Our verdict

The New Balance FuelCell Rebel v4 is a bold refresh, crafted to preserve its famously fun ride with a sleek, low-stack midsole, while boosting both fit and stability. In our runs, we were also excited to discover its upgraded midsole, which now provides better energy return. However, even though it remains as light as before, we found that this update has lost some agility and spark due to its wider dimensions.

Pros

  • Natural, flexible ride
  • Enhanced energy return!
  • Remains a fun ride
  • Finally accommodates wide feet
  • Reasonably priced at £150
  • Ample traction
  • Fantastic stability
  • Plush and comfy midsole

Cons

  • Heel lock needs improvement
  • Now it's even... too wide!

Audience verdict

88
Great!

Who should buy

We believe the New Balance FuelCell Rebel v4 is a fantastic choice for:

  • Those who loved the previous Rebels and desired a roomier upper, as we believe they will find this version to be a perfect fit.
  • Runners looking for a lightweight, stable, and fun shoe that delivers on all fronts while still being priced at just £150.
  • Individuals who need a shoe for daily runs and speed workouts but prefer to avoid stiffer models with a plate.

New Balance FuelCell Rebel v4

Who should NOT buy

The New Balance FuelCell Rebel v4 might not satisfy those who prefer maximalist running shoes due to its sub-30-mm stack height.

We believe there are better choices for runners seeking more cushioning at a similar price and weight. The ASICS Novablast 4 offers a thicker platform, making it a more suitable alternative. Additionally, if budget isn't a constraint and you desire even more cushioning, we recommend checking out the ASICS Superblast.

New Balance FuelCell Rebel v4 parts

We also think that the Rebel v4 is not the best option for runners with narrow feet. Our lab tests have shown it's quite wide, which may lead to a less secure fit. We do not recommend this shoe for such runners—instead, the NB Rebel v3 or the Hoka Mach 5 would provide better lockdown and overall fit.

Breathability

The Rebel v4's upper has undergone a significant transformation from its predecessors. It still features engineered mesh, but New Balance has reintroduced an older technology called FantomFit, which combines excellent ventilation with structured support.

We tested the toebox's breathability with our smoke pumping machine and confirmed it's airy at 4/5 for us.

Next, we examined the upper under a light, which revealed the shoe's construction details. The toebox starts off super-thin, and then the shoe adds more layers to enhance stability, although this slightly reduces airflow in those areas.

Using the light, we also discovered that the upper differs significantly from most engineered mesh designs. Rather than being thicker with some ventilation holes, it's exceptionally thin but includes thicker areas strategically placed throughout.

New Balance FuelCell Rebel v4 microscope

To further analyze these thicker areas, we switched to the microscope.

New Balance FuelCell Rebel v4 microscope

It's fascinating that New Balance opted for a completely opposite approach than most running shoes on the market. We always appreciate when brands try different stuff!

The upper is minimally padded, prioritizing lightness above all else—except in the heel area. But, as always, the Rebel is designed for a lightweight experience—take it or leave it.

Test results
FuelCell Rebel v4 4
Average 3.8
Compared to 221 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

The FantomFit upper delivers a lightweight and breathable experience, yet durability tells a completely different story.

We tested the upper with our Dremel tool—like we do with all our shoes—and unfortunately, we discovered one of the worst durability results we've seen in the lab. This clearly earns a 1/5 rating.

It's evident that it won't be a super durable shoe for those prone to wearing holes. For anyone in that category, we recommend opting for a more robust option like the Endorphin Speed 4.

New Balance FuelCell Rebel v4 Toebox durability
Test results
FuelCell Rebel v4 1
Average 2.3
Compared to 155 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

After applying the Dremel for the second time, we were thrilled to discover an outstanding outcome—the complete opposite of the previous one.

It was so impressive that we awarded it a perfect 5/5!

New Balance FuelCell Rebel v4 Heel padding durability
Test results
FuelCell Rebel v4 5
Average 3.2
Compared to 151 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

The outsole of the Rebel v4 has been significantly upgraded from its predecessor, now sporting a completely new rubber pattern designed to enhance both grip and durability. Indeed, we found the grip to be truly impressive, even on dirt roads.

New Balance FuelCell Rebel v4 outsole

We appreciated the rubber and the lengthy central strip on the outsole, but found that the coverage in the heel area might be a bit too sparse for rearfoot strikers.

During our testing, the hardness measured at 81.5 HC on our durometer, which is fairly average and suggests decent durability—though we'll continue to monitor its performance in our upcoming tests!

New Balance FuelCell Rebel v4 Outsole hardness
Test results
FuelCell Rebel v4 81.5 HC
Average 80.4 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 272 running shoes
Number of shoes
54.9 HC
Outsole hardness
92.8 HC

Outsole durability

In our latest Dremel test, we adjusted our approach due to the tougher nature of the rubber compared to the upper. We increased the speed to 10K RPM and ran the tool for a longer period.

The results were satisfactory, though not astonishing, as we found a 0.8-mm indentation in the rubber.

New Balance FuelCell Rebel v4 Outsole durability
Test results
FuelCell Rebel v4 0.8 mm
Average 0.9 mm
Compared to 133 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

In our final analysis of the outsole, we measured a thickness of 3.2 mm. While this might appear average compared to other shoes, it's actually quite generous from New Balance for a shoe designed to be as lightweight as possible.

New Balance FuelCell Rebel v4 rubber

It's clear there are two approaches to achieving good durability while keeping the weight low, and New Balance opted for the strategy of using thicker rubber, rather than a thinner layer that covers more of the midsole.

New Balance FuelCell Rebel v4 Outsole thickness
Test results
FuelCell Rebel v4 3.2 mm
Average 3.2 mm
Compared to 291 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

One of the standout features of the Rebel series has always been its lightweight design, and despite appearing like a supercharged version of previous models, New Balance has impressively managed to keep the shoe under 8 ounces.

In fact, it weighs just 7.5 oz or 213g—truly remarkable.

New Balance FuelCell Rebel v4 Weight
Test results
FuelCell Rebel v4 7.51 oz (213g)
Average 9.38 oz (266g)
Compared to 292 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

The heel height of just 28.0 mm is notably lower than most running shoes, especially recent launches. However, the Rebel has always favored a moderately low design, and 28.0 mm is well-suited for its purpose—not for long runs, but for fast and fun ones.

It’s also worth mentioning that the midfoot is slightly thicker than 28.0 mm. However, we measure every shoe according to World Athletics guidelines, regardless of its geometry.

New Balance FuelCell Rebel v4 Heel stack
Test results
FuelCell Rebel v4 28.0 mm
Average 33.6 mm
Compared to 291 running shoes
Number of shoes
7.6 mm
Heel stack
42.7 mm

Forefoot stack

Measured in our lab and still following World Athletics guidelines, the forefoot came in at just 21.5 mm.

This dimension is a blessing for those who prefer a natural ride with plenty of ground feel. However, we believe it may not fully satisfy those who favor more cushioned, maximalist shoes.

New Balance FuelCell Rebel v4 Forefoot stack
Test results
FuelCell Rebel v4 21.5 mm
Average 24.9 mm
Compared to 291 running shoes
Number of shoes
7.6 mm
Forefoot stack
35.8 mm

Drop

The Rebel v4 adopts the design and geometry similar to its racing counterpart, the Elite v4, which we've noted that causes the midfoot to be higher than the heel. This design may not be ideal for heel strikers, who could sink into the rear of the Rebel.

We also measured a 6.5-mm drop, which is particularly suitable for runners who utilize a midfoot or forefoot striking technique.

New Balance FuelCell Rebel v4 Drop
Test results
FuelCell Rebel v4 6.5 mm
Average 8.7 mm
Compared to 291 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

The insole, reminiscent of those found in racing shoes, measures just 2.5 mm.

We particularly appreciate this thin footbed because it keeps the shoe low-profile, maximizing the foam over the insole to enhance energy return.

New Balance FuelCell Rebel v4 Insole thickness
Test results
FuelCell Rebel v4 2.5 mm
Average 4.5 mm
Compared to 287 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

And speaking of the midsole, it still bears the FuelCell name, yet the foam has evolved significantly from the previous Rebels. Now, it's composed of 20% PEBA and 80% EVA—an improvement from its predecessor, although it still doesn’t match the premium, pure-PEBA FuelCell found in the Elite v4.

This iteration of FuelCell remains pillowy-soft—like every Rebel—at just 8.5 HA, but feels just a bit firmer underfoot than previous versions because of the inclusion of PEBA. We found this advantageous for heavier runners as it really helps to prevent bottoming out.

Finally, we have to admit that having crafted a massive guide on midsole foams, we find it frustrating when companies use the same name for midsoles that are totally different.

New Balance FuelCell Rebel v4 Midsole softness
Test results
FuelCell Rebel v4 8.5 HA
Average 21.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 219 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Difference in midsole softness in cold

After placing the Rebel v4 in the freezer for 20 minutes and retesting it with the Shore A durometer, we discovered it became 47.1% firmer.

While that might sound significant, because the FuelCell foam is originally buttery-soft, it still measures just 12.5 HA. Consequently, the increase in firmness is not very noticeable.

New Balance FuelCell Rebel v4 Difference in midsole softness in cold
Test results
FuelCell Rebel v4 47.1%
Average 25.6%
Compared to 218 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Rocker

Another significant change from the earlier versions of the Rebel is the introduction of a rocker. It now sports a distinct curved shape in both the heel and forefoot—a shift that moves away from the flatter design of its predecessors.

While this rocker certainly helps promote forward motion and smoother transitions, we feel that runners who enjoyed the racing-flat vibes of the previous models might not appreciate this new feature.

New Balance FuelCell Rebel v4 Rocker

Stability

Lateral stability test

One of the most significant changes—aside from aesthetics—in the latest Rebel is its stability. Previously, the Rebel series was known for being somewhat unstable, but this latest version has completely flipped the script with multiple changes like massive midsole sidewalls.

In our view, this substantial shift in design won't be for everyone. Sure, increased stability might sound great, but it does take away from the fun, wild ride that characterized previous Rebels. That less practical, yet fascinatingly unique aspect was a big part of their charm. After all, having fun is a big reason of why we run, isn't it?

Torsional rigidity

A major factor in the domesticated ride of the Rebel v4 is its torsional rigidity. Although still relatively low at 2/5, this marks an increase from the super-flexible Rebel v3, which scored 1/5 and offered an exceptionally natural ride.

Test results
FuelCell Rebel v4 2
Average 3.2
Compared to 270 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

We discovered another unexpected change— the heel counter is less stiff than before, now rated at 2/5 compared to the previous 3/5.

This is somewhat concerning to us, as the heel isn't very padded, and the lockdown isn't as effective as it used to be. However, employing a runner's knot could potentially resolve any issues.

Test results
FuelCell Rebel v4 2
Average 2.8
Compared to 254 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

Yet, it's in the midsole width where this shoe has undergone its most significant change. Moving from 110.3 mm in the Rebel v3, our lab measurements show the updated version at an impressive 124.7 mm—a massive adjustment with crucial implications.

New Balance FuelCell Rebel v4 forefoot

The most noticeable impact, as previously mentioned in this lab review, is the increased stability provided by the now gargantuan landing platform, similar to some stability shoes. The major downside? Agility and fun suffer, as the shoe doesn't move as nimbly as before.

Think of it this way—if the Rebel v3 was like a go-kart, the Rebel v4 is akin to a lightweight sports hatchback.

New Balance FuelCell Rebel v4 Midsole width in the forefoot
Test results
FuelCell Rebel v4 124.7 mm
Average 113.6 mm
Compared to 292 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

The heel provided an even bigger surprise than the forefoot, prompting us to double-check our measurements due to the dramatic change between generations.

The Rebel v4 features a 101.5-mm heel, a substantial increase from the 81.5-mm heel of the Rebel v3, making it 25% wider than before!

New Balance FuelCell Rebel v4 Midsole width in the heel
Test results
FuelCell Rebel v4 101.5 mm
Average 90.5 mm
Compared to 292 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

Another hallmark of the Rebel series has always been its exceptionally low stiffness, making it a top choice for those who prefer a natural-feeling, flexible running shoe that lets the feet work without the aid of Pebax or carbon-fiber plates.

Fortunately, this feature is not only retained in the v4, but our 90-degree bend test showed it to be even more flexible than its predecessor, requiring just 13.3N to bend.

Test results
FuelCell Rebel v4 13.3N
Average 29.3N
We use an average of four tests. The video shows one of those tests.
Compared to 274 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

With the midsole composed of EVA foam incorporating only 20% PEBA, it was evident to us that its performance in cold temperatures would be less than ideal.

Indeed, it becomes 25.5% stiffer, which, although better than the v3's 55.6% big increase, is still quite noticeable during winter months. 

Test results
FuelCell Rebel v4 25.5%
Average 36.3%
Compared to 274 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Toebox width at the widest part

While the previous Rebel toebox had its fans, there were many criticisms about it being too snug. New Balance responded to this feedback in a big way—just as they did with every other update in this version.

Now, measuring at 99.6 mm, the shoe not only meets but exceeds the width of most other options, making it an excellent choice for those with regular or wide feet, but less appealing for individuals with narrow feet.

It's also worth noting that New Balance also offers this model in a 2E width in select markets.

New Balance FuelCell Rebel v4 Toebox width at the widest part
Test results
FuelCell Rebel v4 99.6 mm
Average 98.3 mm
Compared to 292 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

The big toe area has undergone the most significant transformation. The earlier Rebels were known for their excessively tapered and constrictive toe boxes, similar to track spikes, but this latest design marks a complete turnaround.

New Balance FuelCell Rebel v4

At 81.6 mm, we found the toe cap to be exceptionally spacious, offering a much more comfortable fit.

New Balance FuelCell Rebel v4 Toebox width at the big toe
Test results
FuelCell Rebel v4 81.6 mm
Average 78.0 mm
Compared to 166 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

The tongue is semi-gusseted, meaning it's partially attached to the sides. We believe this is the optimal design for any running shoe aiming for speed, as it enhances the lockdown by preventing the tongue from moving sideways.

New Balance FuelCell Rebel v4 Tongue: gusset type
Test results
FuelCell Rebel v4 Both sides (semi)

Comfort

Tongue padding

In our previous lab review, we highlighted the remarkably low weight of the Rebel v4, though it does involve some trade-offs.

New Balance FuelCell Rebel v4 tongue

Our primary issue with the tongue is not its padding but rather its length, which feels a bit short.

One such compromise is the tongue thickness—measuring just 2.1mm, it's more akin to what you'd find on a competition shoe than on a daily trainer. Nevertheless, we've found it comfortable enough for both short and medium-distance runs, but pairing the Rebel v4 with thick, padded socks for longer runs is a must.

New Balance FuelCell Rebel v4 Tongue padding
Test results
FuelCell Rebel v4 2.1 mm
Average 5.6 mm
Compared to 289 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

The Rebel v3 doesn't feature a heel tab, staying true to the simple, geometric design themes seen in the latest 2024 New Balance launches. In fact, this shoe just looks like a baby Elite v4.

New Balance FuelCell Rebel v4 Heel tab
Test results
FuelCell Rebel v4 None

Removable insole

The insole is removable, as it isn't glued to the last—however, we advise caution when replacing it with another footbed. We discovered that the shoe is designed for a super-thin insole, and using a thicker option may overly restrict the internal vertical space.

We also found that the insole is perforated, which is a delightful addon.

New Balance FuelCell Rebel v4 Removable insole
Test results
FuelCell Rebel v4 Yes

Misc

Reflective elements

We love reflective elements as they enhance safety during after-dusk runs. And we found that including them in a £150 shoe is a fantastic addition—especially since the Rebel v3 featured them as well.

Test results
FuelCell Rebel v4 Yes