WalkingPad X21 Double-Fold Treadmill: problems, parts and running costs

Checked: 2026-10-05

Summary

The X21 is a compact double-fold treadmill for walking and light jogging. The most common owner complaints are the deck hinge seam felt underfoot, belt alignment drift, and the short 47.6 in belt for tall or long-strided runners. Running costs are low — no subscription, just belt lubricant, a floor mat and electricity — though no prices for those were found. At $799 direct it is a defensible buy when floor space is the main constraint; at the $1,199 MSRP it is not.

Common problems and fixes

Deck hinge seam felt underfoot — reported by all four hands-on reviewers; noticeable at first and fades with use, more obvious in low-cushion shoes. No fix; it is inherent to the double-fold design. [3][4][6][7]
Belt alignment drift — PCMag’s belt moved slightly right during a three-month test. Fixed with the included hex key, a quarter turn counterclockwise in the bottom-left adjustment hole, followed by a low-speed run to confirm. [3]
Safety-key clip slips off clothing — PCMag’s reviewer found the thin plastic clip slipped off his T-shirt hem repeatedly; he attached it to his shorts waistband instead. [3]
Interface beeps cannot be disabled — no way to turn them off per PCMag. [3]
Device holder unstable at running speed — TreadmillReviews.com says a device could fall off; restrict it to a phone while running. CarPlayLife reports the tablet wobbled on solid flooring. [4][6]
Small transport wheels struggle on carpet — difficult to move on carpet, rubber mats and deep pile; one person can move it on hard floors only. [3][5][6]
No cup holder — flagged by CarPlayLife on a treadmill meant for running. [6]
No heart-rate input in practice — despite Apple Watch listed on the spec table, PCMag could not connect any Bluetooth heart-rate monitor or smartwatch. [1][3]

Parts and consumables

Belt lubricant (silicone oil) — WalkingPad recommends lubricating the belt every three months; the folding design makes it easy to access. No price found. [3]
Treadmill floor mat — recommended by WalkingPad’s FAQ for slam noise and by TreadmillReviews.com to protect flooring from the folding mechanism’s clang. No price found. [4][9]
Hex key (included) — used for belt alignment adjustment; ships with the machine. [1][3]

No replaceable parts or consumables beyond the above were reported.

Yearly running cost

No subscription is required; the KS Fit app is free. Recurring costs are belt lubricant every three months, a floor mat for noise and floor protection, and electricity. No pricing for a WalkingPad X21 mat, silicone oil or replacement parts was found on any page read. Not enough data for a yearly total.

When it is a good buy

$799 at WalkingPad US store (2026-10) — defensible when floor space is the binding constraint and you plan to walk and jog rather than run. [1]
£699 at WalkingPad UK (2026-10) — same value case for UK buyers. [15]
C$769 at WalkingPad Canada (2026-10) — same value case for Canadian buyers. [14]
Below roughly $700 — a clear step up from sub-$350 walking pads that owners report burning out inside two years (category-level comparison). [19]
At $1,199 MSRP — poor value; compare the WalkingPad X25 (longer belt, 300 lb capacity) or X218 (55.1 x 20 in deck, 300 lb) instead. [7][11]

Alternatives: the KingSmith P1 if you need an under-desk treadmill (the X21’s handlebar is fixed and non-removable) [3]; the WalkingPad X25 if you want a longer belt and higher capacity [7]; a full-size treadmill if running is the primary goal [7].