Late summer 2009. I'm getting "puncture vine" (or Goathead) flats at an alarming rate. Over the past month, I'm averaging about one flat every 13 miles.

Here is what the plant looks like, and some additional images of the thorns in automobile tires, and how they appear when still green on the plant. Another page on them here.

Here's what the thorn looks like after puncturing through my Ultra Gatorskins.

And how the little hole is patched. The first thing I do is mark cross-hairs with a Sharpie so I don't lose the hole once I sand and glue it.

After a light sanding you can still make out the cross hairs. And in this close-up you can even see the hole still. Very hard to see that hole in real life!

You want about the thinnest layer of clue that you can get while still having full coverage. Less is more. Thick is bad. the glue tries to "melt" the two bits of rubber together (volcanizing). If the glue is too thick, the rubber bits never actually combine. A hint here - if you can't find the hole after the glue goes on (in order to center the patch) just pumpt the tube enough for the air to come out the hole. There will be a white dot in the glue where the air escaped.)

Press the patch firmly all around - especially the edges. Leave the clear plastic backing on, and only handle the patch by that backing when removing the sheet from the "sticky" side. Stuff the tube back in the tire and inflate. Do not inflate the tube outside the tire to "test" it. It will fail.

• You realize you have a flat.
• Get off the bike and figure out what went through the tire, and where. Look at the tread AND on the sidewalls.
• If you are close to home and the object will stay in your tire, leave it there and ride home before going to the next step!
• Mark where the puncture is on the tire and the rim (I now carry a mini Sharpie for this).
• Remove the offending thorn/glass or whatever. Pinch the tire to spread the hole and check to see if you got everything.
• Pull off one bead of the tire. Most tires can be removed/replaced by hand. More stubborn ones may need one tire iron.
• Pull out enough tube to expose the hole (this assumes you are confident that you got everything out of the tire. If not, take the whole tube out and the whole tire off. Check the INSIDE of the tire for anything that's still poking through. Be very careful not to tear up your hand looking for it!)
• Find your (usually impossibly) tiny hole in the tube. Match the tube up to the marks you made on the tire and rim until you find it. You may have to put a puff of air in the tube and listen for the hiss.
• Mark the hole in the tube with a big X with your Sharpie. No, bigger. As big as you can make it - like almost all the way around the tube.
• Sand the area lightly with the metal grater or tiny square of sand paper that came with your patch kit. Sad an area a bit bigger than your patch will be. This will expose fresh rubber that has no powder or release agent on it - and give some teeth to the glue.
• Plop some glue where you just sanded, and use a finger to quickly spread it in ever-widening circles until you have a thin, even patch of glue slightly bigger than the patch you'll be using.
• Let the glue dry. On hot days, we're talking about maybe 20 seconds. Cold, wet days will take longer. The glue will sort of haze over when dry, and not look so liquidy.
• Peel the foil backing off of the patch while touching only the clear plastic top cover with your fingers. Don't touch the patch where it came off the foil. Keeping your greasy fingerprints off the adhesive side of the patch is the first use of this plastic.
• Place the patch right in the center of the X that you marked on the tube originally (this should also be the middle of your sanded spot, and the middle of your glue spot!).
• Press the patch flat onto the tube by squeezing between your thumb and fingers. You can also put the tube on a hard surface and press with a pump handle or C02 cartridge. Especially press the edges down. Press some more.
• Leave the clear plastic on the top of the patch. Sure, it doesn't look pretty, but it allows the patch to better slide into the tire without hanging up on anything.
• Do not "test" the patch by partially inflating - it will likely fail!
• Stuff the tube back into the tire.
• Reseat the tire beads around the rim, and be SURE all the tube is inside the tire and rim, and that you do not pinch the tube at any point during this operation. I usually pump up to half way and check the bead to make sure none of the tube is trying to crawl out.
• Pump to full pressure (you did bring a real pump, right?) and try to catch up with the group. C02 makes this part faster, certainly. But if you're like me, after your third puncture of the day, you'll need a pump too!

09.05.2011 - Greg's first flat, and it's a record-holder.

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