"PJ" > wrote in message ...
> Alex wrote:
>> My 94 convertable starts to vibrate around 65 mph.
>>
>> Feels like it is in the back of the car. Can feel it through the gear
>> shift, so could it be drive shaft? Car is just at 100K.
>>
>> Recently acquired the car, first vette, so no history on the car and not
>> sure where to start looking.
>>
>> Is this a common problem, or do I just go through the check the tire
>> balance, rim straightness, etc. routine?
>>
>> Everything feels tight. No clunking on acceleration or deceleration, so
>> at
>> this point I don't suspect U-joints.
>>
>> Ideas anyone?
>>
>> Thanks!
>>
>> Alex
>
> Welcome and enjoy!
>
> Sixty-five is a typical speed for a C4 tire balance problem to raise its
> ugly face.
>
> You 'to-do' list looks good. Add the following:
>
> Assuming you have the orginal factory wheels, check to see if some
> well-meaning grease monkey rotated wheels front to rear.
>
> The original tire sizes were 255/45 on the front and 285/40 on the rear.
> --
> pj

if you have option z07, the tires are the same size front to back.

regards,
charlie