vibration - F-Body Online

badbird5.7 · 11-19-2007, 08:47 PM

i have this vibration coming from underneath my car it seems to be making this humming/vibrating sound it seems to go away alittle upon acceleration and as soon as i let off the gas it gets worse it happens at speeds of between 45 and 60 could it be my rear end or maybe u-joint what do u guys think

Phate · 11-19-2007, 09:16 PM

I'd need a more definate speed to tell you honestly. But if it only happens at that speed, and only in the rear, it sounds like a tire issue. It could be out of balance, bent wheel, seperated or out of round tire, chopped tire tread, etc. If you get free rotations, i'd just get the tires rotated and see what changes.

A vibration in the rear feels like your seat is vibrating, a vibration in the front feels like the steering wheel is vibrating.

badbird5.7 · 11-19-2007, 10:30 PM

when i recently bought the car i didn't realize that the car had four different tire on it i hav'nt been able to purchase new tires yet (to exspensive) but there all the same size and have the same amount of air in them i took it to my local tire shop/inspection station they said as long as the tires are all the same size your car should ride just fine and then he passed my car for inspection. but the vibration is coming from the rear feels like my seat is shaking and the humming is in like a pulsing or throbbing form

Korndogg · 11-19-2007, 11:02 PM

yeah like phate said. One of them could be out of balance or the tires could be wearing improperly. Got a camera? Take pics of the rear tires once.

Phate · 11-20-2007, 03:48 PM

Quote:

Originally Posted by badbird5.7

when i recently bought the car i didn't realize that the car had four different tire on it i hav'nt been able to purchase new tires yet (to exspensive) but there all the same size and have the same amount of air in them i took it to my local tire shop/inspection station they said as long as the tires are all the same size your car should ride just fine and then he passed my car for inspection. but the vibration is coming from the rear feels like my seat is shaking and the humming is in like a pulsing or throbbing form

"As long as they are all the same size it should ride just fine" Wow, this guy must not have ever dealt with tires. I get more complaints from picky people on how their tires ride. I'd still just have the tires rotated and see if that changes the sensation, then you can narrow it down from there.

badbird5.7 · 11-20-2007, 06:35 PM

i will deffinitly do that cause it's driving me crazy

SpecialK · 11-21-2007, 03:06 PM

Quote:

Originally Posted by Phate

"As long as they are all the same size it should ride just fine" Wow, this guy must not have ever dealt with tires. I get more complaints from picky people on how their tires ride. I'd still just have the tires rotated and see if that changes the sensation, then you can narrow it down from there.

No kidding I have one performance tire and three all seasons on my CRX and I hated how it rode, I thought it was the springs. I switched over to all the same brand. (Ricer tires for cars with lots of camber. I know I know, I wasn't the one to put the coilovers on it but I did raise it two inches so I could actually drive it) And it now rides pretty decent.

ling427ttvette · 11-21-2007, 10:14 PM

Here's my theory.

Your tires on the rear are cupped out on the inside, which is another way to say uneven wear. That cupping is causing your noise, and vibration.

Now, the reason that cupping is there? Alignment problems. Those tires were on the front, and were rotated to the rear when it was noticed that they were cupping. I guarantee it.

The only thing that will solve this, new tires. Or, you could ride it out and see if the tread straightens out. But, judging by another post of yours you are getting new tires soon anyway. Get it aligned the same day you have the new tires put on, and make sure the alignment is done after the new tires are put on the car.

I work in a tire shop, this kind of stuff is common.. for me anyway.

badbird5.7 · 11-22-2007, 01:07 AM

thanks for the advice guys you've been extremly helpfull! the place where i bought the car is over 50 miles away from my house so to bring it all the way back it would have been a long ride for probally nothing

Phate · 11-22-2007, 11:36 AM

Alignment rarely causes cupping, or what I call 'chopping' on the tread, lack of rotation does. But alignment will cause it to wear unevenly across the tread (meaning one side of the tread will be worn down alot, and the other is normal). If the tread is worn on both edges instead of just one, its lack of air pressure. The 'chopping' will make high and low spots in the tread, and can cause a vibration and road noise.

As ling said though, the only way to fix the problem is to hope they wear flat again, but its doubtful. To get rid of the noise i'd suspect you'll have to purchase a new set of tires.