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Reebok Nano X4 vs UA TriBase Reign 6

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For the first year, possibly ever, I feel like the Reebok Nano and Under Armour TriBase Reign models are super competitive with one another. Not to be too crass, but the Reign 6 is the first TriBase model that has truly slapped regarding performance.

I’ve had a lot of questions on my YouTube channel about which model athletes to choose, and my answer is always the same: “It depends.” I then follow up and ask, “How do you train? What’s your foot anatomy like? What do you currently wear?”

With these insights, it becomes much easier to narrow down which model will be the stronger pick of the two shoes because, ultimately, the Reign 6 and Nano X4 feel super different on the feet and in the gym. They’re both acquired tastes.

Reign 6 vs Nano X4 Summary and Winner

Construction Specs to Know

The construction specs between these models can be a major factor that can influence which shoe is ideal for you. For example, the heel-to-toe drop and type of midsole used in both models can heavily influence each shoe’s performance.

The 2mm drop of the Reign 6 gives this model a much “flatter” feeling for training, and it also feels much more minimalist on the feet. I’ve loved this about this model, but I’m also a fan of training in barefoot shoes, which are also an acquired taste.

The Nano X4’s heavier upper, traditional midsole, and LAR system around the boot give this model a lot more “structure,” which can be great for those who prefer having more built-out trainers.

 Reign 6
Nano X4
Weight14.25 oz 13 oz
Price Differences

Where I Suggest Buying Them

  • UA TriBase Reign 6: $130. I’d buy through Under Armour, Box Basics, or Amazon. Easier returns with these retailers.
  • Reebok Nano X4: $140-150 (depending on colorway). I’d buy through Reebok, Box Basics, or Amazon. Easier returns with these retailers.

UA TriBase Reign 6 Vs Reebok Nano X4 Performance Comparison

Another spec difference to remember is the drop-in midsole used in the Reign. This is a feature that I find to be polarizing, and lifters either love or don’t mind drop-in midsoles despite them. If you’re in the latter camp, then you’ll want to pass on them and go Nano X4.

Performance Summary

For the record, I think for most recreational lifters and CrossFit athletes, the Reign 6 and Nano X4 can both be great. In both models, I’ve deadlifted north of 500 lbs and have squatted over 400 lbs and their stability has been great.

I’ve also pushed both of these shoes in multiple CrossFit WODs, and in my normal training, I follow a hybrid-style program. As in, I do a little bit of everything and I do this purposely to improve athlticism and test the full bredth of shoes I’m reviewing.

With their stability both being pretty similar, I found that you start to feel the differences between these shoes most when you start running and doing more versatile workouts that include HIIT and full-body circuits.

Under Armour TriBase Reign 6 Stability Testing

  • Reign 6 vs Nano X4 for Lifting: Both shoes are great from a stability point of view. You will notice the drop-in midsole compress a little more in the Reign 6 when squatting north of 365 lbs, but this didn’t hinder my performance or cause a loss of balance and I think this is due to the flatter heel-to-toe drop of this model.
  • Reign 6 vs Nano X4 for CrossFit: Nano X4. The Nano X4 is taking the slight edge for CrossFit; however, not by much. I think this shoe is a little more “universal” regarding its fit and performance for a grander CrossFit audience compared to the Reign 6, as in, more athletes will typically instantly click with the X4 compared to the Reign 6’s more acquired taste.
  • Reign 6 vs Nano X4 for Versatility: Reign 6. When it comes to feeling athletic and moving with the foot when doing plyometrics, multi-directional exercises, and explosive sessions, the Reign 6 is taking the win. It feels more pliable, the drop-in midsole has a bit more responsiveness, and its outsole is wicked grippy.
  • Reign 6 vs Nano X4 for Short Runs: Nano X4. Both shoes will work for short interval runs, but the Nano X4 is taking home the “W” here for running, as you can run more often in them without feeling too beat. This is a shoe I’ll typically rock for 1-3 mile bouts because the LAR system and its construction feed well into that context.
  • Reign 6 vs. Nano X4 for Comfort: Depends on what you like. If you’re a minimalist lover like me, then you’ll prefer the Reign 6 for daily wear and comfort. This shoe also has a more athletic fit compared to the Nano X4, which has a more structured fit. The X4 will be more comfortable for those who like a little more ankle and arch support in their shoes.

Overall Winner: UA TriBase Reign 6. I’m not going to lie; this one is really tough because the true winner between these shoes will heavily rely on one’s tastes and preferences, whereas in cases like the Dropset 2 and Metcon 9, there’s a clear winner.

If you prefer arch support and more structure to your shoes, you’ll enjoy the Nano X4. For those who want an athletic shoe with good flexibility and a more versatile feel to it on the feet, go Reign 6.

UA TriBase Reign 6


UA TriBase Reign 6 Product Image

Best For

  • Strength Training
  • Athletic Workouts
  • Cross-Training and HIIT
  • CrossFit
  • Sprints and Ploymetrics

Falls Short

  • For Exceptionally Wide Feet (<EE-width)
  • For Runs Over a Mile

Sizing Differences

  • UA TriBase Reign 6 Sizing: True to size for most
  • Reebok Nano X4 Sizing: True to size for some; wide feet should go up a half-size.

The fit and feel of the Reign 6 and Nano X4 are wicked different. I like this because it makes it easier to help eliminate which shoe will be a complete miss for you regarding fit, whereas some shoes feel eerily similar, which muddies the water.

UA TriBase Reign 6 Vs Reebok Nano X4 Toe Box Widths
UA TriBase Reign 6 Vs Reebok Nano X4 Toe Box Widths

For context here, I have an E/EE-width foot — this varies depending on the company — and a regular arch. I wear a size 10 in all of the training shoes that I review to draw more nuanced sizing conclusions on models.

I find that both of these shoes fit true once broken in, but the Reign 6 has a more spacious toe box. It took me a solid week to break in my Nano X4’s toe box and I actually felt like they ran snug out of the box which was a change from the Nano X3’s longer fit.

This is why I suggest sizing up a half-size for wider feet in the Nano X4. Save yourself the time of having to do the whole return process and play it safe, or buy from a retailer like Reebok or Amazon that has a more seamless return process.

TriBase Reign 6 Try On

The Regin 6’s toe box is a little more anatomical, and it doesn’t have the same amount of taper, which is nice for blocker feet. I will say the Reign 6’s upper is a little more profile, so thicker feet and higher insteps should tread lightly with this model.

Something I’ve been doing and experimenting with in my Reigns is swapping out their drop-in midsole for my Reign 5’s traditional insole. This has been cool because it gives you more upper volume and a much more “barefoot shoe-like” fit and feel with this shoe.

Reebok Nano X4


Reebok Nano X4 Product Image

Best For

  • Strength Training
  • HIIT and Versatile Workouts
  • Sprints and Short Runs (<2 miles)
  • CrossFit and Functional Fitness

Falls Short

  • For Feet Wider Than EEE-Widths
  • For Runs Longer than 2-3 Miles
  • For Minimalist Lovers

How I’ve Tested These Shoes, Individual Reviews

With all of my cross-training shoe reviews, I put them through similar tests to assess stability, versatility, and durability. For the Reign 6 and Nano X4, my tests revolved around heavy barbell movements, CrossFit WODs, and athletic/hybrid sessions.

For example, a normal workout I’ll do in these shoes when testing them includes sled pulls for warm-up, heavy ascending deadlift triples, walking dumbbell lunges, cyclist squats paired with box jumps, then finish with a circuit of short runs and dumbbell snatches.

Me Deadlifting 505 lbs In the Reebok Nano X4
Me Deadlifting 505 lbs In the Reebok Nano X4

Some of the Consistent Tests I Perform

  • Strength Tests: 505-515 lb deadlifts, 405-425 lb squats, 3-rep max walking or reverse barbell lunges
  • Strength & Power Tests: Power cleans, hang cleans, dumbbell and kettlebell snatches
  • CrossFit Tests: Fran, Cindy, and self-programmed WODs (I use them for conditioning)
  • Cross-Training: Broad and box jumps, skater strides, and plyometric/agility sessions
  • Running: Sprints, 800-meter intervals, 1.5 to 3-mile runs
  • Walking: 2-3 mile dog walks, all-day wear comfort tests

For transparency, these aren’t the only tests I performed on these shoes, but they are staple tests I try to do on every shoe. I ebb and flow my tests based on a shoe’s intent and purpose — and I’ve built this testing protocol over the last seven years of reviewing shoes.

Nano X4 and Reign 6 Reviews

As always, I have in-depth individual reviews for both of these shoes, and I suggest checking them out if you want more depth on either of these shoes before you buy. I’m also always here if you have additional follow-up questions!

Midsole Construction

  • Reebok Nano X4: Utilizes Reebok Floatride Energy Foam, offering a denser and less flexible midsole.
  • Under Armour Tribase Reign 6: Features a drop-in midsole that is plush and bouncy, providing enhanced comfort and flexibility.
UA TriBase Reign 6 Vs Reebok Nano X4 Midsole Constructions With Insoles Shown
UA TriBase Reign 6 Vs Reebok Nano X4 Midsole Constructions With Insoles Shown

Outsole Construction

  • Reebok Nano X4: Equipped with a rubber outsole and LAR chassis system, delivering stability and support during various movements.
  • Under Armour Tribase Reign 6: Boasts a rubber outsole with TriBase Tech, offering a more aggressive tread pattern for superior grip and traction.
UA TriBase Reign 6 Vs Reebok Nano X4 Outsole Constructions
UA TriBase Reign 6 Vs Reebok Nano X4 Outsole Constructions

Upper Construction

  • Reebok Nano X4: Incorporates a Flexweave upper construction with textile overlays, providing breathability and security.
  • Under Armour Tribase Reign 6: Features a combination of chain link mesh and warp material, along with an extended heel counter and padded mesh for durability and support.

UA TriBase Reign 6 Vs Reebok Nano X4 Upper Constructions

Laces and Tongue

  • Reebok Nano X4: Features six core eyelets, a padded mesh tongue, and a higher tongue gusset for additional tongue security and fewer changes of heel slip.
  • Under Armour Tribase Reign 6: Feature 6 core eyelets with a 5th eyelet for lace-locking. It also has a padded mesh tongue with a tongue gusset to promote security.

Is the Reign 6 or Nano X4 Better for Lifting?

Answer: The Reign 6 is a better option for lifters who like flatter shoes for lifting, and they give you more sole articulation, making them great for exercises like split squats and lunges where you want more foot mobility.

The Nano X4 is stable and works well for lifting. However, you have less toe box width in this shoe, and its higher heel-to-toe drop can take away from its performance for heavy deadlifts where you don’t want as much heel elevation.

Using the TriBase Reign 6 for Split Squats

Is the Reign 6 or Nano X4 Better for CrossFit?

Answer: The Nano X4 is a little more well-rounded and universal fitting for CrossFit, in my opinion. It feels like a shoe that most will be used to regarding traditional training shoes, so if you’ve never rocked either of these, you’ll likely click faster with the Nano for CrossFit.

The Reign 6 can work exceptionally well in this vertical, but again, its fit is a little more specific and acquired. Either way, I don’t think you can go wrong with either shoe regarding durability and versatility in most WODs.

Cross Training In the Reebok Nano X4

Is the Reign 6 or Nano X4 Better for Versatility?

Answer: The Reign 6 will be a more “athletic” feeling shoe if you like shoes with lower-profile uppers that have more flexibility. In this context, it kind of reminds me of the cleats I used to wear when running track and playing soccer (football, for my international friends) growing up.

The X4 is a great option for classes where you’re doing some strength and running, HIIT workouts, and general cross-training. The upper security, LAR system, and ankle support help lock the feet down well in this vertical.

Testing the TriBase Reign 6 for HIIT

Is the Reign 6 or Nano X4 Better for Runs, Walking, and Comfort?

Answer: I find that the Reign 6 is a little more comfortable for all-day wear and walking, but that’s with a caveat. I also like wearing barefoot shoes routinely, so their flatter and minimal feel resonates with me. For runs longer than 800 meters, they can feel a little heavy.

The Nano X4 is almost reversed here with its comfort and walkability, which is ironic since it’s more comfortable to run longer distances in. I just find its narrower toe box and more built-out midfoot hinder its all-day wear comfort to let the feet move and do their things.

Skater Strides In the Reebok Nano X4

Final Verdict, Would I Buy These Again?

I would. I’ve been fond of the Nano X4 and Reign 6, and there’s a reason I’ve included them both in my cross-training shoe round-ups for different reasons.

I think that for most lifters and athletes, if you can answer the questions about your fit and construction preferences, you can’t go wrong with either of these options.

Go Reign 6 if you like flatter and more minimalist-feeling shoes, and go Nano X4 if you want more arch support with a higher heel-to-toe drop.

If you have additional questions on about either of these models, drop a comment below or reach out via Instagram (@jake_boly or @that_fit_friend).

Jake Boly, CSCS, MS Sports Science

Jake Boly, CSCS, MS Sports Science

Jake Boly is the Founder and Editor-In-Chief of That Fit Friend. He's often regarded to as a go-to resource in various performance shoe communities. He’s been formally reviewing shoes and training gear for over 7 years and has hand-tested over 400 pairs of shoes. Jake is known on the internet and YouTube for blending his review process with his educational, strength sports, and personal training background.

Jake has a Masters in Sports Science, a Bachelors in Exercise Science, a CSCS, and he's been personal training for over 10 years helping hundreds of clients get stronger, lose weight, and accomplish their goals. He uses his exercise science brain and personal training background to make curated and thoughtful review content on the fitness gear he's testing.

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