Specialized 6Fattie: Our First Impressions

Over the weekend we joined Specialized at Makara Peak for one of their regular demo days. There was the complete fleet of Specialized bikes to test and trial, but Brett and I were there for one reason only; we wanted to get our first rides in on Specialized’s 27.5+ offering, the 6Fattie. We’ll be getting a test bike to review any day now, but we were eager to first get the lowdown from the crew at Specialized, and to gather some initial ride impressions.

27.5+ is the latest wheel/tyre (r)evolution to hit the mountain bike industry and is essentially a genetic amalgamation of the previous (r)evolutions of 27.5 (650b), fat bikes, and tubeless. With 27.5 sized rims and voluminous 3.0″ (plus) tyres capable of being run at very low pressures,  27.5+ promises to provide improved grip in a relatively normal trail bike configuration. Many manufacturers are beginning to offer 27.5+ options, banking on these bikes appealing to the mainstream.

Specialized offer both a hardtail 27.5+ option (the Fuse) and the full suspension Stumpjumper 6Fattie that we rode. The Stumpjumper shares many of the features, build details, and geometry of its less fat brethren. However fitting 3.0 tyres to a trail bike has necessitated some adjustments and so the 6Fattie sees a reduction in travel (135mm) over the regular Stumpjumper (150mm) and some tweaks here and there to geometry. But most of the vital statistics are more or less on par: 67 degree head angle, 74 degree seat angle, 331mm BB, 431mm reach (on a large) and 437mm chainstays (impressively short given the wheel size).

The carbon versions of the 6Fattie also feature the SWAT glovebox in the downtube where you can store all your essentials, an integrated multi-tool on the underside of the top tube and a chain breaker neatly tucked away in the top of the steerer tube.

Despite the fact that we’re at the soggy tail-end of winter and that there was some heavy rain the day prior, Makara put on a beautiful sunny day for us. The trails were surprisingly dry, even dusty in many places. This proved to be the ideal environment for the 6Fattie which, on first impressions, appears to excel in loose dry conditions. Out on the trail the bike felt surprisingly normal considering the voluminous nature of the tyres and the fact that we were running only 16 PSI front and rear (we later dropped this to 14 PSI). There was no wallowing or excessive bobbing as we headed up trail, and traction out of the saddle was great. Climbing on the 6Fattie felt as efficient as any other trail bike of this nature (with normal sized tyres) and the added confidence to stand up and stomp on the pedals, that comes with the increased traction, was a bonus.

Heading back down trail, we quickly found ourselves at home on the 6Fattie. It feels, for all intents and purposes, like its non-fat brethren, with the exception that you could push harder through the corners and brake later on the steeps and loose stuff, confident that the big 3.0 tyres would keep things in check. Intentionally breaking traction with the rear wheel might be bad trail etiquette but it’s also a lot of fun. Doing so on the 6Fattie initially takes some conscious effort as you have to lighten the rear end a little more than you might normally, but you soon get used to it.

Half a day on a bike is really only enough time to get some initial impressions, but Brett and I were both pretty impressed. The 6Fattie seemed to have few (if any) points that could be considered negative and certainly delivered on the promise of increased traction. But we’re going to reserve our final judgement until we have had a chance to try it out in a variety of conditions and on a variety of trails.

If you’ve got any questions regarding the 6Fattie (or 27.5+) that you’d like us to explore and cover in our long term review, or if you’d just like to rant about yet another wheel standard, leave us a comment below.