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RV Tire Safety: Six blowouts! Help! “I’m at my wit’s end”

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Here is a series of posts on tire blowouts from an RV forum. I am inclined to think that the experiences are not that unusual. This is a long post, but I thought that giving the background, and my recommendations, might help others that have tire problems know that they are not alone.

John wrote:

I’m at my wit’s end on tires. 2000 Winnebago Journey, I have blown out 6 tires since I have had this unit, over 10 years, and done over $30,000 of damage to it. Just got back from a 2,000-mile trip to Colorado and back, after blowing two tires in two days. I have tire sensors, the unit is always kept garaged, no sun on tires, always check pressures, have moved up to 255/70R22.5, which is slightly larger than stock but a lot easier to find. I run 110 psi cold, which is less than the listed 120 PSI. Maybe the age of the tires is getting me, but none are older than 6 years. I am going to start buying two tires every 2 years, to keep the age down. Any other suggestions?

John continues in another post:

This is really getting annoying to find tires on the road and then repair all the damage. Thank goodness for insurance. The original tires were 235/80. I upgraded to 255/70, and still have over an inch between tire sidewalls. The tires are not rubbing. It would appear that I have overlooked a very important detail in my quest, and that would be the tire pressure chart many have referenced. I have been running pressure at 110 or slightly below, thinking that might give me a softer ride, when in fact, at that pressure I do not have much “free space” between the load capacity of tires, and the weight of the motorhome.

My coach has a GAWR on the rear of 15,500, and with my tires at 110 psi, the load capacity is uncomfortably close to capacity. I never really understood pressure charts, but do now and will abide by them. In addition, I am going to put my coach in a weight reduction program by removing things I do not need to carry all the time. That, and a program to ensure my tires are not over 6 to 8 years old, and spinning my tires instead of sitting on my concrete slab for months at a time should cure my ills. Thanks to each for your suggestions and help.

There were some replies and suggestions from myself and other RV owners concerning the RV weight.

John posted in reply:

Okay, I finally got my rig weighed, and here are the results. My GVWR on the rig is 24,850 lbs. The weight of my rig with just me was 7,760 lbs. front axle and 13,460 lbs. rear axle for a total of 21,220 lbs.

I figure loaded with people and stuff add 3,000 lbs. with 75 % on rear axle, so that would be 15,710 rear and 8,510 front axle, for a total of 24,220 lbs. weight when loaded.

This is pretty close to GVWR, but the front axle rating is 9,350 and the rear axle rating is 15,500, for a total of 24,850.

Tires are rated 4,670 lbs. @ 110 psi X 4 = 18,688 lbs. rear and front 5,205 lbs. @ 110 psi X 2 = 10,410 lbs. front for a total capacity of 29,098 lbs. for the coach.

So I am close to GVWR but slightly under, closer to limits on axle capacity, but axles aren’t breaking, tires are. Seems that I am within limits, and would be even safer if I air tires up to 120 psi, which would give me 5,070 X 4 =20,280 on the rear and 11,020 on the front. Tires will carry far more than the coach is rated for, so my problem must be just old tires. Thanks for all the suggestions on this.

Another RV owner, Mike, offered:

John, do yourself a favor and don’t guess what your loaded weight is. On your next trip, at your 1st gas up, go to a station with a CAT Scale, and immediately get your MH weighed at it’s full travel weight. You’re at 6 blown tires, and counting, with oversized tires and super high pressures. You need more than a back-of-the-envelope estimate of your real travel weight. Somewhere in that combination is a problem unique to your setup.

At this point, I added another and hopefully a final post:

John, it’s good that you got some info on the weight, but I think Mike’s suggestion to get actual weights and not guess, especially since you are close to the limit, is spot on.
Another point is that GVWR is not what you need to be concerned with. Ideally, you should try and learn the load on each tire position aka “4-Corner Weights”. The reason for this is that tires on one end of an axle do not share the load on the other axle end. The load is almost never split 50/50. One end of an axle could have 200# to 500# more than the other end of that axle. I have seen an extreme case with one end supporting 1,000# more than the other end.

To learn the load on individual tire positions you can check with building supply or gravel sellers. But until you can get “4-corners” I suggest you confirm your GAWR from your Certification Sticker and go to a truck scale. But be sure to get individual axle weights as there will be a significant difference Front vs. Rear. I have a few posts on “4-Corner Weights” on my blog you can read HERE to help you understand how and why this is the best system of weighing.

Then:

1. For each axle weight, I suggest you assume there is a side-to-side load split of at least 51/49% and use the 51% number for inflation selection until you get actual 4-Corner weights.

2. Look on the Load Inflation Tables to learn the MINIMUM inflation for all the tires on that axle based on the 51% number. Yes, all tires on an axle should be inflated to the same level.

3. For your “cold” inflation, I recommend you run at least 10%, with +15% more than the inflation shown in the tables better, if possible. This will provide a larger “Reserve Load“. BUT DO NOT EXCEED the max inflation number for the wheels which might be 120 psi for your coach. So do a bit of research.

4. I also suggest you set your TPMS low pressure to the psi in #2 above.

Hopefully, this confirmation of load and a little bit of math and adjusting your inflation will solve your tire problems.

Have a tire question? Ask Roger on his RV Tires Forum here. It’s hosted by RVtravel.com and moderated by Roger. He’ll be happy to help you.

Read more from Roger Marble on his blog at RVtiresafety.net or on RVtravel.com.

 ##RVT1077

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Ron Jelly
25 days ago

Hi John I do hope this helps you out with the tire situation. I ran the Bay Area for forty five years and I can count blown tires on one hand, give her a try, I’d like to know how things turn out. 1. Never buy cheap tires, I don’t think I can tell you what I run on my dually but they are pricey, don’t forget the shocks!! Always have the tires balanced and don’t let them tell you there to big . If you can find a shop that has, I call it a tire shaver, it spins the tire and shaves it. I never imagined that tires were so far out of round, ya you’ll lose some rubber but what a ride. Get it to a good shop that’s able to do a 4 wheel thrust, then you’ll know everything is in the correct direction. If you’re looking for a smoother ride that’s a different story. 2. Tire pressure, if the DOT has 125 psi max then do it and I’ll bet you know what happens when you don’t? Don’t you? This is what happens when you lower the stated air pressure, It heats up thus exploding. Good luck.

Wallace Wood
28 days ago

As many have asked, is it the same tire location. Front right? Right side?
If it is right side tires my guess is you are driving off into the side of the road to much and picking up nails and what ever is on the side of the road.
Are you buying the same brand of tires? Personally I’m not a big fan of a large german tire brand that begins with the letter M for truck tires. Good for cars not trucks.
I have run Bridgestone for 40 years across the deserts of the southwest in 100+ temp. and have never had a blow out

John
28 days ago

We had 3 tires go. 2 blew out, the third I felt the rough ride and we found the tread had separated inside the tire, so one ridge of the tread, in an area about 1/6 of the round of the tire, was higher than the tread beside it. We were able to change to our spare. In all 3 cases, tire was in same position. Finally realized it was close to the engine exhaust. Had that re-routed, so now it continues well aft of the tires and comes out just beside the generate exhaust pipe.

Last edited 28 days ago by John
Backcountry164
28 days ago

Stop buying the cheapest tires that you can find. He doesn’t specify the brand and he claims the recommended size is hard to find. This is a pretty solid clue that he’s not buying quality tires from a respected brand. I’d bet money that this is 90% of his problem. You can get away with cheap tires on a little car, but if you’re pushing the limits of those tires in any way you’re asking for trouble.

J J
29 days ago

I read that whole thread on iRV2 and I still think this is key: “The original tires were 235/80. I upgraded to 255/70”

As another person on that thread pointed out, the approved alternate tire size is the 245/75R22.5 using the same wheels (rims) . “John” was asked if he assured that the original wheels were acceptable for the super-sized tires he installed and he did not reply. There is a difference in the wheels for those two sizes normally. The OEM would have needed to specifically install a wheel that would also work with the 255’s for it to not be an issue.

SDW
29 days ago

If your driving with your weight close to the top. Then you shouldn’t drive over 60 miles an hour. The faster you go the more friction, the more heat. Tire over 5 years old are really pushing their limit. I pull a 15,000 lb. 5th wheel and at six years on my tires at 60 mph I had a blow out. My left rear tire has more weight than any other and it was the one that blew. Tires aren’t made to last more than five years now.

BZ
29 days ago

Tires, Tires and tires are made to wear out, not blow out.
You did your checks and balances and all seems to be OK or are they.

Six tires! Where they all at the same place! On the rear axle!

Heat creates problems, what caused the heat, Friction.

Did you have the rig inspected? After the blow outs?

It’s possible there could be a manufacturing defect, it does happen.

Axle alignment is a key issue. It is possible, a flexing condition while the unit is moving.

I would have a frame/axle shop inspect the rig for the tire issues you are having.

They will be looking at their list of issues, some are:

Frame cracks or deformities, mounting hardware, installation, axle sizing, alignment (short list).

That should uncover any issues.

(no problems found, then could be design or loading issue)

Happy Travels

roger Marble
28 days ago
Reply to  BZ

Yes mfg defects do occur but they almost always show up early in life and would be in random locations. Defects need to be reported to NHTSA so they can be investigated and appropriate action taken. No reporting almost always means no investigation so no findings that are needed to initiate a recall.

Jim Z
29 days ago

When replacing tires always replace all 4 on rear at same time. Same with steer tires. If you replace just one on rear it will have more tread so it will carry more weight and get hot and blow out.

Leonard Rempel
29 days ago

Where were the blown tires on the vehicle? Left rear, right rear, or front? This could also indicate where the excessive load is.
If I had six blown tires, I would get another RV!

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