As users sought greater running performance without giving up valuable living space, KingSmith developed two distinct approaches to the foldable home treadmill. The Vertical Fold Series introduced double-fold technology and compact upright storage, while the Foldable Classic Series reengineered the familiar treadmill form with a fully foldable running deck and, later, powered incline.
1. Fold Twice, Store Upright: The Evolution of KingSmith WalkingPad’s Vertical Fold Treadmill Series
Building on the success of the Just Walk and Hybrid series, KingSmith turned to a new challenge: How could runners seeking higher speeds, a wider running belt and greater performance still enjoy a capable treadmill in a space-conscious home? This question opened the next chapter in KingSmith’s folding innovation and ultimately led to the Vertical Fold Series.
Why Greater Running Performance Created a New Space Challenge
As running needs increased, treadmill performance and home storage became harder to balance.
- Higher running speeds placed greater demands on the treadmill’s overall structure.
- Runners wanted wider, more comfortable running areas.
- Greater running capability often came with a larger overall footprint.
- For apartments and multifunctional spaces, storage remained a challenge.
- Folding the running deck only once was no longer enough to achieve an even more compact form.
From Folding Flat to Standing Upright
KingSmith began rethinking folding itself—not just how to make a treadmill smaller, but how to change the way it could be stored. The answer was to take folding vertical.
The X21 and the Birth of Vertical Fold
Launched in 2021, the X21 Double-Fold Treadmill marked the beginning of KingSmith’s Vertical Fold format and introduced its innovative double-fold technology. Instead of just folding in half, the running deck folds twice into a compact, streamlined form that allows the treadmill to stand at 90° for upright storage, taking up less than 2 sq. ft. (0.2 m²) of floor space.
The format gained immediate market recognition, and the X21 remains an important part of the series today. The X21 turned folding from a storage feature into a completely new way of storing a treadmill.
Treadmill Review Guru also highlighted the X21’s space-saving design, with Certified Personal Trainer Sydney Kaiser noting:
“The double-fold and lightweight design makes the WalkingPad X21 extremely compact and ideal for apartments.”
From X21 to the Vertical Fold Series
Following the success of the X21, the Vertical Fold concept expanded into KingSmith’s broadest and most strategically important treadmill lineup. The series now covers different performance levels through a speed-based naming system, while variations in running belt width and handrail configuration provide options for different running needs.
- X208: 5 mph (8 km/h)
- X210: 6.5 mph (10 km/h)
- X212 (formerly X21): 7.5 mph (12 km/h)
- X214: 8.5 mph (14 km/h)
- X216 (formerly X16 or X25): 10 mph (16 km/h)
- X218: 11.5 mph (18 km/h)
From everyday movement to higher-speed running, the expanded lineup brings different levels of performance together around the same core Vertical Fold concept: greater running capability with compact upright storage.
What Defines the Vertical Fold Series
Across different models and performance levels, the Vertical Fold Series is built around greater running capability and highly compact upright storage.
- Double-fold structure: Folds the running deck twice for more compact storage.
- 90° upright storage: Stands vertically to minimize floor space when not in use.
- Greater running capability: Supports speeds ranging from walking to higher-performance running.
- Multiple running sizes: Different running belt widths accommodate different running needs.
- Handrail options: Selected models feature side handrails for additional support.
How Vertical Fold Fits into the KingSmith Portfolio
Within KingSmith’s walking and running portfolio, Vertical Fold is positioned around greater running capability and highly compact upright storage.
- Just Walk: Daily walking and increasing step count.
- Hybrid: Walking and running in one compact machine.
- Vertical Fold: Greater running capability with 90° upright storage.
- Foldable Classic: A traditional treadmill experience with folding and incline on selected models.
Vertical Fold combines greater running capability with KingSmith’s distinctive upright storage format, giving users more performance without requiring permanent floor space for a treadmill.
The Future of Vertical Fold
The future of Vertical Fold is about continuing to explore the balance between treadmill performance and space-saving storage. As the lineup evolves, KingSmith will continue exploring new possibilities in speed, running space, comfort and smart features, while keeping compact upright storage central to the Vertical Fold concept.
2. Traditional Treadmill Form, Foldable Design: The Evolution of KingSmith WalkingPad’s Foldable Classic Series
After disrupting three established product formats, KingSmith turned its R&D focus to reengineering the traditional treadmill itself. To meet the needs of households that valued the solid feel and workout experience of a gym-style treadmill but struggled with its large footprint, KingSmith created the Foldable Classic Series—bringing a familiar treadmill form into a space-saving, foldable design.
Why the Traditional Treadmill Needed a New Approach
Traditional treadmills offered the familiar feel and workout experience many runners preferred, but their size created a challenge for home use.
- Traditional treadmills often require considerable floor space.
- Their larger structures can be difficult to fit naturally into everyday living spaces.
- Users wanted a traditional treadmill experience without permanently dedicating part of their home to fitness equipment.
The challenge was to preserve the familiar treadmill form while making it significantly easier to fold and store.
Redefining the Traditional Treadmill Through Foldable Design
KingSmith set out to rethink how a traditional treadmill could fit into the home without losing its familiar form and workout experience. The solution was to redesign its structure around folding, allowing a full treadmill format to become far easier to store when the workout was over.
G1 and G2: Making the Classic Form Foldable
The G1 and G2 established the foundation of what would later become the Foldable Classic Series. When unfolded, they retained the familiar form and workout experience of a traditional treadmill, but after use, the running deck could fold completely flat for more compact home storage.
The format received strong market recognition and became an important product line in KingSmith’s expansion into Costco’s brick-and-mortar stores in the United States. The breakthrough was not changing what a traditional treadmill looked like when in use—it was changing what it could become when the workout was over.
2026: The World’s First Treadmill Combining a Foldable Running Deck and Powered Incline
In 2026, KingSmith took the Foldable Classic concept a step further with the G5i foldable treadmill with incline. By reengineering the treadmill’s base and drive structure, the G5i combines a foldable running deck with an 18% powered incline—bringing together two capabilities long considered difficult to integrate into a single treadmill. This breakthrough opens a new direction for the Foldable Classic Series, bringing incline training into its space-saving, flat-folding format while paving the way for additional sizes and configurations.
What Defines the Foldable Classic Series
Across different models and configurations, the Foldable Classic Series is built around combining the familiar treadmill experience with a more space-saving approach to home storage.
- Traditional treadmill form: Preserves the familiar structure and workout experience of a classic treadmill.
- Foldable running deck: Allows the running deck to fold for more compact storage after workouts.
- Space-saving storage: Makes a traditional-style treadmill easier to fit into everyday home spaces.
- Running-focused performance: Supports walking, jogging and running.
- Powered incline: The G5i introduces an 18% powered incline for more varied training options.
How Foldable Classic Fits into the KingSmith Portfolio
Within KingSmith’s walking and running portfolio, Foldable Classic brings the familiar form of a traditional treadmill into a more space-saving, foldable format.
- Just Walk: Daily walking and increasing step count.
- Hybrid: Walking and running in one compact machine.
- Vertical Fold: Greater running capability with 90° upright storage.
- Foldable Classic: Traditional treadmill form with foldable storage, with the G5i adding an 18% powered incline.
Foldable Classic brings KingSmith’s space-saving philosophy to the familiar form of a traditional treadmill.
The Future of Foldable Classic
The Foldable Classic Series will continue to expand across more sizes and configurations to meet different running needs. As the lineup grows, KingSmith will continue exploring new possibilities in performance, comfort, incline, and smart features while keeping the familiar treadmill form and space-saving foldable storage at the heart of the series.
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