What Roller Spacing Means for Full Roller Pallet Flow Rack Performance | Mallard Manufacturing

When designing a full roller pallet flow rack system, roller spacing is one of the key decisions that must be evaluated early. The distance between rollers affects the amount of contact the pallet has with the flow lane, which can influence flow consistency, restart reliability, and overall system cost. Closer spacing, such as 2-inch centers, increases the number of contact points between the pallet and the rollers. Wider spacing, such as 3-inch centers, uses fewer rollers and may be appropriate for larger or more stable loads that can maintain sufficient contact as they move down the lane. Watch the Video Test comparison. Learn more about Roller Flow Rack: https://mallardmfg.com/full-split-rol... Contact the Mallard gravity flow experts: Go to the complete blog: https://mallardmfg.com/what-roller-sp... Read the blog excerpt: Full Roller Pallet Flow Rack Testing: Comparing 2" and 3" Roller Centers To evaluate how roller spacing impacts flow performance, Mallard's Engineering Test Lab conducted a side-by-side comparison of two identical full roller pallet flow rack lanes. Because 2-inch and 3-inch roller centers are among the most common configurations Mallard sees in these applications, they provided a practical comparison for this Engineering Test Lab evaluation. The lane on the right was configured with rollers on 3-inch centers, while the lane on the left used rollers on 2-inch centers. The team is evaluating for: Consistent, unaided flow Safe, controlled speed Stays centered as it flows Positive restart after sitting To ensure an apples-to-apples comparison, both lanes were configured with identical operating conditions: ✔ 1.9-inch diameter rollers ✔ 33-foot lane length ✔ 3/8-inch per foot lane pitch ✔ FIBA speed controllers installed at 48-inch intervals Both lanes were loaded using the same pallet sequence and load weights ranging from 440 to 1,660 pounds, allowing the test team to isolate the impact of roller spacing on flow performance. Test Results: Plastic Pallets vs. Wood Pallets The evaluation included both plastic and wood pallets to better understand how pallet construction and condition influence performance on each roller configuration. While both lane setups produced positive flow results, viewers will notice that the lane with 2-inch roller centers flowed slightly faster than the 3-inch center configuration during portions of the test. The difference was not significant for this application, and both lanes maintained controlled flow with the assistance of FIBA speed controllers. However, the additional roller contact provided by the 2-inch centers may have contributed to the slightly higher flow velocity observed during testing. Plastic Crates Produced Strong Results The plastic crates delivered positive flow performance in both lane configurations. During testing, the loads moved smoothly through both the 2- and 3-inch center lanes and demonstrated reliable restart characteristics. While the 2-inch centers showed a slightly faster flow rate, the difference was not significant for this application. Both configurations maintained controlled movement with the help of FIBA speed controllers. Full roller pallet flow rack is often specified for plastic pallets and plastic-based load platforms. Plastic can cause a surfing effect in gravity-flow applications, making speed control and tracking especially important. The speed controller assembly includes rubber-coated rollers that work well with plastic surfaces to help engage the pallet and maintain controlled movement through the lane. These results show how properly supported plastic runners can maintain sufficient roller contact even when roller spacing varies. Wood Pallets Highlighted the Importance of Pallet Condition The wood pallets created a different set of challenges during testing. Several of the pallets arrived with missing boards, broken boards, damaged stringers, and exposed nails along the bottom surface. Those conditions prevented the pallets from maintaining consistent contact with the rollers, resulting in flow issues in the lane. To continue the evaluation, the damaged wood pallets were placed on mid-grade donor pallets. Even with that added support, the test team observed restart issues. These were handled using a plugging method, but the results reinforced an important point for pallet flow applications: pallet condition can be just as important as roller spacing. A follow-up test conducted a few weeks later, using better-quality wood pallets on the 2-inch center lane, showed improved flow. The pallets moved down the lane, and the FIBA speed controllers helped keep speed under control. For warehouse teams, the takeaway is practical: both roller spacing and pallet design influence flow performance, but pallet condition is often the deciding factor in achieving reliable operation.