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New Tires For Big Blue

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Nothing Special

Re: New Tires For Big Blue

Rusty_S85 wrote

On my KO2s I had to drop the some 70 PSI that discount put the tires at and reduce it to OE pressures cause my rear tires were pizza cutters with only the center 3" of tire contacting the pavement due to the tires having such a higher weight rating than the OE tires. So I ran mine down to OE pressures and I saw no reduction in fuel economy was still getting 12 mpg city, but I did see the lower pressure resulted in the truck riding so much smoother.

My KO2s were the same weight rating as my truck had OE (load range E), and at 50/40 I'm actually running below the OE pressures of 55/80. But those pressures are recommended with the GVWR in mind, so if I'm not running at full load I don't feel like it's wise to use the OE recommended pressure.

I have also run at 60/50. I don't see any significant difference in handling from 50/40, and the ride is only slightly "crisper."

I get pretty even wear at 50/40, so I don't see any reason there to go any lower.

And if I could get 12 mpg I'd be elated! I'm pretty happy when I can stay in double digits! Running a little higher tire pressure than a chalk test might suggest might not help much. But where I'm running any help is something to grab hold of!

Bob
Sorry, no '80 - '86 Ford trucks
"Oswald": 1997 F-250HD crew cab short box, 460, E4OD, 4.10 gears
"Pluto": 1971 Bronco, 302, NV3550 5 speed, Atlas 4.3:1 transfer case, 33" tires
"the motorhome": 2015 E-450-based 28' class C motorhome, 6.8L V-10
"the Dodge": 2007 Dodge 2500, 6.7L Cummins

Lima Delta

Re: New Tires For Big Blue

In reply to this post by Gary Lewis

For what it's worth I had a set of BFG KOs in 235/85r16 on my truck for 10 years, and they were excellent tires. I'm not sure if the KO2s are that much different, but it seems like it would be hard to wrong with a set of those. I finally got new tires this year. The old KOs still had probably 50% tread left, but were weather cracked.
All that said, I went with a new set of Toyo open country AT3s in the same size this time. I've only had them for maybe 4 months, but already I feel like I can say they're at least as good if not better than the old KOs for what I use them for (which is winter highway driving, towing and off road/farm use). We had some pretty bad late season heavy snow and slush to deal with this year. The Toyos were chewing through 6 inches of slushy snow without any hydroplaning which is more that I can say for the BFGs even when they were new. The other day I was backing a 6000lb trailer up an uneven grassy slope and I was really impressed with the traction. Nice and quiet on the road too.

Just two cents.
Lucas

Lucas
"The truck" - 1985 regular cab F250 4x4 - 351W HO, C6
"Beige Beast" (project) - 1981 regular cab F250 4x4 - 300 straight six, T18

Gary Lewis

Re: New Tires For Big Blue

Administrator

In reply to this post by Nothing Special

I've been running 35 psi in the Coopers and that gives even pressure across the tires and seemingly even wear. But I'll experiment on the new tires to see where they run best. Who knows, maybe they'll need 40 or more psi and I'll be over 13 MPG consistently. Wouldn't take much as I'm at 12.8 now.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Gary Lewis

Re: New Tires For Big Blue

Administrator

In reply to this post by Lima Delta

Thanks, Lucas. I'll read up on those tires.

Gary, AKA "Gary fellow": Profile

Littlebeefy

Re: New Tires For Big Blue

Autoweek just put out a review of all-terrain tires. This may be based on payola:

https://www.autoweek.com/gear/g40559896/best-all-terrain-tires

LittleBeefy aka Chad

“Dot Doitall”: 1984 Bronco XLT
460 (C8VE), Edelbrock Pro-Flo 4, ZF5, NP205, D44HP solid axle, 4.56
urban assault vehicle

"Bebe": 2022 Bronco Badlands 2dr
2.7l, Sasquatch, Iconic Silver, Black Marine-grade interior, hard-top

"Celeste": 1979 Porsche 928
4.5l K-jet, 5-sp, S4/GTS brakes, LSD, Pasha interior

Gary Lewis

Re: New Tires For Big Blue

Administrator

Thanks, Chad. And I really do appreciate you giving us that link. However, that's interesting but ... (what was it that Arte Johnsen said?)

They said these two things, with the emphasis added by me:

We've consulted with our friends at Tire Rack to examine some of the top all terrain tire options. Tire Rack is notorious for its testing and evaluation procedures, and we trust them to help our readers find the best tire, no matter what style they're after.

We turned to the vehicle manufacturers that offer trucks and SUVs with serious off-road capability to see which all-terrain tires they use as standard equipment. The automakers' engineers work closely with tire manufacturers to develop all-terrain tires that meet rigorous requirements for off-road performance, on-road ride-and-handling, noise level, resistance to punctures, wear, quality, and cost.

So they didn't do any testing. They simply did what I've been doing and perused the Tire Rack tests, and then checked to see what the OEM's put on their vehicles.

And they categorized applications by trucks & SUV's, Jeeps, etc. But I have a pickup I'm using as a Jeep. What tire should I use for that? And, does it really matter what vehicle it is on? Wouldn't it be more for the usage of that vehicle?

Also they said the OEM's choose the tire based on many factors, including cost. So if BFG cut a deal with them to sell the K02's at $2 less/tire than Falken did the A/T3W's then they would probably go that way - especially since there is almost a cult following of that tire.

Again, Chad, I appreciate it. But I'm not impressed with that "review". I have the same info available to me, and I disagree with how they arrived at their results. Tires have certain capabilities, like traction in various conditions and noise on various pavements, regardless of the vehicle you put them on. So to say you want this tire based on the vehicle and not the usage is flawed.

Also, do know what "notorious" means? What are they saying about Tire Rack?

Gary, AKA "Gary fellow": Profile

Littlebeefy

Re: New Tires For Big Blue

All true, Gary. Good to have the links for further research but definitely not for the well informed.

I'd like to throw one other piece of info out related to tires that most people don't know. Tire manufactures now produce N-specification tires. The "N-Spec" is a designation of the version of the tire design. You can find it printed on the tire as N1, N2, etc.

When a vehicle manufacturer designs a car, they often work with the tire manufacturer to customize an N-spec to their particular needs. When you produce enough cars, you get to custom order your tires, essentially. It is EXTREMELY common on newer European cars and tire retailers will often match your required N-spec without you even being aware (or they may not).

Even though our trucks may pre-date an N-spec tire, those tires are still out there new so there are some differences in tires that may seem otherwise identical. Two people may think they have the same tire but there may be subtle differences. Although it isn't brought up much, the N-spec matters; it means there is something different that the vehicle engineers wanted.

Littlebeefy

Re: New Tires For Big Blue

Let me clarify one thing. N-spec is an example for European vehicle tires. Different auto manufactures use different designations for tire versions and most don't use any at all. I just want to make people aware that those types of designation exist and to be cognizant of them.

Gary Lewis

Re: New Tires For Big Blue

Administrator

Chad - Thanks. I wasn't aware of the N-spec. But it makes sense that high-volume OEM's can get things custom made to better fit their vehicles.

Lucas - I found that Tire Rack did a test of the Toyo Open Country AT3s vs three other tires, and I added those results to the s/s. I wondered why I hadn't found that test before. But I finally figured it out when I looked up the spec's for an LT285/75R16 - none of those four tires come in my size.

So at this point I think the Falken Wildpeak A/T3W is the leading candidate, with the K02 coming in a very close second. And the wet stopping distance of 135' vs 149', respectively, is a big deciding factor. (And it'll make my son happy that I listened to him.)

I looked on Discount Tire's website and they want $324/tire, which is $32/tire more than Tate Boys and Tire Rack show on their websites. I think I'm just about ready to pull the trigger. Last call!

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

In reply to this post by Gary Lewis

You know Gary a lot of stiff carcass (10 ply) tires are not meant to be run at ridiculous low pressures.
I'm not saying your ten year old STT's aren't ozone cracked but under inflation is far worse than over inflation and can lead to a lot of this type of damage.
Mostly because of a stiff carcass causing a lot of heat when forced to flex much more than designed.

I'm reminded of the Firestone ATX/Wilderness tire debacle with the early Exploders... and that was Ford running them only 4 psi below nominal.
Belt separation and chunking caused more than a few deaths.

If you're going to be driving "aired down" over miles of trails (instead of just airing down across challenges) I'd suggest you stop looking at the door sticker and start looking at something like a load C flotation tire.
https://ok4wd.com/blog/what-are-flotation-tires/
At least they would stand a fighting chance.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

This post was updated on .

This... https://www.discounttire.com/blog/airing-tires-down
And this... https://www.takethetruck.com/blog/airing-down-tires

"One of the biggest issues with underinflating your tires is that if the pressure is too low, the inside of the tires can overheat—risking tire failure at one of the least ideal moments possible"
"Most off-road forums specify that it’s mostly safe to reduce your air pressure by 25% of your recommended PSI for comfort and traction moderate trails. For aggressive rocky terrain, dropping down between 30-35% would allow you to grip onto heavy rocks with ease."
Which would suggest 54-60 psi for the door sticker recommended 80 rear or 40-45 psi for the 60 I usually run on my truck.

I know you "want it all, and more" but I'm not at all surprised that your ten ply tires are getting destroyed when running 35 psi all the time and rock crawler pressures over many (277?) miles of trail.

ETA: a load range C tire (recommended inflation pressure 50psi) is much better suited to your 35 psi inflation, but it still shouldn't be run much below that, even off road.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Rusty_S85

Re: New Tires For Big Blue

In reply to this post by Gary Lewis

Gary Lewis wrote

Four of the K02's for the $1434, and that's $291.99/tire or $1167.96 for four. Tire Rack would get me a set to the house for $1167.96, obviously not including mounting, balancing and tax. So that's the $266 difference.

I'll be price checking 'cause they told me they'll match prices. But since the alignment was done at Tate Boys and they will redo it for free so the difference will have to be significant to make me want to change.

Dang thats pricy. When I got mine they were under $200 a tire which was the only reason why I got them.

"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2

Gary Lewis

Re: New Tires For Big Blue

Administrator

In reply to this post by ArdWrknTrk

Jim - I'll read up on that. We are out and about, running errands again, so I can't at the moment, but will.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

This from the Wikipedia page on the Firestone tires.
These tires were brand engineered for Ford, also relating to Chad's statement above.

"Operating temperature

A tire's operating temperature will increase with higher vehicle load, speed, air temperature and with lower tire inflation pressure. The combination of inflation pressure, speed, and vehicle load could increase the tire temperature as much as 50 degrees C above the ambient air temperature.
Higher operating temperatures will increase the rate of oxidative aging. Tires that were used in southern climates were also less ductile and stiffer than tires that operated in northern climates.
Tires in warmer climates also showed higher levels of cure and had somewhat lower peel strength.
The role of air temperature would explain why geographic regions with higher air temperatures had the highest tire failure rates. These results held up even for tires that had zero percent tread wear."

By this I mean to suggest if you want the compliance of lower tire pressure perhaps you ought to consider a tire with a lower recommended tire pressure (and a more compliant carcass)

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: New Tires For Big Blue

Administrator

Ok, I'm home now and have skimmed the material you linked to. And what you are saying makes sense, although I'm not quite sure yet what to do about or with it.

Basically my understanding is that running a tire at "reduced" inflation causes heat, and the farther you are under the target inflation # the more heat. And the faster you drive the more heat. Of course, the heat comes from energy created by burning gasoline, so having the right inflation pressure also helps MPG.

But is the "right" inflation pressure the max # on the sidewall? None of the vehicles we have recommend anywhere near the max inflation pressures for even fully loaded conditions. So when someone says "Traversing slickrock or more challenging trails with loose terrain, a 30-35% pressure reduction may be in order", are they talking about a 25% reduction from the max #?

Also, I want a 33" tall tire, and yet when I drop down to anything less than a E-rated tire they don't go that tall. Is that where the flotation tire comes in? According to the link you sent their sizes would look something like 40x13.50R17LT. But below is the table of available 16" tire sizes from Tire Rack and none of them look like that. What am I missing?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

The heat comes from the vehicle weight distorting the tire carcass.
And the stabilizing piles in that carcass flexing the rubber between plies.
Yes, speed means more distortion cycles per time, and therefore more heat input

The articles are talking about the tires rated inflation pressure...
With less than the sidewall pressure the load capacity is reduced and the self heating of the tire goes up. (WAY up if your pressure is way too low)

If pressures are too low you can spin the rim in the bead or corner your tire right off the rim.
That's why hill climb tires have bead locks and dragster tires are screwed to the rim.
They generally only have to operate for a few seconds at a time.

We used to play a lot with tire pressure and alternate inflation gasses like nitrogen when motorcycle racing.
Trying to get heat into the tire while not causing so much that it would get greasy or cook off the compound.
Or cause pressures to rise too much due to expansion.
Things are much better 40 years later....

I was suggesting you look at something like a 33 x 11.5 tire that would be a similar overall size but with a lighter carcass rated at 50psi.
I see some of the guys on Tacoma World shifting to 17" rims because 16" is basically an antiquated work truck size and only has E rated tires available.
Whatever.... unfortunately

I'm pointing out that your drastic under inflation in daily use is most likely causing a lot of the problems you're seeing with cracking and chunking. (because that heat has caused the rubber itself to cure more than the manufacturer ever intended)
You're already dangerously under pressure and "airing down" on trails is making it worse.

I don't have an answer for your tire situation.
The KO2's were available in a C construction but I guess not enough were sold so they were discontinued.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: New Tires For Big Blue

Administrator

I do understand what you are saying. Running a tire rated for a max of 80 psi at 35 psi daily is hard on it, and then airing it down to 15 psi is REALLY bad. But since I want a 33" tire on a 16" rim and the only ones appear to be E rated, I'm kinda stuck.

So perhaps I need to increase the pressure I'm running on the highway a bit, although I still want the tire to be running flat on the pavement. And maybe not go down to 15 on the trails.

The takethetruck site said:

General off-road driving on rough dirt roads, two-track, and mild trails - a 25% reduction or 10 PSI is a good place to start

Traversing slickrock or more challenging trails with loose terrain, a 30-35% pressure reduction may be in order

Very soft terrain conditions such as sand or mud may benefit from up to a 50% pressure reduction

So for the trails Bret and I are going on in New Mexico, which are typically forest service roads, maybe drop to 30 psi if we are running 40 on the highway. And then on the really loose or rocky stuff down to 20. And finally, if we get the truck into really soft stuff like sand or mud we could go down to 15. But we wouldn't plan on going over maybe 20 MPH at anything south of 30 psi.

Does that sound like a reasonable plan?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

You seem to miss the point.
10 psi from a 80 psi rated tire is 70 psi.
I'm running my tires at 25% from 80, which is 60 psi
80 minus 35% is 52 psi (an absolute minimum) and suggested for rock crawling (very low speed, and not all day long)

If you want to go down to 15 psi then even a P rated tire at 36 psi would be too much.
That's why companies like Mickey Thompson and Dick Cepek make entirely off road floatation tires for these conditions.
But you don't like noise or wear.

I mean, I don't care what you do but what "I want" and the reality of life and safety are completely at odds.
I'm only trying to point this out.
Do you wear ice skates in the house?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: New Tires For Big Blue

Administrator

LOL! No, I'm not missing the point. But I'm not going to run the tires on Big Blue at 80 psi. And maybe not as high as you are at 60. However, I will try different pressures.

But I do thank you for pointing the issues out.

And no, I don't wear ice skates in the house.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: New Tires For Big Blue

Administrator

What I'm saying is that 10 psi below your already too low 35 is NOT what those articles are suggesting.... 💡
And 35 is probably why your tires look like they do.

People that run 15 psi in deep sand are likely wearing very specialized paddle tires or if in deep mud, huge 'boggers'
50% of 32 is 16.
They don't travel 65 on the highway or expect their tires to last for years.
They tow their rig to the trailhead and likely air down for conditions. (i.e. they aren't even traversing terrain at those pressures)

You would do well to try and find some 6ply rated tires if you want to drive at 35 lbs for comfort.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

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