I can get a better picture if needed. The T handle, spring loaded pop pin, does all the weight support. The pins are very heavy duty, they taper from 3/8's to 1/2" for easier seating. The bolts are temporary till my threaded star knobs come in. They are used to to keep the pins seated and to take the slack out of the upper tube. Physical speaking, the pins can't come out of the upper tube when seated. The bolt is just to prevent the tubes from rattling in transit or allowing any movement when in the high position. I had planned for a secondary pin to pass completely through the tube to secure the rack in the upper position, but it doesn't seem necessary at this point.