Hi Guys, on the road with the kids this weekend and here's what happened...

A belt separated on one front tire, then went flat. Got it swapped for the spare and made my destination. Next morning, I took it into Discount and let them have a look. The set of tires had about half their life left, so we just replaced the bad one and the one with the least tread-life left so I was replacing a pair. I have never had a problem with this before.

When I got back on the road, the truck's handling now feels "mushy" for lack of a better term. It was very responsive before, but now, if you swerve or switch lanes, whatever, it feels like it is in slow motion. I can almost see the rear of the truck trying to catch up to the front. Feels like what I expect with weak sidewalls on a truck or maybe even shocks that are going bad. Doesn't quite feel like it is about to break loose, but close enough to concern me. It did not handle this way before.

I'm still on the road and have adjusted the tire pressures to see if that helps any today. I mentioned it to my step-father and he said he had the same thing happen to him on his Dodge. Said that it didn't stop until he put another pair of new ones on there. The only thing the tire shop told him was that maybe the new tires were gripping better than the old ones and that caused the suspension to act different front to back. Ever heard of that?

Here's the specs of what is on the truck now.
Front (old tires): 285/75/16 Load range D - Dominator Sport AT
Rear (new tires): 285/75/16 Load range E - Pathfinder All Terrain

I wouldn't expect the different load range to cause this. I know that the D sidewalls are weaker, but that's what I had to start with and they were fine. Unless the stiffer Es are making the rear more responsive and the mushiness I feel is really in the front and tricking me. Shrug.

Please don't turn this into a E vs D argument. Bottom line is I put the Ds on there because they were what I could get in the size I wanted at the time and have been just fine. I prefer the Es though. They don't make that model of tire (old ones) anymore and the new ones are the model that replaced them. I did not know that the new tires were Es, I was in a hurry, dropped off the truck, told the clerk to call me with what he could do. After they were on and I picked up the truck, I noticed they were Es.

Any thoughts? I'll go buy another pair if I have too, but I hate wasting that half (or more) of life left on those treads.

Thanks for any input.

 

How much pressure on each set? You know the E's need a lot more pressure than the D's, right? The mushy feel sounds like soft tires, maybe due to pressure.

I don't think the difference in tires front to rear would cause that problem, as long as each tire type is inflated properly. Assuming proper inflation, I would test swapping the fronts with the rears.

You didn't mention how much load you are hauling.

 

You may have answered your own question here. The difference in the sidewall strength and flex is probably the culprit. I agree with Bill on the inflation and I would check that as well. However, if you swap them and continue to have the same problem, I would guess that replacing the two "E" rated tires you have with "D"s may exacerbate the problem and give you more of the mushy feel you talked about. With the "D"s, you may have to inflate them to the max. PSI to get them stiffened up enough to get rid of the flex you're experiencing.

 

Just got home and it was a pretty irritating and stressful trip. I can better describe this feeling as the same as if you were hauling a trailer and the fishtailing you may feel when swerving or changing lanes abruptly. Everytime I turned the wheel or came out of a curve, it felt like I had a trailer behind me fishtailing and pushing me around. I also noticed that the wake off the tractor-trailers pushed me around too. I can always feel them and the never really affect me, but today when one would pass, my truck just moved right over like it was a Honda.

To answer the items mentioned above...

Yes, the Es need more pressure. When I left the tire shop, both sets were at the max. I drove around like that for a while and then lowered the pressure to see if that helped. (I have had issues before with the back of this truck getting squirrelly when empty and tires aired to the max) No change regardless of the pressure in the tires front to back. I stopped and tried a few different levels.

Empty this trip. Just me, the kids and some luggage. But the truck has never been this bad unloaded. Even before the tire blew on Friday, it was fine.

The new tires are the Es. If I replace anything, it will be the remaining Ds for new Es. The last two sets of tired have been Ds and I have never had this kind of issue. I am thinking that either the difference in sidewall strength is causing the front/rear to act different enough to cause this OR that maybe the diameter on the new and old tires is enough to cause a problem. When tires are different diameters front to back, they will roll at the same linear speed, but at different rotational speeds and that can cause some strange things to happen. It's a little different than if they are different diameters side-to-side. In that case, they are at the same rotational speed, but different linear speeds and you get a pull to one side. Anyway, there shouldn't be much difference in those diameters since the existing tires still have half their life left, but I guess anything is possible.

 

It could very well be the difference in the deflection of the tires much like how sway bars can be miss matched. If the fronts are very stiff (less deflection), then they are more responsive then the rear, the rear (less stiff) would flex as it tried to follow the fronts. You can probably reduce the pressure on the fronts to get the same deflection as the rears and match it back up some.

I'm only guessing though, but I've heard of over/under steer problems with miss matched anti-sway bars.

 

The situation you describe Scott is similar to what I experienced years ago when mixing bias ply tires with radials. Each axle tries to do it's own thing. Your best bet is to get the same load range on each axle.

Terry

 

You've got mismatched tires front to rear.There is no way a D vs. E debate can be avoided.

 

I posted a thread with the same issue a month or so ago.
Pulled the same stunt with the same results.
Running Firestone "pavement" tires on the front
Installed General grabber at2's on rear.
All 265/57/16, all rane E, all at sticker recomended air pressure.
Running empty, it behaves just like you described.
Loaded, no problem.
Drove 1800 miles from PA to western KY and back and it was not cool.
Anytime the pavement was uneven or just drifting out of the "tire tracks" in the right lane, the truck would just take off.
Like what was said, it was as if there were an 8000 lb trailer throwing the rear of the truck around.
We drove home in one day (13 hrs) and I was physically exausted from the continuous two handed strangle hold I had on the steering wheel.
I've driven trucks with big mud tires and I don't expect them to handle like a corvette, but this is rediculous.
In the other thread, someone said that it might be that the tires are mismatched, I'll see if I can prove it when the other tires come in. I might make them put the replacement tires on the front, first, so all 4 are the same.
Someone else said that the problem is "tread squirm", meaning that the blocks on the tread squish around independently of one another causing poor handeling. Once again, yes, I don't expect a AT tire to handle like a street tire, but this is beyond that. I have had many sets of BFG at's and these grabbers, without one bit of problem, period. Nothing ever like this.
Getting the back tires warranty swapped this week. I'm not leaving the tire store until I would feel comefortable letting my girlfriend, father, or anyone else drive the truck.
Good luck and I'll let you know.

 

OK, I spent the morning at Discount trying to fix the problem. As a last resort, I ended up buying another set of these tires so I have four matching all around. One suggestion was that the tread pattern on the old tires was more open and the pattern on the new ones were interlocking so that was causing a different reaction to the pavement. I'll say this, with the new tires on the front, the problem is diminished, but still there. Just feels slow to respond now. As mentioned above, I don't expect this to handle like a sports-car, but I want it to at least handle like it did last week.

I have never used anything with an "interlocking" pattern. Always either a highway tread or a open pattern. Is this "tread squirm" characteristic of the interlocking treads.

This is getting frustrating and expensive. I suppose that when the belt separated on the first tire, it could have broken something, but I didn't let it shake very long and I haven't seen anything loose or broken. In fact, on the spare, the truck handled fine.

I just meant the debate about whether we should be running Ds on these trucks or not. Search the forums, there's plenty of those to go round.

Thanks for the replies guys.

 

Did you happen to see how they lifted your truck to install the first pair of tires? Did they lift it by the frame and let the front axle hang by the springs?

 

bpounds, it's a 2wd, so that is probably not and issue, but it is a good point. I did notice that this Discount has been remodeled and they have all new racks. Hopefully they are lifting the trucks correctly.

Anyway, I did a little research on these particular tires at a couple of review sites (including theirs) and it looks like I am not alone with this behavior. It seems that if you have a half ton or below (any brand) you love these, 3/4 ton and above (any brand) they walk and fishtail. There are enough people describing the exact same problem I am having to convince me that these tires are the culprit. I am thinking that I was seeing a combination of two things originally.

1. These particular tires don't perform well on these trucks.
2. The mismatched front/rear compounded this issue

They have agreed to refund these for me and order in a set of tires I have used before with good results. Getting back to a more highway type tread will be nice anyway. I'll post next week after this happens if all is well. Luckily, I can park the truck this week and not fight it.

Thanks for all the input.

 

Interesting thread.

I had the same behavior when I put Goodyear Silent Armors on my '01. Putting the cap/topper on it, it went away completely. About 200 lbs and it changed everything? Very weird. Took the cap/topper off two years later, and no fishtailing whatsoever.

Put Nitto Dura Grapplers on, and it's doing it again. Have yet to figure it out, haven't had the time to play with it.

I do have a Hellwig rear sway bar which is MUCH larger than the stock ones you see. I might disconnect it to see if it's got anything to do with it.

 

Update on my truck. The tires came in sooner than expected and so I had them installed yesterday. Night and day. The truck doesn't handle like a sports-car, but it is back to what I expect. No more crazy fish-tailing, over adjusting, or drifting.

So, I am going with the Pathfinders causing this issue and the mismatched tires initially exaggerating it.

 

Not related to the original topic, but I mentioned it earlier, so for what it's worth, I put my spare back up under the bed, and the fishtailing is almost completely gone. Weird.

 

Truck is fixed!!!
I'm not going to post the same thing twice, they will hunt me down!
You will have to read about it here.
I hope I got the link right.
https://www.ford-trucks.com/forums/8...ml#post7672468