October 2006
This article appeared in Highways Magazine, October 2006. I hope it is helpful as it relates to a problem many of us have.
JoeW
Tech Topics
Bob Livingston
This article appeared in Highways Magazine, October 2006. I hope it is helpful as it relates to a problem many of us have.
JoeW
Tech Topics
Bob Livingston
Tire Expert
I’m responding as an expert to the many letters you get dealing with tires and tire-related issues. My credentials for writing this letter include that I’m an engineer with a PhD in mechanical engineering and I owned a tire store for more than 30 years. During that time, I attended many training courses taught by many of the major tire manufacturers. As evidenced by recent letters, there is a general lack of understanding of tire issues. I will address several of those issues.
Inflation: This is the source of most tire questions. You never inflate a tire except to that pressure recommended by the vehicle manufacturer. Period. There are occasionally reasons to ignore this rule. An example of this is a severely overloaded pickup truck carrying a huge load of rocks and only going a relatively short distance. Never should this apply to an RV.
The tire pressure on the sidewall of the tire is a “never-exceed pressure.” This is a pressure that has been established by testing and/or design by the tire manufacturer and it’s on the tire because of federal mandates. Most folks don’t know that every tire (sold in the USA) of the same size and ply rating has exactly the same load rating and maximum allowable tire pressure regardless of where or by whom the tire was manufactured. What the sidewall really shows is that the tire can carry a certain amount of load if inflated to the corresponding pressure. It doesn’t indicate that the tire should be inflated to that pressure. The tire manufacturer never knows beforehand on what vehicle a tire will be installed; so, how could they recommend a tire pressure? The vehicle manufacturer knows all about the vehicle and specifies the tire fitment.
The vehicle manufacturer puts every vehicle through a series of handling tests before the vehicle is ready for sale. Of utmost importance is the actual handling of the vehicle, especially in adverse conditions such as swerving or severe braking. Improper tire inflation can and does materially affect the way a vehicle handles in such cases. Further, if the vehicle manufacturer’s inflation specifications are found to be too low, that means the user is overloading that vehicle. Rather than increasing tire pressure, the load should be decreased.
Overinflation subjects the tire to increased danger of damage caused by bruising due to impact with objects on the roadway or with potholes.
Most tire problems occur on the farthest to the rear on the right-hand side of a vehicle, because foreign objects (nails, etc.) are swept to the right-hand side of the road by passing vehicles. A front tire runs over the object and starts it spinning and the rear tire catches it just right so that the object can penetrate the tire.
Tread separations, sudden tire failures and blowouts: These, of course, are very traumatic and often cause damage to the vehicle. These incidents are seldom understood by the vehicle owner. They always blame the tire and ultimately, the manufacturer. These incidents are almost never the fault of either the tire manufacturer or the tire installer. There has never been an owner who thought his or her tire might be severely underinflated due to a leak. I’ve never spoken to anyone who didn’t “just” check his or her air pressure before the tire blew out.
When a tire fails, it’s usually caused by an impact that occurred quite a while earlier, perhaps months. The owner doesn’t even recall the hole he hit so hard it jarred the fillings in his teeth. When nothing happened right then, he breathes a sigh of relief and goes on. But the tire was most likely damaged at that time and it takes many more miles before that damage becomes a tire failure.
There definitely have been many cases of entire tire lines suffering from some defect in the manufacturing process that ultimately leads to tread separations. No tire manufacturer is immune from these problems. They’ve all had them. All tire manufacturers know of these problems and take care of them as they occur. A tire-tread separation should never become a severe problem to an RV owner who is paying attention. A driver can always feel increased vibration, pulling or other handling changes to the vehicle in sufficient time to have it checked by a tire professional before the tire comes apart and damages the vehicle. Obviously, this is more difficult on a trailer but with vigilance, you can usually prevent it from happening on a trailer as well.
As I said earlier, tread separations often result from an impact when the tire is overinflated and might not occur with proper inflation.
Tire life: Tires have a life. It is generally accepted that tires more than six years old should be replaced. This is easy to say but hard to do. But realize that the amount of tread remaining has nothing to do with the strength of the tire. The tread is only there to give the tire traction and, of course, to allow the tire to wear for many miles. More tread adds little to penetration resistance. Over time I have frequently had customers say that they couldn’t see why they had a flat since the tire was new. It adds essentially nothing to the strength of the tire. Tires deteriorate with time regardless of whether they are in constant use or mostly parked. In fact, being seldom used can be detrimental to a tire. Covering a tire can be somewhat beneficial but really does not extend the six-year time limit.
If your tires are more than six years old, replace them. I had a customer who had a spare tire mounted on the back of his motorhome. This tire had never been on the ground and was eight years old. One day it just blew out, causing severe damage to the rear of the motorhome.
I recently replaced the full set of tires on my travel trailer even though they looked great: lots of tread, etc. And please don’t say, “Well, he owns a tire store.” The tires are certainly not free to me.
Anecdotal evidence indicates that tires age about 12-to-1 as compared to humans. You know, elephants age so much compared to humans and so do horses, dogs and other animals. Whether this is true or not, it should give all RVers food for thought as we are mostly a population of, shall we say, “seasoned citizens.” So we should be able to identify with the increased aches and pains of our old tires.
Floyde Adams
Mimbres, N.M.
I’m responding as an expert to the many letters you get dealing with tires and tire-related issues. My credentials for writing this letter include that I’m an engineer with a PhD in mechanical engineering and I owned a tire store for more than 30 years. During that time, I attended many training courses taught by many of the major tire manufacturers. As evidenced by recent letters, there is a general lack of understanding of tire issues. I will address several of those issues.
Inflation: This is the source of most tire questions. You never inflate a tire except to that pressure recommended by the vehicle manufacturer. Period. There are occasionally reasons to ignore this rule. An example of this is a severely overloaded pickup truck carrying a huge load of rocks and only going a relatively short distance. Never should this apply to an RV.
The tire pressure on the sidewall of the tire is a “never-exceed pressure.” This is a pressure that has been established by testing and/or design by the tire manufacturer and it’s on the tire because of federal mandates. Most folks don’t know that every tire (sold in the USA) of the same size and ply rating has exactly the same load rating and maximum allowable tire pressure regardless of where or by whom the tire was manufactured. What the sidewall really shows is that the tire can carry a certain amount of load if inflated to the corresponding pressure. It doesn’t indicate that the tire should be inflated to that pressure. The tire manufacturer never knows beforehand on what vehicle a tire will be installed; so, how could they recommend a tire pressure? The vehicle manufacturer knows all about the vehicle and specifies the tire fitment.
The vehicle manufacturer puts every vehicle through a series of handling tests before the vehicle is ready for sale. Of utmost importance is the actual handling of the vehicle, especially in adverse conditions such as swerving or severe braking. Improper tire inflation can and does materially affect the way a vehicle handles in such cases. Further, if the vehicle manufacturer’s inflation specifications are found to be too low, that means the user is overloading that vehicle. Rather than increasing tire pressure, the load should be decreased.
Overinflation subjects the tire to increased danger of damage caused by bruising due to impact with objects on the roadway or with potholes.
Most tire problems occur on the farthest to the rear on the right-hand side of a vehicle, because foreign objects (nails, etc.) are swept to the right-hand side of the road by passing vehicles. A front tire runs over the object and starts it spinning and the rear tire catches it just right so that the object can penetrate the tire.
Tread separations, sudden tire failures and blowouts: These, of course, are very traumatic and often cause damage to the vehicle. These incidents are seldom understood by the vehicle owner. They always blame the tire and ultimately, the manufacturer. These incidents are almost never the fault of either the tire manufacturer or the tire installer. There has never been an owner who thought his or her tire might be severely underinflated due to a leak. I’ve never spoken to anyone who didn’t “just” check his or her air pressure before the tire blew out.
When a tire fails, it’s usually caused by an impact that occurred quite a while earlier, perhaps months. The owner doesn’t even recall the hole he hit so hard it jarred the fillings in his teeth. When nothing happened right then, he breathes a sigh of relief and goes on. But the tire was most likely damaged at that time and it takes many more miles before that damage becomes a tire failure.
There definitely have been many cases of entire tire lines suffering from some defect in the manufacturing process that ultimately leads to tread separations. No tire manufacturer is immune from these problems. They’ve all had them. All tire manufacturers know of these problems and take care of them as they occur. A tire-tread separation should never become a severe problem to an RV owner who is paying attention. A driver can always feel increased vibration, pulling or other handling changes to the vehicle in sufficient time to have it checked by a tire professional before the tire comes apart and damages the vehicle. Obviously, this is more difficult on a trailer but with vigilance, you can usually prevent it from happening on a trailer as well.
As I said earlier, tread separations often result from an impact when the tire is overinflated and might not occur with proper inflation.
Tire life: Tires have a life. It is generally accepted that tires more than six years old should be replaced. This is easy to say but hard to do. But realize that the amount of tread remaining has nothing to do with the strength of the tire. The tread is only there to give the tire traction and, of course, to allow the tire to wear for many miles. More tread adds little to penetration resistance. Over time I have frequently had customers say that they couldn’t see why they had a flat since the tire was new. It adds essentially nothing to the strength of the tire. Tires deteriorate with time regardless of whether they are in constant use or mostly parked. In fact, being seldom used can be detrimental to a tire. Covering a tire can be somewhat beneficial but really does not extend the six-year time limit.
If your tires are more than six years old, replace them. I had a customer who had a spare tire mounted on the back of his motorhome. This tire had never been on the ground and was eight years old. One day it just blew out, causing severe damage to the rear of the motorhome.
I recently replaced the full set of tires on my travel trailer even though they looked great: lots of tread, etc. And please don’t say, “Well, he owns a tire store.” The tires are certainly not free to me.
Anecdotal evidence indicates that tires age about 12-to-1 as compared to humans. You know, elephants age so much compared to humans and so do horses, dogs and other animals. Whether this is true or not, it should give all RVers food for thought as we are mostly a population of, shall we say, “seasoned citizens.” So we should be able to identify with the increased aches and pains of our old tires.
Floyde Adams
Mimbres, N.M.
