WalkingPad X Series Smart Vertical-Fold Treadmill
The WalkingPad X21 is the entry model in KingSmith's X Series, a vertical-fold treadmill built for buyers who want more speed than a desk-only walking pad without stepping up to a full home treadmill. If you searched for a kingsmith walking pad that folds upright against a wall instead of sliding under furniture, the X21 is the model behind that description, not the smaller, slower WalkingPad Z1. It runs 1 to 7.5 mph on an 18.1 inch wide, 47.6 inch long belt, folds in two steps for vertical storage, and ships fully assembled.
- Two-step vertical fold stands the whole deck upright against a wall, so it does not have to slide under furniture like a flat-fold pad
- Speed range runs to 7.5 mph, enough for a light jog on top of a walking pace, not just a desk shuffle
- Ships fully assembled and pairs with a companion app in minutes, per multiple owners
- Aluminum alloy frame and a brushless motor keep it quiet at typical walking speeds
- Single handrail keeps the LED display and speed dial within reach without a bulky console
Where the X21 lands against the other WalkingPad and incline options in this catalog: Beats the WalkingPad C2 on top speed, 7.5 mph against a 4 mph ceiling, at the cost of a larger footprint even when folded, Loses to the WalkingPad MX8 Plus on stated weight capacity, 220 to 240 lb against a flat 330 lb, though both fold vertically, Trades incline for speed against the UREVO 12% Auto Incline; pick the X21 for jogging pace, the UREVO for adding intensity without more speed.
Which rider are you?
From this page to your first ride
Read the tested review
Real specs, the weight-capacity conflict, and what owners actually say, all on one page.
Check today's price
One click to Amazon. We check the listing regularly and note it here if anything changes.
Unfold it against a wall, not under a desk
The X21 ships assembled. Pair the companion app the same day and test the belt and display before you settle on where it lives.
Why the X21 earns its spot in this class
A fold that solves a different problem than flat-fold pads
Most walking pads slide flat under a desk or a sofa. The X21 folds in two steps, first the standard 180 degrees, then an additional 90 degrees, so the whole deck stands upright against a wall instead. That trades floor space for wall space, the right trade if your room has more of the second than the first.
Enough speed for a light jog, not just a shuffle
A 1 to 7.5 mph range puts the X21 well above the 4 mph ceiling common on compact walking pads, including WalkingPad's own C2. It will not replace a dedicated running treadmill, but it covers a walk-to-light-jog range a pure desk pad cannot.
What owners keep saying
This section adds four attributed quotes from Sydney Kaiser's hands on WalkingPad X21 review at Treadmill Review Guru, where her team tested the fold, the motor noise, and the weight capacity in person. That is one outlet's test unit, so read it as one team's hands on account rather than a wide sample of owners.
When walking and jogging, the seam can be felt underfoot. Compared to other treadmills that don't have decks that fold in half, it feels like a slight bump or dent in the deck.
comfortThe X21 goes up to 7.5 mph, so if you're short like me (I'm only 5'1") and if you have a short running stride (hi, me again), then you'll be able to get up to a good pace.
fitThe X21 has a decent 240 lb weight limit. Our largest team member is 225 lbs and was able to walk on the deck. He didn't notice any change in performance or noise, so users up to 240 lbs should be able to use the X21 just fine.
durabilityThe motor is fairly quiet, making it suitable for most shared spaces.
noiseTwo-step vertical fold, 7.5 mph top speed, and a spec conflict worth reading first.
Shop on Amazon →The honest cons
- Amazon's own spec table and its own comparison chart disagree on max user weight and item weight for this exact model; this page uses the lower, spec-table figures rather than picking silently (see FAQ)
- The control panel sits low on the handrail, and one owner reports having to constantly look down to adjust speed or check a phone on the holder while walking
- It beeps on power-on and with every speed change, per one owner, loud enough to plan around if it sits near a bedroom
- One owner's belt developed a sticking noise after about a month of light use and described KingSmith's email support as unresponsive until the warranty had already expired; a different owner had the opposite experience after a damaged first unit, so support quality reads inconsistent across reviews
- No calorie tracking. The display reads distance, speed, and time only
WalkingPad X21 vs MX8 Plus vs C2 vs UREVO 12% Incline
If you're comparing the WalkingPad X21 against other options in this catalog, the short version is fold direction and speed: the X21 and the MX8 Plus both fold vertically for wall storage, the C2 trades speed for the smallest footprint, and the UREVO swaps speed for auto incline instead.
| WalkingPad X21 | WalkingPad MX8 Plus | WalkingPad C2 | UREVO 12% Incline | |
|---|---|---|---|---|
| Speed range | 1-7.5 mph | 1-5 mph | 1-4 mph | 1-4 mph |
| Fold type | Two-step, vertical | Vertical | Flat, under furniture | Flat, under furniture |
| Max user weight | 220 lb, spec conflict | 330 lb | 220 lb | 300 lb |
| Incline | None | None | None | 12% auto incline |
| Connectivity | Bluetooth, app pairing | App-based control | Remote control, no Bluetooth listed | Not listed for this model |
| Our take | Best if you want jogging speed and vertical storage | More weight capacity, slower top speed | Smallest footprint, walking pace only | Best for adding intensity without more speed |
| Spec | WalkingPad X Series Smart Vertical-Fold Treadmill |
|---|---|
| Model | WalkingPad X21, entry model of the X Series (model number TRX21F) |
| Speed range | 1 to 7.5 mph |
| Motor | 2 hp max, brushless |
| Belt / deck | 18.1 in wide, 47.6 in long, 3.78 in deck height |
| Fold type | Two-step tri-fold: a 180 degree fold plus an additional 90 degree fold for vertical, upright storage |
| Folded footprint | 27.9 x 37.6 x 8.9 in, as listed |
| Unfolded footprint | 55.8 in D x 27.9 in W x 41.4 in H |
| Frame | Aluminum alloy |
| Control | Single handrail-mounted LED display with a rotary dial, no touchscreen |
| Metrics tracked | Distance, speed, time (no calorie tracking listed) |
| Connectivity | Bluetooth, pairs with a companion app |
| Noise | About 75 dB at top speed, no load |
| Power | Corded electric, 110W input |
| Max user weight | 220 lb (100 kg) per Amazon's spec table; a separate chart in the same listing says 240 lb, see FAQ |
| Item weight | 55 lb (25 kg) per Amazon's spec table; the same chart says 81 lb |
| Included | Power cord, safety key, user manual |
| Warranty | 1 year, manufacturer |
| Color | Silver Black |
FAQ
Is this the WalkingPad Z1?
No, this page covers the WalkingPad X21, the entry model in KingSmith's X Series. The Z1 is a separate, lighter WalkingPad model built for slower, desk-only use. Amazon's own data for this listing names the model X21, model number TRX21F, throughout, never Z1, so if you specifically want the Z1 you are looking at the wrong product.
What is the actual weight capacity on the WalkingPad X21?
Amazon's structured spec table for this listing states 220 lb (100 kg), but a separate comparison chart embedded in the same listing's images states 240 lb for the same model. The two do not agree, and we would plan around the lower, spec-table number until KingSmith or Amazon resolves the mismatch.
How loud is the WalkingPad X21 at top speed?
About 75 dB at top speed with no load, per KingSmith's own listing content. One owner separately notes the unit beeps loudly on power-on and with every speed change, worth knowing if it will sit near a bedroom or a shared wall.
Can you actually jog on the X21, or is it walking-pace only?
Yes, within limits. The 1 to 7.5 mph range covers a light jog on top of a walking pace, and one owner describes using it before playing tennis. A 6 foot former athlete in another review says it cannot match his full sprint speed, which tracks with a 7.5 mph ceiling rather than a dedicated running treadmill's range.
Does the WalkingPad X21 need assembly?
No, assembly is not required. Amazon's listing marks it as no-assembly, and one owner confirms it arrived ready to use straight out of the box.
Does the vertical fold actually save space over a flat-fold walking pad?
It saves floor space specifically. A flat-fold pad like WalkingPad's own C2 slides under a desk or sofa and stays low, while the X21 folds in two steps and stands the deck upright against a wall instead. Pick whichever trade fits your room, wall space or floor space, before comparing anything else.
What's included in the box?
The power cord, a safety key, and a user manual, per Amazon's listing. No mat or floor protector is listed as a standard inclusion, though one owner reported receiving one at no charge, so treat that as a possible promotion rather than a guaranteed extra.
The verdict
The short version: the WalkingPad X21 is a well-liked, quiet vertical-fold treadmill built for buyers who want a walk-to-light-jog machine that stores upright instead of sliding under a desk. Amazon owners land near 4.4 out of 5 across 300 reviews, and the pattern in our own excerpt sample matches that: praise for the two-step fold, quiet operation at typical speeds, and arriving fully assembled. The real catch is a weight-capacity number that Amazon's own listing does not agree with itself on, plus a control panel mounted low enough on the handrail that a few owners have to look down to use it.
Buy it if you want more speed than a desk-only walking pad offers and your room has wall space to spare. Skip it if you are close to either weight-capacity figure and want zero ambiguity, or if you specifically want the WalkingPad Z1, which is a different, lighter model this page does not cover.
If it’s close but wrong
WalkingPad X Series Smart Vertical-Fold Treadmill