A brick came off a truck in front of me and I couldn’t avoid it - driver’s front tire ran over it. Now, I get a moaning noise starting at around 55-60 MPH - kind of like the noise when two airplane prop engines get out of synch. I replaced both front tires and the noise is still just as bad. There is no steering wheel shake, the car does not pull to either side and there is no noise under 55 MPH. Above 55 it is kind of a low pitched wha-wha sound which varies in intensity. It sounds nothing like a rock or cut in a tire (i.e., not rythmic)… more like a harmonic vibration that is only triggered above a certain speed. Has anybody out there ever experienced anything like this and found the cause???
One important thing you left out. What kind of vehicle are you talking about?
Tester
you could have a alignment check,to see if something got bent and for piece of mind on those new front tires
I wouldn’t discount the tire. It might be starting to separate from the impact. It might not show it right now, but why wait?
And even if it isn’t the source of the noise, if something is damaged as a result of the impact, then the tire might also be damaged - and the cost is relative low compared to the cost of an accident.
I replaced both front tires and the noise is still just as bad.
I would guess it is not a tyre unless he also ran over the brick with the back tyre and did not notice it.
I agree with old, and I also suggest that the OP provide more vehicle information - make model year and miles would be good. Add in color if you like.
With the vehicle up on a lift, check the entire path that the brick took under your car. Disc brake gravel shield, oil pan, transmission pan, drive shaft, park brake cables, splash shields, etc. I ran over a 2x4 which resulted in a bzzzzzzz. When i pulled over to inspect for damage…nothing. Start to drive again, bzzzzzzz. Pull over…finally I found the air flow while driving would flip up the splash shield from the running boards and it would rub the tire. When stopped it would fall back down into position and not be obvious. The 2x4 knocked out just one retainer from the shield and what a puzzle that was.
There are a lot of possibilities including having damaged a bearing.
And do not discount the rear tires as a possible source. Noise propogates in strange ways. The tires can be checked on a machine that does “road force balancing”. It spins the wheel with a spinning drum pressed against the tire to simulate road forces. It can detect internal problems that cannot otherwise be found.
The car is a 2004 Infiniti G-35 coupe with about 40,000 miles on it.
Many thanks to everyone who replied with a suggestion; I will try to follow your suggestions and will post the solution if I am successful.
Ken, thanks very much for your suggestions, which I’ll print out and bring to a mechanic. I suspect the problem is similar to what you describe… something knocked loose that only starts making noise when it resonates at a particular harmonic frequency. I’ll let you know if I find something.
Again, thanks so much for helping me.
Thanks, I’ll try to find a road force balancing machine here in Asheville. Worst case, I may just replace each of the two remaining (rear) tires with the spare, one at a time, to see if the noise goes away. I’ll also ask my mechanic if there is some way to inspect the bearing (I hope I don’t have to start replacing them just to eliminate them as a probably cause).