10.6 oz. (301 g.) for a US M9
8.9 oz. (252 g.) for a US W7.5
It’s a Nordic invasion, but the good kind
Saysky style meets Karhu technology and reliability
The shoe feels decidedly European, take that as you will
Available now for $150
RENALDO: God morgen! Today, we’ve got a one-two punch of a collaboration between the Finnish brand Karhu and the Danish brand Saysky. They’ve teamed up for a little taste of something made up north. It’s built on Karhu’s Fusion 3.5 silhouette, and it melds the style and flair of Saysky with the reliable performance of Karhu’s innovation. As a relative newcomer to the world of Karhu but a major fan of Saysky, I had to give the Karhu x Saysky Fusion 3.5 a try, and I’ll admit I’m pleasantly surprised.
SAM: Wanna know how old I am? I can date myself pretty quickly by the music that was my high school soundtrack. Sure, most of us can do this — point to songs, albums, or shows that highlighted our formative years — but it’s especially apparent when the word “collaboration” comes up. It came up a lot when I was getting my miles in for this review, and I could only think of one collab to fit the bill: Jay-Z and Linkin Park teaming up on Collision Course. That’s an album that dropped into my social circles like someone opened the bay doors on a B-17.
The album defined the genre mash-up, which was having a moment in the mid-aughts. Who knew tracks from the Black Album, already settled as a classic, could meld so seamlessly with the angsty grind of Hybrid Theory?
We’re here, however, not to talk about music from decades back that’s faded into the static of the airwaves but to instead talk about a collaboration between running brands. The Fusion 3.5 is, in its own way, a Collision Course, but one between two great nordic names: Karhu and Saysky. They took Karhu’s hundred-year history and mashed it with Saysky’s love of bold patterns to create an urban camo design that feels distinctly Scandinavian. It’s an attractive package, but how does it run?
RENALDO: Let’s kick it off with looks because what else matters? As a Saysky collab, you already know the Fusion 3.5 is gonna bring a little more punch than the standard colorways. The look is called Saysky Splinter Camo, and it blends a white upper smoothly into undyed whites (which are all the rage these days), off-whites, and grays. It’s adorned with the Karhu bear and Saysky star, each complete with a dull metallic sheen. You get a splash of navy on the heel to help the logos pop and a bit more navy on the tongue and liner. The whole Karhu x Saysky Fusion 3.5 package is capped off by a subtle gum sole for a look that will turn heads on the group run.
Almost as important as the looks — the shoe runs pretty well.
At 10.6 oz. for a US M9, this true neutral trainer felt reliable on the road. A bit firmer than most these days, but if you’re familiar with other European styles, like those from On, you’ll feel right at home. The real star is the Fulcrum technology, marketed as the quickest roll in Karhu’s collection. It takes up the entire midsole and caps off with a triangle at the midfoot. Essentially, the Fulcrum technology helps to keep all of your forward momentum, well, moving you forward.
SAM: Renaldo covered the looks on the Karhu x Saysky Fusion 3.5 well — it has a clean flash that we don’t see as often as we should in running shoes. Saysky’s reserved pattern and dual logos really settle together, and we love the look of a gum sole here at BITR. The cover on this collaboration is way better than what we were given on Collision Course — but I guess the looks were the point here and not with that album.
Karhu’s upper material — Ideal Knit — is thick but breathable and comfortable. This shoe seems to fit true to size, but there’s space to accommodate higher-volume feet. I particularly like how the toe guard overlay is a constellation of plastic bumps, not a firmer wrap. It keeps the toebox protected but still plenty flexible. The tongue is well cushioned and fits nicely underneath the M-Lock overlay. Karhu’s lockdown is unreal — I’m talking trail shoe levels of lockdown, specifically in the midfoot.
The midsole is firm, and I appreciate Renaldo comparing it to brands like On. It has plenty of stack for protection, and the 6 mm drop combined with the quarter-length Fulcrum device — a molded plastic plate — in the midsole does aid in propulsion. I’d often find myself going faster than I wanted in the beginning miles of a run and would have to make a conscious effort to slow down. The outsole is attractive and seems to be durable. There’s plenty of rubber down there that will hold up to long miles.
RENALDO: With all that praise, the Karhu x Saysky Fusion 3.5 just about makes the mark of being an above-average daily trainer. Karhu talks a lot about its Ideal Knit upper, M-Lock lacing, Aero Foam, and OrtixFit, but it’s tough to notice any individual element while running. Honestly, the Fusion 3.5 feels more like a decent shoe with a thick midsole, which I had to break in.
I could really feel the extreme firmness while taking the Fusion 3.5 for a Thursday tempo run with the Believe Run Club. My toes crashed around each corner and shuddered to a stop at red lights. Bringing them back out for a mellow 8-miler with A Tribe Called Run felt a lot better, the shoe is more of a 9-minute pace cruiser. I can’t call this an outright complaint, but the Fusion 3.5 sure isn’t a workout pick.
SAM: Occasionally, I’ll find a shoe that doesn’t seem to show its true colors with the way I midfoot strike.
Occasionally, I’ll find a shoe that doesn’t seem to mesh with my midfoot strike. The Inov-8 Trailfly Ultra G 280 was one of those — even though there were enough great aspects of that shoe that I forgave its heel-striking build — and the Fusion 3.5 is another. There isn’t any outsole rubber at all on the lateral forefoot of this shoe. It’s pure midsole foam, and most of the definition in that foam was gone after my test miles. I didn’t have any bad slips on wet or slick surfaces, but I expected them constantly. After even moderate distances, the way my foot rolled from bare foam to outsole rubber under my big toe felt uneven, and I began to sense the differences in densities, despite the firmness in the foam.
My midfoot strike had me landing on the front edge of the Fulcrum device, and running in the shoe felt a little like an endless forward fall. This is great when working on cadence, and it’s great for speed, but it prevented me from settling into a comfortable flow in my test miles.
Despite the great lockdown in the midfoot, I had extra room in the heel and toebox on this shoe. The heel especially felt very loose, which is unfortunate. There’s a lot of good structure to this shoe that gets lost in some of that extra room.
RENALDO: As a collab shoe, the Karhu x Saysky Fusion 3.5 rocks. If you’re really into running and repping your favorite brands, it’s a great shoe. It’s a little heavy, but the 6mm offset and $150 price aren’t too terrible. However, it’s not a workout pick, and I’d tell serious runners with high-mileage goals to keep looking for something with a little more substance.
SAM: Renaldo and I have similar thoughts here. This is a beautiful shoe that would serve modestly well as a daily trainer — if you heel strike. At 10.6 oz for a US Men’s 10, the shoe sits in a strange place — most of the construction seems built with the idea that this is an uptempo shoe (firmer foam, more aggressively located and shorter Fulcrum), but it’s just a little heavy to sit nicely into that category.
The Karhu x Saysky Fusion 3.5 seems to be more of a shoe you would buy primarily because it’s a limited collaboration between two respected companies. It’s made to flash some uniquely beautiful looks, and you can also wear it out on a variety of runs where it will serve you decently. If you have a penchant for a shoe with looks and firm foam, plenty of room, and a hefty serving of propulsion, this could be for you.
You can pick up the Karhu x Saysky Fusion 3.5 for $150 by using the shop link below.
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Renaldo is a running enthusiast that’s enthusiastic about pretty much everything. Born and raised Baltimore, Renaldo still resides in his home city and has shared miles with a good chunk of the Baltimore running community. A captain in A Tribe Called Run run group, Renaldo can easily be spotted running with Faster Bastards, Believe Run Club, or doing a solo long run through Baltimore’s midtown. If you spot him, be sure to give him a big “REEENOOO!” or challenge him to a game of pool 🎱
All-time favorite shoes: Hoka Mach 4, Skechers Razor Excess 2, Asics Noosa Tri 13More from Renaldo
Sam lives in Baltimore with his wife and two kids and spends his days fixing espresso machines for Ceremony Coffee Roasters. He runs with the Faster Bastards when he can, races ultras, and has been working on completing the AT section by section. He thinks the best days are made of long miles on nasty trails, but that a good surf session, a really stunning book, or a day of board games are pretty all right too.
All-time favorite shoes: Saucony Xodus Ultra, Topo Athletic Ultraventure 3, Altra Lone PeakMore from Sam