Pivot launched its Vault in 2019, which didn’t strike me as anything too different from what was already out in the gravel world. It had the normal-looking carbon frameset and understated visuals, so I didn’t give it much thought. But Pivot lauded one small difference — an elastomer sleeve isolates the frame from the seat post. It is unique, patented, and deemed “ISO FLEX,” but I didn’t think it would make much difference.
Tires, saddles, and other component choices can partially mitigate small bump compliance on a gravel bike. Seeing how vertical forces matter, ISO FLEX seemed like a nonstarter, as it seemed to affect forces in all but the vertical plane. But I’m skeptical about that.
I outfitted the frame with the then-new Shimano 2x GRX Mechanical 12-speed and rode the Vault for 6 months around my rural Central Texas home. It traversed terrain ideal for a “soft tail.” I’m surrounded by hardpacked dirt roads with square-edged limestone blocks and stones. The Vault lived through a brutally hot, dusty Texas summer and an unseasonably wet and cold winter.
In short: The Pivot Vault is indeed different. The “square” chassis geometry delivered a snappy road race feeling, but the ISO FLEX provided just enough damping to allow me to stay seated when powering across bumps that normally would have me jostling my weight around, thus losing pedaling efficiency. The Vault is aimed at the faster side of gravel riding, but it gives a nod to comfort without the drawbacks of more complicated suspension.
- Frame material: Carbon fiber, proprietary hollow-core internal molding
- Fork material: Carbon fiber
- Bottom bracket: BB386EVO
- ISO FLEX material: rubber and fiber-reinforced elastomer
- Sizes: XS, S, M, L, XL
Pros
- Effective damping via ISO FLEX without mechanical complexity or effect on drivetrain
- Road race bike inspired "square" geometry gives a familiar feeling
- Even with ISO FLEX, it is lightweight
- Great paint for a mass-produced frameset
Cons
- Higher pricing compared to other brands
Pivot Vault Frameset
Geometry and Form Factor
My large sample frame (Pivot offers XS, S, M, LG, and XL) had familiar geometry. The top tube was 1 cm longer than the seat tube, promising a fit that mimics my favorite 56cm road bikes. Also notable is the non-dropped seat stays meet at the “old school” location at the top tube. Since the Vault has ISO FLEX, Pivot doesn’t need to engineer as much compliance through things like dropped seat stays. I like the appearance of old-school seat stays since I started riding in the ’80s.
Another notable detail was the dropped chain stay on the non-drive side. It’s common to see the drive side chainstay dropped to maximize clearances for cranks, chainrings, and tires. Pivot drops the non-drive side to accommodate crank-mounted power meters. This mostly caters to racers, but it was nice to notice Pivot thinking this through. The Vault can accommodate all this and tires as wide as 45c (or 47c on 650b wheels), but it still has short, racy 420mm chainstays.
Mounts and Internal Routing
The Pivot Vault has more mounts than its race-oriented geometry suggests. These include a triple-boss downtube water bottle cage array, a seat tube water bottle cage mount, and a top tube Bento box mount. Both the front and rear ends of the bike have hidden fender mounts. One note on the downtube water bottle mounts: using the lower two bosses eliminates the option to run a cage on the seat tube.
The Vault is 2x compatible, with a cover to hide the unneeded front derailleur mount for 1x setups. I appreciated this, as some gravel frames are only 1x, and I am a holdover who still prefers 2x on a gravel rig. The frame is integrated for cables and hoses, utilizing Pivot’s cable port system.
Bolt-on port covers anchor cable housing and hoses at each end so they carry tension within the frame, minimizing noise. Pivot doubles up by using foam wrap on cable housing and hoses, ensuring silent operation.
Pivot has a plan for internally routing every conceivable component. From Shimano Di2 batteries and derailleur wiring to dropper posts, there are ports if you need them and covers if you don’t.
BB386EVO Bottom Bracket
Pivot doesn’t follow the crowd and avoids a T-47 bottom bracket. Although keeping up with all the bottom bracket standards is confusing and frustrating, Pivot chooses the BB386EVO for solid reasons. A rather bulbous bottom bracket shell (86.5mm wide) means the large press-fit bearings have a wide stance, improving torsional rigidity compared to narrower bottom bracket shells.
A 30mm diameter spindle means the same rigidity and resistance to twisting for the crankset. This also negates aluminum inserts for threads, saving weight.
Before you roll your eyes at yet another bottom bracket standard, the BB386EVO setup can be stepped down to a 24mm crank spindle. Although maintenance is more of a hassle due to the press-fit bearings, at least the system accepts a wide array of cranksets.
Pivot Cycles ISO FLEX
As I stated before, the Pivot ISO FLEX system is about as simple as “suspension” can get. A rubber and fiber-reinforced sleeve wraps around a standard 27.2mm seat post to isolate it from the frame, damping vibrations and impacts. This works in conjunction with the normally occurring seat post flex to improve comfort.
Pivot also includes an insert that works with 30.9mm dropper posts. Although there is more material to damp impacts and vibrations on the 27.2mm version, and the smaller posts will flex more, dropper post addicts can enjoy “suspension” effects. Pivot claims that there isn’t a difference in damping or comfort between the two ISO FLEX elastomer sleeves.
Of course, the damping rate depends on the rider’s weight and how much the post extends out of the frame. For reference, I’m 168 pounds, and I had about 6 inches of seat post extending beyond the ISO FLEX system.
That Paint!
I have to comment on the paint. My sample frameset had the “Firebrick Red” color option, which was stunning, especially in the sunlight. Deep, lustrous, smooth, with tiny shiny flecks, it was one of the finest mass-produced paint jobs I’ve seen.
Combined with the minimal branding and old-school seat stays, the bike was visually pleasant to me. And I look at a lot of bikes. I felt bad that I got it dirty all the time. Kudos to Pivot for the fine finish job. Pivot also offers a Deep Metallic Blue color scheme.
My Pivot Vault Build
The timing of my Pivot Vault test period couldn’t have been better. Shimano had just released its GRX 12-speed Mechanical RX820 groupset, finally getting the same number of cogs as its competitors. I rounded out the build by going all Shimano with the new carbon GRX wheelset and sister brand PRO gravel components.
The build went smoothly, with zero incompatibility issues, and it was very hassle-free for a frame with internal cable and hose routing. When it was all done, the large-size Pivot Vault weighed a verified 20 pounds, complete with the new 2x GRX, Arundle carbon bottle cages, Eggbeater 3 pedals, and tubeless setup. Pivot claims a medium Vault frame weighs 988 g.
How Does the Pivot Vault Ride?
I was pleasantly surprised the first time I rode the Pivot on my local gravel roads. Right out of my driveway, the surface can be so challenging that FedEx and UPS have refused to deliver to me when it rains. The seemingly minimal ISO FLEX proved effective right away.
The most notable thing was the damping of the square edges, which my pelvis and spine reluctantly suffer through for the sake of pedaling efficiency. The elastomer sleeve smoothed the initial hit of the rear tire against the edge. The faster I went, the more I smiled at how well such a simple thing worked.
The effect was multiplied when the hits came in quick succession. When I’m seated, powering away, a hit comes up through the seat, and if there’s another bump coming, my weight often comes back down as my rear wheel hits an obstacle again. This “double whammy” usually makes me unweight or hover over the saddle, and I lose pedaling efficiency and the associated forward drive.
The Pivot Vault’s ISO FLEX minimized this double-whammy effect when it couldn’t be avoided, and often, I could keep hammering away at the pedals. These effects remained intact over golf-ball-sized obstacles.
I totally appreciated the Pivot ISO FLEX’s rear quadrant damping ability. It was such an advantage on my area’s faster but still rough terrain, and there was little downside. It weighs very little and is not mechanical, so there are no worries about failure or maintenance. And importantly, it’s 100% separated from drivetrain forces, so there’s no loss of efficiency. What a deal!
Ah, but What About the Front?
The ISO FLEX obviously worked, but I felt disconnected from the rigid front. While I enjoyed the rear quadrant damping, I felt the bike wasn’t “whole.” I wanted to match the front damping to the rear’s bump-smoothing abilities. I didn’t want to add much weight or complexity, nor did I want the front’s damping characteristic to be starkly different from the rear.
The answer was a Redshift ShockStop Pro suspension stem. It also uses elastomers to damp both compression and rebound, so I thought it would have a similar quality and feel to the ISO FLEX. And it turned out that this was absolutely the case. The bike felt connected with the Redshift ShockStop Pro suspension stem and rode like an organic whole.
With ISO FLEX, a ShockStop Pro stem, and tire pressure management, the Pivot Vault rode like a dream at speed over my local hardpacked clay roads embedded with rocks. I could keep my pedaling dynamics intact and avoid a death grip when powering through rougher sections, and any edge, regardless of size, didn’t upset the chassis or my body as much.
The Pivot Vault and ShockStop Pro stem also greatly improved comfort. I have a reconstructed left wrist and knee. Both joints pay their dues on long rides with no respite from square edges. But riding this setup resulted in much less discomfort and pain. Again, all these benefits were without a loss of pedaling efficiency, mechanical durability, or a gain in maintenance tasks or significant weight.
Conclusions on the Pivot Vault Gravel Bike
Even as a skeptical bike editor, I found it hard to fault the Pivot Vault gravel bike. It has enough damping and suspension travel to make a real difference, with minimal weight gain and no mechanical complexity or maintenance. Adding the ShockStop Pro suspension stem, I also enjoyed the same benefits in the front, making the Vault feel congruent and whole.
If there is one gripe, it would be the pricing. Pivots has always stuck to higher pricing compared to many other brands. But they have developed many things (like BB386EVO and hollow core internal molding on the frame) and numerous lauded bikes.
The lowest-priced Vault comes with 1x mechanical GRX, aluminum wheels, and components and has an MSRP of $5,799. As a comparable example, a similarly equipped Revel Rover has an MSRP of $4,500. Pivot sells the frameset for $2,899. By comparison, a Ventum GS1 frameset sells for $2,599.
Ultimately, the Pivot Vault warrants serious attention if you seek a little separation from the chatter and prefer a road race chassis feel. It offers the benefits of enhanced bump compliance without the usual drawbacks of more complicated suspension systems.
