Bike tires are mostly known for simple flats. However, you may have heard (or experienced) horror stories of bicycle tires exploding, either in storage or while a cyclist is on the bike!
So, what’s behind this. And do bike tires actually explode?
Bicycle tires can explode whether they are being ridden, or sitting unused. The most common cause of exploding bike tires, is an overheated wheel rim caused by too much braking. Other causes of tire explosions could include excessive tire pressure, an improperly seated tire, a damaged tire, or extreme temperatures.
It’s an interesting subject, and something every cyclist should know about. Let’s move on and we’ll cover the following:
What Causes Bike Tires to Explode
It’s more common for a bike tire to simply leak air until it goes flat, rather than having a dramatic explosion. Generally speaking, normal flats are caused by a pinch or a puncture in the bike’s inner tube.
However, a tire explosion can occur in the situations highlighted below:
1. Over-Braking
Brake pads, instead of disc brakes, can cause the rims on your bike’s wheels to heat up. The friction produces heat each time you pull the brake. That’s not a problem normally. There’s plenty of time for the heat to dissipate.
This can become a problem on long downhill sections. If you’re running V-brakes and dragging on them, you can create enough heat that the entire rim begins to get hot. That includes the interior, where your inner tube sits.
Enough heat and the inner tube will fail, often in a dramatic fashion.
The best way to avoid having this happen is just to not use V-brakes on a bicycle intended for long downhills. If that’s not an option for you, just be very aware of how often and hard you’re braking to avoid overheating your rims.
A good way of avoiding over-braking is to alternate braking from one side to the other (i.e. pump the right brake, then left brake, etc.). If you use this approach, just make sure you don’t brake too hard on the front brake (which is usually the left-hand brake) when you’re not also braking with the rear brake. Think about it. This could send you over the handlebars.
2. Pinched Tube
More than one newbie has tried filling their first inner tube only for it to go off with a bang. The cause is a pinched tube.
When you’re putting a new tire or inner tube on a bike, you need to make sure that the tire is beaded properly. The entire tube should be covered by the edges of the tire before you begin working the pump.
Pinches can also occur while riding, sometimes causing massive failure instead of just a tear. Pinch flats most often occur when you hit a sharp edge that pushes the tube against the rim, hitting directly on a curb, large rock, or other obstacles.
Avoiding pinch flats is largely about being careful while riding, but it may also mean that you’re running your tires with too low of PSI.
3. Hole or Cut in Tire (Causing a Pinched Tube)
If your tire has run into an obstacle that’s slashed or punched through the exterior it can cause an explosion. Often these happen when someone installs new tubes without checking their tires beforehand.
The tire will inflate normally, and may not explode immediately. Instead, it will press hard into the rubber of the tire and push through the hole or cut until the inner tube pops.
Always look over your tires before installing new tubes. You can keep the same tires but prevent them from killing your tubes by patching the interior of the tire if you’re not ready to replace it.
4. Overinflation
Overinflation is another cause of bike tire explosions.
It’s pretty simple: too much air and the tube can’t contain the pressure. It’ll let off that excessive pressure with a bang, but it may not do it immediately.
Experimenting with pressures is something every cyclist has done at one point or another. Most road bike tires run at a very high PSI and the inaccuracy of many gauges can cause user errors.
The danger of over-inflation is typically lower with road bike tires, which is where many failures seem to occur. Wider tires will cause more dangerous explosions, so be careful when you’re filling up fat bike tires.
Over-inflation is best avoided with an accurate tire gauge and by simply paying attention. An old tube or tire may fail at lower than the rated pressure as well, but they’re more likely to fail in the form of a slower leak before reaching the point of explosion.
5. Extreme Temperatures
Not every climate experiences enough shift in temperature to cause a bike tire explosion, but in some cases, a tire can overheat just from the ambient temperature. It’s most likely to occur when a bike is left in the sun.
There are recorded cases of it happening, so it may be a problem if you live in an area like Texas or Arizona. The best way to prevent temperature issues, is to lower the pressure in your tires when you know that a heatwave is coming.
Usually, the failure comes from drastic temperature swings when a tire is already nearing maximum pressure. Ambient temperature effects your tire pressure, with the PSI increasing alongside the temperature.
Lower tire pressure may not stop all heat-related failures, since the material can fail or melt in extreme cases, but it will keep them from going off with a bang in the backyard. You should also store your bicycle out of direct sunlight no matter where you live.
Can a Bike Tire Pop on Its Own?
The tires on an unattended bike can explode due to excessive tire pressure, an improperly seated tire, a cut or hole in the tire (which can cause an inner tube pinch flat even when the bicycle isn’t moving), or extreme temperatures. A tire explosion could also occur from a combination of all of these issues.
There are a lot of anecdotes about people walking away from their bike and the tire exploding, usually right after inflating a tire. It happens, and the resulting sound is usually enough to get your attention.
Just doing a good job on maintenance goes a long way, like double checking the condition and proper installation of your tires, before inflating your tires to the correct pressure. These are simple steps, but they can prevent a lot of tire problems down the road.
How to Prevent Bike Tires from Popping
The best way to avoid having your tires blow up is to perform regular maintenance and not let the tires go through drastic temperature swings at high pressures. Improved riding habits and proper tire PSI are also important.
Your tires don’t have to explode, and the best way to prevent it is by forming good habits. The following tips will help dramatically reduce your risk of ever having a bike tire explosion:
- Double-check the bead on your tires when inflating a new inner tube. You’ll be in for a scare if the tube is peeking out and gets caught, so make sure the tire is beaded on both sides.
- Inspect your tires for cuts and holes regularly, even if you haven’t had any flats. Patch the interior if you get a flat due to debris. You should also make sure nothing has breached the tire when you install new tubes.
- Be aware of exterior temperatures and keep your bike out of the sun when you’re not riding. Lower the pressure a little bit if you know that you’re going into a heatwave, and double-check tire pressures before riding in extreme heat.
- Never exceed the recommended PSI for a tire. You probably shouldn’t even get close, unless you know you have an accurate tire gauge. The majority have too much wiggle room.
- Avoid hitting your tires on sharp edges like curbs as much as possible. Pinch flats can ruin your ride and good riding habits will prevent most problems.
It’s a little less conventional, but you could also consider rotating your bike tires, although that can be risky.