Hey guys,

I'm curious what is causing my whole front end to shake when I reach speeds of 60mph and higher. I had recently gotten two new back tires, and I had spoken to the people who point them on. When I asked them for their opinion, they stated that about 95% of the time a balance would correct the issue. So when they installed the rear tires, I had also requested that they perform a front end balance to correct the issue. So they said they did it...

The first time I had taken it on the highway, I hadn't noticed it bad... I just assumed that was part of normal driving... but now when I hit 60+mph, the tires are shaking just as bad if not a tiny bit worse than they have before. What would be causing this to happen? Is there anything I have to worry about, or is this just a general nuisance?

Again, it'* a 1989 Pontiac Bonneville LE.

Thanks.

Well.. your rims could be bent which could cause this, even with an alignment, however any good alignment shop would be able to tell if a rim was bent in the alignment process. The other thing is, it is just not aligned.. make sure the bolts are tight.. My wheels aren't aligned, and i've got a smooth ride to 100.. after that it gets a little bad.. and scares the crap out of me [suspension related.. crappy shocks or springs IMO].


-justin

maybe tierod or a ball joint?...

check the drive axles while you're looking in there

Tire having a belt separation can do the same thing and come on suddenly. If you jack the car up and spin the tire it will be visible.

I also have this problem, ive done it all.. just wont go away.. only went away when I put my summer tires on than it came back.. these cars are confusing sometimes I tell u

might want to get the rotors in the front looked at too. if those are screwed up, that would cause imbalance too. also, make sure all of the front aerodynamics are intact and secured. that could cause a bit of drama too. heres an idea. get on the highway with another car, and have the person in the other car look at the bonneville doing highway speeds. he might be able to see if it a wheel off balence, aerodynamics loose, or what ever. lemme know if it works. i am kinda interested to see if you could figure it out doing that.

Just a thought: the Bonneville has a "loose" rotor that is sandwiched between the wheel and the hub. The lug nuts need to be torqued to 90-100 lb-ft to seat everything properly.

If it is a tire, swapping ends or increasing the tire pressure will often change the symptoms. If it does, it is probably a tire.

Going away after a tire change then coming back does not make a lot of sense.

BTW some sections of I-95 and I-75 in Florida were so bad for vibration that shops had signs out for balancing when a few miles further on they would just stop.

For some reason tires seem to have a harmonic around 700 rpm. This means short tires vibrate at 50 and tall ones at 70. Around 60 mph is a likely harmonic for the 15" tires though would expect 16s to be a bit higher.

with me I had to replace the rotors and do the brakes for stopping rattle shack #1, Now it is a matter of a bent rim on the pass frnt side on the inner and as well as
$h1tTy struts all around.. the airs are sagginsg and the fronts just are gone.... as well as the sway bar ends/links/bushings. not to bad to have repalced just time consuming....I priced out my fronts to be like 85-92bux a peice.