? Because the bond is weak, inflexible, and can’t keep up with the re-shaping of the tire.
Additional Info Nuggets
- The company Rema Tip Top offers tire patches with SVS Vulcanizing fluid, which eliminates the need to wait. You can place the patch directly on the punctured spot after applying the cement.
- Many people fail to use a standard patch properly. The main errors are applying cement to a smaller area than necessary and not waiting. (Many noobs don’t even know they have to wait.) If you don’t wait, the bond will be weak and the patch will open.
- Not every puncture can be repaired, especially if it’s near the valve. In such cases, the tube must be replaced.
There you have it, friends.
All you need to know about glueless tire patches.
My choice? I carry a few glueless tire patches with me just in case I run out of cement, but I always count on the real deal. I have some tubes with 3-4 standard patches running fine for years.
Until next time,
– Rookie
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