Warehouse storage systems are often designed around the inventory an operation has today. But inventory rarely stays the same for long. New products are introduced, seasonal demand changes, and packaging is updated over time. Customer requirements shift, and 3PLs, for example, regularly onboard new accounts with entirely different SKU profiles.
As inventory changes, carton sizes change with it. More specifically, widths can vary significantly across SKUs, creating challenges for storage layouts that rely on fixed lane spacing. When products do not fit neatly into the same lane widths, operations can lose valuable rack space, increase re-slotting labor, and make it harder for pickers to work efficiently.
That does not mean every operation needs the same type of carton flow. Dedicated carton flow lanes are ideal for stable SKU profiles and predictable carton dimensions. But when product mixes evolve and widths vary, carton flow beds offer the flexibility needed to keep products accessible, organized, and flowing to the pick face.
The Challenge with Changing SKU Profiles
In order picking environments, small layout issues can create major inefficiencies. If pickers are walking farther, reaching awkwardly, waiting for product to flow, or working around poorly slotted inventory, those inefficiencies add up quickly across every shift.
Product width is one of the most important design considerations in carton flow because it determines how much horizontal space each SKU requires within a rack level. When every product has a predictable footprint, fixed lanes can be designed to match those dimensions. But when an operation stores SKUs of varying widths, the storage system must accommodate multiple product profiles.
A narrow SKU may only require a small amount of space at the pick face. A wider case may need significantly more room. If the system cannot adjust easily from left to right, the layout can become inefficient as products are added, removed, or re-slotted.
For operations with changing inventory, flexibility is not simply a nice feature. It is a design requirement.
A changing SKU profile refers to the way an operation's product mix evolves over time. This can include changes in the number of SKUs stored, the size and shape of product packaging, order velocity, storage requirements, or the way products are grouped and picked.
These changes happen for many reasons. Retail and eCommerce operations may introduce seasonal assortments or promotional products. Food, grocery, and cold chain operations may manage packaging variations across brands, suppliers, and product categories. Manufacturing and distribution operations may add new products or change case configurations. In 3PL facilities, customer onboarding, customer turnover, and changing contract requirements can completely reshape the SKU mix moving through the same storage area.
This is where carton flow beds can provide a major advantage.
What Are Carton Flow Beds?
Carton flow beds are gravity-fed storage solutions designed to move boxes, cases, and cartons from the loading side of the rack to the pick face. Instead of relying on static shelving, carton flow uses angled tracks to allow products to flow forward automatically as items are picked.
The key difference with a carton flow bed is coverage. Rather than using individual lanes sized to specific cartons, wheel beds flood entire levels of pallet rack with carton flow. This creates a flexible surface that allows products of varying widths to be positioned across the level as needed.
SpanTrack Wheel Bed is designed to drop into new or existing pallet rack, creating a flexible carton flow solution for operations that need to store and pick products with a wide range of sizes. The result is a more adaptable storage system that supports efficient picking while maximizing usable space within each bay.
How SpanTrack Wheel Bed Improves Storage for SKUs of Varying Widths
SpanTrack Wheel Bed is built for operations that need flexibility across the full width of the rack level. By creating a full-bed carton flow surface, it allows products of varying widths to be stored side by side while maintaining efficient gravity flow to the pick face.
This makes it easier to re-slot products as SKUs change. Instead of being limited by fixed lane widths, operators can adjust lane positions to fit the current product mix. For facilities that manage frequent SKU changes, seasonal inventory, or evolving customer requirements, that flexibility can help maintain picking performance without sacrificing valuable rack space.
UNEX offers light-, standard-, and heavy-duty wheel bed options, including plastic and heavy-duty steel skatewheel configurations, depending on the application. For temperature-sensitive operations, SpanTrack Wheel Bed is freezer- and cooler-rated to below zero, making it suitable for cold storage environments.
Like other SpanTrack solutions, Wheel Bed can be added to new or existing pallet rack. This allows operations to improve storage flexibility and picking efficiency without requiring a full facility redesign.
Improving Picking Efficiency with Flexible Storage
Storage flexibility directly affects picking efficiency. When products are slotted properly, pickers spend less time searching for inventory, travel shorter distances, and work from a more organized pick face. When SKU widths change and storage layouts no longer match the current product mix, picking becomes less efficient as operators work around wasted space, poorly sized pick locations, and frequent re-slotting.
Carton flow beds help maintain an efficient pick face by allowing the storage layout to adapt as inventory changes. Products can be positioned across the rack level based on their actual width, demand, and picking requirements. As new SKUs are introduced or product mixes evolve, lane locations can be adjusted to better utilize available space and keep inventory organized for faster, more efficient picking.
The benefits extend beyond the pick face. Like all carton flow systems, carton flow beds support simultaneous replenishment and picking by allowing inventory to be loaded from the rear of the rack while order pickers continue working from the front. This helps reduce interruptions, maintain product availability, and keep workflows moving throughout the day.
Because SpanTrack Wheel Bed is not limited to fixed lane widths, replenishment locations can also be adjusted from left to right as SKU profiles change. Optional accessories like infeed guides further improve visibility into each lane, making it easier for workers to quickly identify loading locations and replenish inventory accurately. The result is faster replenishment, fewer loading errors, and less time spent managing changing inventory.
This combination of flexible slotting, gravity-fed FIFO product flow, and uninterrupted replenishment is especially valuable in high-change environments. A 3PL may need to adjust layouts as customer contracts change. A retailer may reconfigure storage for seasonal demand. An eCommerce operation may introduce new SKUs every week. In each case, the ability to adapt the storage system while maintaining efficient picking and replenishment helps reduce labor, improve productivity, and maximize the value of available storage space.
Learn how to save space in your facility. Download The Guide To Optimizing Warehouse Space Utilization!
Space Utilization Starts with the Right Fit
Maximizing space utilization is not just about adding more storage positions. It is about using the right type of storage for the products being handled.
For operations trying to increase capacity within an existing footprint, that matters. Better space utilization can help delay expansion, reduce congestion, and create more efficient picking areas without adding more rack.
Common Signs You Need More Flexible Carton Flow
A carton flow bed may be the right choice if your operation is constantly adjusting to inventory changes. Some signs are easy to recognize. Others become clear only after pickers and replenishment teams spend too much time working around a storage layout that no longer fits the product mix.
You may need more flexible carton flow if:
- Box widths vary significantly across SKUs.
- New SKUs are introduced frequently.
- Seasonal products require regular re-slotting.
- Customer contracts change the product mix.
- Re-slotting takes too much time or labor.
- You need one system that can adapt as the operation changes.
These challenges do not always require a complete redesign. In many cases, the right carton flow bed configuration can improve flexibility within the existing rack structure.
Finally, design should account for future change. A storage system that works only for today's SKU profile may become inefficient as inventory evolves. Building in flexibility early can help operations avoid unnecessary rework later.
Choosing Between SpanTrack Wheel Bed and SpanTrack Lane
The best carton flow system depends on the products being stored, the pick strategy, and how often the operation changes.
Choose SpanTrack Wheel Bed when flexibility is the priority. It is a strong fit for products with varying box widths, changing SKU profiles, seasonal inventory shifts, and operations that need left-to-right re-slotting flexibility across the rack level.
Choose SpanTrack Lane when products have dedicated locations and predictable widths. It is ideal for high-volume case and each picking applications where fixed lanes support consistent flow, organization, and picking performance.
Use both when different areas of the operation have different needs. Stable, high-volume SKUs may be best served by dedicated lanes, while variable or frequently changing SKUs may require the adaptability of wheel beds.
It is also important to consider picking volume. High-volume, stable SKUs may benefit from dedicated lanes, while slower-moving or frequently changing SKUs may be better suited to wheel beds.
This balanced approach helps operations design around real product behavior instead of forcing every SKU into the same storage strategy.
FAQ: Carton Flow Beds for Flexible Storage
What is a carton flow bed?
A carton flow bed is a gravity-fed storage solution that uses wheels across a rack level to move products toward the pick face. Unlike dedicated carton flow lanes, a wheel bed provides a flexible flow surface that accommodates products of varying widths.
Can carton flow beds handle different-size boxes?
Yes. Carton flow beds are designed to support storage layouts where box widths vary across SKUs. Because the wheel bed fills the rack level with flow wheels, operators can adjust lane spacing from left to right to fit the products being stored.
Why are carton flow beds useful for changing SKU profiles?
Changing SKU profiles often introduces new box sizes, new product velocities, and new slotting requirements. Carton flow beds make it easier to reconfigure the pick face as inventory changes, helping operations maintain space utilization and picking efficiency.
What is the difference between a carton flow bed and a roller lane?
A carton flow bed provides flexible left-to-right slotting across the rack level, making it a strong fit for varying box widths and changing product mixes. A roller lane is a dedicated flow lane designed around a specific carton width, making it ideal for stable SKU profiles and consistent, high-volume picking.
Are carton flow beds better than carton flow lanes?
Not always. Carton flow beds are better when flexibility is the priority. Carton flow lanes are often the better choice when SKU locations are fixed and carton dimensions are predictable. Many operations use both solutions in different areas of the same facility.
Can carton flow beds be added to existing pallet rack?
Yes. SpanTrack Wheel Bed can be added to new or existing pallet rack, helping operations create flexible carton flow storage without a complete storage system redesign.
Can SpanTrack Wheel Bed be used in coolers or freezers?
Yes. SpanTrack Wheel Bed is freezer- and cooler-rated, making it suitable for cold storage and temperature-sensitive applications.
How much weight can SpanTrack Wheel Bed support?
SpanTrack Wheel Bed is available in multiple capacities depending on the application. The 98 Series is rated starting at 35 lb. per square foot, the 99 Series is rated starting at 50 lb. per square foot, and the heavy-duty 100 Series is rated starting at 100 lb. per square foot.
What types of operations benefit most from carton flow beds?
Carton flow beds are especially useful in 3PL, eCommerce, retail, omnichannel, food, grocery, and distribution operations where product mixes change, box widths vary, or re-slotting is frequent. They are also useful in any operation that needs to maximize storage flexibility within existing rack space.
How do I know if I need SpanTrack Wheel Bed or SpanTrack Lane?
If your operation has varying box widths, changing SKU profiles, or frequent re-slotting needs, SpanTrack Wheel Bed may be the better fit. If your operation has dedicated SKU locations, predictable carton dimensions, and high-volume picking requirements, SpanTrack Lane may be the better solution.
Improve Space Utilization and Storage Flexibility with UNEX
Operations that handle cartons of varying widths need storage systems that can adapt. When SKU profiles change, product mixes evolve, and product widths vary, designing for flexibility can help improve space utilization, simplify re-slotting, and maintain efficient picking.
SpanTrack Wheel Bed gives operations the left-to-right flexibility needed to accommodate changing inventory without sacrificing performance. SpanTrack Lane remains the right solution for stable, dedicated lanes. Together, these solutions give operations the ability to design carton flow around the way products actually move.
Use our free SpanTrack design tool to start building the right carton flow solutions for your application, or contact UNEX today to work with our storage specialists on a system designed to maximize space, improve picking efficiency, and support the needs of your operation!
