The Viathon G1 Gravel Bike: Fast and Affordable, with a Little Room for Improvement

The Viathon G1 is one of the more affordable carbon, gravel bikes that's well suited to riding sketchy roads.

For a new, and relatively small brand, Viathon stirred the pot with their debut. Last April, when we saw them at Sea Otter, they dropped the G1, R1, and M1 all at once, dipping their toes into the gravel, road, and mountain bike pool. A few months later in June, we got to take the M1 hardtail for a spin in Idaho.

A few things are apparent with Viathon. They seem to offer a solid value for a full carbon bike. The M1 carbon hardtail, with a SRAM GX Ealge driveterain comes in at a bargain price of $2,200, with the top-level SRAM AXS electronic drivetrain equipped model hitting $6,500. A similarly specced Specialized Epic S-Works hardtail goes for about $3,000 more. The geometry, however, told a different story than what Viathon portrayed as the M1’s intent, and it felt much more like an XC race bike, than an everyday trail bike.

The G1 gravel bike starts at $100 more than the M1. For $2,300 (at, the G1 has a new Shimano GRX 600 groupset, an entry-level, gravel-specific drivetrain, with a hydraulic brake set. I was excited to try out the G1 to get a better taste of what Viathon as a whole has to offer. Gravel as a discipline also seems to be a little more straightforward than mountain biking, where there are countless sub-genres of bikes.

About the Viathon G1

The G1 itself, judging by its cover, looks like a tailored gravel race bike, where carbon matters in terms of stiffness and power transfer, and a more racy geometry means better aerodynamics, and less playing around. It’s also not the Bike Utility Vehicle that you get out of a Salsa or even the Santa Cruz Stigmata, with their functional braze-ons intended to extend time away from home base. And, it’s certainly not the Evil Chamois Hagar.

So, what does Viathon say that the G1 is? Basically, just a gravel bike. “Fast as a road racer, rugged as a mountain bike, and priced beyond compare.”

Viathon made the G1 with certain features in mind: Thru-axles, flat mount disc brakes, and dropped seat stays for compliance. Tire clearance is on the narrower side, but it’s wide enough for 700x40c tires, or 2.1″ width tires with a 650B diameter.

There are rack and fender mounts on the G1 frame, internal routing, and mounts for up to three water bottles, so it is possible to get pretty far from base camp on the G1, and there’s frame clearance for bags and all that.

On top of the frame features, the G1 comes with a pretty respectable build kit. The GRX 600 is a 2×11, with a 50/34T up front, and an 11-34T cassette — Viathon offers the GRX 800, SRAM Force, and AXS builds in a 1x configuration.

The GRX 600 build also has Mercury G3 wheels, with a 25mm internal width, and IRC Boken 700x40c tires, for a setup that should provide a wide footprint.

Extra bottle mounts on the downtube.

Geometry on the G1, like the M1, is fairly conservative. My 54cm test bike has 382.8mm of reach, coupled with a 110mm stem. There’s a low 69mm of bottom bracket drop, making for increased stability and cornering, and a 74° seat tube angle and a 71.5° head tube angle. The 1019mm wheelbase keeps the handling snappy. My 54cm Viathon G1 without pedals weighs 19.6lbs.

Ride impressions

At the beginning of the pandemic, governments and mountain bike organizations made it clear to all of us that we should be sticking close to home, and refraining from unnecessary risks. Enter the gravel bike.

Gravel bikes can generally be ridden from home at a lower risk level than mountain bikes. With a network of green-rated trails down the street from my house, the G1 came into my hands at the right time.

I set up the G1 with a quick home fit, and away I went. Viathon offers customers choices when it comes to fit. Usually, they can change the bar width, stem length, and crank length, but Viathon hasn’t been able to do this during the pandemic because of supply chain issues, and it’s not clear yet when they’ll be able to offer this option again. None of the standard specs were an issue for me in terms of fit, and even the Selle Italia saddle wasn’t problematic for me at any point.

My first takeaway on the G1 was how light and stiff the frame is. It picks up speed quickly – like road bike quick – and feels very responsive to cornering and rider input.

The stiffness of the Viathon G1 is where the bike feels like it’s ready to be more competitive as a gravel race bike, rather than something for adventure.

Although Viathon has dropped the seatstays for a more compliant-feeling ride, the ride dynamics still feel harsh in the rear, and especially so up front.

As I mentioned above, customers might be able to swap out the bars for something wider that will flex more, but the narrow 430mm bars clobbered my hands going over rough terrain. The handlebars could have been wider, with a shallower drop, and an extra helping of bar tape would have also been welcome.

A handlebar with any degree of flare through the drops would be nice as well to widen the rider’s stance going downhill. As I rode the G1 down some green- and blue-rated trails, the straight and narrow bars stuffed my wrists into an uncomfortable position. Something like these Spank Vibrocore gravel bars we tested would certainly take the edge off.

Over mostly flat and undulating terrain, the G1 can actually be a little fun on certain trails, if that’s what you enjoy from a gravel bike. With the tire clearance limited to a 40c wide tire though, the G1 reminds me again that its intentions rest on dirt roads.

Noting the stiffness, and feathery weight of the G1 again, it’s an excellent climber, and the Shimano GRX 600 worked flawlessly for me. After spending some time on 1X and 2X gravel bikes, I appreciate the 2X drivetrain, because it covers the spectrum of what a gravel bike will encounter on any ride. 1X drivetrains feel great, if you’re riding your gravel bike exclusively on the trails.

The IRC Boken tires and Mercury wheels were a good match for the Viathon as well. I didn’t expect much from the Bokens, but they were predictable on dirt with a fast rolling speed.

Viathon seems to have taken a conservative aesthetic approach on all of their bikes, including the G1. There’s nothing wild going on in the tubing — no weird bends, or protrusions. The only thing that caught my eye was the cable routing gathered around the head tube, which looks a little messy.

Closing thoughts

Viathon again drives a hard bargain with the G1. To get a full carbon gravel bike with a Shimano GRX600 groupset for $2,300 is a pretty sweet deal, although there are still other great deals on gravel bikes, for those who like steel or aluminum. In this case, carbon doesn’t work entirely to its benefit, and the G1 is a little overly stiff, and calls at least for a more compliant set of handlebars. That said, if carbon is your jam, you want a solid groupset, and don’t spend a lot of time gravel biking on trail, or in real bumpy terrain, the G1 delivers.

⭐️ Find the Viathon G1 at