We began our long term look at the Specialized Fuse Pro 6 Fattie with this OOB post here and then our First Impressions, then the Midterm here.  In this time I have been over lots of local trail, used it to test mud fenders on rainy rides, went on two bikepacking trips with it, and recently took it out on what I consider to be a quintessential So Cal Mini Epic type of ride. It has been a very interesting taste of the new Plus sized tires, in this case 27.5 Plus (or 6Fattie, as Specialized calls it), and has given me a good feel for what this platform does and does not do, at least for me and for where I live.

And so, let’s look at what we ended up with.

Specialized Fuse Pro 6 Fattie

Streamside, So Cal style. Poison Oak awaits.


I made few changes to the Specialized Fuse Pro 6 Fattie in the test period.

  • I did purchase a frame bag from Revelate for bikepacking, but I did not keep it on there full time.
  • I tried swapping the stocker 60mm stem for a 75mm stem but, although I liked the extra cockpit room, I really did not like the steering feel that resulted.  I might re-visit that, but I am OK with it the way it is now, 60mm stem and all.
  • I swapped the front Ground Control for a Purgatory version of the 3.0 rubber.  I left the rear GC in place.
  • I did end up with less PSI in the fork than the sticker on the fork leg suggested for my bodyweight…like maybe 10psi less…and that felt better.
  • I ended up increasing the tire pressure from the 12-13psi range to more like 15psi.  2-3psi makes a big difference in a tire like this.  Although the bike was more comfy at 12psi and the traction was off-the-hook good, I did not care for the increased self steer and wallowy-ness on hard surfaces.

So, after all this, what do I think of this genre in general terms, that being Plus trailbike hardtails…slacker head angles, 120mm forks, short back ends?  And what about the Specialized Fuse Pro 6 Fattie specifically?

Well, I love them, actually, both the family this bike belongs to and this particular model as a fine example of the new breed.  It is what hardtails want to be when they grow up.  That combo of the mid-travel-ish fork and the laid back front end, the stubby rear and the fat tires…wow.  It is amazing how fun that is to ride.  And the worse the trail surface, the better it gets; sand, ruts, loose rocks…it’s all good. The crappier the trail the better it is. It gets to where you stop looking at transverse rain ruts as the enemy.  Cornering on crummy dirt is really not a big deal.  That big rubber contact patch and low PSI lets you hook up like crazy.  Climbing traction is all you could want short of a full on Fat Bike.

Specialized Fuse Pro 6 Fattie

The more your trails look like this, the happier the Fuse is with those Plus tires and trailbike demeanor.

As an adventure based trail bike, like for bikepacking or exploration stuff, the Plus Hardtail is gaining an enthusiastic following.  Quite a few brands are out there now, typically steel, and often with 2x drivetrains to get a wide and deep gearing range.  And I bet that many folks who bought Fat Bikes really wanted one of these, but they did not exist yet.  For some trail conditions, this might be the only bike you will ever need to own.  Even on rougher trails, that stable front end lets you point and shoot and the back end, though a bit bouncy, just follows behind like a happy puppy dog.  You can really surprise your buddies on their FS bikes when you are piloting a bike like this, although you have to keep in mind that there are limits.

More things that are sooo good:

  • The Specialized Fuse Pro 6 Fattie is pretty light, and from what I have seen on the market so far, with most of these other bikes being steel framed with 2x or maybe 1x drivetrains, it is lighter than the others by a good few pounds.  That may not mean all that much if you are looking at this type of bike as an exploration platform with bags, etc, but for all around trail use, long climbs, and so forth, being under 30 lbs is really nice and 27.5 lbs without pedals and with a cage and SWAT multi tool…that is a really good weight.
  • IMG_4011That Purgatory front tire was just the right choice for the rubbly and hardbaked trails of So Cal.  Plus tires put down a lot of rubber on the ground so really aggressive tires are not as important, but the cornering punch and ability to climb out of ruts took a good jump up with that tire swap.  It did feel a touch slower on pavement, but it was not something I thought to be important.
  • The Dropper post, the 120mm fork, the forgiving angles, short stem/long top tube, the short stays, the moderate width rims and house brand tires that perform well…Specialized really nailed all that and the bike feels very ‘together’.  It also rides decently well, and that is not all that uncommon in aluminum these days although those tires do blur the lines a bit, masking the frame material more than normal.  Likely steel would be a bit springier and smoother overall, but at a weight hit that I doubt that many pure XC/trail riders want to buy into.
  • IMG_3887No doubt the SRAM 1x drivetrain helped keep weight low, and this bike is the first one I have had under test where I felt that I really got along with the 1x set-up.  I can only think of one ride where I wanted a lower gear, and that was just to keep some freshness in the legs, not a make or break deal.  And as far as top end, I have not felt like the Plus tires really are all that crazy about long, drawn out speed runs in the 30×10 but if you do it anyway, it felt tall enough to me on this bike for the way I was riding it.

But it is not all roses and lovely sunsets.  There are some things that need to be considered.

  • The tires that allow all that traction also have a certain personality to them.  There is a lot of tire deflection and although that gets less so at higher pressures, that is a big sidewall and it lets that tire squirm and compress quite a lot; enough to feel imprecise sometimes, especially on hard dirt.  And the amount of tire compression…tire ‘Sag’, if you will…takes a less than 29″ tall static tire and makes it even smaller on impacts with stair steps, drops, etc.  I remember noticing that way back during a ride on one of the Scott Bikes 27+ models at Park City.  I was on one of the more techy trails, and came around a slow corner which switchbacked into a root drop into a hole.  I had enough travel in the fork and the bike was slack enough not to worry, so I got my weight back and rolled in.  I was surprised how, for a fraction of a moment, that 27+ tire seemed to compress and stall before popping out and moving on.  Hmmmm.  Take a 28″ tall tire and let it compress more than a typical 29×2.3″ tire is able to and you are getting to an effectively smaller wheel in micro moments all along the trail.  Most of the time at home I did not notice this, but as well as it does roll along, it does not quite give you the same roll out as a 29er and not at all what the king of ‘Mo’, the 29+, does in that regard.
  • Is it boring, making the trail safe for noobs and old guys?  Sort of.  For me, 29+ felt like you gave the trail inputs a big shot of Novocain.  The 27+ is less so, but still calms things down enough to where even a 29×2.3″ tire and wheel feels kind of sketch in comparison.  And the thing is, that corner that used to feel fine on your 29er…the one that has you tip toe-ing through it now after riding time on the Plus bike…that corner did not change.  You should still be able to go through it just as fast on your 29er as you used to, but it feels iffy now.  Are you going faster on your Plus bike in that same corner?  Maybe so, maybe not, but it feels safer. Am I losing some skills, letting the bike’s big tires dumb the trail down?  Is that really what is happening?  Or am I just experiencing a better way to ride off road and going back feels odd and less fun?  I am not sure.
  • You know how, on those 29er wheels, where you would be moving along and get on top of that gear a bit, slide back in the saddle and just feel like the earth is rotating under you as you cover ground?  I never felt that way on the 27.5″ Plus tires.  Never.

Specialized Fuse Pro 6 Fattie

In a high place after a long climb, the Fuse with the Pacific Ocean as backdrop.

The last ride before I wrote this post was a typical So Cal type mini epic.  It was a 31 mile loop with 5k’ of elevation gain, mostly on dirt.  It began with an 8 mile paved road to get to the trailhead and connect the loop, then began a long series of climbs through a bouldery old jeep road leading to the quintessential open fire road experience we have out here.  Three hours later you end the grind and after a few miles of rolling, ridgeline dirt road, much of it with pretty horrible, neglected surfaces, you drop into a few miles of steep-ish singletrack; loose, scruffy, scrabbly, and brushy with tight switchbacks and lots of loose and not so loose rock.  Then we roll out to to town and our cars.  Then we eat Mexican food.  Perfect day.

Specialized Fuse Pro 6 FattieOn the pavement to the trailhead, there is little upside to the Plus tires except for the fact they are not horribly slow.  But compared to a typical 29er wheel and tire, they are a bit dull.  On the boulder field and in the steeps, FS would have been better for me than a Fatty tire, if I was being honest.  On the long fireoad climb, the Plus tires were just there, neither getting in the way or helping.  Would my time have been faster on a different set up?  Maybe, but I doubt it would have been a lot, unless we are talking carbon and skinny race tires.  On the rolling ridge line sections, and down the scree fields that made for roads up there, they were a bonus, but it was not a biggy there either.  But when we got to the trail, well that was when the Plus tires just woke up and said good morning.  Every off camber section in the sloughy trail was solid. The Specialized Fuse Pro 6 Fattie handles tight switchbacks well enough to make me look good and it is a notch up from any 29er I have ridden in that regard, save perhaps the Niner ROS9. The long sections of baby-head to bread loaf sized rocks just passed under the big tires like nothing ever happened and the wide bars and slack build gave me a calm feel to it all.  No fuss, no muss.

For where I live, and for what I value, the Plus bike would not be a full time, one bike only deal.  That big loop ride only really paid off for the Plus on the trail section, something that I have done many times on a 29er without any real difficulty. But. If my riding experience was tilted towards that kind of trail use for most all my rides?  If I typically began at a trail head and rode loose, rutted, or rooted trails all the time or pedaled across sandy, washed out desert roads for miles and that was my norm…no pavement connectors or long, smoothish fireroad climbs for hours and hours?  No contest.  Plus bike.

So that leaves me with final thoughts.  I am struck by how accurate my initial impressions were for this new Plus deal.  While I have refined my feelings somewhat, the key points remain.  Plus, especially 27.5 based Plus, is here to stay.  It is still getting figured out and polished, but it’s the real deal.  I would not want to be without one in my quiver and the Fuse is something I would be quite happy to call mine.  It is a really neat bike and I bet Specialized will sell every one they make. As it is it’s a fine trailbike and with some tweaks it could take you bikepacking across the nation.

Specialized Fuse Pro 6 FattieBut I also would not give up owning a decently light, mid-travel FS 29er.  As good as Plus tires are, they have some inherent drawbacks.  And riding something like the Salsa Horsethief I am building up reminds you just how good a 29er really is for all around MTB use.  In my opinion it is still the king. So I am definitely ‘in’, but not exclusively in, the Plus bike camp.  Where you fit in this Plus revolultion will be up to you to figure out. I predict you just might have a blast and if you are on the Specialized Fuse Pro 6 Fattie, I can almost guarantee it.


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Note: Specialized provided this review bike at no charge to Twenty Nine Inches for test and review. We are not being paid, nor bribed for these reviews and we will strive to give our honest thoughts and opinions throughout.