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About 2 months ago I started hearing what I describe as a load humming sound that seems to increase with MPH speed (I don't recall replaceing or modifying anything at this time) - at the same time components in the front passenger area vibrate - sun glass holder - headlight switch. The sound seems to come from the right front passenger tire area of the car. I have had both front tires balanced - they are different brands and size - 225/65/16 & 215/60/16. I thought maybe the sound/vibration was coming from the engine/transmission but if I put the car in neutral while rolling down the road the hum/vibration remains. Are the tire sizes enough to cause this issue? Should I be checking wheel bearings, CVJ joints, etc?

Thanks...Bob

check sway bar link ends when I replaced mine it made a huge difference in my ride stability noise and greatly reduced shaking

Humming is typically worn tires or wheel bearings. Vibration could be anything. I don't know if mismatched diameter tires cause any of that by themselves, but I do encourage you to get matching size tires at least on the front. The difference causes the differential to be constantly be accounting for it and can cause premature failure. Maybe that's what's already happening?

225/65/16 and 215/60/16 on each of the front wheels? That's a huge difference and a 5% wheel speed error between the two sides. You're shredding your differential! And knowing that the diff is the weak spot on our cars, I would not drive the car more than to the tire shop. How long have you been running this mismatch?

About two months ago - I'll swap a back tire of the same size to the front and see what happens - I hope I have not caused any damage to the differential - I didn't know about the differential being a weak spot on these cars - I also didn't realise what I thought was a small difference in tire size is a big deal concerning wheel sensors and differential adapting - I'll also check bearings and sway bar if noise/vibration persists. I'll report back in a few days.

Thanks.....Milty

I swapped a same size tire to the front but still have the humming sound and vibration. I checked the sway bar it looks good and mounting hardware is in place and secure. I spun the tire and moved it in and out - to my knowledge the wheel bearing is ok. I drove the car down a long hill at about 30 MPH and put shift into neutral and shut off engine - noise and vibration remains. I'm wondering if brake shoes rotor caliper is hanging up and causing the issue - not sure what else to check. Any thoughts? Any other road test I should do?

Thanks....Milty

My vote is for the bad hub. Easy fix.

Sounds like a bad hub to me too, if it is the hub assembly try to get a Timken if possible.

I'm with the last two guys, thinking its a bad hub/bearing assembly. Had one go bad on my avalanche did the same thing at first, but that went south real fast on that thing.

I'll pull wheel this weekend and take a closer look - sounds like the problem .....Milty

milty wrote:I'll pull wheel this weekend and take a closer look - sounds like the problem .....Milty

If you have to pull the hub, spray the bolts with PB Blaster and wait 30 minutes or so before trying them. You'll need a GOOD 55MM Torx. Use a breaker bar to start loosening them gradually, no impact wrenches.