Demon_Speeding

iTrader: (24)

Somebody please give me an idea here...

I have a strange vibration that starts around 75-80mph and goes away around 90-95. This is a pain in the *** since I travel interstates that the speed limit is 70-75. I have had the tires balanced, it's got new(er) rotors. They're not warped. Car is an M6, stock 10 bolt rear, and suspension. What's the odds the driveshaft could need balanced? Tire wise, I'm running Kumho Ecsta ASX (the all seasons) up front and Nitto DRs in the back. There is no rear end noise at all. The car has seen around 6K RPM in 5th gear. Could I have screwed something up there? There's no noises in the car...other than the typical F-body squeaks/rattles.

OldeSkool

Have you changed your clutch/flywheel recently?

Also, that poly trans mount is going to magnify any driveline vibrations you may have had.

Demon_Speeding

iTrader: (24)

Good point on the poly mount...Didn't think about that.

I haven't changed the clutc/flywheel. Actually my stocker is toast and as soon as TSP gets the backordered parts in my cart is heading that way for a Billet Fly and RAM Powergrip HD.

EDS01SS

iTrader: (30)

sounds like a tire balance problem to me.

Mybluey

I had a bad vibration problem around those speeds as well, it was tire balancing. Do your wheels have weights on the outside? If they only balanced the tires with weights on the inside, that might not be enough. Putting weights on the outside completely fixed my problem.

Good Luck!

Mike2000Z28

Check the wheel bearings and tires. Also if you hear some slight banging or movement under the car check the u-joints.

Odessastangslayer

iTrader: (1)

my car started doin this about the exact same speed when i put the poly trans mount on it i just ignore it i think it may bee the poly trans mount (thats when mine started) and i have the same setup as you

Demon_Speeding

iTrader: (24)

Mybluey, I do have my tires balanced with weights on the inside only. I may take them somewhere and see if they will balance them with the tape weights. If nothing else I'll just have them balanced with weights on both sides instead of the static balance.

I've checked everything I can and it all seems good. I'm going to bet it's a balance thing.

Thanks guys!

lt1fbody355

I had the same problem. It was either the 4:10's, a twisted output shaft or the driveshaft. I changed everything. so I don't know the exact problem.

Demon_Speeding

iTrader: (24)

Thanks again to all for the input. I just got paid my bonus and nearly a year's salary difference...Daddy's getting all new rear suspension, 9", driveshaft and a cam. I think I'll get rid of the vibration...


Just to wind up with another headache I'm sure.

VIP1

When you go to get your tires re-balanced, take it to a place that can do a "road force" balance. In addition to the balance, a roller is pressed against the tire to see how it handles "road force". This will show defects in the tires that can become evident as an odd vibration at certain speeds or premature failure.

Demon_Speeding

iTrader: (24)

Duly noted.