Making sense of the tire talk

[SeattleLion]

I think I am pretty typical. We bought our first RV a TT last June. In February we sold it and bought a Bighorn. So we are fairly new to all of this RV stuff. Reading the dire posts about the Tow Max tires caused me considerable anxiety until I started thinking about it. While I am new to RV's, I am not new to tire issues. Over the last few years I have done performance (on the race track) driving. To do that safely, you need to understand a lot about tires and tire performance. Consistent driving over 100 MPH puts special demands on a car and its tires.

I learned about loading, heating, etc. This is very relevant here. First of all there is no real evidence that the Tow Max tires are any better or worse than any other load range E tire. There seems to be a strong feeling that Chinese products are inferior. This further fed the idea that the OEM tires are dangerous. Since I don't want to ignite further debate, for this post let's leave it with the fact that we just don't know if the Tow Max tire is better or worse than any other ST LR E out there. (There aren't many)

If we start with that premise, I think we can get to the root cause of all this tire concern. I really think the problem is that Load Range E tires are too close in capacity to many of our trailers. As far as I can tell, the Tow Max LR E tires have a static load rating at about 3,000 lbs. That gives them a 12,000 lb total load capacity for the two axles. My 3160 is about 12,000 lbs dry. 2,100 lbs go to the hitch, leaving 9,100 lbs on the wheels. Add 1,500 lbs of load and the wheels are carrying about 10,000 lbs. This is about 85% of capacity. Now it is very unlikely that my load will be evenly balanced across the trailer, so one side will be carrying more than 5,000 lbs. So there is a risk of pushing the tires on one side closer to capacity.

In defense of Heartland, a 15% margin on the tire loading isn't really bad. It's acceptable engineering. However, it is a smaller margin than I want. On the race track I wouldn't drive on tires that were rated for 125 mph max speed even though my top speed was only 110. We all know that the closer we get to a limit on a mechanical system, the more likely a component will fail. This brings us back to the original point, the overall failure rate of Tow Max across all RV's wearing them is probably acceptably low. However, those of us with heavy fifth wheels have a higher risk of failure because of the smaller margin of loading. How big this increased risk actually is, we don't know. The anecdotal evidence here is no help.

There is one other factor that dramatically reduces a tire's load capacity: inflation pressure. If a tire is inflated to less than the correct amount, the load carrying capacity is going to go down. Since we were at 85% capacity at full inflation, a small reduction in pressure will overload the tire. This is what I think causes the most failures. Does that mean that by maintaining proper inflation pressure we can reduce our risk of tire failure? I think it does. Does it mean that we will never have a tire fail? Nope.

Again the issue is percent of rated capacity. The reason my car and truck tires don't fail is largely because I am operating well below rated capacity. All of my vehicle tires are running at 75% or less of rated capacity. That margin really pushes down the likelihood of tire failure. I think it stands to reason that if I can do the same thing with the trailer, I can similarly reduce my risk.

I think this is why we have so many happy campers after they buy load range G tires. They have increased the load rating of the tires to around 4,000 lbs each. The two axles now have a 16,000 lb capacity. This will provide the desired 25%+ margin.

The reason I am writing all of this is to try to help keep things in perspective. Basically, if I stay with the OEM Tow Max tires for a year or so, and I keep them at 80PSI, I can expect a relatively small chance of a failure. If I want to push that probability down further, I can spend about $1,400 for a set of Goodyear LR G tires.

I think the above is an accurate picture of what is really going on. Those of us who are financially stressed buying a new luxury trailer don't have to be emotionally pressured into thinking we need to scrape up even more money to replace brand new tires. It seems to me that before making that additional expenditure, we should weigh the facts versus the emotional pain that people who did have a failure experienced. If we can afford to further reduce the risk, fine. But if we can't, we are not putting our families and our new property in serious jeopardy.

 

[scottyb]

Seattle, that is a very well written point and I suspect there is some validity in what you say. However, IMO, all tires are not created equally, and just because tire X claims the same rating as tire Y and Z, doesn't mean it has the same quality of build. There have always been ultra cheap junk tires on the market and there always will be. The old adage of "you get what you pay for" also applies to tires as well. There is a reason that Power King Towmax cost less than 1/2 as much as it's piers. I have only been on this site for the last 2 years, but the occurrence of Towmax problems has been going on for a while, and has been way too high for me to consider leaving my driveway with them. The stress in anticipating a failure in the middle of nowhere exceeds the stress of forking out an extra $2K, IMO. I'm still waiting on reports of failures from the many of us who have changed to a superior product.

 

[TravelTiger]

I found this bit of news interesting, Prime Time is partnering with Tredit to provide their customers with two new premium benefit programs that will “enhance the safety, convenience and overall ownership experience included with the purchase of a Prime Time recreational vehicle.”

One of the benefits: "Tredit’s premium Towmax tires used on many Prime Time brands now include a five year – lifetime warranty coverage plan offered by the tire manufacturer."

One of things that stood out to me: “Prime Time Manufacturing goes the extra mile by requiring upgraded tire specifications and large carrying capacities on their customer’s units,” National Accounts Manager Missy Rogers said. “Using our Towmax premium tire plus the additional safety margin built into a Prime Time recreational vehicle translates into one of the industry’s lowest failure rate and highest safety rating.”


Here's the story: http://www.rvbusiness.com/2014/04/prime-time-tredit-partnering-on-tire-coverage/




Gee, "safety" is marketable. How many folks are going to say "no" to a premium safety package, even if it costs more?

 

[SeattleLion]

Seattle, that is a very well written point and I suspect there is some validity in what you say. However, IMO, all tires are not created equally, and just because tire X claims the same rating as tire Y and Z, doesn't mean it has the same quality of build. There have always been ultra cheap junk tires on the market and there always will be. The old adage of "you get what you pay for" also applies to tires as well. There is a reason that Power King Towmax cost less than 1/2 as much as it's piers. I have only been on this site for the last 2 years, but the occurrence of Towmax problems has been going on for a while, and has been way too high for me to consider leaving my driveway with them. The stress in anticipating a failure in the middle of nowhere exceeds the stress of forking out an extra $2K, IMO. I'm still waiting on reports of failures from the many of us who have changed to a superior product.

I agree that there are quality differences in tires, just like other products. My main point is that we don't have much information. Hearing stories on a forum doesn't really prove anything good or bad. Anecdotal evidence isn't a good predictor of overall performance. Bear in mind that pretty much every RV (trailer) maker uses Tow Max as OEM tires. The reason is pretty clearly that they are cheaper. But in such a large population of tires if the quality was really as bad as many think, there would have been action on the part of DOT and others.

In terms of performance, a tire maker does have to qualify for a DOT rating. I don't believe that Tow Max tires don't conform to the DOT standards. If they didn't, the samples the DOT tests would have triggered a government action. I'm not suggesting that Tow Max are premium quality tires. I agree with you that they aren't very good. But I do think that they will do the job, just not as long as better made tires. So I expect the Tow Max to be replaced in three years, while a better tire would last longer.

I do agree that if in fact Tow Max is lower quality, then we could expect the failure rate to be higher than the competition. Sadly, I can't find a single statistical report suggesting that. The reason is probably that no one does this sort of research. Consumer Reports doesn't rate trailer tires. Trailer Life is not big enough or sophisticated enough to do this either. That means that you can be completely right about the risk or you can be wrong as well. We can't find out.

I am not suggesting that people keep Tow Max tires if they are concerned, just that they recognize that pretty much all the trailers they see on the road were sold with the same brand. I think I have a reasonable chance of getting through the season without a blowout.

 

[dave10a]

Tires are like everything else in life. Very few facts and a lot of emotion... One thing that might be helpful for selecting a tire manufacturer is to determine if that company is ISO certified to assure a better measure of quality control. Tires need to meet government criteria for their rating, but if they have questionable QC all bets are off.. I am not sure how RV manufacturers select tire, but I have concerns about their selection process.

 

[SeattleLion]

Tires are like everything else in life. Very few facts and a lot of emotion... One thing that might be helpful for selecting a tire manufacturer is to determine if that company is ISO certified to assure a better measure of quality control. Tires need to meet government criteria for their rating, but if they have questionable QC all bets are off.. I am not sure how RV manufacturers select tire, but I have concerns about their selection process.

You are right. Some ISO 9000 would help. I don't think many Chinese manufacturers bother with it. I doubt the RV manufacturers worry too much about the tires, but I suspect that if the Tow Max tires caused too much trouble on new coaches, they would react. it's bad for business.

 

[wal_mart]

I just blew one this week. This was after airing up to 80 lbs, drove 225 miles, blew tire completely apart. All that was left was 3 inches of sidewall both sides.They looked excellent when I inspected them before leaving. DOT date was 1811. about 4000 miles on them. fifth wheel Trailer weight 11500 plus maybe 500lbs of stuff. hitch weight listed at 2075. Tires 235 80r 16E.

 

[dave10a]

You are right. Some ISO 9000 would help. I don't think many Chinese manufacturers bother with it. I doubt the RV manufacturers worry too much about the tires, but I suspect that if the Tow Max tires caused too much trouble on new coaches, they would react. it's bad for business.

Well if you look up ISO certifiaction by country, you will find that China is no. 1. I can understand why people want to bash China for political reasons. But one can not bash them for QC reasons unless they have factual examples. Many USA companies have relocated their manufacturing to China and other Asia countries because of our government policies. That may be a major reason for the thousands of ISO requests coming from China. One should hold their Senators and Congress folk accountable and complain to them if they want to change things to where companies are not forced off-shore. Remember companies are about profit and not social engineering.

 

[sbryan]

Seattle has made a reasoned and well thought out "argument" on tires. Tire and oil threads have a lot in common - lots of emotion and sometimes not a lot of data. Just because a tire is made in China doesn't necessarily mean it is garbage. I ride motorcycles, where tires are a critical component and Metzeler, a French company, is known for making very high quality tires; and those tires are made in China. Much of the quality in a Chinese made tire will have to do with the company overseeing the manufacturing process. I have been told (but haven't verified) that even the Goodyear G614 tires are now made in China. As long as Goodyear oversees the quality control and manufacturing process it wouldn't put me off the tire; it would still be a G rated tire and offer a superior margin of safety over any E rated tires.

Good discussion.

 

[Miltp920]

I really appreciate the well articulated view Seattle. I have been trying to make sense of all this tire talk. I bought my tire monitoring system. My tires are aired up to 80 psi. I am going to get the 5er weighed on my first trip out. After I have those additional inputs, I will weigh the "risk". It seems the tire failures seem to happen with 3000-4000 miles on the tires, not brand new tires a year old. I do not know what the mileage expectation is for a 14,000 LB 5er trailer tire, but I read 4000-5000 miles somewhere. Maybe I just need to plan on new tires in a few years, since I am mostly local camping. I may still replace if I do not have the 25% margin you spoke of, but I feel even more informed no. Thanks Seattlelion. I feel that I dont have to rush to the tire store this week now before my first 2014 voyage.

 

[DesertThumper]

I just blew one this week. This was after airing up to 80 lbs, drove 225 miles, blew tire completely apart. All that was left was 3 inches of sidewall both sides.They looked excellent when I inspected them before leaving. DOT date was 1811. about 4000 miles on them. fifth wheel Trailer weight 1150 plus maybe 500lbs of stuff. hitch weight listed at 2075. Tires 235 80r 16E.

Hey Walt ,

if you filled up your tires to 80 lbs before you hit pavement for 225 miles, did you consider the heat rising and increases the new tire pressure reading afterwards? Destination+weather temps+tire pressure settings before departing will be different every time. Example: It is 55 degrees at the time I am filling up my tires, I will top them off at 72 lbs knowing the weather after being on the road for a few hours will warm up to 75 degrees. By the time we take our rest stop and check the tire pressure, it registers at 80lbs at max. There are different ways of doing tire inspections for everyone else. I find the way I've been doing it has kept us out of trouble. Tire pressure inspection on the road is key.

 

[danemayer]

Hey Walt ,

if you filled up your tires to 80 lbs before you hit pavement for 225 miles, did you consider the heat rising and increases the new tire pressure reading afterwards? Destination+weather temps+tire pressure settings before departing will be different every time. Example: It is 55 degrees at the time I am filling up my tires, I will top them off at 72 lbs knowing the weather after being on the road for a few hours will warm up to 75 degrees. By the time we take our rest stop and check the tire pressure, it registers at 80lbs at max. There are different ways of doing tire inspections for everyone else. I find the way I've been doing it has kept us out of trouble. Tire pressure inspection on the road is key.

Here's what Goodyear says in their RV Tire Care and Maintenance Guide.

How to check your tire pressure:
• Tire pressure should be checked when your tires are cold and haven’t been driven more than one mile. The
load capacity for a given cold inflation pressure is based on ambient outside temperatures. The pressure in
a hot tire may be as much as 10 to 15 psi higher than the cold tire pressure. That means you’ll only get an
accurate reading when you check your tires when they’re cold.
• To ensure your tire pressure readings are accurate, Goodyear recommends that you use a quality truck tire
gauge with a dual-angled head. This way, you can check inner and outer dual wheels at the same time.
• Do NOT bleed air from hot tires.
• Inflation pressure should be adjusted to the tire carrying the heaviest load, and all tires on the axle should
have the same inflation pressure.
• Use proper sealing metal valve caps or quality flow-through valve caps.
• Tires that have lost more than 20% of their recommended inflation pressure should be considered flat.
• Flat tires should be professionally inspected and repaired or replaced by a Goodyear Retailer.

You should not be setting pressure low when tires are cold to anticipate the increase generated while driving. You can either get individual wheel weights and set the cold pressure to the pressure appropriate for the actual wheel weight, or use the max cold pressure as indicated on the sidewall. Since most of us don't have individual wheel weight, and those weights may change from trip-to-trip, using the max cold pressure is probably more appropriate.

If you're setting your pressure to 72psi, you could be 10% low. Gauge inaccuracy could make it even lower (or perhaps higher). Depending on how close your wheel weights are to the max load rating of the tires, you may be damaging your tires.

 

[DesertThumper]

Here's what Goodyear says in their RV Tire Care and Maintenance Guide.

You should not be setting pressure low when tires are cold to anticipate the increase generated while driving. You can either get individual wheel weights and set the cold pressure to the pressure appropriate for the actual wheel weight, or use the max cold pressure as indicated on the sidewall. Since most of us don't have individual wheel weight, and those weights may change from trip-to-trip, using the max cold pressure is probably more appropriate.

If you're setting your pressure to 72psi, you could be 10% low. Gauge inaccuracy could make it even lower (or perhaps higher). Depending on how close your wheel weights are to the max load rating of the tires, you may be damaging your tires.

Our local industrial tire guy actually recommended for us to do it this way. Just to make sure I understand, instead of filling our tires with the example I provided above, instead fill them up to 80 psi cold. You check your tires 2 hours later with the temp now being 75 degrees, the tire will read at 88+psi. So will the tire pressure reading be ok to keep driving?

 

[danemayer]

Our local industrial tire guy actually recommended for us to do it this way. Just to make sure I understand, instead of filling our tires with the example I provided above, instead fill them up to 80 psi cold. You check your tires 2 hours later with the temp now being 75 degrees, the tire will read at 88+psi. So will the tire pressure reading be ok to keep driving?

Yes it's safe to continue driving as the tire heats up and pressure climbs. Ambient temps go up, the road gets hot, internal flex heats up the tire. All these factors drive the pressure higher. The tire designer knows this and designs for it. They also know that the only consistent approach is to set pressure while cold, not driven on for a while, and out of the sun. Btw, cold = 70F.

Our Goodyear G614s start out at 110psi. On our recent trip the monitors showed pressure increased up to 119. On a 100 degree summer day driving at 55mph, I've seen them go to 130psi.

 

[DesertThumper]

Yes it's safe to continue driving as the tire heats up and pressure climbs. Ambient temps go up, the road gets hot, internal flex heats up the tire. All these factors drive the pressure higher. The tire designer knows this and designs for it. They also know that the only consistent approach is to set pressure while cold, not driven on for a while, and out of the sun. Btw, cold = 70F.

Our Goodyear G614s start out at 110psi. On our recent trip the monitors showed pressure increased up to 119. On a 100 degree summer day driving at 55mph, I've seen them go to 130psi.

That is amazing stuff. I wonder why a professional tire guy would tell us to do it the way I've been doing it... I've never had a blown tire with owning three trailers. When they installed my tires, I asked the installer the same question, what are you setting them to and how should I carry forward with pressure maintenance? He said what it have been doing. Wierd... Ok well if tires can go 10 + psi when you set them to 80 psi cold after driving then I will top them off at 80psi. I just hope they don't go kaboom.

 

[SeattleLion]

That is amazing stuff. I wonder why a professional tire guy would tell us to do it the way I've been doing it... I've never had a blown tire with owning three trailers. When they installed my tires, I asked the installer the same question, what are you setting them to and how should I carry forward with pressure maintenance? He said what it have been doing. Wierd... Ok well if tires can go 10 + psi when you set them to 80 psi cold after driving then I will top them off at 80psi. I just hope they don't go kaboom.

I've discovered that guys who work at tire dealers are not experts at all. They don't have the training. The Goodyear recommendations are echoed by every tire maker. If you start out cold at 73PSI, you are almost 10% under inflated. That will reduce the tire's load capacity substantially. Even on the track we over inflate by 7psi above the tire's spec. This is on a hot summer day and the tires will get very hot. Why? Because side wall flex is what destroys a tire. Every tire is designed to handle the increase in pressure that heating up will cause. This increase further stiffens the sidewalls and ultimately reduces the amount of heat the tire generates.

 

[BobX2]

Don't know if any of you follow NASCAR racing, but they have had a rash of tires blowing out this season for some of these same reasons. Teams are starting a run with low pressure, knowing that as the tires heat up, the pressure will build. Goodyear is saying that the damage to the tires is happening in the first few laps while the tire pressures are low, due to the excessive flexing of the sidewalls while the air pressures are still low. Once the damage has occurred it is just a matter of time before the tire fails. I know this is an extreme example, but our trailer tires will do the same thing. So, starting out with low pressure when cold, knowing that it will increase as you drive, can be damaging the tire regardless if they are overloaded or not. The damage is happening while the tire may still be cold, and then the heat will finish them off.

 

[wal_mart]

Bob. You are absolutly right I may have damaged this tire at some other time. I do remember cutting a turn and running over a curb on that leading tire. It was at least 1000 miles ago though.

 

[DesertThumper]

That makes sense. Thanks for the correction.

 

[scottyb]

I don't think cold means cold. I have been told that ambient temperature should be 72 degrees. If all my tires are low, but the same, when it is freezing outside, I never add air because I know that it is due to the temperature change and not because they have all lost exactly the same amount of air overnight.