Jeff Jones 3D Spaceframe

This is the kind of bike that turns the heads of both riders and casual observers, with its graceful lines masterfully executed in titanium, but this bicycle is about much more than good looks.

By Karen Brooks

Jeff Jones is one of those bike world visionaries who will have a lasting influence on the equipment we use. The Oregon-based framebuilder has been doing some high-caliber garage tinkering since 2003, testing out ideas formed through extensive study of the craft and lots of riding, creating an evolving line of frames that get ever closer to his lofty ideal of "the perfect bicycle." His current pinnacle is the 3D SpaceFrame.

This is the kind of bike that turns the heads of both riders and casual observers, with its graceful lines masterfully executed in titanium, but this bicycle is about much more than good looks. Jones eschews any modern forms of suspension in favor of working with 3Al-2.5V titanium tubes to produce his idea of a naturally compliant frame without the design constraints of shocks and suspension forks. This makes for a very different sort of ride, but at the same time familiar—the SpaceFrame rides like a lightweight, precise-handling cruiser, not like other unsuspended mountain bikes.

The frame and fork are built on the "space frame" architectural principle, meaning that triangulation helps spread loads. The frame has three small-diameter, curving top tubes, one in the center that turns up to meet the seat tube and two that continue past it to form the seatstays, welded together where they touch side-by-side. It’s an elegant way to achieve those twin standards of vertical compliance and lateral rigidity, as well as lots of standover clearance. Then there’s the Truss fork, a miniature version of the architectural wonder of the frame, which is designed to absorb some vertical shock while resisting rearward bending under braking forces. (I could fill this entire review with many other structural details of this frame, but you can go to the Jones Bikes website or check out my blogs for that.)

The SpaceFrame’s geometry positions the rider’s weight back, over the rear wheel, and low, for fast handling but lots of control. It has a fairly slack 72° effective seat angle which can change with seat height due to the rearward bend in the seat tube. Using a Thomson Setback seatpost, I felt the larger than normal horizontal distance from saddle to crank allowed my thigh muscles to work more efficiently, and thus I was able to put more power to the pedal than with just about any other bike. The bottom bracket is settled low between the wheels at 11.5"; although I struck the pedals a few times, the low BB was much easier to adjust to than the higher BB of some 29ers that feel like I need a ladder to get on. Up front, the head tube angle is also slacker than a normal cross country bike’s, at 70°, but it doesn’t make the steering slow—in fact, combined with the fork’s 55mm rake, it gives a shorter than "normal" trail and achieves impressively tight steering for a 29er, plus there’s no toe overlap. The curving seatpost allows for fairly short chainstays (17.1" to 17.6" depending on the Bushnell eccentric bottom bracket position). The bike’s 29" wheels fit into the frame so compactly, with a 42" wheelbase, that it was hard to tell at first they were not 26" wheels, except of course for their superior grip. I’ve often felt that a slacker seat tube combined with a shorter top tube would be great for me, yet the dudes in the office rode this same frame comfortably with only seat-height adjustment.

With the Jones Cut H-Bar (a narrower version of the original H-Bar) the contact points for my hands line up just behind the front hub, which had the very desirable effect of making the bike difficult to endo. The handlebar’s several hand positions, accentuated with pre-installed foam grips and cork tape, were so natural and comfortable that I wonder how people ever put up with conventional straight, flat bars. Usually I hate fatter foam grips, but with this bike’s relaxed position, I didn’t have to grip the grips as tightly and could just rest on them easily, allowing the foam to be another layer of simple vibration damping added to the Ti frame and fork. Overall the riding position is more upright than on a standard cross country frame, yet in a way that felt more stable and natural than, say, a hybrid bike, and also more rearward, which gave me extra confidence on steep descents and at higher speeds. Essentially it was the bike version of the "athletic stance" they teach you in snowboarding or hockey or many other sports—weight centered on the balls of the feet, crouched and ready to attack anything. Website photos of Jeff jumping this bike off of large rocks attest to the frame’s capabilities better than I could, but it did give me enough confidence to tackle wooden obstacles and smaller jumps. It was very easy to manipulate with a little bit of body English, without any twitchiness or weird, unexpected feedback. To steer I could lean and carve from my hips, yet the bike’s stability also allowed sharp, slow-speed turns initiated from the handlebar.

Jeff included the Fat version of the fork on this tester, an experiment inspired in part by the Surly Pugsley: spaced for a proprietary 135mm Paul front hub, the fork can accommodate either a standard-width 29" rim and tire, or a wide 26" rim with a huge tire. During the test I switched between a "normal" front wheel, with Paul 135mm hub, Edge Composites 24mm carbon rim and Schwalbe Racing Ralph 29"x2.25" tire, and a "fat" one with a 50mm-wide Speedway Cycles alloy rim and Surly Endomorph 26"x3.7" tire. When I first rode the SpaceFrame extensively, it was during the SSWC08 in Napa, California, on the skinnier tire, and I was bounced around quite a bit on the rocky course; although this bike isn’t "rigid" in the strictest sense, I suspect that some of the frame’s compliance kicks in with more body mass than I’ve got. But on later rides, the fat Surly/Speedway wheel took care of bouncy situations very well. Compared to the same tire on the Surly Pugsley (tested in issue #120), this fat front tire benefitted from the Jones’ quicker steering, as it didn’t feel nearly as truck-like. The big tire absorbed bumps and sharp edges well enough to make the bike as comfortable as my RockShox-equipped hardtail, quickly becoming my favorite set-up for dry, rocky trails. It took some experimenting with tire pressure to avoid basketball-like bouncing—I ended up running it incredibly low, between 5.5 and 8psi. However a major drawback of the fat setup was the paltry knobs on the Endomorph; for all its size, it just couldn’t handle more than a little mud or snow without sliding.

Jeff included a singlespeed and a six-speed drivetrain, the latter with a modified XTR cassette mated to a singlespeed Chris King hub for a dishless rear wheel, and I used both in equal measure. In geared mode, six speeds were plenty for most situations, especially given the efficiency of the frame. Of course that efficiency was great for singlespeeding.

At one point Jeff Jones had a waiting list for handmade frames over five years long; in the interest of letting the most people possible ride his bikes, he formed a partnership with Merlin so that they could produce frames in stock sizes in a more timely manner and for less money. Now Merlin is able to produce custom frames as well as stock. Jones also offers a Diamond frame option with the same basic geometry in both Ti and steel.

All in all, this is an amazing bike, and I don’t use that term lightly. It is also expensive. I have said before that titanium is forever, but given that this frame doesn’t depend on shocks, pivots or other parts that may become unserviceable, and that it is one of the more versatile frames out there, this may well be the last mountain bike you buy.