When Tires Attack

Working as a bike mechanic for over a decade offers myriad opportunities to experience the terror of unanticipated tire explosions. Fortunately for me, I’ve worked mostly in small service departments with few full time mechanics on staff. It’s fortunate because the more mechanics you have, the busier the shop tends to be, thereby leading to more tire changes and more opportunity for failures that feature an audio signature similar to the firing of a snub-nosed .38 special.

Standard practice within the industry is that mechanics who are responsible for blown tires are obliged to purchase a six-pack to treat the PTSD suffered by the innocent bystanders. The part about the PTSD is no joke. In shops where a series of three or more butyl pipe bombs are detonated within a week or two, mechanics’ nerves can become extremely frayed. There are multiple periods in my career where a month or more went by when I winced every time I inflated a tire. While it is true that most tire explosions can be prevented, there are times when no amount of preparation can forestall the inevitable result of ill-fitting or defective tires.

In an effort to work through the mental and emotional trauma I’ve endured, I feel that there is cathartic value in sharing these experiences with the world. One recent example that illustrates the intensity of the experience is when a mountain bike tire exploded in the Art’s showroom. The blast was so loud and concussive that the employees working on the floor above rushed downstairs to aid those that had most assuredly fallen in an ill-conceived Al-Qaeda bomb plot to attack Central California bike shops. Upon arrival at the scene we found a very pale employee with a sheepish grin on his face and fragments of a shredded inner tube. I’ll be the first to admit that describing these blasts as being bomb-like sounds a bit hyperbolic, but one experience proved that even professional law enforcement has trouble telling the difference between exploding tires and real bombs.

They may look quite different, but when they explode...

...you'd be hard-pressed to know the difference.

About seven years ago I had a tubeless mountain-bike tire that was returned to the shop by a customer that claimed it had blown off of the rim while on his first ride on the tire. We replaced the tire under warranty and when the manufacturer declined to have us ship it back to them, I held onto the essentially new tire that I suspected had simply been installed incorrectly by the customer.

Many months later the time came that I needed a new tire for my personal bike, so I retrieved the warrantied tire from the stockpile and mounted it on my wheel during a lunch break. As my break ended I set the wheel next to my workbench and went out to help a customer. A couple of minutes into our discussion, BAAAAM!!! The customer took an attack stance and reached for his belt, but then hesitated. It turned out that the customer was an off-duty cop with a concealed weapon. He nearly drew his service weapon to respond to the threat! After he apologized for being jumpy, we both had a good laugh. A good, nervous laugh.

Beware of the bulging tube...your ear drums will thank you.

Sometimes mechanics get a warning just before a tire explodes. If an inner tube becomes wedged between the tire bead and the rim, you get about a second to watch the bead lift up and out of the rim while the inner tube forms an aneurism in the gap that develops, just before the inner tube bursts. At the same shop where the cop nearly drew his sidearm on me, there was a mechanic I worked with that was prone to detonating butyl bombs due to careless work. It happened so frequently that he developed his own procedure for mitigating the trauma. When he would see the tire bead lift up, the indicator that life was about to get very interesting, he would toss the wheel across the shop and yell, “Hit the deck!” before turning his back to the IED and covering his ears as he crouched next to his work bench. As you can imagine, his tenure of employment lasted about a month, which was about half of the period where I found myself wincing during every tire inflation I executed thereafter.

The most dramatic tire explosion I have experienced not only left me rattled, but it also gave me ringing in my ears for nearly three days and necessitated a shower shortly after the bang. It all started with a completely normal tubeless mountain-bike tire installation. I had a tubeless-rated tire, a tubeless-rated rim from the same manufacturer, and tire sealant made by the same company. Experience has taught me that in order to have the best possible chance of getting a tubeless tire to seat, one must not allow the tire to rest upon the ground and deform the tire bead that must seal against the rim sidewall. To this end I’ve made it a practice to hang rims from the workstand while I inflate tubeless tires. The downside of this arrangement is that the tire is raised to head height, dramatically increasing the consequences of failure. While I had considered these consequences when developing my technique I reasoned that if I was always careful to use the right components, I had the reasonable expectation of safety. While this is broadly true, no product is completely free of defects.

With the tire at 35psi (well within the limits of this particular tubeless system) and with one hand steadying the tire while the other held the compressor fitting onto the tire’s valve, the inevitable occurred as the wheel detonated. Thankfully the bead that blew out was facing away from me. Nevertheless, my eagle-like mechanic’s hand was pried open instantaneously and I found my fingertips stung by the force of the explosion. Meanwhile my ears rang like a thousand childrens’ jingle bells shaken in unison. The green sealant instantly atomized and sprayed a thin coating on my upper body, a nearby window, and the wall below. Despite my best efforts to clean up the mess, years later I found crystallized droplets of the sealant all around the shop, even in the deepest, darkest corners—much like the droplets of trauma found in the inner recesses of my psyche.

While I have eventually regained what could be termed a normal life, as the old saying goes, “You can’t unring a bell” especially when that ringing in your ears is the result of the idiosyncratic concussive force generated by the pneumatic rubber we all rely upon to experience the sport we love.

Daniel Slusser is a professional bicycle mechanic with over a decade of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.

2013-11-25T17:32:09-08:00