Automotive Forums

I have a bad shaking during acceleration between 40-50MPH.  Above that it seems to run along fine.  I do not feel this in the steering wheel as it does not shake at all.  If it was in the drivetrain, steering or front suspension I would think that I would feel it in the steering wheel.  I can feel it throughout the car.  I have rotated the spare onto each wheel one at a time without making a difference.  I have taken it in for balancing and have been told that the tires are balanced but I know that at low speeds  (5-10) I can feel a side to side rocking of the car so I do think the tires have a problem.  I don't want to put new tires on only to find out that wasn't the issue.  I did have it into an alignment shop and they said the alignment is good and they recommended tires although they stand to benefit if I buy from them.  The tires do look good and have lots of tread left.  Any help is appreciated.  

Tire related vibrations usually occur in the 50 to 70 mph range and are there regardless of accelleration or braking or turning.  If you are experiencing something outside that, then it is most likely not the tires.  The fact that changing the positions of the tires doesn't affect the vibration is a confirmation that the tires are not the problem.

In this case, I suspect the CV joints.  The low speed side to side rocking is the clue.  At higher speeds, this might not show up in the steering wheel - too much input from other sources.

However, you can get a vibration on acceleration if engine is a bit out of tune and struggling to make power, but that doesn't explain the low speed side to side rocking.

Hope this helps.  

Thanks for the input.  

I know that the engine is not out of tune.  I have had that checked.  I can see a CV doing it but if it is in the front I thought I would feel it in the steering wheel.  In this case I feel it in the floor, seats etc but not the steering wheel.

I have had bad tires on other cars and the low speed side to side was bad tires, that is why I gravitated to the tires themselves.

I am leaning to replacing the tires and see what comes of it but that is not cheap with the speed rating on these tires (V}.  

Nowhere have I seen any reference to tire air pressure. Just this afternoon one of my front tires was repaired, a slow leak, and the "wobble" I felt at low speeds disappeared. Possibvility.