I came across another post on an RV forum regarding tire blowouts. I am sorry to report that many of the posters did not understand the concept of Cold Inflation. The original poster asked: “Why did I have three blowouts?” He continued:
I’m pulling my hair out. I’ve had three blowouts in 18 months of ownership of our 2020 Keystone Outback. We have ST225 75 R 15 Load E tires.
The blowouts have been on 3 of 4 points on our dual axle TT.
The first blowout was road hazard / excessive speed (I was routinely doing a few mph over on the interstate), and the second and third appeared to be heat-related in that both tires were running hotter than others and PSI had climbed to 95 on our max 80 PSI.
I feel like I’m inflating my tires every few days when leaving a campsite. This can’t be normal. When starting this trip from SC to FL, I found them all down 3-6 PSI in GA after I had inflated all to 80 (cold) two nights before in the SC storage yard.
Before this last blowout, they were all sitting around 74/75 PSI in the morning and I topped them up to 80 PSI according to TPMS. I had barely left the campground when each had climbed to 82. One went to 95 within an hour and temp was running mid to high 70s and the other three were in mid 60s. I pulled over and let the air out of them all. But the eventual blown tire just kept running hotter and then popped 2-3 hours later. The center tread separated completely from the tire.
Haven’t weighed trailer
No, I haven’t weighed my trailer, but I’m just a guy with a wife and three kids, 5 and under. No modifications to my trailer, etc. I don’t pack every inch of floor space with gear that then spills out at the campsite upon arrival, so I can’t imagine I’m overloading.
I don’t understand why I have to top up my tires all the time. And it’s not clear why the last two blowouts occurred when I’ve been trying to stay on top of the cold PSI and stay under the speed limits.
We are “on the road” so I’m contemplating buying whatever replacement tire I can get, and then asking my local RV service center to check bearings and alignment upon our return. Could either of these be the underlying issue?
Then, if that isn’t the case, I’ll consider investing in a complete set of tires with a better reputation, in case the current tires are truly bad.
I would welcome any thoughts or comments!
My reply regarding tire failures
There were 3 tire failures. A puncture is not the fault of the tire as any tire can be punctured or cut. An increase of 20% to 25% in pressure is an indication of a combination of excess load and excessive speed. A dragging brake or wheel bearing problem can also generate excess heat which can affect both TPM temperature reading as well as increase tire pressure. We do not know what the ambient temperature was or what the TPM pressure readings were, which might provide additional clues as to the reasons for their failures.
Others have posted that bleeding air out of a hot tire is definitely the wrong thing to do. There is the potential that this action resulted in two tire failures, depending on the actual loads and how much air was actually let out. We do not know the actual truck scale load for each axle, so this is important information that is missing. 80 psi on the tire is the minimum inflation needed to support the load number on the tire sidewall. It is NOT the maximum operating pressure. The ONLY pressure we need to be concerned with is the “cold” inflation, which is the inflation measured before the tires are driven on or exposed to direct sunlight for the previous 2 hours.
Inflation pressure
Inflation pressure when the tires are stationary and out of direct sunlight will change about 2% for each change in the ambient temperature of 10° F. A 6 psi drop with no other cause would indicate a drop in ambient temperature of about 37° F for a tire inflated to 80 psi. We do not know the ambient temp at the time of tire measurements. However, that is a considerable drop in temperature, so I think there is probably some other reason for the reported pressure loss.
We do not have to fill every space in the RV with “stuff” to end up overweight. The RV Certification sticker indicates the maximum load for each axle when the RV is fully loaded. This load GAWR should not be exceeded. If a scale indicates the RV has an axle at GAWR, then the tires MUST be inflated to the pressure stated on the sticker. BUT we can still have one tire overloaded, as most RVs have a side-to-side imbalance of their axles. They also have an imbalance between the two axles, so that is why we need to confirm the actual load on each axle.
Weigh on a truck scale
This can be learned on truck scales as long as we get readings for each axle, which requires careful parking on the platform scales. I have seen air loss due to small tread punctures, leaks around the rubber valve stem, and leaks between TPMS and the valve stem. Also I’ve seen leaks through the aluminum due to casting errors, and leaks between the tire and the wheel due to improper mounting. I have posted an example of a leak through the valve core.
A couple of other actual tire engineers and I follow some of the RV posts. Plus, there are many self-appointed “experts.” So you do need to always consider the source of the information you find on the internet as not everything you read here is the truth, believe it or not.🙄
Roger Marble
Check out my Blog www.RVTireSafety.Net
Read more from Roger Marble on RVtravel.com.
##RVT1130
Watched a guy at Buc-ees the last time I stopped there. He was going from wheel to wheel, measuring air pressure and letting “excess” out. Auugh! And then he’s back on the high speeds of the Interstate. I wonder what his tire life was like.
Great article! A couple of red flags for me and I am no expert by the way! Once I set my tire pressure and verify with my TPMS, that’s it unless something serious happens, (which hasn’t)!
I never speed, keeping it to 55-60 mph as even the best RV tires aren’t rated past 65 mph, I believe.
As I drive the tire pressure does go up, but this is normal. I also notice that the tires on the sunlight side of my Montana 5th wheel go up several degrees more than the shaded side. In three years of owning my rig, I have added air once after my initial purchase because the dealer did not inflate them properly. Oh yeah, I have nearly 4,000 lbs. CC, and rarely have more than 2,000.
The cheap no name tires that are OEM for most trailers are 65 mph an/or no rating present. But quality trailer tires like Goodyear Endurance are rated to 87 mph. Not that you should go that fast while towing. But the point is that a higher rated tire is theoretically built stronger. The OEM tires are absolute garbage compared to Carlisle or Goodyear.
Good to know. I have the Sailun tires on mine and after three years and 30,000 miles they have performed flawlessly. I believe the ratings on the Saliun is also excellent. I will need new tires after five years. What do you suggest?
Thanks!
I can remember back when I had my 2001 Coachmen Catalina, Carlisle tires were considered junk and had many reports of tire failures with them. I had Goodyears on my trailer and they performed perfectly and never once in the years I had that trailer, had a blow out or even a flat. But Carlisles really had a bad name. Sounds like that company has made some changes for the best.
A bent axel will of course cause tire wear and in the process cause a tire to heat up.
I suspect few owners have wheel alignments done. Since highways are in rough shape and rumbling over railway tracks can jar your teeth I have an alignment done about every 10,000 miles.
It always needs it.
Exactly. I had a tandem axle well built TT that had tow bent axles when I bought it used. After careful inspection of the suspension I realized the axles were bent…so I had a local truck and trailer shop bend the axles into factory specs. It seemed to pull easier after installing rebuilt suspension and new tires so a word to the wise…have tour rig checked for bent axles and worn suspension.
In over 25 years of RV’ing with travel trailers, I’ve only had one tire incident. A cap just rolled off the tire and out into the desert. It was on the original tires that came with our new 97 trailer. Since then (knock on wood) I’ve had no problems. A friend asked me if I’d had any tire problems because he had three tires blow on his last trip. He asked what kind of tires I had. I’ve run Hercules tires (E range) for my last three sets. He said those were the tires that he ran and he’d never buy them again. When I asked how fast he drives he said “The speed limit plus 5-10 mph. 75-80 all the time”. I told him 60 was my max. Might that be the difference?
We are full-timers with a 3 axle, 24K# fiver. Tire pressure and wear is one of the most important checks before every move. At least 2 of our six tires require a few lbs. of air every week. I turn the TPMS on the day before we travel so I can check pressure mid day. If it’s really cold, I go by the tires I know have a constant, non leaking pressure and adjust other tires to that pressure. Our tire pressure regularly goes up 20 lbs. or more during travel with no issues. I would never remove air during travel. We carry a 23 inch “welding tank” filled with nitrogen; light weight, no electricity required, generally lasts a year between tank exchanges.
Had a new set of tires put on my Chevrolet crew cab dually in July. I live in Los Angeles and the daytime temp was about 85 degrees F. The tire store asked what pressure I wanted in the tires; I said 80 PSI. The following week I drove through San Bernardino County, and it was 105 and the tire pressure went to 90 PSI. I didn’t touch them. 5 days later leaving the campground in the mountain’s tires were at 78 but driving home climbed to 90. Drove to Colorado and Wyoming in Sept. and it snowed. Tire pressures dropped to about 74 but when they warmed up while driving climbed back to 78-80. I don’t worry about changing tire pressures as long as the tires are at 80 PSI plus or minus 10 degrees.
To the person with three blowouts. Castle rock tires have a recall, one of mine blew out in the middle of the nite while i was asleep. Check it out, they sent me a refund for all five tires.
Thank you, Roger! I am so thankful that you take the time and make the effort to monitor internet posts and to write this column for RV Travel. The death of Mac the Fire Guy reminds me that the wealth of information that you, Dave Solberg, and other technical experts have and share with RV Travel readers should never be taken for granted. Thank you, thank you!