Washboard Dirt Roads = Major Problems

zombiekiller said:

to supplement some of the commentary here, I will also say that the stock BFGs that come on raptors leave a lot to be desired.

They are light, they are load range C, so they have more give than most tires folks are used to.

any other tire on the market has a stiffer sidewall and makes the truck more predictable in the dirt.

I thought that my general grabbers, and the extra rolling resistance that they provide actually helped my truck A ton. It dorve way way smoother back to back when comparing bfg ATs to generals.

My truck likes that extra unsprung weight and resistance. YMMV, but this is what I've experienced.

I also recently switched back to MPT tunes from Cobb canned tunes. WOA. TC and stability control pull a TON of power. Once I disabled both, I'm able to spin heavy 37s going 35 MPH. My point in mentioning this is that some of the trucks weird behavior might also be alleviated with even a canned tune.

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I've only had my new tires for two days, but the difference between the two tires is substantial.

Ford knew what they were doing with tire choice. The BFG is serviceable in all conditions, but very biased towards road conditions, specifically road compliance and high fuel efficiency.

That said, they don't grip particularly well anywhere. I would argue my new coopers have 3x the traction - to the point where (even during break in) I can run 2wd in areas I previously had to use 4wd.

BushwiickBill said:

Airing down for proper offload usage is mandatory but you don't have to go to the extreme with it either. I just finished a desert run (77 miles) all dirt today running 38F, 34 rear with some heavy washboards with no issue of control in my 19. I would air down more for offloading but that pressure works great for street and offload and I'm lazy because I don't have a Power Tank or Viair. I feel some of it is the driver...can't be afraid to push these trucks. High speed is what they love!

I'm wondering if there is a valid issue with the original poster's truck if it's as extreme as he states? He's comparing it to an old 4-Runner which performed better in his opinion than his Raptor on the same terrain. Just that statement means there has to be an issue with truck, driver (not sure of experience) or both.

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When you say you run 38F and 34R is that checking them cold or hot?

Side note - how accurate are the TPMS? I find a few psi and random difference between what my vair400p reads and also a small Jaco reads

tacomoth said:

Side note - how accurate are the TPMS? I find a few psi and random difference between what my vair400p reads and also a small Jaco reads

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Who knows. Is every TPMS accurate to the same +/-? I use the Viair to fill, one gauge to read pressures and use the TPMS as early warning.

Dhowell said:

When you say you run 38F and 34R is that checking them cold or hot?

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Cold

BushwiickBill said:

Cold

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Hot

With reference to airing down for off road play time, what kind of speeds are considered safe at ...lets say 22psi?

rsbug said:

With reference to airing down for off road play time, what kind of speeds are considered safe at ...lets say 22psi?

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It depends what terrain you are running on. Asphalt heats up more than dirt and heat is the real problem of airing down. I have fun my Jeeps at 50 mph on dirt at about 12 psi with no problems. The faster you go and the hotter the tires get, the higher the pressure will go. I just wouldn't run it down the pavement at speeds higher than about 45 at PSI lower than normal for very long. Short sprints would be no problem. Radials are very forgiving, not like the bias plys back in the day. Also, if the temps outside are 100, the tires will get hotter faster.

jzweedyk said:

It depends what terrain you are running on. Asphalt heats up more than dirt and heat is the real problem of airing down. I have fun my Jeeps at 50 mph on dirt at about 12 psi with no problems. The faster you go and the hotter the tires get, the higher the pressure will go. I just wouldn't run it down the pavement at speeds higher than about 45 at PSI lower than normal for very long. Short sprints would be no problem. Radials are very forgiving, not like the bias plys back in the day. Also, if the temps outside are 100, the tires will get hotter faster.

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Thanks for the info

rsbug said:

With reference to airing down for off road play time, what kind of speeds are considered safe at ...lets say 22psi?

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I'm going to disagree with the 45 mph remark.

I've done up to 100 miles on pavement at 20Psi Cold ( Showing as roughly 25 Psi Hot) without issues. Would I try to drift around a bunch of switchbacks in a 7000 lb truck at 22psi? no.

But, I've logged almost all of my road miles at 32 psi cold, which is a fair bit below what the manual says. How many you say? New Orleans to Santa Clara, CA. Shortly thereafter, Johnson Valley, CA to New Orleans, LA.

Keep in mind that most of ultra4 drivers put the tires at 25 psi and leave them there. bashing rocks, then zipping across a lake bed at over 120 mph.

I wouldnt press my luck and drive for hundreds of miles below 20 psi ( cold), but I'm still here ( as are the 25 other trucks that were aired down to similar pressures the last time i did it.).

and none of us were particularly nice to our tires in between the 20-100 miles on highway from end of trail to hotel for the night. We were doing anywhere from 100-260 miles in the dirt each day, with the highway drive afterward.