Continuing the discussion from About the Maintenance/Repairs category:
Hey all! I’m curious if anyone can help me troubleshoot this oddity. Coming home from vacation, I noticed a cyclical vibration in my '96 Volvo 960. The cycle shortens with increased speed, and specifically at 85 mph it would swell to a peak and then smooth out to disappear over ten seconds. It’s not real noticeable, steering wheel slightly shakes and you can feel it in your feet. At 80 mph it was about a 15 second cycle. Any thoughts? And thanks!
These types of oscillations on a 20 year old car can come from countess sources, including worn out struts/shocks, tire wear and/or imbalance, a dented rim, worn out components (or which there are many including tie rod ends, ball joints, subframe mounting bushings, and on and on), and any of these can be exacerbated by an alignment problem. I’ve even seen rotted out strut towers on an old Volvo. The only way to find out what the cause(s) is(are) is to take it to a reputable chassis shop for a good going over.
If I were looking at it, I’d start with a good thorough check of the chassis followed by a spin balance of the wheels, looking for rim dents while it was on the machine. Of course, if upon starting I saw irregular tire wear that suggesting something, I’d take that as a hint of where to focus more intensely, and if the problem were found I’d be sure you wanted to get it repaired before bothering to spin the wheels. No wheel balance can compensate for chassis problems.
This sounds very similar to a situation I encountered many years ago.
The tires had a very slight vibration and because the tire diameter is ever so slightly different between them, the vibrations would go in and out of phase over a period of about 10 seconds or so.
Now I’m not saying it is the tires, I’m saying that this kind of sounds similar and it just might be 2 components that can go in and out of phase - like CV joints.
Thanks Capri and The-Same. Appreciate your thoughts.