First Impressions: Jeff Jones Diamond Frame Bicycle (Part-I)

Is there such a thing as a truly do-it-all bicycle? Gravel bikes–which are often praised for their versatility–come pretty darn close. Despite their flexibility, however, gravel rigs still share many of the design traits and limitations associated with conventional road bikes. Last summer those limitations became abundantly clear when I began including more technical off-road sections in my mixed-terrain rides. Despite the gravel bike’s wider tires and lower gears, its road-based design placed more emphasis on aerodynamics and smooth surface efficiency than off-road capabilities.

Around the time of my existential off-road crisis, a press release from Oregon-based bike wizard Jeff Jones found its way into my inbox. The press release announced that Jones was now offering a carbon version of his popular Loop handlebar. Having previously testedand liked–the aluminum Loop bar, I figured the new carbon version might be just what I needed to improve my gravel bike’s off-road capabilities. After a series of email exchanges, Jeff suggested that I give him a call.

The Jones in its natural habitat.

I told Jones of my plan for his carbon Loop bar, and he politely explained that his handlebars perform best when used as part of a system. That system–which includes his company’s handlebars, frame and fork–is specifically designed to maximize comfort and control while maintaining the bikes’ nimble handling. To get the full benefit of the Loop bars, he instead recommended that I test them in conjunction with his steel diamond frame and matching truss fork. Riding one of Jones’ unique bikes has been on my bucket list for several years, so this was an offer that I definitely couldn’t refuse.

Jones is known for taking a very hands-on approach to fitting customer’s bikes, and my demo rig was no exception. To dial in the bike’s fit, I supplied my height, inseam, and saddle height. Jones also wanted to know the top tube length (615 mm) and stem length (90 mm) of the bike that I used to test the alloy Loop Bars back in 2014. After performing some quick arithmetic, he recommended a 70 mm stem to complement the diamond frame’s 23″ top tube. Why such a short cockpit? According to Jones, many riders negate the Loop bars’ advantages by pairing the bars with stems that are too long. Running a shorter stem encourages the use of the bars’ forward sections, which improves comfort, weight distribution (i.e. handling), and aerodynamics.

While the Jones Diamond frame may technically be a mountain bike, my demo bike was spec’d for maximum versatility in response to my request that it would see equal parts dirt and pavement. Whatever the Shimano 2×10 drivetrain may lack in trendiness, it more than makes up in reliability (which could also be said about the XT hydraulic disc brakes and Thomson Elite stem and seatpost). The biggest surprise, however, was the custom-built wheelset. Boasting an inner width of 45 mm, Easton’s ARC Plus rims absolutely dwarf conventional road–any many mountain–rims. As spec’d, the bike carries a price tag of $3655. Definitely not cheap, but less expensive options are available from Jones or one their dealersFramesets and rolling chassis options are also available if you prefer to build your own bike.

Is Jones’ 29er the one bike to rule them all? Stay tuned for Part-II…


CHASSIS
Frame Jeff Jones Diamond steel
Fork Jeff Jones Truss steel
Headset Jones H-Set
Seatpost Thomson Elite setback (27.2 mm)
Seatpost Clamp DKG bolt-style
DRIVETRAIN
Crankset Shimano XT (28-40, 170 mm)
Derailleurs Shimano XT (top-swing front, long-cage rear)
Shifters Shimano XT RAPIDFIRE Plus
Cassette Shimano XT 10s (11-36)
Chain Shimano XT 10s
WHEELS
Rims Easton ARC Plus 45 (32h)
Spokes DT Swiss Competition (alloy nipples)
Front Hub Jones 135-F (32h)
Rear Hub Shimano XT M785 (32h)
Tires Schwalbe Super Moto 29" x 2.35"
CONTROLS
Handlebars Jones Carbon Loop H-Bar (710 mm)
Grips Jones H-Grips (50D)
Stem Thomson Elite X4 (70 mm, 10°)
Brakes Shimano XT M8000 hydraulic disc
Rotors Shimano Ice-Tech (180 mm rear, 203 mm front)

9 thoughts on “First Impressions: Jeff Jones Diamond Frame Bicycle (Part-I)

    1. No, the chainstays won’t clear a tire that wide. The fork has clearance for a 29″ x 3″ tire, but the frame will only accommodate a tire that measures 2.5″ when mounted on the Easton ARC Plus rim. Most 2.25″-2.3″ plump out quite a bit on those rims.

        1. It is true that it the bike won’t clear the 29×2.8 tires but It will clear 27.5×2.8 WTB Trailblazers with plenty of room left for mud clearance. This is the setup I have on my Jones. However, the true measurements for the Trailblazers are less than 2.8” (I think they are somewhere midway between the actual 2.8 and 2.4).

          1. Thanks, that’s good to know. I want to try a 26″ fat wheel up front, but can’t seem to find an affordable 28h rim that’s wide enough (I have a spare 135 mm Paul front hub that’s 28h).

          2. I don’t think a 27.5″ x 3.00″ tire would fit. The chainstays are semi-flattened and tire clearance is greatly reduced outside the 29″ sweet spot.

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