By Carl J. Haddon
This article was inspired during a recent call for a vehicle rollover with entrapment and injuries. En route to the call, which was roughly 12 miles out of town, I found myself following, or trying to follow, a local ambulance that was responding to the same call. I admittedly was exceeding the 65-mph speed limit. As I looked down at my speedometer, I saw that it read 85mph. The ambulance ahead of me was pulling away from me like I was standing still. This type 3 ambulance was traveling down a two-lane highway that runs alongside a river, well in excess of 90 mph. Interestingly enough, by way of radio traffic, I knew that this rig was not only operated by a senior EMT, but in the passenger seat was the County Emergency Services Director. Hello?
I couldn’t help but think that in addition to the obvious potential for disaster that surrounded what I watched before me—mountain road, falling rocks, lots of deer, elk, tourists, and other wildlife crossing the road to and from the Salmon River this time of year—I wondered if they knew what the age, load range, or speed rating of the tires on that 14,000-pound ambulance was. Alas, the topic for this article was born.
Before I continue with important information regarding commercial tires, I feel compelled to remind you that ust because you CAN exceed the speed limit to whatever extent DOESN’T mean that you SHOULD. Remember, everyone goes home! Responding at greater than 90 mph to a call on a rural highway in a type 3 ambulance—or any other fire/rescue/EMS vehicle—dramatically reduces the odds of everyone going home. Don’t become part of the problem. The first rule of EMS still stands: “Do No Harm!” That includes harm to yourself or your crew! OK, rant finished.
Now, on to the meat and potatoes of this piece: emergency vehicle tires. Without getting into all of the technical stuff surrounding tires, there are three important things to know about tires on your emergency vehicles. The obvious first one is general appearance, tread depth, and condition. The other two are a little more interesting. The second deals with commercial tires and vehicle load. Although the tires on your rescue or ambulance may be “R” speed rated, (which is said to be 106 mph), the weight and profile of the vehicle has to be taken into consideration. The commercial tires on our emergency vehicles do not dissipate heat like the tires on our personal trucks because of their weight and payload. Engines, ladder trucks, and so on build up heat in their tires because of this weight and retain that heat much longer than passenger or light truck tires. The heating up and cooling off eventually takes their toll on the tires, even though we may not ever see the tread wear out. That leads directly to the last, and possibly most important thing to know about emergency vehicle tires and also the least recognized—tires’ age.
The age of an emergency vehicle’s tires is probably one of the most important, but least recognized, factors in this equation. Does your department change tires based on age, or solely on wear? Although there is no established expiration date for tires, most manufacturers of passenger car tires suggest replacement between five and 10 years. Emergency vehicle manufacturers that I’ve interviewed suggest replacing the tires every five years. Think about it. What do most rural fire and other emergency apparatus spend most of their time doing? Yup, sitting in quarters or sitting outside in the weather. The weight of the vehicle sits on one spot on the tires for an extended period of time, and that is not good for tires, as it helps with things like tread separation and dry rot. Tire Chains (auto or manual), road salt, 4WD, and unpaved roads all contribute to tire deterioration whether the tread and sidewall show it or not
It would probably blow your minds to know how many 15-20 year old tires I’ve discovered on first-due apparatus in rural firehouses over the last few months. Please understand that I know just how expensive replacing tires is and that doing so every five years may not be an option for your department. Tire age simply needs to be a consideration as part of the department’s preventive maintenance program.
Hopefully, the combination of good, safe driving practices, coupled with the knowledge about the weight, age, load, and speed rating of your tires, will help to further ensure that you and your crew arrive safely to, and from, your calls. Might this same information be a good idea to apply to your personal vehicle tire maintenance as well?
CARL J. HADDON is a member of the Fire Apparatus & Emergency Equipment editorial advisory board and the director of Five Star Fire Training LLC, which is sponsored, in part, by Volvo North America. He serves as assistant chief and fire commissioner for the North Fork (ID) Fire Department and is a career veteran of more than 25 years in the fire and EMS services in southern California. He is a certified Level 2 fire instructor and an ISFSI member and teaches Five Star Auto Extrication and NFPA 610 classes across the country.