First Ride: The Ventum GS1 Gravel Bike Sticks to the Go-Fast Formula

If you only glanced at Lauren Stephens’ Ventum GS1 we found at Sea Otter Classic, you’d think it was the same as the previous generation bike. Frankly, I wouldn’t blame you; this new gravel bike generation looks a lot like the old one.

There are a few key differences, however. Tire clearance is boosted to fit over a 50 mm tire. The flip chip in the fork is gone. Typical claims of the bike being more aero, stiffer, and lighter ring true here. And in a somewhat surprising turn, Ventum has shrunk down its à la carte component ordering system.

Ventum didn’t seek to completely overhaul its GS1, as it found Ventum athletes and fans alike already liked the bike’s go-fast personality. The bike feels rapid on smoother dirt and tarmac, but the updates found here should make the bike much more usable without getting rid of the road bike-like feel Ventums says its athletes and buyers love.

Quick hits: Seven things to know about the Ventum GS1

• The third-generation Ventum GS1 is the brand’s go-fast gravel bike
• Max tire clearance: 700c x 50 mm (rear); 700c x 56 mm (front)
• Frameset saves a claimed 150 g over the previous generation GS1
• Features a T47 threaded bottom bracket, SRAM UDH (Universal Derailleur Hanger), and standard 1 1/8-inch steerer tube
• Sizes: Six, from XS to XL
• Prices: Starting at $3499 (complete Apex AXS build); frameset at $2899
• For more: ventumracing.com

Build details

Well, there’s certainly a focus on speed here, at least visually. There’s the somewhat common dropped seat stay junction where the seat stays flatten as they approach the seat tube. The down tube gets the same aero-look treatment as well, with a flat back at the bottles and a pointed shape down below. Even the top tube is more level than most road bikes on the market.

Really, it looks a whole lot like the outgoing GS1. What gives?

According to Ventum, the GS1’s focus on speed resulted in three goals: make it lighter, make room for more tire, and simplify the bike where possible. They’ve succeeded on the tire component, as the bike now fits a 700c x 50 mm tire out back and a 56 mm tire up front. It’s not quite as wide as the likes of the Allied Able, but this bike also has much shorter chainstays. More on that down below.

Ventum says they’ve been able to trim the overall frame weight down by 150 grams over the previous generation bike. Cutting weight comes from increasing the carbon modulus to increase stiffness without adding more material, yes, but Ventum says it has also made the frame stiffer too: 12 percent stiffer at the head tube, 8 percent stiffer at the bottom bracket, and 8 percent smoother at the saddle.

Simplifying the bike also helped cut weight. The new GS1 ditches the bottom bracket bottle cage mounts, but it also ditches the flip chip at the fork dropouts of the previous bike. According to Ventum, neither were used much by its athletes nor its customers. While I don’t particularly care for the fork flip chip, could I be one of the few folks using the bottom bracket bottle cage mount?

Elsewhere, the new GS1 gets a lightly slimmed-down head tube (to tie it into its Tempus TT bike). The seat post is slightly wider than the old one, which Ventum says was done to facilitate easier access to its seat post wedge. And while there’s just one seat post length available, there are two offsets available (0 mm and 25 mm).

Otherwise, the GS1 follows the course of the existing bike. There’s fully internal cable routing, the two bottle cage mounts on the down tube and seat tube, and a top tube bag mount as well. As before, the GS1 is only compatible with electronic drivetrains, and it fits up to 180 mm brake rotors front and rear.

My only question was why there isn’t any downtube storage hatch, certainly one of the biggest trends in gravel bikes today. According to Ventum, it was a calculation of whether the hatch would be worth the added frame weight, and whether the potential fiddliness of a hatch would be better than just taping tubeless plugs to your frame in a race. Further, Ventum says its riders and athletes alike would rather have the lighter frame and go from there.

I personally think a downtube storage hatch can be incredibly useful when designed properly, particularly if you’re ditching the mount under the bottom bracket that might be used for a toolbox or the like, as Ventum has done here. Not everyone uses them, however, and certainly not most pros in the heat of the moment.

Geometry

Geometry is unchanged from the previous generation Ventum GS1. That means the bike gets a 72.5-degree seat tube angle and between a 69 and 72.5-degree head tube angle across the sizes. Ventum specs just one 50 mm fork rake across the sizes, however, resulting in trail figures that range from roughly 83.2 mm in this test size XS and 59.9 mm in a size XL.

Those numbers are on completely different sides of the spectrum; 81 mm going toward the likes of a Santa Cruz Stigmata, Norco Search, or ‘is it a drop bar mountain bike and not a gravel bike’ Kona Ouroboros. Meanwhile, that 59.9 mm trail figure in a size XL is firmly in road bike territory. I suspect the bike was designed around the size M and M/L sizes that have a still-broad range between 69.6 and 63.3 mm of trail.

The short 420 mm chainstays and 70 mm bottom bracket paired with the front end geometry of this test bike make the bike quite willing to turn in, at least initially. More on that later.

Fit geometry is decidedly aggressive in the gravel bike market, with reach and stack numbers within 5-10 mm of its own Ventum NS1 road bike. Thankfully, those numbers are far more consistent across the sizes.

Builds, specs, and pricing

At launch, Ventum will offer the GS1 in three build kits and one frameset. Four colors will be on offer, though not every colorway will be available on every build.

Ventum is also ditching its à la carte build program, where riders can choose between a slew of wheels, cockpit options, saddles, and more. Replacing it is the ability to customize fit dimensions, including bar widths, stem lengths, and crank lengths. Swapping the bar and stem measurements is available for a $75 upcharge, while swapping crank lengths (between 165 mm and 175 mm) also gets a $75 upcharge.

And while Ventum will still continue its direct-to-consumer sales as a priority, it has slowly expanded its range of dealers in the US. While we’re bummed to see the semi-custom component ordering system going away, we appreciate the ability to customize key fit components at any level.

Riding the Ventum GS1

In for review was a Ventum GS1 with a SRAM Red XPLR AXS groupset. Wheels came courtesy of Zipp, while the bike uses Ventum’s CR5 integrated bar and stem and a Fizik Vento Argo R5 saddle. Total weight for my size XS bike without pedals is 7.8 kg (17.2 pounds). That makes it one of the lightest gravel bikes I’ve ridden in years. While I am personally of the belief that weight on a gravel bike doesn’t seem to matter all that much, a lightweight bike certainly feels good.

You look at the Ventum GS1 and assume it’s going to go fast. The top tube is essentially level, the clearances appear tight (though they’re bigger than you’d think), and the frame’s sharp angles and deep rims make the bike look like it just got out of racing a criterium. The only thing really defying those assumptions is the fact that my bike had 50 mm tires.

However, those go-fast assumptions are confirmed the moment you start pedaling. Compared to other gravel bikes, the GS1 is one of the most responsive to pedaling I’ve ridden in recent memory, reminding me of the BMC Kaius and Canyon Grail. I wish I had a better way of saying it, but if there were a gravel bike that felt like every bit of energy you put into the pedals went into forward momentum, the Ventum GS1 would be it.

That responsiveness continues on dirt, where again, in a straight line, the bike feels like one of the speediest gravel bikes I’ve ridden in recent memory. It feels especially quick as the speeds increase, where the bike’s responsiveness is still prevalent.

Among other things, the GS1 is far from the smoothest riding gravel bike you’ll find. There’s enough smoothness here to put the power down when the going gets rough, but tires and seat post extension here do most of the heavy lifting.

Oh, and a fit note for smaller riders: the seat post used on this size XS will almost certainly need to be cut if your saddle height is below 675 mm. I was able to get away with not cutting it by swapping to a different saddle, but your results may vary here.

The GS1 is a good climber. Though the 72.5-degree seat angle is fairly slack against the competition, the bike still feels quite responsive. With the stock Goodyear XPLR Inter 50 mm tires, the rear wheel sticks on even steep loose-over-hardpack stuff you probably shouldn’t be riding a gravel bike on.

Despite my size XS test bike having that 83.3 mm trail figure, the front wheel doesn’t flop around on climbs like it might on longer gravel bikes. I attribute that to the comparatively shorter front center lengths of the GS1, which allowed me to more easily move my weight onto that front wheel.

Where that high trail figure and taller bottom bracket height reared itself is in two places. The first was on technical, winding single track, where it took me quite a bit longer to feel comfortable on the bike. The bike tended to get unsettled more quickly on this bike than on other recent gravel bikes riding the same routes, even with the wider 50 mm tires here.

The second place where those figures seemed to rear themselves was on the road, and more specifically on the faster, more technical road descents I have here. Turn-in in these higher-force turns felt like a story of two halves: very quick turn-in as you enter a corner, followed by a much slower turn-in toward the apex and out of the exit. I consider myself average to slightly above average as far as descending on the road is concerned, and it took me some time to adjust to it.

That being said, it didn’t prevent me from going fast. My descending time from the top to the base of my local mountain was within a few seconds of my personal best on a road bike with 30 mm tires. Call it a quirk of the bike’s handling, but I never quite got adjusted to it on the half dozen or so rides I’ve done for this first ride review.

More than in recent memory, the Ventum GS1 feels like a road bike stretched out just enough to fit a big gravel tire rather than a dedicated gravel bike, much less a hardtail with drop bars added like some bikes. The GS1 lets you take advantage of the bigger tires that folks want to ride, though the bigger tire clearance does not necessarily result in making the bike better suited for underbiking.

And the rest of the kit?

What is there to say about SRAM Red XPLR AXS that hasn’t already been said? The 1×13 gearing is excellent on the road, with its small jumps between gears on the high end and range on the low end being more than enough for even the steepest ‘gravel’ riding we have here in the Bay Area. Shifts are quick, precise, and consistent. No real complaints here.

The Ventum CR5 integrated handlebar and stem are also a good match for the bike. There’s loads of front-end stiffness to be found here in a sprint, both in the tops and in the drops. Further, the brake levers don’t flare out all that much despite the wider drop area than in the hoods, furthering its road bike-like comparison. My only complaint is the computer mount, which angles the computer slightly upright rather than the level mounting style I prefer. Horses for courses, but angle adjustment would be nice.

The Zipp 303 XPLR SW wheels are surprisingly comfortable off-pavement on smoother gravel, considering their 54 mm rim depth. I still have some doubts as to whether a gravel bike needs a 32 mm internal rim width – and one that limits the tire you can use – but the combination of these wheels with the 50 mm Goodyear tires (made for these wheels) felt cohesive, grippy, and fast on and off tarmac.

More to come

The Ventum GS1 feels like one of the fastest gravel bikes I’ve ridden on fast, straight, and chunky gravel roads. It seems to fall behind on faster, more technical road descents with lots of turns, where I was more immediately comfortable on other recent gravel bikes, and more technical, underbike-y types of singletrack. Chances are that you’re not riding a GS1 on this type of terrain, anyway.

There are plenty of unanswered questions. How has the pursuit of out-and-out speed affected the bike’s long-term longevity? How does the GS1 compare against the competition? Do I wish I could fit an even wider tire than I have here, even on a bike like this? Stay tuned for more to come with the Ventum GS1 as I ride it more and more as the season goes on.

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