Gfrktyl

Is there any special technique for using self-adhesive puncture repair patches?

Today, I've had two different tubes fail within a minute of being inflated because the air pressure had split through the glue, effectively forming a little pipe from the puncture out to the edge of the patch. These were both patches that had been on the tube between one and three months, and I've had other patches fail the same way.

I figure I've not done anything catastrophically stupid, since the patches haven't been failing immediately. I've followed the instructions on the patches as closely as possible ("Lightly scuff tube with sandpaper. Peel backing from patch and press patch firmly onto tube. Tube must be clean and dry for patch to adhere." – that's it). They're decent quality patches (Park Tool GP-2).

I've never had any problems with old-school glue and patches. Is there something I'm missing or are pre-glued patches just useless pieces of excrement?

This kind of failure is basically the reason sticker-type patches have a reputation for not being reliable.

Scrupulously sanding the area and getting it as clean as possible (ie, with alcohol or other residue-free solvent, cleaner than anyone can probably get it on the side of the road) wards off the problem but doesn't eliminate it.

Sticker type patches are essentially bad products. You can't trust the tube long-term, so you really should change it back out when you get home, because if you don't you'll likely get another flat sooner or later when it fails.

Vulcanizing patches are superior. The system of carrying a spare tube and a vulcanizing patch kit, using the patch kit only if you get multiple flats in the same ride (should be a very rare occurrence), and patching your punctured tube when you get home so it can become your spare is popular and time-honored because it works and is cheap. You almost never actually wind up using the vulcanizing kit on the side of the road, and when you do it's no big deal because you've developed good technique. Vulcanizing patches make the tube as reliable as new, so it's fine to leave the tube in there and forget about it.

Self-adhesive patches play to peoples' desire for a simple one-step solution, contrasted to how vulcanizing patches do require a degree of technique and care - keeping track of where the puncture is, applying a nice even patch of glue that's the right size and waiting long enough for the it to dry, comprehending at all that you let the glue dry and then apply the patch, handling things carefully so as not to contaminate the patch contact surface or the tube with skin oils, etc. A lot of people running around now just can't and won't jump through those hoops, and in that sense there is a place for self-adhesive patches, but what's unequivocally true about them is they don't save time or hassle once the need to change the tube out again later is factored in.

I believe pre-glued patches were always intended to be a temporary fix to get you home. When they first came out on the market I remember explicit warnings that these were not a permanent fix.

Waiting for glue to set up on the side of the road is a pain, and these were intended to solve that issue by providing a quick fix to get you moving again. Afterwards you should replace the tube or properly repair the puncture.

Once applied these patches are easy to peel off again (a good indicator that they are not permanent fixes). A bit of sandpaper can remove any residual adhesive and as a bonus the surface has now been prepared for gluing with a proper vulcanizing glue and patch.

I have always viewed them as an option of last resort when you have run out of tubes and you need to quickly patch a tube so that you can keep going.

In practice I would never trust them to last more than a few days after application.

Since almost all of the other answers (except for Criggie's) seem to focus on telling you that self-adhesive patches are bad, I feel like I have to add an answer that actually focuses on the question (i.e. technique for applying these) ;-)

I have only carried self-adhesive patches for about half a year, but never had one fail on me (Lezyne branded, but I doubt that there are major quality differences). From my experience and what I read of reports from failing patches, two things seem most important:

1. Clean and roughen up the area around the puncture, e.g. with the scuffer that is included in most patch kits or a bit of sandpaper.


2. Firmly press on the patch for about half a minute, rubbing a bit from side to side in varying directions.

Especially the second part seems to be overlooked quite often; after that, I immediately re-install and inflate the tube.

Minor techniques that seem to help.

1. Use an abraider/scratcher around the damaged bit. I have a saw and a coarse file on my leatherman which work well enough. This gives the adhesive somewhere to key into rather than the shiny slickness of the Butyl tube.




2. Then have the tube inflated to about the size it will be inside the tyre, before sticking on the patch. Not swollen up and not loose and floppy.




3. As for all punctures - making the effort to find the cause is a very good idea. Try to not move the tyre relative to the valve-stem hole, and then once you find the hole compare the tube to the wheel to isolate a small area to find the cause of the damage.

My primary solution is better tyres. I average something like 5000 – 10 000 km per puncture, or 1 – 2 per year. That's with marathon supremes on the distance bike and marathon plus on the hybrid/commuter.

Then I carry a spare tube attached to each bike plus another in my tool kit. I've never needed two spares in a single ride; if I did I'd patch a dead tube using proper patches and vulcanising solution at the next warm dry stop, because I carry a tiny tube of glue and a good supply of patches.

Glueless patches (and I do carry a couple) are an absolute last resort for if I'm out of tubes in the rain - hunched over to keep the rain off, drying the tube on my jersey, and patching is easier with glueless. I tested this approach on a commute a few years ago and it got me home but leaked a little; my only failures with glued patches were caused by not being able to keep them dry.

Note that I haven't gone down the tubeless route - I know where I am with tubes and see no compelling reason to change something that works.