Tire help

[Holiday27]

So, we were heading to Yellowstone last week. 20 miles outside of Twin Falls, ID. and bang. The inside dual on the pass side blew. Called AAA and they were clueless. They wanted to send a tow truck. I laughed and said you have to be kidding. There contractor couldn't do anything for me so she put me in touch with Les schwab. Schwab wanted me to drive to there shop 20 miles away. I said no way! I did agree to drive to the next exit. I went about 15-20 miles an hr max for 3 miles. They met me there and had the tire swapped in 10 min! My question is did I ruin the outside dual by driving that short distance? I ask because when I got home yesterday I noticed the outside tire looks like a donut! It is completely separated. It is a miracle that we didn't have another blow out from Boise to Portland. That would not have been fun. The tires are Michelin, and the po said they were new. That was 2 years ago. I checked the pressure before leaving the Tetons and Boise and they were at 80 psi. I do have 2 slides and I am maxed out on the weight so this could be a factor. The driver side duals did great and are still at 80. Thanks in advance for the help.

[j-d]

If the inner dual was low on air, it was shirking its load, causing the outer to carry more than its share, before the inner tire blew out.

One of those cases where a TPMS would have helped.

I remain glad that you didn't have injury, damage, or extensive delay.

[pianotuna]

Hi,

Yes they are still load range E, however the 225 is 2680 LBS at 80 PSI and the 235 is 3042 LBS at 80 PSI. You have to derate for the duals, of course, but the difference is still about 362 lbs of load capacity per tire. These numbers are from the Michelin web site.

[Holiday27]

Hi JD,

Thanks for the reply, I'm pretty sure traveling that short distance did it. We were not going over 20mph but I realize that's a lot of wt. for 1 tire and 3 miles on the interstate. Maybe I should have refused to drive on it? AAA was paying for schwab to drive to me so that wouldn't have mattered. The tires are 2011 so it's not an out dated thing and they only had maybe 4000 miles in them. After the inner blowout the outside tire made it around 1500 miles before going south. The tire shop said it was probably heat and it was over 100 for the last 600 miles. I hear you on the spare. I should have one I just can't figure out where to put it. No room underneath. Might be able to rig something in the back but I need to keep the hitch clear.

Oh, one more thing. You mentioned cause of the blowout. The tire was low before we left. I aired it up and it must have lost pressure along the way. Schwab said a low tire creates heat and causes it to separate, so I'm assuming that's what happened.
Thanks,
Ryan

[Holiday27]

pianotuna wrote:
Hi,

You may want to "bite the bullet" and go to larger wheels with an offset for 235/85R16. I just finished doing so and so far I love the improvement on ride. I'm not sure yet whether fuel economy got better or not. I weigh in at 14000 lbs.

southwest wheel

I chose to do this to improve weight capacity on the tires.

Hi Don,

Thanks for the input, I asked the tire guy about this today and he said that wouldn't help. Being a curious person I didn't take his word for it. I looked them up on the web (235/85R16) and didn't see a difference. Still a load range E 10 ply tire. If I'm missing something please educate me. Thanks again!!

[j-d]

Yes, H27, to answer your question directly: Driving those miles on only one tire took whatever your rear axle weight is and put approximately 50% of it on the remaining tire instead of the normal roughly 25%.
**OR** and maybe worse, your words "next exit" tell me you were on a limited access, maybe Iterstate, rolling at or close to your highwa cruising speed. Tires already hot and stressed when all of a sudden all that weight dropped on the surviving tire. It was probably close to blowout right then.
Ironically, the rear inner seems to be the most likely to blow, and we think it's several things:
Inner, running hotter, with exhaust next to it
Extra load because the crown of the road loads inners a little more than outers
Repeated shock loads when the driver runs the outer tire off the edge of the
pavement, momentarily throwing the full load to the inner
What you went through was difficult, but you have lots of blessings to count. Most rear axle blowouts cause damage to tye coach body. In some cases LOTS of damage. We had one that was only minor damage but it still separated the body skin from the framework, ripped out the mudflap and bracing, loosened and nearly damaged the dump valves. I've heard of holding tanks broken, LPG lines torn out, etc. etc.
There may not have been enough of the inner to ever tell why it blew. If it was a road hazard, your fronts and the other duals might be just fine. Look at the tire date codes and see how old they actually are. That will help you decide what to do next. Michelin may be able to help you. I'd like to see you on a full set of known-good, trustworthy tires.
PS - Why I carry Spare, Jack, Blocks, HD wrenches, etc...

[pianotuna]

Hi,

You may want to "bite the bullet" and go to larger wheels with an offset for 235/85R16. I just finished doing so and so far I love the improvement on ride. I'm not sure yet whether fuel economy got better or not. I weigh in at 14000 lbs.

southwest wheel

I chose to do this to improve weight capacity on the tires.