Can a motorcycle gas tank explode the way they do in the movies? Or maybe it is all just special effects designed to create a stunning show?
Knowing how close riders sit to the gas tank, it is important to understand how likely it is for a gas tank to explode.
Can a motorcycle gas tank explode? Although extremely unlikely, a motorcycle gas tank can explode under the right conditions. Gas vapors are highly flammable but not explosive. For a motorcycle gas tank explosion to occur, there needs to be just the right mixture of gas vapors, oxygen which need to be ignited by an open flame or a spark.
In this article, I will dive a little more in-depth about how gas works and what this means for our motorcycle gas tanks. If you want to find out more, continue reading below. After reading this article, you will have a better understanding of what you can expect from your motorcycle gas tank.
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How likely is it for a gas tank to explode?
Technically speaking, a motorcycle gas tank can explode. However, you will find that this is very unlikely to happen because for that to happen, certain conditions need to be met. Gas tanks are designed to be as safe as possible if the pressure starts to build up due to internal gas vaporization.
There are a few common misconceptions about gasoline that should be cleared out as well.
Gas is viewed as something extremely flammable and dangerous. To a certain degree, it can be. However, gasoline itself does not burn—gasoline vapors do. Gas is also not explosive, but its vapors can be. So the problem is not gasoline per se but its vapors.
So in order for the motorcycle gas tank to explode, there needs to be enough gas vapor mixed with enough oxygen, which then needs to be ignited. As the gas vapors heat up, expand, and burn (and cause the gas to release even more gas vapors), this will cause a rapid expansion, which will cause the tank to explode.
This is exactly what the motorcycle’s engine does. It takes tiny bits of gas, vaporizes it, mixes it with oxygen, and ignites it, creating a small but powerful controlled explosion. But as mentioned, all that is a carefully controlled process. One of the problems is that you need just the right ratio of air to fuel vapors; otherwise, it is unlikely for the gas vapors to ignite.
There are a few realistic scenarios where a gas tank can explode:
- After a lot of pressure has been generated until the gas tank cracks.
- After heating the gas up until it self-combusts.
- Producing favorable conditions for the gas to ignite.
Can a motorcycle gas tank explode from too much pressure?
Gas will expand under heat, which can generate lots of pressure, especially to a full fuel tank.
But this is why motorcycles also have vent or pressure release tube where gas will leak if it starts to expand and there is not enough room in the tank.
If there is too much pressure and the pressure release tube cannot prevent it from building up, then it is very likely that the tank cap will just pop off immediately, releasing the pressure and preventing any major explosion.
Can a motorcycle gas tank explode from gas self-igniting?
The second way a gas tank can explode is by having the gas self-ignite. We all know that fuel can get very hot during a particularly sunny and hot day. However, gas is not that easy to self-ignite. So at what temperature does gas self-ignite?
The flashpoint of gasoline or the lowest temperature at which it can produce vapors capable of igniting when mixed with oxygen is -45 °F. However, the autoignition temperature of gasoline at which it can spontaneously ignite without a source of ignition is around 477 to 536 °F.
Although diesel is not a popularly used type of fuel on motorcycles, there are some that use it. Generally speaking, diesel is even safer than gasoline. Diesel’s flashpoint is 126 °F, and its autoignition point is around 410 °F
Since gas has a very low flash point, this means that your motorcycle will start even on very cold days. But the auto-ignition point is so high that it is almost impossible for it to self-ignites under normal conditions.
Can an open flame cause a motorcycle gas tank to explode?
Gasoline vapors are not that easy to ignite. One study aimed to test how likely it is to ignite gas vapors using a lit cigarette. After over 4,500 different tests, there were no instances of ignition.
The odds of a motorcycle gas tank exploding are higher if we somehow get a spark or an open flame in the tank, keep the tank fairly empty so that there can be more oxygen in it, and leave it open so that more air can get inside and keep the flame burning.
Nonetheless, this is also very unlikely to produce a huge explosion. It is more likely to be a big whoosh than a proper movie-style explosion.
On the other hand, if the motorcycle’s fuel tank were to break open and a spark is introduced simultaneously, igniting all the gas at the same time, this can result in a big fireball. But again, it will not be a huge devastating explosion, as seen in the movies.
A good example of this can be observed in the video below. Just take a look at this video of the opening lap of Moto 2 at Aragon.
You can see how the fuel tank got detached from the motorcycle’s body and was sent flying into the air, crashing onto the track. However, that did not make it explode. But when the other racer hit the tank with their motorcycle, they caused the tank to explode.
It is hard to say how exactly everything happened. However, a lot of fuel likely got spilled, or they simply cracked the fuel tank as they hit it with the motorcycle. Then the gas vapors got ignited by either a spark or the hot exhaust of the passing motorcycle.
Can a motorcycle gas tank explode from the heat?
Depending on where you live, the summer can be very unrelenting. Riding your motorcycle or leaving it outside under the sunlight can really heat it up.
Left outside in the direct sunlight, soda cans, bottles, lighters, hair sprays can actually heat up so much that they will eventually explode.
When subjected to heat, gasoline tends to expand, which will not cause your motorcycle gas tank to explode per se, but the internal pressure that can build up can eventually send the fuel cap flying and gas spilling out of the tank like a Gaiser.
Technically speaking, it is possible to heat up gasoline so much that it self-ignites. However, as we have seen, gasoline’s self-ignition point is between 477 to 536 °F. This makes it very unlikely under normal conditions for gasoline to reach the temperature at which it will auto-ignite.
Can too much fuel in the gas tank cause it to explode?
Filling up your motorcycle’s fuel tank can be associated with some negative side effects.
- First, there is the possibility of overfilling and spilling fuel all over your fuel tank. Overfilling the fuel tank too much can lead to gas spills that can be detrimental to your motorcycles paint job and could possibly be ignited under the right circumstances.
- Second, having too much fuel in the tank can build up too much pressure inside the tank. In particularly hot days and higher loads, the heat will cause the gas to expand, which can lead to a pressure buildup.
See article: Can you overfill a motorcycle gas tank?
Just because your gas tank has more fuel in, it does not mean it is more likely to explode. Even if there is a lot of pressure in the gas tank, it is very unlikely to explode. However, the pressure that builds up can be so much that it can force the fuel cap to pop off the gas tank and gas to spill out.
See article: How to clean gas off a motorcycle?
A gas tank that contains more fuel can actually be considered less likely to explode because there is not enough oxygen inside.
Experts theorize that leaving a fuel tank mostly empty can be more dangerous. As the gas vaporizes inside the tank, the gas vapors will mix with a higher amount of oxygen in the tank and create a potentially dangerous fuel-air mixture that can cause an explosion if ignited.
See article: How often do you have to fill up a motorcycle?
Can a motorcycle explode if you shoot the gas tank?
Since we are on the subject of fuel tanks exploding, some of you may wonder how likely it is for a motorcycle gas tank to explode if somebody shoots it.
Even when somebody shoots the gas tank, the same principles apply. You still need gas vapors and a source of ignition.
Shooting the tank will create small holes in it, causing gas to leak out of the tank. Gas will release gas vapors, which can be ignited by a spark or an open flame. Some bullets may be capable of creating a spark that can ignite the gas—especially trace bullets.
However, since the gas is leaking and the gas tank has been punctured. This may prevent the gas vapors from creating enough pressure for the tank actually to explode. The fuel to air mixture will not be favorable to produce ignition. Even if the gas somehow catches fire, the more likely result is just some intensely burning gas.