Before I ask the question, yes I've had my tires balanced twice (road-force and regular) in the last month and yes they are new tires and yes I have searched the forum and can't find anything on this particular issue...

2008 Infiniti G35 w/ NAV 18" wheel package 29,500 miles (3,000 miles on the new tires Continental Extreme Contact DW 225/45 fr and 245/45 rear - the 45 front is not a typo, they don't make 225/50/18 in this model)

So, at 75-80 mph I'm getting an alternating vibration starting in the pedal and working it's way up through the steering wheel. The vibration lasts about 2-3 seconds then goes away for about 5 seconds, then comes back. It doesn't happen all the time but it is fairly constant. It's not the road I'm driving on because I just took a trip from Nashville to Indy and it happened the whole way up and back (thru 3 states). I checked the cold tire pressure on all 4 tires and they read 34psi. I don't have an alignment problem (something Sears checked when I had a 2nd balancing done last week). I get this whether I use cruise control or not and this isn't when braking but when I'm just cruising.

Any thoughts?

 

well, got the same problem around 75-80mph - vibrating feel in the steering wheel and from the pedals, like the wheels are out of balance (thugh they were balanced several times).

everything is ok with my car too, but i hear one cracking sound from the cold stop from the left and from the right another one, then no sounds. weird...

 

Dude I just realized i have the same problem you do, its only happened to me a couple times, and it cant be the tires because i just got new rims and tires installed, i thought it was the road, but it happens on any road -_-.... its starting to scare me.

 

It can happen when lower control arm bushings are weakening.

 

doh.. thanks for the tip!