Yet another BFG Tire fail.

[REF]

Right, my point was, hot or cold that's still very high, tire pressures only change so much dependent on ambient air temp or whether you've been moving or not. Assuming they were they set at 70-75 cold and they're an 80 psi max tire, while running in hot temps they could have easily been at or exceeded max pressures. Not saying they should have failed, but just trying to come up with a possible explanation to the failure so you can avoid a repeat. Better yet, avoid another set of BFG's, too many stories, try the Toyo a/t in an E rating.

[coyotearms]

Yikes! There seems to be some very strange info flying around this topic. The Ford sticker at the drivers side door for stock LT245/75/R16E tires says use 60/80 psi COLD for back/front and I am talking about my 2008 E350 just as stated in my signature below. There is no mention on that sticker about how much is being carried as many passenger vehicles do. When I up-sized those stock "city" tires with Goodyear Wrangler Pro Series LT265/75/R16E at Discount Tire, nothing changed regarding tire pressure; their computers say that is the correct pressure for the larger tires---it is right there on the receipt for the tires and each time I have them rotated. I am right at 10,000 lbs when fully loaded for long trips. I would never think of highway travel within the speed limit at any other setting and any ambient temperature, and I mean checking them every few mornings "cold" whatever the ambient temperature is.

I owned a 2006 Mustang GT that came with high performance tires. When I looked at detailed tire data from the manufacturer for 100+ mph highway driving for those 150 mph tires I was surprised to see how HIGH the recommended pressures were for those higher speeds. I did that after reaching 140 mph on a highway in Oregon that seemed to be the perfect place to see how the car felt up there. The tire data made me feel like I did a pretty stupid thing by going that fast without changing the pressure! What is done at race tracks is an entirely different story and beyond my pay scale, nor do we need to worry about that when driving our monsters on the highway.

I have no answer for exactly what to do when airing down over long runs of unpaved roads, but I do not drive very fast in that situation. Wall flexing when airing down in itself is a heat generator and you have to be careful. An apparent "mystery" for why a tire failed while on paved roads could indeed be related to the entire history of how that tire was treated. I traveled throughout Alaska during the summer of 2014 and had two flats, both on unpaved roads. When the first was patched side cords started to pop when it was inflated on the machine, so it was toast. The second one was patched and became the spare for the rest of the trip because a blister was discovered inside the tire on the side wall. Discount tire replaced it when we got home. So I too, have "unsolved mysteries."

[MadScience]

coyotearms: How do you like the Goodyear Wrangler Pro Series? They are a non-like replacement that popped up in my size that looks promising so far.

To further clarify, the procedure that coyotearms outlined is correct. My cold pressure choices are based on discussing my use with my tire shop. I fill/set mine at ambient in the mornings. Since something felt funny while driving home, we stopped, checked temperature, pressure and looked at the sidewalls. What I also should have done at that time, is check for bulges on the tread as well.

We can't really talk about a couple PSI this way or that way between 60 and 80: All my gauges (milton, viair, arb, cheap stuff) disagree by 3-4 PSI in that range.

My other take-away is that with off-road use, I really can't rule out any sort of damage that could have easily resulted in something that led to this. This means picking a tough tire and doing a good job during regular inspections.

[rallypanam]

Originally Posted by MadScience

Pressure was 78 PSI a couple miles prior

Originally Posted by MadScience

I fill/set mine at ambient in the mornings.

So, out of curiosity, if they were 78 on a hot day after driving for a while, what is the increase from cold? i.e. what did you have them set at in the morning at ambient?

[MadScience]

I'm curious what the thought process behind the concern about the precise pressure is? As coyotearms points out, Ford tells us to run 60 and 80 on different ends of the vehicle. These are the same tires. Clearly the tires can handle that range. My axle weights are pretty similar, a bit higher in back, much higher if I had been towing.

Originally Posted by rallypanam

So, out of curiosity, if they were 78 on a hot day after driving for a while, what is the increase from cold? i.e. what did you have them set at in the morning at ambient?

I filled them to ~77 with the milton that's attached to my compressor. When I checked them I used a viair gauge. I know the two don't entirely agree. The tires all felt warm, but not hot to the touch, most importantly, no outliers. -- I'm not sure that answer helps, but it's all the real data I have, and why I'm not overly worried about a couple PSI one way or another. With the gear that I carry (or anyone can reasonably expect me to carry), this is as close as I will come to 80PSI while generally erring on the side of slightly under. Why under? Because that puts it within the range that the tire and vehicle manufacturers tell me to use.

I stopped past my usual tire shop to order replacements and discussed the failure, as well as my procedures, with them. They did not advise any change in filling. They weren't even sure that I would have seen anything if I had checked the tread at the time, but did agree with doing it.

[REF]

I think the idea was to see what the range of pressure change occurred in your tires from cold to hot, and if it's possible a large enough swing in pressures over a period of time could have caused the failure. I hope that going back to the same shop, and running the same tires, you don't end up with the same results.....

[E350]

Michelin.

[coyotearms]

Originally Posted by REF

I think the idea was to see what the range of pressure change occurred in your tires from cold to hot, and if it's possible a large enough swing in pressures over a period of time could have caused the failure. I hope that going back to the same shop, and running the same tires, you don't end up with the same results.....

I am sorry, but if you are implying that setting the pressure cold to 80, but reducing it after driving if it exceeds 80, I strongly disagree. The spec sheet for my Wrangler Silent Armor LT265/75R16E state "Max Load @ INFLATION (LBS) = 3415@80, which happens to correspond to the pressure spelled out on the Ford sticker for the rear tires. Given that my rear axle load has been measured at a little over 6,000 lbs. if I set those tires COLD to 80 at whatever the ambient temperature happened to be, I would never lower it after driving as I am so close to the max load rating. LOWERING the pressure after driving would most likely cause the tire to get even hotter due to more sidewall deformation. BTW, I just read all the text on the side wall, and it clearly states the above stated load rating/pressure explicitly adds in big letters COLD.

MadScience,
Out of the carnage of two tire failures in Alaska I learned from a Goodyear Truck Tire Garage that the above tire no longer has the snow flake on it due to a change to a harder rubber and thus is no longer considered in some states and Canada as legal when chains are required. That garage happened to have a used Silent Armor, which I bought. Later, after talking to tour drivers who use E350's to take tourists up to Prudhoe Bay I learned that the Goodyear Dura Trac (more aggressive tread) is a popular tire in Alaska, including E350 tourist vans, and has the snow flake. The Ford dealer in Fairbanks also indicated the tour company whose vans they service uses the Dura Trac exclusively. Thus, when I got back to Seattle, I replaced the second failed tire with a Dura Trac for the spare. Whether I will buy a complete set when the time comes, depends on what is available then. I think the Dura Trac does not have the tread wear warranty that the Silent Armor has, which is probably even better with the harder rubber. At about 40 kmi on my Silent Armors they have quite good tread.

A further interesting fact that I learned from one Tour driver was that he does not air down but never drives over 35 mph on unpaved roads and almost never gets flats on the Dalton Highway (to Prudhoe Bay)---food for thought!

One last thought. A couple of weeks ago I attended the NW Overland Rally near Leavenworth, WA. There was a "class" where two car drivers and one motorcyclist discussed their travels on both the Dalton and Dempster Highways. They said unless you neglect your tire horribly, you should have no problems. I stood up and strongly disagreed! Poop happens, I said, and told the audience that I doubt I would return to Alaska without having TWO spares and repair kit, in part due to the latter item unable to fix the rip in the tread I got on the Dalton even with 4 plugs. I did hear from truckers that it is not unusual for them to put even eight plugs in to fix a flat---I guess I was not persistent enough! Of course my experience could be due to being incredibly stupid about something I did with my tires, but I challenge anyone to tell me what I do wrong.

[rallypanam]

Originally Posted by MadScience

I'm curious what the thought process behind the concern about the precise pressure is?

I'm just wondering, as I've never actually measured cold and then measured hot, so I was wondering what the delta was.

Originally Posted by MadScience

I filled them to ~77 with the milton that's attached to my compressor. When I checked them I used a viair gauge. I know the two don't entirely agree. The tires all felt warm, but not hot to the touch, most importantly, no outliers.

So, not accounting for a few degrees swing between gauges, they only went from 77 when cold to 78 when hot? That is lower that I would have thought, but leads me to believe it doesn't really matter when you check pressure, as long as you're not seeing huge swings in ambient temperature.

[rallypanam]

P.S. I've run BFG ATs (always load range E) on a four different Ford trucks, generally overloaded, generally on very poor roads, and for tens of thousands of miles, and never had so much as a flat.

Not sure what my secret is, but I do usually run on the lower end of pressure, around 60. But I am not religious about checking.