1998 F-150 4x2 with 82,000 miles. Front end vibrates at about 25 mph on up. The tires are Kelly AWRs with 18,000 miles on them. They have some cupping, the rear tires have more cupping. The front end was just aligned and the front end has been checked by Ford and all is OK.

This spring replaced all 4 shocks, lower ball joints, and outer tire rods.

It seems for the14 months I have had the tires I have noticed some vibration. Nearly every time the tires were rotated I needed to go back in a week to get them rebalanced because of vibration - mostly at higher speeds. Now the vibration is at lower speeds.

Today, the kid at the tire store where I purchased them called Goodyear and said they would prorate the rear tires 50%. I said that's great, but what about the front tires. He said they are not that bad. When I asked him why the I get vibration coming from the front end - he just said that thge vibration is is actually coming from the rear tires and is transferred to the front end. I think that is B.S.

Any opinions? Would bad tires cause a vibration at speeds of 30 MPH? I'm not sure what my next step is. First I want to make sure I am not missing anything, so any advice is appreciated.

 

It could be your tires. I have a vibration between 40 and 45, which has been diagnosed as a tire problem, that feels like it shakes the whole truck. Depending which pair of tires is on the front, sometimes the vibration is more pronounced in the front.

Does it vibrate when you have a relatively heavy load in the bed?

have you tired geting them raod force balanced?

 

I usually don't have anything in the back of the truck, and I don't even know what road force balanced is.

At this point in time, I don't think balancing will help because the tires are cupped, and when driving, aside from the vibration you can fee/hear the results of the tires being cupped. I also think there is more going on with the tires other than cupping, but I just don't know what it could be. They just don't give a smooth, quiet, vibration free ride.

 

Maybe you need to change the air in your tires... ??

Just kidding.. sounds to me like its your tires. You've replaced everything else already.

 

"Maybe you need to change the air in your tires... ?? "

Actually, that's not as funny as you may think. Someone at work today suggested adding 4-5 pounds of air pressure. I went out and checked the air pressure which, according to Ford should be 32 front and 35 rear. When the tires were rotated a few weeks ago the pressure wasn't adjusted and the fronts had 36 and the rears had 32. So I adjusted the font down to 32 and the rears up to 35 and this resulted in less vibration.

I'm thinking that:
1) my shocks that I replaced may have caused the cupping
3) the cupping is causing the poor ride, and
2) these particular tires are just not a good match for my truck

 

Road force balancing is a newer method where the tires balances while pressure is being put on the tire to similate the weight of the vehicle on the road. Using this method, they are able to align the tire to the wheel better and balance the wheel/tire combo accordingly. A lot of places still do not have this type of balancing equipment, yet. However, it is becoming more popular.

Try jacking up the rear end, putting it gear, and watch the tires from the side and the back. Do they look like they wobble either horizontally or vertically?