The ride can be affected by a number of different contributing factors.
1. One or more tires may be out of balance
2. The tire may not be properly mounted to the wheel
3. The wheel could be out of round
4. The brake drum/rotor may be out of balance
5. The wheel may not be mounted to the hub correctly
6. The tire may be out of round
7. The tire may have internal structural "uniformity" problems.
Many times people jump to the conclusion that the tire must be "Out Of Balance" and they want to ignore all the other possibilities.
Back in Nov 2011 I covered a number of possible contributing factors when I answered the question of Do You Need To Balance Your Tires? Obviously, those that just focus on "balance" did not review this blog post.
In that old post, I said it was possible to balance a cinder block. You might consider reviewing this post as it has some good pictures of the other conditions that can give poor ride.
I have used this comment a few times in my RV Tire Seminars but I bet few believed me. Well here is the proof.
Even those used on my Camaro race car
Now first I confirm the balancer is adjusted to a near-zero level of out of balance itself. We can see the bubble is very near to perfect balance with it right at the center point.
Next, I loaded the cinder block onto the balancer. I chose to not try and pile standard wheel weights on the block, so just grabbed some hand wrenches. After some moving these "balance weights" around I ended up with a
very acceptable level of balance.
I do hope this clears up some of the confusion on Ride vs Tire Balance.