Porta-Jib Porta-Glide Dolly Sled with Wheels, Set of 2

About Porta-Jib Porta-Glide Dolly Sled All dolly sleds using skateboard-style wheels develop flat spots on the wheels very quickly. This requires the dolly grip to roll the dolly back and forth repeatedly to reshape the wheels until the bump from the flat spot is no longer detected. Their new Porta-Glide sleds have solved this problem because each of the 16 wheels has a different diameter. They are positioned on the wheel block so that all wheels are touching simultaneously, and, like the other systems, these wheels will flatten slightly. However, as they turn, instead of 16 flat spots hitting in unison, each of their wheels returns to its flat spot at a different time, making the spot undetectable. This 4- hole pattern is the same as that used on the speed rail plates made by Modern Studio Equipment, a piece of equipment many dolly grips already own. These plates accept two pieces of speed rail. Putting their wheel assemblies onto these plates and adding a couple pieces of speed rail is an easy way to make a wider sled for those times when one wants to mount the dolly perpendicular to the track. Another purpose is that sometimes one may want to mount the wheel assemblies on some other sort of platform not conducive to the U-Channel shape of the sled, so having them easily detach like this can be helpful. The Porta-Glide sled has one locked arm and 3 floating arms. If desired, the floating arms can be locked by simply adding a 3/8-16 x 0.75″ screw through access holes shown here. They do not think this is often necessary, but some grips requested this feature, so they added it. Obviously, you cannot lock the arms if using curved track and they prefer having the arms floating, even on straight track because it ensures that the wheel clusters will always seat properly on the track rails, even if the track were to be slightly scissored. If all the arms are locked, the wheels will line up with the 24.5″ spacing of standard dolly track. Therefore some grips prefer this so that the sleds drop directly onto the track without one needing to reach under the sled to set the wheel clusters onto the rails. However, they recommend leaving them unlocked so that optimal alignment of each wheel cluster is obtained.