You are on the right track. Basically, you bottom out when you put a stress or load on your suspension causing it to reach the extreme compression limit of its travel. You literally hit the bottom.

The easy cure is to make sure the shocks are rated for the load you are trying to dampen. If you are too far off the rating, either high or low, you'll have ride and handling issues.

That is my understanding. Don't take it for gospel.

 

It doesn't have an exact definition but I consider it when ever a part of the bottom of the car hits the pavement because the suspension is being forced to travel so far in that part of the bottom of the car hits the road. When you bottom out your car/truck you will know it. Bottoming out is always followed by cursing.

 

345 and you are on the right track. The rear axle housing hitting the bumpers on the frame rails or third member hitting a bumper on the floor/trunk pan would be bottoming out, So could reaching the compression limit of any installed shocks, front or rear, be bottoming out. It should be easy to tell if you are contacting rubber bumpers: a little more difficult to tell if
it is the shock. You would have to do some measuring with the shock off the vehicle and re install to see how much travel you have from the installed length of the shock to the fully compressed length. If it is less than the space between the Axle housing and bumper, then you have to decide how you want to fix the problem. Options are: stiffer springs, lower your bottom shock mounting point, or get a shock with a shorter compressed length.

Notice I did not mention the spring being totally compressed or a leaf spring traveling over center. These would be considered an extreme screw up in building.

Trees