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Jim Grant's Tech Tips
'98
Oldsmobile Bravada, High speed Vibration
Q: I recently purchased a 98
Oldsmobile Bravada. On a long distance trip, I noticed a significant vibration
in the dashboard from 55 to 65 mph. When I arrived at my destination, I took
the vehicle in for a look-over. Nothing was found as to the reason for such
a display. I have had multiple people tell me to get the front end aligned;
I have had the tires balanced. The drive train was checked, is there anything
else I can do?
- Tim
A:
I doubt an alignment will correct the condition. Why? The complaint you have
is speed related. When speed is the factor you have to look at what parts of
the vehicle are spinning, example the tires, drive axles and drive shaft. Because
the tires and rims have the greatest amount of mass that is rotating, theyre
suspect from the start. It only takes 1 oz. of imbalance to cause a vibration
or shake to be noticed at those vehicle speeds. If the balance is correct then
look closely at the tire and rim condition. There is not a tire balancer made
that can correct for worn or cupped tires, or a rim that is bent or damaged
in some way. It does not take much of a ding on the edge of a rim to cause a
tire to not run true to the road. A common problem we see in our snowy region
is due to rims that are bent. When the vehicle slides on the ice and then bumps
into a curb or hard snow bank, the vehicle will not look to be damaged but the
side load of the impact can bend the rim just enough to cause a shake that can
never be balanced out. A closer inspection of the rims and tires may provide
the answer.
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