Reply to "Extreme Rear Suspension Compression"

I would take the spring off of the shock and reinstall the spring. You can then compress the suspension thru its full travel. If the tire contacts something and you are worried about the contact point ruining the tire, then that should be considered your maximum compression. Mark that point on the shock. You then need to add a bump stop to the shock to make sure the shock cannot compress any further than your desired maximum compression. The bump stop will compress a bit before it acts like a hard stop and different stiffness bump stops are available to help control the hit before max compression is achieved.

You cannot rely on the spring to completely stop the compression of the suspension unless the spring is in full bind which is of course very bad. You'll never know when you could hit something in the road and rapidly overpower the spring via a near instantaneous force. The hard stop should be engineered into the shock via a bump stop.