I just received the first 2 of 4 BFG Mud Terrain tires for my '01 Screw, they are 285/70-17. I had to put these 2 on the back because the backs were bald. Here is the thing, when I drive down the road now when I go into a curve it feels like the backend is coming to slide out. Before you say it, no I'm not going too fast, can't here on Italian roads. I'm just wondering what is going on. Anybody have the same problem? Here are some theories I have:

1. The tall tread of the tire lends it self to bend more in turns and cause the back to feel like it is sliding out.

2. I aired the tires up to 65PSI as stated on the side of the tire, maybe too much air for this truck, any suggestions/ experience?

3. Because I only received the 2, I still have the 265/75-17 stock tires on the front, waiting to get the other 2, looks dumb I know. Could the difference in size be causing an "unbalancing" from front to back?

Any suggestions or help is greatly appreciated.

LT Dan

 

65 psi seems like a lot of air for that size tire, I would think more around 35 to 40 psi. I really don't know why it feels like your backend is sliding out, I would check your lugnuts incase they didn't tighten them properly, that might make it feel loose. Good luck, and I am sure you will feel a difference once you get all 4 new tires on.

 

First, that is way too high an air pressure. I run 40 psi in mine.
Second, you should never mix tire sizes on a 4x4. It will cause your transfer case to bind up. That may be what the problem is.

 

AIR DOWN !!!! Having run BFG MT's on my last lifted truck, you need to keep them around 35PSI for good traction, I would even run them at 32PSI for most of my in-town driving.

Second, the galvanized rubber on the MT's was a bit "hard" when they are new, and soften with some wear-and-tear. You can also have the tires "siped" when new to reduce the breaking in period.

Hope this helps!

 

Those tires are rated for 65 psi, but you would prolly like them better at about 45 psi. I have the BFG AT's and that is the psi I run mine at (45), unless I am towing a heavy load, then I air the rear tires up to around 60 psi.
Don't deflate them to 32 as another member has stated. The outer edges will wear prematurely. These tires are LT rated tires. That means the sidewalls are stiffer than "P" rated tires. These tires need the extra air pressure to keep the center of the tread in good contact with the road. If you air them down below 40 psi, the outer edges will wear more than the center of the tread because of the stiffer sidewalls.
LT rated tires are built with higher inflation pressures in mind and should be ran with those higher pressures as they were intended.
Think of it this way....you would never inflate a "P" rated tire to 65 psi, because it isn't built for it, so don't deflate an "LT" rated tire to 32 psi, because it isn't built for that.

 

Oh yeah, I have never heard the term "galvanized" in reference to rubber....only metals. I would be interested to learn exactly what that means.

 

DANZITSCREW..............
Just curious....
I would like to hear how you have come to find yourself in Italy with a Screw? It must be an interesting story. Please enlighten us.

 

Interesting read! Buy why rear slide? Hum? Sounds like you're driving on non-paved surface? Anyway, 4x4's really should run all 4 tires as closely matched as possible. In your case I would recommend removing the front driveshaft until you get the new fronts. 4x4's can usually only stand about a 1% difference front to rear for highway use. And I'd guess that you've approximately 5% or more difference if the fronts are stock.

For tire pressure there's a simple trick; take a piece of chalk and mark a line across the tread block of the tire. Drive straight on paved or concrete surface just far enough to wear some of the chalk off. When the chalk wears even across the tread surface, you've got the correct running pressure. If you carry a heavy load repeat the above and remember the pressures optimal for that load. I would not recommend going over the maximum printed on the sidewalls.

With pressure high the center wears faster, low and the shoulders wear faster. Factors other than weight that effect what tire pressure is optimal for tread wear can also be effected by wheel width.

 

Wandell-
As for the matched tires, I agree, but the Navy doesn't and has misplaced the other 2 that I ordered. So until I get them, this is how I have to run it. As for the transfer case, I agree, running 2 different sizes will tear up the transfer case. However, I haven't run the truck in 4x4 since I did this, because of that reason. My understanding is that the transfer case is not connected unless I have it "shifted" into 4x4, this is how it has been on all my other trucks, is the Screw different?

Rebelyell-
I appreciate the idea and will give it a try, I think 45-50PSI is much better.
As for how I ended up in Italy with a Screw, that is a decent story. If you read above, I am in the Navy. After September 11th, my wife wanted me to get out of the Navy after 5+ years so I could be home with the family more. However, after the war in Iraq started and my operational unit with the Marines was sent there I just couldn't sit on the sidelines anymore, I needed to be back in the Navy. We talked and I decided, after being out for 11 months, to go back into the Navy. I quit my civilian job and went back to where I belong. I couldn't go to Iraq because my unit was already there, so I asked to be as close as I could, so they sent me to Italy. Interesting thing is, when I rejoined the Navy my wife joined too. So now we are both stationed in Italy, was able to bring my family here as well, got 2 boys with 1 on the way. We are located on the Island of Sicily at the southern tip of Italy. We are nicknamed the Hub of the Med. Nothing goes into or comes out of the Middle East without going through us. The Screw definitely drwas a lot of attention around town. The ocals have no idea what to think of it. Ford sells the Focus and a car called the Ka, smaller than the Yugo, here. So when they see the Screw with the Ford emblem, they don't know what to make of it, it's funny to watch them stare. Thanks again for the help.

Tycreek-
I appreciate the thoughts, but no off-raoding with them yet. However, many of the roads here in Sicily feel like dirt roads even though they are paved. The roads here are beyond horrible.

Thanks guys.

LT Dan

 

Thaks for the reply Lt. Dan
We appreciate your service!

As for the transfer case, I am pretty sure everything is being powered except one front axle. The open front diff makes it 2 wheel drive. When you select "4x4", it mechanically engages the other front axle, making it 4 wheel drive.

But I have been wrong before...maybe two or three times I will check my truck tomorrow, time permitting, and get back to this thread to verify if I am right or wrong about this, but most late-model 4 wheel drive systems work in a similar manner.

Perhaps someone who already knows for sure will post ???

 

Rebelyell-

I did airdown the tires to 50PSI and they still seem to do it. I also noticed that I do not have a "complete" contact patch as well. The dirt doesn't go all the way to the edge of the tires, so maybe a bit more needs to come out.
I hear what you're saying about the 4x4 system. I thought the transfer case was not running unless the 4x4 system was engaged, at least that's how the older ones worked, the new setup maybe different. It would make sense that the rear is trying to "overdrive" the front because of the difference in tire size. However, I would have expected some binding of some sort. I'll try and check with Ford today, see if they have some answers about how the system functions. Stay tuned.

LT Dan