New Balance FuelCell Summit Unknown v3
Test Location: Durango, CO
Test Duration (so far): 65 miles
Stated Stack Height (Men’s): 30 mm (heel) / 20 mm (forefoot)
Stated Heel-to-Toe Drop: 10 mm
Stated Features:
- FuelCell midsole foam
- Full-length outsole made from “Hydrohesion” rubber
- “Rock Stop” rock plate for added underfoot protection
- Bootie-style upper construction with a gusseted tongue
Stated Weight per Shoe (US Men’s Size 9): 294 g / 10.4 oz
MSRP: $130
Size Tested: US Men’s 9.5 / EU 43 1/3
Reviewer: 5’9”, 148 lbs / 180 cm, 67 kg
Intro
With the recent release of the FuelCell Summit Unknown v3, New Balance is off to a hot start in 2023. The latest iteration of the Summit Unknown series marks the long awaited arrival of New Balance’s beloved “FuelCell” midsole material to the trail world. This composition of proprietary foam has amassed quite a loyal following from its use in many of New Balance’s road shoes, like the FuelCell Rebel v2, a model lauded for how well it balances both speed and cushioning. I happen to know that shoe well, and having ticked off quite a few miles in my pair, can substantiate the general consensus around how well it performs. Its FuelCell midsole impressed me by how lively it felt underfoot, delivering energy return on par with some carbon plated shoes I’ve worn in the past. At the same time, the FuelCell Rebel v2 retained enough softness to deliver comfort deep into my long runs.
Fit
I will start this section of the review by saying that if you are a runner with a wide foot who tends to seek out shoes from brands such as Altra or Topo, this is likely going to be a tight squeeze for you. I tend to get along best with shoes that offer a normal width, if not slightly narrower in the toe box, so this was not something that was too alarming to me. However, the FuelCell Summit Unknown v3’s distinctly pointed toe box was still pretty noticeable when I put it on for the first time. In addition to the shoe’s aggressively tapered forefoot, New Balance also uses an extremely rigid and hard “Toe Protect” toe rand that encircles the toe box, in effect making the fit all that more restrictive. After many days this winter spent in ski boots, this rigidity felt a bit harsh on my toes and really did not lend itself to a comfortable, accommodating feel up front.
All that said, FuelCell Summit Unknown v3’s fit did create solid lockdown with the help of a gusseted tongue and a well-designed upper. This is a shoe that really cradles the foot similar to that of the La Sportiva Kaptiva and Bushido II and should work well for folks who tend to get along with European brands that design their footwear to fit precisely. These features also make this shoe quite ideal for technical terrain, where that type of snugness, especially in the heel, is an advantage.
Speaking of the fit in the heel, this is one area that I could see some folks running into issues, particularly those without significantly low-volume, narrow feet. The FuelCell Summit Unknown v3 has an extremely stiff heel and ankle collar that did give me hotspots on any runs longer than 6 miles. I kept thinking that this pattern would abate once I broke the shoe in properly, but even after the 65 miles I have in it so far, The FuelCell Summit Unknown v3’s heel collar continues to give me a hot spot despite trying various socks and lacing strategies. Perhaps this issue will resolve once I take the shoe past the 100-mile mark, but that seems like a rather lengthy (not to mention uncomfortable) break-in period. If anything changes over the coming weeks, I’ll be sure to chime back in with an update.
Weight
Despite the FuelCell Summit Unknown v3 coming in at a not-all-that-slim 294 g / 10.4 oz in a US Men’s Size 9, I felt that the shoe did in fact feel lighter than that on foot. To be honest, I was quite surprised by the weight listed on New Balance’s website, as I would have guessed its weight to be closer to 269 g / 9.5 oz in my US Men’s Size 9.5 test pair. Nevertheless, the shoe did not feel bogged down or sluggish in the slightest. I think much of its extra bulk can be attributed to the FuelCell Summit Unknown v3’s overlay-ridden upper and full rubber outsole, both of which do enough in the way of adding durability / performance to earn their place. For reference, here’s how the FuelCell Summit Unknown v3’s stated weight compares to the stated weights for some other similar models. All weights are based on a US Men’s Size 9.
246 g / 8.7 oz — Hoka Torrent 3
252 g / 8.9 oz — Scarpa Spin 2.0
255 g / 9.0 oz — ASICS Fuji Lite 2
255 g / 9.0 oz — La Sportiva Kaptiva
270 g / 9.5 oz — Salomon Pulsar Trail Pro
275 g / 9.7 oz — Brooks Catamount 2
280 g / 9.8 oz — Dynafit Alpine
284 g / 10.0 oz — Topo Athletic Mtn Racer 2
289 g / 10.2 oz — Topo Athletic Terraventure 3
289 g / 10.2 oz — Nike Terra Kiger 8
294 g / 10.4 oz — FuelCell Summit Unknown v3
298 g / 10.5 oz — La Sportiva Bushido II
314 g / 11.0 oz — Altra Lone Peak 7
After testing, I’d liken the feel of the FuelCell Summit Unknown v3 to a mix between the Hoka Torrent 2, Saucony Peregrine 12, and La Sportiva Kaptiva, all of which are significantly lighter. The FuelCell Summit Unknown v3 is not designed to be New Balance’s high mileage, long-distance shoe, so comparing them to other models in this mid-distance category is more appropriate. Provided that context, I don’t think its weight should be a huge concern based on what most people will ask from it, which I’ll go into more detail on later.
Upper
The FuelCell Summit Unknown v3’s upper consists of a synthetic mesh that offers excellent protection from debris and is meant to be incredibly durable. Its bootie construction hugged my forefoot well with fabric that remained stretchy and soft. The front of the shoe benefits from the aforementioned Toe Protect toe rand on the medial side and an additional, much thinner overlay that runs laterally toward the midfoot / heel. While this format is ostensibly pretty simple, it creates a system that performs well in practice. I found that aside from the overly firm and stiff toe bumper, the overlays were placed appropriately in high-use areas and should help keep the FuelCell Summit Unknown v3 from falling apart from wear. The shoe’s padded heel collar, gusseted tongue, and bootie-style upper hugged my foot from heel to toe, contributing to a fit that helped prevent me from slipping around on icy terrain. I think the simplicity of the shoe’s upper also helps keep overall weight down and allows New Balance to indulge in other areas, like the FuelCell Summit Unknown v3’s full-coverage, deep-lugged outsole. The features it does have — like a gusseted tongue and adjustable lace closure — are accents that act as smart compliments without adding unneeded bulk.
Midsole
As I touched on in the intro to this review, the midsole is supposed to be the real star of the FuelCell Summit Unknown v3. The FuelCell foam compound has been a huge success in New Balance’s road department and seeing this midsole technology finally being implemented into a trail shoe feels like a long time coming. FuelCell is known for being an extremely lightweight, lively, protective, and high-rebound foam that works well at a variety of different running paces, from jogging to sprinting and everything in between. New Balance didn’t skimp out on this material in the FuelCell Summit Unknown v3; the shoe’s 30 mm of stack borders what’s seen in the maximalist shoe category. Its 10 mm of heel-to-toe drop also means that it’s most cushioned under the heel to best absorb impact from heel striking. Interestingly, I found out through further research that the women’s version of this model features a 6 mm drop rather than 10 mm. In my opinion, New Balance should have stayed consistent with a lower drop across both models. While common in many road models, 10 mm is quite a lot for a trail shoe and I felt that it created some imbalances whenever I took The FuelCell Summit Unknown v3 on off-camber terrain. A 6 mm drop in the men’s version would have gone a long way in helping to stabilize the midsole, as well as just make the shoe a bit more viable as an everyday option for training.
After my first run in the the FuelCell Summit Unknown v3 (and after pressing my thumb into its midsole) it became clear that the particular version of foam New Balance elected to use is significantly firmer than the midsole compound they have installed in the Rebel v2 and other road shoes. A stiffer midsole compound makes sense in a trail shoe; it’s a material better attuned for technical trail environments and provides a bit more rigidity and stability underfoot.
The FuelCell Summit Unknown v3 also features a “Rock Stop” plate, which, while shielding feet against rocks, adds to the shoe’s overall firmness. While I acknowledge the need for rigidity, I would have loved to have felt the familiar plushness of the FuelCell compound I grew to love in the Rebel v2. The FuelCell Summit Unknown v3’s fairly inflexible midsole felt a little generic to me, especially when measured against my expectations. The shoe’s extreme heel-to-toe drop also doesn’t leave a ton of material under the forefoot, which did not pair well at all with my tendency to forefoot strike. As a result, the FuelCell Summit Unknown v3’s ride ended up feeling pretty harsh. I’d welcome a bit more of a balanced geometry in future iterations of this model. A stack of 30 mm / 25 mm would help the shoe feel more supple underfoot and add to its overall versatility. Perhaps my expectations were just a bit high here, but the midsole was not as exciting or revolutionary as I had hoped. That said, I don’t think it’s reason alone to cross the FuelCell Summit Unknown v3 off your list entirely.
Outsole
The FuelCell Summit Unknown v3’s outsole is one of the shoe’s standout features and does a lot to make up for what turned out to be a pretty underwhelming midsole. New Balance uses their own proprietary “Hydrohesion” rubber compound to line the entire bottom of the shoe with beefy, evenly distributed 4 mm lugs. Unlike many models that attempt to save a few grams by leaving sections of midsole foam exposed, New Balance doesn’t take any half measures. The Hydrohesion rubber excelled on every condition I threw at it, from snow-packed trails and icy forest service roads to muddy singletrack and sandy desert terrain. The outsole thoroughly impressed me (I was even once mistaken for wearing microspikes by a passing runner).
On Trail
I was lucky enough to test this shoe on a wide range of trail conditions, with snow-packed singletrack being the primary surface type given the time of year in Durango. Due to the shoe’s lack of stack height under the forefoot, which contributed to a harsher feeling ride, this is not the first shoe I would choose for anything over the marathon distance. I could see some feeling comfortable racing in this shoe up to a 50k, but given its weight, I feel like there are better options on the market, namely the Brooks Catamount 2, Topo Athletic Mtn Racer 2, and the Salomon Pulsar Trail Pro. The mantra I developed around the FuelCell Summit Unknown v3 was, “sufficient at a lot, master of none,” and I think that encapsulates it perfectly.
If you heel strike I could see this shoe working quite well for folks, especially while descending, given the higher drop places more foam toward the rear of the shoe. Because I am a forefoot striker, I did find the lower stack in the forefoot to be a tad harsh, and although this wasn’t an issue on steep climbs, I would have loved to have a bit more protection up front. Although it is quite different in a lot of aspects, the FuelCell Summit Unknown v3 does share some attributes with the La Sportiva Mutant. Both shoes have 10 mm of drop, are each quite versatile, and both have full rubber outsole coverage with aggressive, deep lugs. That said, in my preferred terrain and style of running, I would likely reach for the Mutant over the FuelCell Summit Unknown v3 nearly every time. This is largely due to the shape of the Mutant fitting my specific foot shape better as well as providing a bit more confidence when scrambling over steep sections of rock. I really think that if the next iteration of the FuelCell Summit Unknown v3 series had a slightly lower heel-to-toe drop and a bit more midsole stack in the forefoot, it would evolve into a much more versatile shoe that I would reach for ahead of daily runs when I just need a shoe I can count on that won’t break the bank.
Durability
As alluded to above, the FuelCell Summit Unknown v3 retails for a relatively affordable $130. Considering I’d wager that I should be able to wring about 400 to 500 miles out of my pair, on the conservative side, I think the FuelCell Summit Unknown v3 makes a great value add to most folks’ shoe quivers. The weakest point that I see in this shoe in terms of build quality is the soft, stretchy upper material used in the forefoot. While I have not seen any notable signs of wear thus far, I do think this area is pretty vulnerable to damage from trailside debris.
Who’s It For?
The FuelCell Summit Unknown v3 is a shoe that is going to work just fine as a daily trainer for folks whose daily runs are below, say, 8 miles, or for those wanting a shoe that can do a little bit of everything (and not break the bank). I could see this being a great shoe to reach for on sloppier days when you need reliable grip and want something that is going to feel light on foot and likely hold up well to frequent use. Given this shoe’s competitive price point, I think it could also serve as a great option for folks just getting into trail running or for those transitioning over from roads; the FuelCell Summit Unknown v3’s high heel-to-toe drop is consistent with many popular road models, after all. Additionally, the FuelCell Summit Unknown v3 could also serve as a stellar shoe for soft surfaces like those found in the Pacific Northwest, given its phenomenal outsole design and toothy lugs. It should be noted that the FuelCell Summit Unknown v3 isn’t very receptive to wider feet due to its tapered toe box, so folks with broader foot shapes should look elsewhere. Some of New Balance’s other trail models — thinking specifically of the Fresh Foam X More Trail v2 — offer wider toe boxes and significantly more stack height if you’re looking for a more cushioned and roomier option.Bottom Line
I am really excited to see New Balance start to incorporate FuelCell foam into their trail shoes while also not using its addition as grounds for exponential price hikes. With that consideration in mind, I think the FuelCell Summit Unknown v3 legitimates itself as a solid option for folks new to trail running in general or for those looking to transition over from the roads. While certain aspects of the FuelCell Summit Unknown v3 definitely fell short of my expectations, particularly the underwhelming performance of the shoe’s midsole, other areas, like the outsole and upper, left me presently surprised. I think folks with narrow foot shapes will find the FuelCell Summit Unknown v3’s bootie-like fit plenty secure enough for technical terrain; however, runners with average to wide feet might run into issues with the shoe’s aggressively tapered toe box. As this model continues to evolve, I look forward to seeing how future iterations benefit from New Balance’s increasing investment into the trail space.