I have an Accord and Firestone put directional tires on the car two years ago. The tires are getting very loud and Honda said directional tires should not be put on Accords. Firestone said the tires don’t matter, that the car was not aligned, and that’s causing the “cupping” on the tires. I have record of my car being aligned twice last year, once in July at Firestone and once after a fish-tailing accident where I bent my rim. What’s the truth here?

How old in the Accord, and how many miles?

Here’s a discussion:

There can be more to it than just out of alignment.

"# Unfortunately, when the cause is the suspension, a qualified mechanic must replace the suspension and the tires. Since there’s a risk of the cause being a serious repair like suspension, having a mechanic check the vehicle is often worth the expense, in spite of the time it will take.
Odd Cupping Situations

If the tires experiencing cupping are on the rear only, the cause of the problem may just be with the vehicle’s alignment. Fortunately, in such cases, purchasing new tires and an alignment adjustment is more economical than replacing suspension and tires. If in doubt as to the condition your tires, take your vehicle to a qualified mechanic.

Since you don’t say how old or how many miles your Accord has on it, you need a good suspension check from a trusted mechanic. Then go from there. It would also help to know which model of Firestone tire you are using, as well as how many miles you have put on them since they were purchased. All of these factors enter into this particular equation.

To me, directional vs uni-directional tires are the least of the issue, but I have never owned a Honda so have never been confronted with Honda’s advice on this matter.

The big drawback of directional tires is that you can’t do full rotations on them.

I can’t really imagine why it would be model-specific though-- the only thing I could think of is that big front-wheel drive cars like the Accord do tend to have more uneven wear issues, which could perhaps be covered up by doing full rotations on them. So it may be more of a situation of the the guy at the dealer wouldn’t put directionals on an Accord, but Honda doesn’t say not to.

The Honda dealer is wrong and the Firestone dealer is correct.

Irregular wear is caused by misalignment and aggravated by insufficient inflation pressure and insufficient rotation practices.

My experience says that the published alignment tolerances are too wide. Not the target value, but the allowable deviation from that value. I think it ought to be half of what is published.

Put another way, the alignment should be within the inner half of the spec.

You should be aware that even vehicles that do not have a pull can be out of alignment. There are settings where one out of spec condition is offset by another out of spec condition ? typically camber vs toe.