Flat Tires

6 Jan

I’ll bet everyone has had a flat or two. I would hazard a guess that I or we have had a hundred or so flats over the years. When we started MtBiking in the early 1990’s we would have a group of say five riders and have one or two flats each ride. So out of ten tires over a two hour ride we would have to fix at least one flat and often two or more. Some times of year are worse than others. Out of all the flats I don’t remember ever fixing one caused by a nail. I have fixed a few from glass. By far they come from two sources.
I think it was an early visitor to Texas that said “I can tell when I’m in Texas, everything has thorns on it.” That may not be an exact quote but it serves it’s propose. Here in south Texas we are on the edge of desert but have enough rain to make the desert plants do well and enough drought to keep the nicer plants away. Everybody knows about cactus. The prickly pear earns its name. Yep they got a bunch thorns on them. Then comes the Mesquite tree, the thorns can be two inches long and hard enough to go thru a truck tire. Then next are the grass burrs. There are several types of these but most of them can cause a flat tire. The Yucca and the century plant have a large thorn on the end of each leaf.
Between the thorns are the rocks. If we grow anything better than thorns it is rocks. Our riding area is part of the area called the Balcones escarpment. Partly due to the Balcones fault, it describes the southern edge of the Texas hill country. When you combine hilly country with a regular rain drought cycle you get lots of erosion that leads to a lot of exposed rock. Not the smooth sheds of sand stone. You get the loose jagged limestone. This makes the perfect formula for snake bite flats. For the new rider out there it has nothing to do with Rattle snakes. Yes we have those also. It gets its name from the two little cuts your rim puts in your tube when you run over the hard corner of a rock. We would go to extremes to try to prevent snake bite flats. We would try different tires, going to maximum air pressure of 65 psi. Really high air pressure helped with the snake bites but made the handling almost non-existent. The tires would bounce and chatter instead of biting for traction. Forget about a tire that hard molding to a slick rock section. The ride was abusive to say the least. We tried heavy duty tubes and even talcum powder. It’s an old school car race trick. You put a fine dusting of talcum powder on the tubes so they can move slightly in the tire. Racers would do it to help keep tire temperatures down. Well it never seemed to help prevent snake bite flats. We were desperate!
In our efforts to stop the flats we tried all sorts of things. We tried tire liners, they help but I had a set eat thru the tubes after they had been in for a time. We tried self-sealing tubes with some success, but they don’t stop snake bite. We tried slime and it worked well on the thorns but not for snake bites. It is hard to find presta valve stem tubes with removable cores to be able to use the slime. As the years went past we heard more and more about going tubeless. Using latex sealant and how it would almost end flats. Our group of riders has begun to convert to tubeless. Since I went tubeless on my MtBikes I have not had a flat. Not one! I was riding with Jonathan the other day. When we stopped for a breather he saw a large Mesquite thorn sticking out of his tire. He flicked it with his finger nail and it popped out. He said not to worry and spun the tire a few times so the latex would get to the hole. It sealed it just like it is made to.
The moral of the story is if you get a lot of flats go tubeless. We run a mix of tubeless, tubeless ready and tube type tires as tubeless setups. I must say, what we do or don’t do is not advice or recommendation. This blog is for entertainment only. The information contained is not to be considered accurate. Your safety is your responsibility. I or we make no claims to suitability and take no liability. Now with the legal stuff out of the way. Some of the wheels we use are tubeless, tubeless ready and tube type. We are shade tree mechanics; we are mostly on tight budgets, so we find ways to make things work. When I went tubeless I found traction that I had been missing so long I didn’t know it existed. Tires running 35 to 40 psi (remember I weigh 230 lbs.) have such different handling than tires running 60 or 65 psi. It was like riding a completely different bike. The tire can work and mold like the engineer designed it to.
The added benefit is that the tubeless setup is lighter. It is lighter where you need it most, in un-sprung and rotating weight. Have you ever noticed how even economy cars often have alloy wheels? It is because they weigh less. Yes they save gas by reducing weight, but more importantly is it is rotating weight. Rotating weight requires horsepower to turn it. If we think of the human as the motor we are very small engine. We must work as efficiently as possible. By going tubeless we reduce the total weight a little. On a MtBike and rider that total weight may be 260 lbs. as in my case. So going tubeless may save say 1 ½ lbs. That would be about ½ of one percent. We also reduce the rotational weight by a much greater percentage. Using our example that same 1 ½ lbs. saved is then a portion of the weight of the wheel and tire combo. Given a combined tire and wheel weight of 8 lbs. that would mean our 1 ½ lbs. saving becomes an 18% reduction in rotational weight. True the amount of energy (horsepower) to rotate the tire may not drop by 18% any savings is an advantage. To tell you how much energy you would save will require someone more educated than a shade tree bicycle mechanic.
You say this guy has no idea what he is talking about. Remember my two favorite bicycle mechanics. They dreamed and figured out how to do what the great scientist before them had not done. Who were these bicycle mechanics? Orville and Wilber Wright are the fathers of modern aviation. By the way the Wright Brothers bicycle on display at the National Air and Space Museum looks very much like a modern fixi.

To quote Christopher Cross “Ride like the wind”

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