The cost of transporting a shipment can be determined by the amount of space that it occupies, rather than the actual weight. This is the dimensional (gdim?Eor gvolumetric?E weight. You should calculate dimensional weight for every shipment, compare that to its actual weight, and use the greater amount to determine your shipping cost.
If the dimensional weight exceeds 70 lbs., the price will be at the 70 lbs. rate.
The maximum size is 130 inches in combined length and girth and will classified as Oversized.