Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike

Specialized has peppered it’s lineup with “Plus” bikes, and its Fuse lineup is helping bring new life to the hardtail by combining trail bike nimbleness with near fat bike traction. Using modern trail bike geometry and a dropper post, the Fuse rides a lot like a small-travel full suspension rig. I didn’t expect to be this smitten over a hardtail, but I’ve been all grins for the last two months on the 27.5+ Fuse…

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

Many companies are now offering 27.5+ bikes via the Boost standard, and the plus-sized tires make a lot of sense for a hardtail. The extra tire volume softens the ride nicely, taking the edge off small hits. It had been years since I ripped dirt on a hardtail, and I was worried I was in for sore muscles and chattering teeth. But I’ve spent a lot of saddle time on the plus-sized Fuse, without any issues. The carbon frame also adds to the forgiving ride. Overall the Expert Carbon 6Fattie is comfortable, well spec’d, uncomplicated, versatile, and super fun.

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

The Fuse is available in aluminum or carbon frames, with several build options. The $3,500 Expert Carbon 6Fattie test bike shares the same high-end carbon frame as the much pricier S-works option ($6,500). Both have Specialized SWAT (frame storage and tools), and Command Post IRcc dropper post. The Expert Carbon tested is built up with Race Face cranks and SRAM X1 drivetrain, SRAM Guide R brakes, and a Fox Rhythm FLOAT 34 (120mm with Boost thru-axle). Internal cable routing and bright Nordic Red paint make the wide frame that much more noticeable, and looks to be well designed for strength and vertical compliance. Much of the build is house brand, with Specialized bars, stem, saddle, grips, and tires, helping keep a good smiles per dollar ratio.

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

The SWAT (Storage, Water, Air, Tools) frame door and integrated tools might seem gimmicky, but are really well designed and useful. It’s nice knowing that on every ride you have a metric wrench (set below the cage), and chainbreaker (in the top cap of the stem) handy, and I thoroughly enjoyed pack-free riding. I ran a water bottle (remember those?) and extra tools strapped to the cage, and a tube and pump stowed inside the frame. I was surprised by all the storage space inside the downtube compartment, where one could alternatively cram in a thin rain shell and a tightly rolled burrito.

The Specialized Command Post IRCC isn’t the smoothest dropper I’ve tried, but it works fine, and just having a dropper maximizes the Fuse’s trail bike potential. The post’s under bar remote paired well with the X1 SRAM shifter on the other side of the bar (so well I tried to shift gears with it a few times ). There was some stiction on very cold rides (well below freezing), but Specialized has a winter tune kit, so diehard Northern riders should be covered.

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

The Specialized 38mm Roval Traverse 650b alloy rims held up remarkably well, especially considering the questionably low tire pressure I was running. I’m 170lbs, and often ran 10 psi in the back, which supplied oodles of traction, but could easily bottom out on bigger hits and make that horribly expensive sounding “ping”. I had started with 16 psi in front and back, but found the rear wheel bounced off the many small hits. Lowering the pressure way down fixed the bounce, but I’ve since compromised on 12-15 psi for most rides, with 16-20 psi in the front. Setup for tubeless, pinch flats were never an issue, and the rims are somehow still running true.

The Fox Rhythm FLOAT 34 paired well with the 3” Ground Control tires, providing predictable steering, and matched well with frozen trails of late fall and winter in coastal New England. It’s impressive the overall absorption that a 120mm front suspension provides, allowing me to hit jumps I’d have regretted on my fully rigid fat bike.

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review

With a modern 67.5º head angle and low slung bottom bracket, the Fuse liked to go fast. Without rear suspension, I was often glad to have the 200/180mm rotors of the SRAM Guide R brakes. Even with the big rotors, I occasionally needed 2 fingers on the brakes, to reign in the Fuse and it’s big wheels. I got myself in trouble once or twice, forgetting the Fuse was a hardtail. Steep rock garden descents had the bike, my legs, and the rest of me, all bouncing out of sync, and on the edge of control. But for everyday trail riding, once limits and a safe word were established, the Fuse became my new bestie.

Specialized Fuse 6fattie Carbon 275plus trail hardtail mountain bike review and actual weight

Almost 29 pounds (without pedals) isn’t light for a carbon hardtail (size Large), but not bad considering the Fuse’s trail bike intentions. It’s the trade-off for the extra traction and stability of a plus-bike.  The high volume 27.5+ tires tend to bob a bit under hard pedalling, which makes them feel inefficient, and so the bike’s weight feels noticeable on long uphill slogs. While I’m not convinced that 27.5+ tires are really any less efficient than skinny 29” tires, they do feel slower. So, whether deserved or not, long fire road climbs felt longer. However, with extra traction, I could clear more steep climbs with less dabs. On a dry fall day, I rode my neighborhood test loop in record time, cleaning all the short punchy climbs and technical bits.

I had almost forgotten how snappy a hardtail is. Even with its tall wheels, the Fuse manuals and hops well, without any rear suspension to preload before the hop. The Fuse is a great bike for getting one’s bunny hop groove back after many years of clipless laziness. I often ran flat pedals for rolling jumpy trails, or for technical slow speed trails.  When I wanted to turn faster loops, I switched back to clipless for efficiency and powering up steep sections. With a lot of granite “slickrock” in my area, the spiderman grip and stability of plus-bike tires let me climb crazy steep rock faces, setting a new standard for out of saddle traction.  And despite the tall wheels, cornering was good, thanks to relatively short chainstays and the dropper post which allowed more room to lean the bike over.

Like other low slung trail bikes, pedal strikes were more frequent, but manageable. The only other adjustment to my riding style came from the wide, flat, top tube, which my knees occasionally bumped. Overall though, it’s a comfortable cockpit, with fairly wide 750mm bars and short-ish 60mm stem.

The Fuse packs a ton of fun in a versatile and budget friendly package. I saw (and passed) a lot of fat bikes on frozen but not very snowy trails. It wasn’t until late winter that two big snowstorms ended the season for the Fuse. In the spring I’ll occasionally wheeze through a few local XC races, and with some light 29er wheels, the Fuse would be race ready. Summer bike-packing with the family, check. And that trip to Knoxville in May… in other words, the Fuse is a jack of all trades (master of fun), and for me comes very close to the one bike dream, where I could grab the Fuse for just about any ride all year.



  1. Brian on

    Have you put 29er wheels/tires on there to try yet? Curious about how it rides with them. Could be a good xc / bikepacking rig with some versatility.

    • John H on

      The bike is designed to accept 29ers, but I didn’t have any boost 29er wheels handy. Someone below gave me the idea of 29er up front only. That might be interesting. Shouldn’t change geometry too much. I’ll post my findings.

    • Don H. on

      Did you ever get an answer to the 29er wheel question?
      Im seriously thinking of ordering one of these , to be used mostly as a 29er…….. I have some nice Roval Traverse Carbon wheels that would fit right on.

      • John H on

        As long as your 29 wheels are 148/110 boost standard, they’ll work. Specialized gives geometry spec for both 29 and plus. But I haven’t had any saddle time as 29er yet.

  2. bearcol on

    Still not clear on why you would want 3.0 tires? If you want floatation over sand/snow you need to go wider. If you want 29″ height you’re better off with a 29″er. Trying to have the best of fat bikes and 29’ers leaves you with the worst of both worlds.

    I listened to the latest vitalmtb podcast where it was mentioned that the bike industry is down 30%. The industry is out of ideas because bikes have been dialed in for many years now. Digging up old tire sizes we found to be of no use 15 years ago isn’t going to boost the industry. 650b bump is over. What’s next? Mopeds, plus bikes, another axle standard?

  3. LS on

    Demo’d the aluminum version when these first came out. I was so excited I almost bought one without riding it first. WORST bike I have ever ridden. So slow in the turns, small bumps killed any speed you managed to pick up, and it was absolutely miserable climbing on this bike.

    • mnorris122 on

      I own one, and personally disagree. It shreds pretty much everywhere. Sure, long gravel climbs kinda suck, but in technical climbs it’s hands down the best climbing bike I’ve ever ridden. It’s far from slow in the turns, and your comment about small bumps killing speed is laughable.

    • Andrew Spaulding on

      Quoting the article: “Almost 29 pounds (without pedals) isn’t light for a carbon hardtail (size Large), but not bad considering the Fuse’s trail bike intentions. It’s the trade-off for the extra traction and stability of a plus-bike”. Total contrarian bs. No reason to trust anymore Bikerumor so-called reviews that sugarcoat everything and can’t seem to say things for what they are. 29lbs for a hard tail is heavy. There, it wasn’t so hard was it?

      • Mr. P on

        Andrew, the tires are the Grid versions = for getting rowdy and fast in rough, sharp places. They add at least 2 pounds compared to a weenie XC racer bike. So, yeah, the bike is heavy so you can smash, rather than dance, through technical trail at speed.

  4. David on

    If it’s going to weigh in at 30lbs (lots of that rotating mass too) and cost $3000, I might as well buy a full suspension. Perhpas a 29 in front and a 27.5+ 2.6/2.8″ in the back if you need extra climbing traction. I tested out AL version and was not impressed with the 3″ tires.

  5. patrick on

    Lots of negativity here. I helped dial in an aluminum comp 6 fuse fatty after it was set up like crap straight out of the shop. Since the rims were already taped and tires were ready, we went tubeless and ended up at something like 13.5 psi front and 15 rear for tremendous grip and cushion. We literally used less than half of the pressure that was in the fork and adding a bit of rebound damping for the right sag and feel. After that, I was really impressed for our twisty Midwest roots and rocks. Good acceleration for such large wheels (when compared to a 5″ FS bike), no handling complaints and tremendous grip. Roots and rocks that you would stand up for on a 29 with 2.25 rear tires you could ride sitting down on the 27.5 x 3 tires. I really could see this being a cheaper and more playful alternative to a FS bike on our WI/IL border area trails.

    • bearcol on

      More playful than a FS? I find 3.0 casings roll in the corners with WAY too much undamped rebound, and WAY too much drag everywhere from the ups to the downs. Traction can be great but because there’s no feel when you push them to the point of drifting you can’t modulate the drift with any kind of precision. There’s zero shoulder lug feel. Drifting is an act of faith with the on off traction and non communicative feel. For those that like to gap even small root or rock riddled trail sections you land with a soft undamped pogo stick bounce. It almost feels like the wheels flex too but I believe it’s just the casing deforming and squirming on landings that leaves this feeling. These things belong in walmart where the looks of fat tires will sell to people that know nothing about riding bikes.

      • 46541156 on

        I hear what you’re saying. They are heavy, lots of rotating mass and still can bounce around despite the “magic correct” psi being found.

      • Sammybikes on

        I have this bike and have found the experience on this is determined by 3 things:

        Fork setup
        Tire setup
        Your attitude

        The New 34 is much better than I expected. GRID casing tires (as are spec’d) are a MUST. It allows running appropriately low pressure without tires wallowing around.

        Anyone who I know who has ridden one (it’s a pretty long list) has had a blast. If you get it dialed then ride with the intent of finding the bike’s limits, you will be impressed.

        • bearcol on

          I disagree. The only way to cope with wallowing around on tires of such high volume is to go with DH casings like we experimented with 15 years ago. These lighter casings just exacerbate all the negatives associated with such high volume tires. Grid is a light casing compared to DH. Sure it’s a lot better than some + casings which are just a joke, but if you want to deal with undamped rebound, and wallowing, even DH won’t completely remedy those issues. Nature of the beast. 3.0 just has a ton of air volume.

          If you don’t experience these issues than it’s nothing for you to worry about, but for those of us that push hard, these ballon tires reveal why they aren’t used in WC DH, or the EWS.

          • Bill on

            Pretty sure most of us that love this tire size are not quite as “core” and are also not thinking about riding this 120mm hardtail in a world cup dh race. (Duh) You do sound very impressive though.

  6. Brian on

    Yeah I’ve test ridden the old version and felt (and every review says this) that tire pressure on 27.5+ tires makes a night and day difference. So being 1 psi off could completely alter your ride.

  7. BoostYo! on

    Why all the hate on the babyfat?

    I’ve been riding the Al version as my only mtn bike for over a year now and I’ll say for sure, this bike handles and rides beautifully if you pay attention to set up.
    I agree the carbon hardtail on 3.0s seems absurd at that price/weight. IMO this platform (plus hardtail) is best suited for the beginner rider or someone looking for a do it all ride.
    The bigger tires do need more attention to pressure but with the advantages they pose, it will make a difference on the trail as opposed to a 29er ht.
    If you are getting ‘squirm’ or feel bouncy, then you need to adjust pressure. Its not as simple as saying you need to run __psi; rider weight, air temperature, tubless/tubes, speed, tire brand and many other factors affect performance. Best thing to do is start high (no more than 19 on 3.0s/ 20 on 2.8s/ 21 on 2.6s) and drop in 1 psi increments. Use a digital psi guage and bring it with you on your first couple of rides, you don’t need it but it will give you more control on the long run if you log what pressure you started the ride with and what pressure you ended up in.
    I’m 6’/165lbs and typically run 16/17.5psi on schwalbes running tubless but different trails ask for different set ups. If I’m hunting KOMs I generally add .5 psi to both tires. On the other end of the scale, I drop .5 if I want a comfy recovery ride. NEVER do more that 1 psi changes unless you know the trail on this tire size.
    Also, just as John mentioned, these feel slower, but are actually faster. They have lower rolling resistance than 29×2.0-2.4s but they are heavier. So that translates into slower acceleration but easier to keep momentum.

    My only complaint on the fuse is the fkn bb height…. so. low.

    PS, if you start whining that you don’t wanna mess with the details on your bike then go to walmart and get a dolomite. If you don’t set up your gear right, it will never perform to its full potential 😉
    Idk why i took the ten minutes to write this hsit up but theres my 2cents. I’ll eventually talk fork pressure/rebound on this subjet

  8. Flatbiller on

    I ride the carbon version and replaced the 3.0s with 2.8s (Butcher and Purgatory). My FS is now gathering dust; this thing is way too much fun now.

      • Flatbiller on

        What is Plus anyway? We all agree 3.0 is Plus, but is 2.8? I also have 2.6s I am going to try; might lower my BB too much, but where I ride my Fuse isn’t considered rocky/techy. Should be good on nice flowy singletrack.

  9. Rick on

    I think the suggestion that plus bikes are for beginners, or for bikepacking is nonsense. I do think that they are better in some terrain than others, just like every other bike.
    There are a lot of factors that you should consider before saying it’s the worst bike ever.

  10. ChrisL on

    I love my fuse. Swapped to 2.8 tires and a 140mm pike and my aluminum fuse is under 28 lbs, climbs like a goat and descends better than a lot of bikes ive tried. The 2.8s have nearly as much traction as 3.0s and more sidewall support at a reduced weight.
    On paper the stays may seem long, but the bike is just as agile feeling as my fs with 420mm stays, and the solid rear make for instant response. To me the plus size tire is not only a blast to ride for all skill levels, but saved the hardtail from only living in the realm of xc racer and budget riders.

  11. splatshot2017 on

    I bought the carbon Fuse Expert in November and have never had as much fun on a bike in my life. I ride it everywhere. We had a bad winter in my neck of the woods and I couldn’t take it on trails like I normally do in winter–so I just rode it on pavement and paths and even there it was a total blast to ride. Little tweakings in the set-up are all it takes and it has basically become my road-bike, commuter bike, and mountain/trail bike. I wouldn’t trade it for any single bike out there, period. If you’re wondering–buy it. Promise you won’t be disappointed!

  12. Stunnerbear on

    I rode FS only since 2001. 2012 I bought a SS 29er to hone my skills. I learned fast that I was riding lazy and all of the sudden my skills got way better. The Fuse is for someone like me that has great bike handling skills and can rip a HT with capabilities of a 5″ to 6″ trail bike. I can send the Fuse and land it with ease, charge gnarly rock gardens and Rip single track wicked fast. Nearly all of my ridding buddies can’t keep up on their FS and I feel the Fuse is the weapon of choice for the alternative set up maintance of a FS. Plus you have to spend a lot to get a low weight FS that no one will have support for after 6 years. Why should I spend more time on up keep when I can ride more. Also 80% of people riding FS don’t have them set up correctly. 20lbs XC bikes are delicate and you should know better to abuse that kind of equipment. So a 25 to 30lbs 650 plus can be anything you want it to be if you know what your doing.

    One more thing. Remember when they said 29er’s couldn’t do DH. Look who’s winning on them now.

  13. Rob on

    Been riding a Fuse for over three years now. I admit I take out my Enduro on more hardcore rides and the extra squish is more comfy on technical rides. I love my Fuse and no bike has ever given me as many smiles per mile as my mid Fattie. The fun factor is off the charts and it’s very playful-the wider tires do not dampen the party. Unlike other reviews here, I find handling superb, but like others have mentioned, I believe once the bike is dialed in and set up properly for you, it feels nimble, sure footed, and grippy. Great bike!

  14. dave on

    I have a 2017 Fuse Comp. Manitou Machete fork. Great hardtail. I’ve run different tire pressures from 15-20 lbs. 15 seems best but more wasn’t that big a deal. Super fun bike for me. No racing, just riding trails. For 1420.00 out the door, a steal. Just get on and ride.

  15. Charlie W on

    I have found that wider inner rim width on the wheels, 40-45 inches, wtb scrapers for instance, really help with the plus tire profile and sidewall support. There is no wallowing with wider rims.


COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.