Pulsating tire like noise?

mitsubishi
lancerevolution

#1

I have a pulsating noise that sounds like tire noise but its difficult to tell whats making it. I get the noise when cruising around 40-55 mph, if I go any faster it dissipates. If I could compare it to anything its like the noise wind makes when you have a rear window down and the pressure difference makes that pulsing sound. I can tell its definitely coming from the front wheels though and is much louder on smooth roads. I tried shifting the wight of the car on a smooth road but it doesn’t get any louder or quieter toward either direction. I jacked up both sides of the car and none of the wheels have play when shifting them from the 12 and 6 o’clock position. Im doubting its bearing, but my tires have more wear on the inside edges when my toe was out but that was corrected quickly when I noticed. I also had the wheels balanced twice at two different places and they’re perfect. I dont get any vibration in the steering wheel at all. Theres also a torn cv boot on the drivers side and that axel is being replaced tomorrow. Im not sure CV joints can make a noise like what I’m having though. Any insight is appreciated.


#2

As a test, rotate your tires front to back. Did the noise move? If not, it isn’t tires and/or wheels,

Best guess is that the noise will move and that it is the one sided wear you have that is causing it and the only fix is to hope that rotating your tires allows another wear pattern to be worn - but that is unlikely.


#3

Let us know if the new half shaft solved the noise.


#4

I’m guessing it will.


#5

dam unfortunately it didn’t… I tried something different and threw the car in neutral while coasting at 40 with the windows up and swerved back and forth and when the weight is shifted to the passenger side it gets much louder, meanwhile I thought the drivers side axel was the thing causing it. the sucky thing is I just had that hub/bearing assembly replaced on the passenger side less than 15,000 miles ago… I don’t understand what happened to cause that bearing to fail so early, theres no play in it or anything.


#6

I just pulled the passenger side hub/bearing and it still feels brand new, it doesn’t make a sound when rotating it, at all. It feels smooth as can be and still new. The last thing I’m going to do is rotate tire but I’m at a loss as to what the sounds coming from.


#7

Maybe try some experiments first. Drive in high gear at a speed you notice the noise. Then speed up a little and coast back through that speed still in high gear. Do the same thing again, only coast back through that speed in neutral. Notice any difference between the two? Try it again, only in the next to highest gear. Now do those same experiments, only this time press on the brake pedal a little. Any difference?

If all indications are the pulsation frequency is related only to wheel speed and the loudness to turning direction, nothing to do w/the transmission, or brakes, and no obvious problem with the wheel bearings, axle shafts and what they mate to on each end, or the wheels/tires, are about the only thing left. Swapping the tires as an experiment around makes sense. If not that, looks like you’ll be replacing the passenger side half shaft in the near future.


#8

Okay so I tried what you said in 4th and 5th because its only noticeable around 40-55 mph before wind and road nose drowns it out. Shifting into neutral doesn’t change the sound at all but I did notice when I brake the sound increases momentarily maybe because the weight is shifted to the front? I had disassembled everything on that passenger side to check the axel and bearing and brakes and the axel and bearing hub assembly don’t make any nose when moving them by hand and feel smooth and solid as new. Im going to replace the bearing anyway. Is it possible that only the rear passenger side bearing has failed? I check that wheel for play and there wasn’t a hint of movement.


#9

Not all bad wheel bearings will feel wobbly when you check for play

Some will feel rough when you spin tire

A good way to narrow down these noises is using electronic “Chassis Ears” . . . Ray and Tommy mentioned this many times on the radio show, by the way. It really works, I use it myself, from time to time


#10

Concur w/ db above, see if you can find a shop with the microphone tool. That will tell you for certain which corner the noise is coming from. Once you are sure which corner it is, I’d guess it isn’t coming from the bearing hub ass’y based on what you say, but either the brakes or the axle. If you don’t want to seek out the advice of an expert at a local shop, you may just have to replace all that stuff one by one until the problem goes away. It is possible for a wheel bearing to make noise only when weight loaded and at speed, and test perfectly ok otherwise. But that’s unusual. Usually it will show push/pull/twist play, or make a grinding noise spinning it by hand on a lift. Some shops have the ability to spin up the wheel to a high rpm using an electric motor to see if the noise appears only at high spin rate, but I don’t think they’d do that on a drive-axle wheel. Only a free spinning wheel. I guess for a drive axle wheel they could put in in gear on the lift and spin it up that way using the car’s engine.

Good news that the sounds stays the same in neutral vs in gear, b/c that makes a transmission problem unlikely. Assuming you’ve swapped the wheels around w/no change, then you know it isn’t a wheel or tire problem. And since you’ve proved the frequency corresponds to wheel speed, you know it isn’t a suspension problem. Not much left other than brakes, axle, or bearing.