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On YouTube and Instagram, I’ve had a lot of questions about the On Cloud 6 and On Cloud X 4, and which people should buy. Both of these models have a bit of crossover, so it makes sense why some are confused about which to go with.
I’ve reviewed and tested both shoes to purposely assess, 1) how their durability fares long-term and in different settings, 2) their thresholds in the gym, and 3) whose foot anatomies they’ll work best with. For context, I buy a size 10 in every shoe so I can better compare different shoe fits with one another.
Because I know most people don’t feel like buying multiple shoes at $150 a pop — On shoes ain’t cheap, y’all. I buy everything myself that I review.
I’ll also try to be clear on which shoe I think you should go with based on your lifestyle and needs. This way, you can make sure you’re getting into the shoe that will give you the most bang for your buck.
Quick Performance Takeaways
- Which Is Most Comfortable: On Cloud 6. When it comes to sheer midsole density and plushness, the On Cloud 6 will take the edge over the X 4. It’s worth noting, though, that the 6 does feel a little denser than the Cloud 5, if you’ve worn that shoe.
- Which Is Better for Walking: Both can be solid. The Cloud 6 will be a little “softer” but the Cloud X 4 does a good job for walking, too, especially if you’re outdoors more often. I actually like the X 4 a smidge more for primarily outdoor walks because its durability tends to be better long-term.
- Which Is Better for Exercise: On Cloud X 4. Its midsole is denser for “heavier” lifts, and it’s more stable overall. I like its platform a lot because it’s wider for cross-training and lifting, too. The Cloud 6 can work, but its thresholds are wayyyy lower in the gym — more on this below.
- Which Is Better for Running: On Cloud X 4. I know some people run in their 6, however, I don’t love doing so. Their upper security is so-so and if you use them primarily for daily wear, you’ll get a lot more out of them. The X 4 works best for jogs and runs that range from 2-5 miles.
- Which Is Better for Wide Feet: Similar. Both of these models can accommodate E-width feet and sometimes EE feet. If you’re pushing 3E+ foot widths, then you’ll want to pass on both of these.
- Which Is Better for Flat Feet: Neither is great, but I’d give the edge to the 6. Since the 6 has a little more upper volume to it and less midfoot taper, it can feel a bit better for flatter feet. Definitely try them on first if you can.
If you stop reading this article here, take my advice and grab the 6 if you’re most worried about walking comfort and daily wear use. Grab the X 4 if you plan to train, but also want a shoe for some walking and casual wear. Yes, you can train in the 6 — it will be sub-par, though.
On Cloud 6
On Cloud X 4
Sizing and Fit Thoughts
Narrow Foot Suggestions
- On Cloud 6: True to size.
- On Cloud X 4: True to size.
Medium Foot Suggestions
- On Cloud 6: True to size.
- On Cloud X 4: True to size.
Wide Foot Suggestions
- On Cloud 6: E, true to size. EE+, potentially pass or go up a half-size.
- On Cloud X 4: E/EE true to size. 3E+, pass on them.
Flat Foot Thoughts: Both shoes have a fairly significant arch. I find the X 4’s arch to be a little more pronounced, and I think that has to do with the snugger-fitting upper and the SpeedBoard used.
Performance Assessment
Testing These Shoes for Lifting
If you want to strength train at all in these shoes, then the Cloud X 4 will take the edge as the stronger performer. This shouldn’t really come as a surprise, though, since the X 4 is On’s flagship shoe built for cross-training and general gym sessions. The CloudTec midsole in this shoe has the densest feel under the foot, too.
When it comes to lifting thresholds, I purposely lifted up to 365 lbs with deadlifts in the Cloud X4 and 225 lbs in the 6 to see when noticeable compression started. After about 315 lbs in the X 4, you’ll start to notice the CloudTec compress, especially at the forefoot, and the 7mm heel-to-toe drop will pitch you forward a bit. In the 6, noticeable compression started at about 225 lbs. This is why you’ll want to limit your lifting in the 6.
For machines and general strength work with dumbbells and kettlebells, both shoes can be fine. If you do heavy single-leg work, then you’ll likely notice instability pretty quickly in the 6. For example, with 60 lb walking dumbbell lunges, I noticed a lot of medial and lateral shifting in the 6. I didn’t have the same issue in the X 4 until passing 80 lbs.
All that said, if you plan to regularly strength train, do yourself a favor and go with the X 4, even if you like the look of the 6 better. The 6 is what I call a hotel workout shoe, as in, you can use it for super casual stuff in the gym, but that’s about it. Even on heavier upper days, where I’m doing barbell overhead presses, I don’t love this shoe.
Cross-Training and Hotel Workouts
Similar to lifting, the X 4 is bringing home the “W” for cross-training. It has three features that dust the 6 in the context of cross-training. First, the SpeedBoard feels a little more lively, as in, you get a little more pop for jumping with it compared to the SpeedBoard used in the 6. I think this is also why you have better midfoot stability in the X 4, comparatively speaking.
Second, the upper security is better in the X 4. The mesh and knit have a double layering, so it gives you more support when moving dynamically. The 6’s mesh is okay, but you’ll have quicker spillover rates due to it lacking the same level of reinforcement. Not to mention, if you’re big on the Speed Lacing that comes with the 6, then you’ll also run into security issues and the last thing you want to do is swap laces every time you train.
Third and lastly, the outsole grip is better in the X 4 and I find that the midsole on the outside of the shoe breaks down at a slower rate compared to the 6. I think this is due to the difference in midsole density and rubber thickness. Regardless, the X 4 will be the winner for anything dynamic.
The takeaway here? If you’re taking classes or like to blend jumping with some lifting, go X 4. If you want something comfortable for travel that can tackle some chill machine, bodyweight, and free weight lifts, then you can get away with the 6. Just keep in mind that you will be limited with this shoe.
On Cloud X 4
$149.99
Pros
- CloudTec Midsole Is Comfy
- Good for General Training
- Can Work for Walking and Short Runs
Cons
- Not Great for Heavy Lifting
- Rocks Can Get Into Midsole/Outsole
- Not Great for Flat Feet
Best For
- Casual and Lighter Lifting
- Cross-Training
- HIIT and Classes
- Walking
- Short Runs
Falls Short
- For Flat Feet
- For Tough Athletic Training
- For Heavier Lifting
- For CrossFit
Walking and Running Comfort Assessment
For running, the X 4 will be your best bet, especially if you like to do faster intervals (400-600 meters) in workouts or plan to run 2-5 miles at a time. For these distances, the X 4 does a solid job. Note, it won’t feel as plush as some of the running-dedicated On shoes, but for short stuff, it gets the job done.
Can you run in the On Cloud 6? That’s debatable. I have some commenters on YouTube who say they run in theirs, but I don’t find them that comfortable. If I’m running, then I want something that’s optimized or built for accommodating that ask. No need to use a sub-par option or “force” a shoe into a setting it isn’t built for. Not to mention, you’ll run into durability issues faster running in your 6, IMO.
For walking and daily wear, you’ll want to go with the 6 if those are your main objectives. The heel-to-toe drop of the Cloud 6 sits at 8mm and for the X 4 it has a drop of 7mm, so they feel similar in that regard. The 6 has a softer ride, and the slip-on ability with the Speed Lacing is such a nice quality-of-life feature. I also appreciate that On made its upper a little more spacious compared to the 5. And I know people still love the 5, but I just found it way too narrow in the forefoot.
My only gripe with the 6 is that its midsole durability still falls victim to easy scuffing just like the 5 did, so you may want to consider the X 4 if you primarily want your shoes for concrete walking. For indoor and some outdoor/mostly indoor wear, the 6 wins.
On Cloud 6
$150
Pros
- Picks up fewer rocks
- Lightweight construction
- More spacious fit
Cons
- Midsole durability
- Narrow feet may find too loose
- Still picks up some rocks
Best For
- Casual Wear
- Walking
- Traveling
Specs
| Heel-to-Toe Drop | 8mm |
| Weight | 10.05 oz (size 10) |
| Width | Medium/Wide(r) |
| Lifting Threshold | <185 lbs |
| Run Distance Threshold | <1-2 miles |
Final Remarks
In case I wasn’t clear in this article and you’re still confused about which On shoe to go with, let me reiterate one more time:
- Go with the On Cloud X 4 if you need a shoe primarily for working out with some walking and casual wear. If you’re primarily walking outdoors, then the X 4 can also be a solid option to explore.
- Go with the On Cloud 6 if you need a shoe primarily for walking/commuting, indoor wear, and working on your feet all day. For a softer ride, you may want to look into other On shoes if you enjoy how the CloudTec midsole looks.
If you have additional questions on this article, drop a comment below or reach out via Instagram!
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