At some point in just about every car’s life, something will begin to wear in the “front-end” and you will feel a vibration in your steering wheel. Most of the time the vibration starts out quite subtle and then gets more and more pronounced until there is no question that something’s gone awry. When it gets to that point, it’s probably becoming unsafe and you should see a mechanic to diagnose and fix the issue. That being said, knowing what things cause steering wheel vibration will allow you to better informed about the situation and likely put you in a better position to take care of it.
1) Tires –Tires are perhaps the number one source of steering wheel vibration. The main issue is simply that tires often wear asymmetrically and when they turn, they can shake and wobble in very unsubtle ways. What do you do? First, a good garage can balance your tires to eliminate vibration and this often cures the problem. In many cases, however, it’s probably just time for new tires.
2) Axles – The axles on a front wheel drive car connect the transmission to the wheel hubs and they have flexible joints in them. These joints are generally called Constant Velocity Joints (CV Joints) and, big surprise, they wear out over time. One of the main reasons they wear is that CV joints are usually covered by “boots” -- rubber, accordion-like coverings around the ends of the axles - that seal out junk like road salt and sand. The problem is that boots often tear open when they get old and the CV joint, now operating with lots of gritty stuff inside, will soon fail. When this happens, you can actually hear it “crunching” when turning corners and usually feel it in the steering wheel. The solution is to replace the axle shafts.
3) Front Wheel Bearings – The front wheel bearings on cars and trucks can wear over time and become loose. When this happens you can feel it in the steering wheel and it usually makes a nasty grinding sound when driving, usually when turning corners. You generally don’t want to mess with worn wheel bearings, time to check in with your local mechanic when this occurs.
4) Brakes - Do those bad vibrations appear or intensify when you step on the brakes? If so, there's a strong possibility that your car has a warped brake rotor, or rotors. Rotors are the shiny disc-shaped components that you can see through your wheel rims. They can get bent out of shape due to heavy wear and tear -- basically, overheating from excessive use. Instead of being uniformly flat all the way across, a deformed rotor is “lumpy” and the calipers and brake pads can't get an even grip and hence vibrate. Often very noticeably.
5) Tie-rod ends and ball joints – These are the mechanical parts in the front-end that move around when you steer and your car absorbs road bumps. And because they are moving parts, they wear out. At driving speeds, this translates to annoying vibrations that are often felt in the steering wheel. Sometimes it just feels like your steering wheel is loose and sloppy. Fortunately these worn out parts are easy to spot by a good mechanic and aren’t difficult to repair.
So, there’s our top five reasons that steering wheels can do the shimmy when you drive. Note that these five reasons aren't the only possible culprits. When in doubt, it's always a good idea to see an automotive service professional if you have this going on. They diagnose this sort of thing all day long and can usually spot the source of a steering wheel vibration quickly.
Source: Chuck Peterson Dodge Chrysler Jeep Ram