Gravity Conveyor: How Many Skatewheels do You Need?
Typically, it's ten wheels total beneath any conveyed load
Gravity skate wheel conveyor is probably the most economical conveyor option around for quick, portable movement of lightweight boxes, totes, or trays.
You see it used in shipping & receiving areas, in assembly operations, or as a transitional piece between workstations and powered conveyor lines. You can even slap casters on it for a conveyor that can be rolled in & out of use areas. We even plug it into gravity flow racks to create heavier-duty, FIFO flow storage.
For such a simple piece of conveying equipment — in fact the simplest — errors can and do crop up when it’s ordered incorrectly.
The easy way to specify skatewheel is the “rule of ten”
That is, every conveyed carton should have ten wheels underneath it. When you order a skate wheel conveyor, you should understand that there are varying numbers of wheels per axle, depending on the width of your conveyor and the roller centers. A roller center is the distance between axles along the length of the conveyor bed.
Standard models list wheels per foot
Widths are pretty standard. Straight sections are offered in 12″, 15″, 18″, & 24″ widths with other sizes are available. Skatewheel curves are offered with the same range of specifications.  All of these models list a “WPF”, or Wheels Per Foot rating. This tells you how many skatewheels are in a foot of conveyor. For instance, a 12″ wide skate wheel conveyor with 3″ roller centers will give you 10 wheels per foot.
The same conveyor at 18″ wide gives you 16 WPF, and 24″ units provide 20. If your box can be conveyed on that 12″ wide conveyor, and it’s at least 12″ long (as it moves along the conveyor), no problem. A shorter box might snag due to insufficient wheels beneath it.
When you specify a skatewheel conveyor, think in terms of the shortest carton. If you are moving many different sizes, other conveyor types, or wider conveyors with more wheels per foot, may be necessary.
Keep in mind that there should never be less than 10 wheels under a particular box.
Video: gravity skatewheel spur
This video features gravity skatewheel spurs and illustrates the importance of the proper number of wheels beneath a carton. If there are too few, the carton may not properly track of balance on the conveyor. If you convey smaller cartons or totes, consider tighter wheel spacing or using gravity rollers for adequate load support.
More resources
Download Cisco-Eagle’s guide to conveyors & systems
Well-executed conveyors and systems will optimize your operation–and we can help you make that happen. Cisco-Eagle’s detailed guide to conveyors gives you advice from our expert employee-owners, links, articles and more.
Download the guide today
Tags: Conveyor, warehousing, Material Handling, Hytrol
Scott Stone is Cisco-Eagle's Vice President of Marketing with 35 years of experience in material handling, warehousing and industrial operations. His work is published in multiple industry journals an websites on a variety of warehousing topics. He writes about automation, warehousing, safety, manufacturing and other areas of concern for industrial operations and those who operate them.