New Tires : Knocking sound as I drive

I have a 2003 Mazda Protege5. My rear tires were shot so I had my two front tires moved to the rear and had two new Kumho tires put on the front and balanced. Now when I drive, there is a faint knocking coming from the driver side rear wheel. It makes a thunking sound about once per revolution and exacerbates as I turn right.

Any idea what this could be?

I can’t comment on the knocking sound, but your tires were installed incorrectly. The tires with better tread always go in the back so that you don’t go into a spin (oversteer) if you lose traction in a turn.

That knocking sound could be loose lug nuts! That is not safe. Don’t drive the car until you check!

Also switch those tyres around. The best tyres always go on the back. That’s right, they go on the back FWD or RWD. In an emergency stop or evasive action, you need the best tyres on the back. With the best tyres on the front, the back end has a habit of swinging around to the front and you end up looking at were you were and not where you are going and have no control. Most good tyre shops would not have let you do that, but it sounds like you did not get a good tyre shop.

I want to second what lion9car said, namely that no responsible tire dealer will put the “better” tires on the front. All tire companies now mandate that the tires with the most tread should be mounted on the rear, so that you don’t lose traction on turns.

As to the noise coming from that one wheel, my strong suspicion is that the lug nuts were not tightened, and that the wheel is currently in danger of coming off!


In fact, you should check the lug nuts on all of your wheels for proper tightening. Ultimately, a torque wrench should be used to assure that all lug nuts are uniformly tightened to Mazda’s specifications, but for the time being, since this is a serious safety issue, do not drive the car until you are sure that no lug nuts are loose.

If I am correct about lug nuts being loose, that factor, coupled with the fact that the new tires should have been mounted on the rear, makes me wonder about this place where you bought your tires. Personally, I would avoid that place in the future, as they clearly lack competency, and this lack of competence has placed your safety at risk.

Incidentally, if you think that I am being judgmental about the tire dealership, I will admit that once, about 38 years ago, I was distracted while mounting my snow tires, and I neglected to completely tighten the lug nuts on one wheel. Luckily, when I came to the first turn, I realized what I had done, and I immediately returned home to finish the job. After I tightened the lug nuts properly, I gave myself a HUGE dope slap for being such a dolt.