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Flat Prevention
About the Goathead (Tribulus terrestris)
Let us start by discussing the goathead plant or puncture vine, bane of the cyclists existence. This small ground hugging annual plant produces a little seed with a protruding spike that one could imagine was created to puncture bicycle tires. Their affect on cyclists is seasonal. They are worst in the late summer and fall, when the plants have recently dropped their seeds. In the spring many of the seeds decay and the robustness of the spines is diminished. They also tend to be worse if we receive more than average summer rains. Areas that receive little motor vehicle traffic tend have fewer goatheads, as they are propagated more by motor vehicles than bicycles or shoes. They also are more common at lower altitudes. On rain soaked days (rare in NM) their spines become soggy and they cease to be a problem.

I have observed that the goathead plants often have an ant bed at their base, always the tiny 3mm long ants. Perhaps the goathead protects the ants, and the ants loosen the soil for the plant. They have pretty little yellow blossoms in the spring and early summer. The plants are not native to the New World, and are thus relegated to developed and urban areas,where they have been spread by vehicles.

In addition New Mexico has a bit of a DWI problem, and drivers, especially those already inebriated, occasionally toss their glass beverage bottles out the window. This gets ground into little glass bits on the side of the road.    

What to do?

Tubeless tires:
Most MTBs and now some roadies use tubless tires. They seal the goathead punctures pretty well. The latex, in our warm dry climate, tends to dry out in the tire after a while, and then it will no longer seal the punctures. Larger punctures and sidewall tears will put you out of business though. Seating the tires requires an air compressor and at times some persistence.       

Slime or similar sealant with clinchers:
This works pretty well, but it works better if you have fitted or even slightly oversized tubes. I use a 30mm tube in with a 26mm tire for training. If the tube is stretched, it is harder for the sealant to work. This is a cheaper option that getting a tubless setup.
You can inject sealant into most non-removable presta valve tubes by unscrewing the little cap nut with a pair of pliers, and pushing the valve core though inside of the tube. An old spoke works well for this. The valve core will then be loose in the inside of the tube. Ideally you can catch the valve core and pinch it between your fingers while you squeeze the sealant in. If you need an extra hand you can usa a clothespin to hold the core. If you lose the core entirely, you can feel around inside the tube and find it eventually, but it is kind of a pain. To reassemble, you push the core back into the inside of the presta valve, then hold the tube about 6 inches back from the valve and swing it it down to smack onto a workbench. This will usually force the core out enough that you can start the cap nut back onto the core.
I think Slime or other similar non letex sealants work better on clinchers. Straight latex or Stans does not work well with inner tubes, as it tends to squeeze out between the tire and tube without sealing. I have tried some mixes of Slime and Stans. It seems to work better, but maybe it is just my imagination. I had a friend who swore by a Slime/Stans mixture in his tubeless tires. If you have more experience with this, let me know.

Tubeless Tubulars:
The Czech manufacturer Tufo makes tubless tubulars. Continental and Dugast make some too. They function as well as tubless tires as far as sealing goathead holes goes. I think that the latex stays liquid longer in a tubular than in a tubeless tire. You swap the hassle of seating tubless tires for the hassle of gluing tubulars. I used to train a lot on 21mm Tufo S33 pros. They are about $40, and they now make them in a 24mm width instead only 21mm like the old ones. Tufo also makes good cyclocross tubulars. Some tread and sidewall punctures are irreparable as you cant really take the tire apart to fix it. The tread compounds (particularly the non black compounds) tend to dry and
harden after a few years in out desert climate, sometimes developing little cracks. For dry cross courses this does not seem to matter much.  

Regular Tubulars with sealant:

This works so-so. It depends on the tubular. Sometimes a hole just won't seal. There seems to be some problem with Stans degrading latex inner tubes, maybe Slime degrades them as well. I have had pretty good luck with Vittoria cross tubulars and low end Continental and Clement road Tubulars. I have a Dugast cross tubular that I can't get to seal. I have also had trouble getting FMB MTB tubulars to seal. I did get them to work for a while.
Sometimes CX race tubulars will need quite a bit of sealant to resist courses with goatheads. It is just tragic to add the weight to a nice tubular, but it is better than getting a flat. I would not dump a full load of Stans in my road race tubulars, but small hole in a race tubular can often be fixed with a little bit of latex.          

"The System":
You can make your tires more or less flat proof with a little work and an extra set of old tires. They will also be pretty heavy and ride a bit rough. Back in the day in NM pretty much all the serious racers had a pair of system wheels to train on. You could be ridiculed for having a flat riding lighter non system wheels when everyone else was riding on heavy system wheels, and they had to stop while you changed your tire. Basically you use an old tire as a liner for a new one. I had a friend who used to use a 22mm tubular tire stuck inside of a 25mm clincher for more or less the same effect. If you would like to try the system, Steve Matthias has prepared the following step by step directions:

Items you will need.
1. Box cutter or sharp knife
2. Scissors (preferably a large, heavy pair)
3. Baby powder
4. A new set of tires
5. An old set of worn out tires (liner tires)

Note:It generally works best to use liner tires that are a size or two smaller than the tires they will go inside. So for example, if your new tires are 25c then try to use 23c or smaller tires as liners. I have used the same size tires before, but it is harder to fit it all together.

Step 1. Remove the beads from a pair of old worn out tires.
Use your box cutter to make a starter cut - large enough to get your scissors through - in the sidewall of the liner tire. Depending on the model of the tire, half way down the sidewall, or ~3mm from the edge of the tread is a good place to cut.
 
Next, use your scissors to cut all the way around the liner tire to remove the bead.  


Repeat the steps above to remove the bead from the other side of the liner tire. 



Check that there are no barbs or rough edges on your liners. If there are, try to remove them and ensure that the edges of your liners are as smooth as possible.

As should be obvious, repeat all the above steps so that you have two liners.

Step 2. Assembly

While not essential, coating your tubes, liners and the insides of your tires with baby powder will make getting all this rubber stuffed together a lot easier. I also think that it improves the ride quality once you are out on the road.
First coat the inside of the tires with baby powder.

Then, insert the liners inside the tires.     


You can either try to coat the liners with baby powder before you put them in the tires, and/or coat the insides of the liners after they are inserted.


Finally, insert your tubes inside the tire/liner combinations and mount them on your wheels.      

That's it! Put your wheels on your bike and go for a flat-free ride.

Be safe.

Addendum:
A few days after setting up this set of system wheels, I was on a ride and hit a large bent rusty nail that went in the tire and out the sidewall. The tube was NOT punctured! Unfortunately, there were some rather nasty gouges in my brake caliper.


All photos Jennifer Buntz

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