Our 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 our wheels returns to its flat spot at a different time, making the spot undetectable.
 

Note: Some of you may remember that we previously manufactured a sled dolly that was called the Porta-Glide 90. This new Porta-Glide is not the same. The Porta-Glide 90 did not have the multi-dimensional wheels, like our new version. However it did have an elaborate floating wheel system that allowed it to be used with a special, ultra-tight radius steel track that we also used to manufacture—90 degrees on a 2 foot radius, and 45 degrees on a 4 foot radius. The new Porta-Glide will not work on those ultra-tight tracks that we used to manufacture. However, they will work on the various curved tracks made by Matthews, Norms, American Grip, Egripment, etc. We felt that since there were not a lot of those ultra-tight tracks sold, it would be better to simplify the floating wheel design to keep the cost down. The new Porta-Glide is $100 less than the previous version, even though it has the added expense of the multi-dimensional wheels.