16.It's now time to prep-fit the upper 'bag mounts. To do so, the suspension is reassembled and pushed to full "bump" by placing a transmission jackstand beneath the lower control arm. We plan on installing 215/35ZR18 tires after this truck is 'bagged, and because we know our tires will measure approximately 24 inches in diameter, we bumped the suspension upward until our imaginary tire line was even with the bottom of the framerail. This equaled the position of the suspension when the truck would be laid out on the 18s. We then compressed an airbag to determine the upper 'bag mounts' best possible mounting location.