Billed as Black Diamond's most technical approach shoe, the Fuel (not to be confused with the axe of the same name) has an expectation to live up to. But while lightness and breathability are two points in its favour, it is let down on more gnarly ground by its soft sole and shallow tread. This shoe would be best for easier approaches to roadside venues at home, or for use in warm dry environments. For scrambles or mountain crags in the UK it falls short in some key respects. On the other hand a lot of us wear approach shoes as much as a badge of climber identity as for technical performance, and spend more time in them in the urban wilderness than the wet and slippery outdoors.
If you want something comfy and forgiving on the foot for day to day wear, but which also has some degree of capability at the crag, then this could be a contender.
At just 726g for my pair of size 47/UK12 (BD say 312g per shoe, size not specified), the Fuel is a real lightweight. The other approach shoe currently in my cupboard, La Sportiva's TX4, weighs a comparatively hefty 902g, but while the TX4 is a rugged and supportive all-rounder that is at home on the mountains, the Fuel very much feels like a lightweight in terms of softness and minimal support, so we're not comparing like for like. With its low weight and webbing loops, you'll quite happily hang the Fuel off your harness for the descent, which is one thing in its favour over a lot of the competition.
Approach shoes must be difficult to design, because while they're sold on climbing ability, the majority of the mileage they get is plain old walking. They've got to be comfortable enough to get you to a remote mountain crag, or spend a day walking between scrambles, without losing too much front-end performance on steeper ground. It's a tough square to circle, and all models are going to represent some sort of compromise. I think the Fuel is comfortable largely thanks to having a soft and forgiving upper, but when we come down to brass tacks it's neither notably good for walking any great distance in, nor particularly impressive on the rock.
Good news is that the Fuel comes in both a men's and a women's/lower volume version. I'd describe this as a narrow-to-medium-width, mid-volume shoe, with the sort of middle-of-the-road fit that ought to suit a lot of people. Blessed with big, wide and fairly broad-ended feet, I rarely get on with approach shoes, which in my experience tend to have a tight toe and some front-end asymmetry to boost climbing performance (or at least the appearance of performance). While the Fuel is pointier at the toe than I'd personally prefer, it doesn't go mad on the asymmetry, and as a result I can wear it for a few hours without feeling crippled. However my toes do push against the sides on both the inside and outside edge, and I also get a bit of toe strike when walking down steep slopes, so on fit alone I am not going to be wearing this shoe on full hill days or bigger mountain crag walk-ins. As always, try it on before you buy.
As you'd hope from a more climbing-oriented approach shoe, the lacing runs down to the toe to allow some front-end adjustment. The flat laces have a slightly flimsy feel, get twisted easily, and on my size 47 pair they're also a bit too long. On the plus side, the lace eyelets are concealed on the outer side of the shoe, which should help protect them from wear and tear.
The heel is cut comparatively low, and with its soft feel and minimal padding I don't find it holds my foot as firmly in place as I'd like; there's some heel lift when stepping up on steep ground (probably most evident when smearing up a slab). However this may be down to the fit on me, while others might get on better with the low profile heel.
A knitted fabric gives the upper a good level of breathability, and so far I've found the Fuel comfortably un-sweaty in warm weather (mid teens and sunny counts as warm in the NW highlands). For durability, this is overlaid with welded TPU patches, while on the outside of the foot there's a tougher but much less breathable fabric panel. A decent rand adds toe protection. Being synthetic, the upper doesn't readily absorb water, and I've hopped across boggy Scottish hillsides without ending up with wet socks.
The wrap-around tongue minimises seams, and gets around that annoying habit tongues have of slipping to one side, but while it's good and breathable, and feels comfortably soft across the bony top of the foot, I do find the inside edge can curl and fold over on itself into an obtrusive ridge of fabric.
The grippy rubber outsole is great on dry rock, with plenty of stick, but as it's quite soft I would expect it to wear reasonably quickly (time will tell and I'll have to report back). As so often with approach shoes, which tend to be designed with drier climates in mind, you get a flat, 'dotty' outsole with a very shallow tread. This has the potential to get lots of flat rubber in contact with the rock, which is good if you're padding up acres of slabs, but it also has the potential to be worrying - if not downright lethal - on the familiar UK combination of broken ground, mud and steep grass. Find me a British mountain crag approach or a scramble (OK, other than on Skye) where greenery is not a thing - and it's often damp greenery too.
Even off the steep ground, this shoe has limitations. When you're walking off-path there's really not a lot of bite here to keep you on your feet, and no heel for downhill traction. On the strength of its outsole alone, the Fuel is emphatically not a shoe for UK scrambles or mountain crag approaches. I would save it for roadside crags or hot rock holidays.
The spongy dual density EVA midsole soaks up impact nicely when you're walking on hard-packed ground, but its lack of stiffness and support in the midfoot is telling. There's really no lateral rigidity in the sole whatsoever, so you can twist the shoe into a spiral in your hands. I can easily fold it in half toe-to-heel, too, and even lengthwise with a bit of effort. This translates into a low level of support for the foot on rough ground, a relatively insecure platform underfoot when you're traversing steep slopes, and an approach shoe that's really quite poor at edging. Let's look at that...
Performance on rock
Though Black Diamond mention 'exceptional edge control' I don't find the Fuel edges well at all. People with strong feet and an affinity for softer rock shoes might get a bit more oomph out of them, but for most users an approach shoe this flexible may seem a niche idea. While there's a degree of stiffness right up front, for me there's simply too much flex in the rest of the sole, and this lack of support in the midfoot means that when I try to hold a small edge with the tip of my toe, the shoe just bends. The inside edge of the toe offers more security, but nothing exceptional. Insecure edging may be partly to do with the fit - size 47 looks long and thin on me - but it's got a lot more to do with the flaccid sole. An upside of its softness is that the Fuel inspires confidence on slabby ground, as you can get a lot of shoe in contact with the rock, so while it's poor in terms of support compared with more substantial approach shoes, it's good on smears.
According to Black Diamond this shoe is 'capable of easy 5th class climbing with confidence and comfort'. We all have different thresholds, and some could doubtless push the envelope, but I would draw my line at Moderate (which translates as about 5.1-5.2) - and I'd try to make it a slabby one.
The Fuel must be one of the softer approach shoes on the market, both literally and in terms of ideal use, so if you're seeking something for scrambling or UK mountain crag approaches then look elsewhere. On the plus side however, this shoe combines a light weight and a casual feel with a degree of on-rock ability, so assuming you're after an approach shoe largely for wearing to roadside crags, sunny sport trips, or going to the wall, then it would be worth a look.
Black Diamond say:
Engineered for days when the word "approach" actually involves full-on climbing, the Fuel is our most technical performance shoe. The Fuel's upper combines breathable EnduroKnit, a durable stretch woven lateral panel, and welded TPU film overlays for maximum durability and precision fit. The internally overlapping tongue allows for fewer seams and a sleek comfortable fit with minimal bulk, while the lace-to-toe construction features webbing and scalloped eyelets for variable, adjustable fit and tensioning to suit different conditions. A climbing-specific forefoot construction allows for exceptional edge control and our BlackLabel Mountain rubber is ultra-sticky for superior grip on rock. Finally, a tag-loop on the heel and tongue gives you the option to clip the Fuels to your harness once you rope up.
- Sizes: 3-8.5 (women) 5-13 (men) - including half sizes
- Weight: 726g/ pair size 47 (our weight)
- Capable of easy 5th class climbing with confidence and comfort.
- Upper construction of Black Diamond developed knit and woven textiles with welded TPU film overlays for adaptable fit and maximum durability
- Low profile molded collar padding and lining
- Protected lateral laces and smooth upper construction
- Overlap tongue means fewer internal seams for precision fit
- Lace to toe with webbing and scalloped eyelets for adjustable fit and tension depending on conditions Functional climbing forefoot construction for edging control and durability
- Tuned dual density EVA midsole with stiffness and comfort
- Black Diamond BlackLabel Mountain is a high performance sticky rubber
- Rubber toe protection
- Multiple webbing loops for tagging options