Ironman pro triathlete mixes it up on the gravel at the Cedar City Belgian Waffle Ride
(Image credit: Ian Matteson / ENVE Composites)
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Heather Jackson's Argon 18 Dark Matter(Image credit: Ian Matteson / ENVE Composites)
There is quite a bend in the fork of the Dark Matter(Image credit: Ian Matteson / ENVE Composites)
This appears to be an ISM Breakaway saddle, which was discontinued in 2015(Image credit: Ian Matteson / ENVE Composites)
...and it is slammed back on the rails(Image credit: Ian Matteson / ENVE Composites)
Pro cages are looking after Jackson's drinks(Image credit: Ian Matteson / ENVE Composites)
The Enve SES 3.4 AR wheels aren't as light as the G23 gravel specific wheels, but they are more aero(Image credit: Ian Matteson / ENVE Composites)
Jackson is a Wahooligan(Image credit: Ian Matteson / ENVE Composites)
A bolt-on bento box keeps Jackson's nutrition to hand(Image credit: Ian Matteson / ENVE Composites)
There is some interesting cable and hose wrangling happening under the cockpit(Image credit: Ian Matteson / ENVE Composites)
The IRC Double Cross tires have lots of knobs, but nothing is overly tall(Image credit: Ian Matteson / ENVE Composites)
The 11-34t cassette is the biggest 'road' cassette Shimano currently makes — though you can run a Deore cluster with a 40T big cog with the GRX long cage mech(Image credit: Ian Matteson / ENVE Composites)
Professional triathlete Heather Jackson traded her tri-suit and TT bars for knobby tyres this weekend at the Cedar City Belgian Waffle Ride, taking fourth place in the women's race behind Rose Grant, Kathy Pruitt, and Crystal Anthony.
The current American Ironman record holder is an Argon 18 sponsored athlete, so it's no surprise to see here riding the Dark Matter gravel bike at the BWR. The race route saw the riders pedalling mostly unpaved roads through Southern Utah's desert, and Jackson opted for a full Dura-Ace Di2 2x drivetrain, including a non-clutched rear derailleur.
The triathlete was running pretty tall gearing too, pushing a 50/34T combo at the front, paired with an 11-34t cassette at the back.
Rolling stock comes in the form of ENVE's SES 3.4 AR hoops paired to 700x38mm IRC Boken Doublecross rubber with 32 psi in the rear and 29-30 psi in the front. The ENVE sponsored athlete says she opted for this setup over the gravel-specific G23 wheels due to aerodynamics — the G23's are about ~100g lighter than the SES, but the SES 3.4 AR are considerably more aerodynamic.
The IRC Boken Double Cross tyre has a clear off-road bias with short knobs throughout, with a tightly packed centre strip to minimize rolling resistance and blocky transition and shoulder knobs for cornering grip.
There is plenty of tread there for a 700c tire (Image credit: Ian Matteson / ENVE Composites)
Jackson's cockpit is comprised of a set of ENVE road handlebars, interestingly not the new SES AR drop bars, an alloy Pro Vibe Stem, and a red Wahoo Element Bolt.
Seating arrangements come in the form of what appears to be an ISM Breakaway saddle, done up with custom graphics just for Jackson. This saddle was officially retired from ISM's range in 2015, but it seems the Bend, Oregon-based pro must have a stockpile of her preferred saddle.
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Gravel racing is one of the few places we see race bikes with luggage; mounted beneath Jackson's saddle is an Arundle Medio saddlebag, which has room for two gravel tubes plus the fixings to get you back up and running. Bolted to the top tube is an unlabelled bento box, which appears to be the Argon 18 E119T Top Tube Triathlon Nutrition Box.
Click through the gallery above for a closer look at Heather Jackson's Argon 18 Dark Matter.
Heather Jackson's Argon 18 full bike specifications
Frameset: Argon 18 Dark Matter
Front brake: Shimano Dura-Ace R9170 Hydraulic Disc calliper
Based on the Gold Coast of Australia, Colin has written tech content for cycling publication for a decade. With hundreds of buyer's guides, reviews and how-tos published in Bike Radar, Cyclingnews, Bike Perfect and Cycling Weekly, as well as in numerous publications dedicated to his other passion, skiing.
Colin was a key contributor to Cyclingnews between 2019 and 2021, during which time he helped build the site's tech coverage from the ground up. Nowadays he works full-time as the news and content editor of Flow MTB magazine.
