Test Sessions has always been our way of dissecting a bunch of bikes from a specific category. It's been a successful format as it allows the cream to rise to the top while simultaneously helping riders discover what bike is right for them. And this got us thinking: why not apply Test Sessions to components? Mountain bikes are more reliable than ever, and there are a ton of great aftermarket parts available. There is no reason you can't ride a bike for years and simply replace or upgrade things along the way.
Realizing our epiphany had legs and the space existed to nerd out on some bike parts, we decided it was time for some component-focused Test Sessions. Our goal remains the same as any Test Sessions—find out where each product excels and falls short, and help riders determine which product suits their style and terrain best. So whether you are currently riding the best components and want to know what the competition has to offer, or you want to ditch your dated parts for the latest and greatest, you'll find out where your money is best spent.
To kick things off, we've wrangled together seven high-end enduro forks for comparison. With endless promises of life-changing mid-stroke support and broad ranges of external adjustability, there is a lot of tech to break down surrounding modern enduro forks. Lucky for us, we spent a week twisting knobs and eating compressions for breakfast to see what separates the best forks in 2024.
(We apologize in advance for the excessive use of words including, but not limited to, compression, harsh, supple, damping, fast, slow, open, closed, bump, or impact.)
Video Contents
- 0:00 - Intro, Forks Tested
- 2:48 - Judging Criteria, Testers, Location
- 4:56 - DVO Onyx 38 Overview
- 8:29 - DVO Onyx 38 Test
- 13:28 - SR Suntour Durolux Overview
- 16:40 - SR Suntour Test
- 20:07 - Formula Belva Overview
- 24:18 - Formula Belva Test
- 30:04 - X-Fusion Vengeance 38 Overview
- 32:47 - X-Fusion Vengeance 38 Test
- 36:28 - FOX 38 Factory Overview
- 40:39 - FOX 38 Factory Test
- 44:38 - RockShox Zeb Ultimate Overview
- 48:32 - RockShox Zeb Ultimate Test
- 53:45 - Ohlins RFX 38 M.2 Overview
- 56:55 - Ohlins RFX 38 M.2 Test
- 1:02:08 - Which Fork Would They Take Home?
Table of Contents
- How we tested
- Fork critics
- Where we tested
- RockShox Zeb Ultimate Review
- FOX Factory 38 Review
- Ohlins RXF38 Review
- SR Suntour Durolux 38 Review
- Formula Belva Review
- DVO Onyx D1 38 Review
- XFusion Vengeance 38 Review
- Overall Scores
As enduro bikes have progressed into their current state, they've slowly morphed into mini-downhill bikes. They can still pedal decently well, but descending performance reigns supreme over factors like weight and versatility. Modern enduro forks nicely illustrate and mimic this progression. They've grown burlier with time, featuring larger diameter stanchions, stiffer chassis, more travel, and internal hardware similar to what brands spec in their downhill forks. It's a welcomed and warranted evolution to match the speed and aggression that enduro bikes facilitate.
We tested forks from FOX, RockShox, Öhlins, Formula, DVO, XFusion, and SR Suntour. All forks are the highest model offered by each manufacturer and have 170 or 180mm of travel. Skimming over the spec sheets of our test field highlights a few common themes and peculiarities within the group. 38m stanchions have become the most popular tube diameter for longer travel enduro forks thanks to the balance of weight and stiffness they provide. However, the test has an outlier in the form of Formula's Belva fork with its 35mm stanchions. The Belva is also the only dual-crown fork in the test, with all other forks utilizing a traditional single-crown architecture.
All forks use an air spring instead of a coil and feature some way to adjust the spring curve, whether that be volume spacers or, in the case of Öhlins' RXF38, a secondary ramp-up chamber. Some forks also have bleeders on the lower legs to equalize pressure with changing climates. On the damper side, we see a mixture of cartridge, bladder, and spring-backed IFP designs. Regardless of the damper guts, riders have a combination of high and low-speed compression and rebound-damping external adjustments.
Despite plenty of differences, all the forks weigh within 300 grams of each other. As expected, there is a cost to ride premium forks. The cheapest fork in our test, SR Suntour's Durolux 38, cost $849, while the most expensive fork, the Belva, cost $1,549.
Upgrading to a new fork is a great way to impact the performance and feel of your bike, especially when you consider all the adjustments available to fine-tune your setup. There are no excuses in 2024 not to have a fork that performs exactly as you'd like. The flip side is that more adjustments can lead to more problems if you don't understand the changes you are making. Suspension tuning is all about patience, repetition, and solving one problem at a time. To give us a fighting chance of testing and arriving at an ideal setup on every fork, we started with the manufacturer's recommended settings. From there, we made changes based on comfort, rider preference, and testing conditions.
How We Tested and Rated 7 Forks
So what makes a fork a strong performer and cut out for the intensity of enduro riding? We separated on-trail performance into four categories to help organize our thoughts as we bounced between forks. Each fork then received a score out of ten in each category, plus an overall score. Here are the judging criteria that we focused on:
- Support & Stability: How well does the fork maintain a comfortable and confident ride height through deep, fast compressions? Does it avoid diving without feeling harsh? Can it handle success hits and remain composed?
- Tunability: Analyzing the usability of external adjustments and the ease at which an ideal setup can be achieved.
- Comfort: Analyzing small bump compliance and vibration damping through high-frequency compressions, as well as chassis flex and deflection during large, high-speed impacts (ex., rock gardens).
- Traction: How well does the fork allow the front wheel to maintain contact with the ground, providing control and grip across various surfaces.
Fork Critics
To maintain a high degree of puzzling and proper fork smashing, testing was handled by Vital Tech Editors Jason Schroeder and Jonny Simonetti, along with returning Test Sessions rider Dennis Yuroshek. Dennis is a New Jersey native and Mountain Creek local who participated in our Downhill Bike Test Sessions two years ago. Unfortunately, his testing ended early after he broke his leg on day one. With Test Sessions again taking place in his neck of the woods, it was only fair to have him back for some well-deserved redemption.
| Jason Schroeder | Jonny Simonetti | Dennis Yuroshek |
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Where We Tested
After a two-year hiatus, we took Test Sessions back to Vernon, New Jersey, the home of Mountain Creek Bike Park. Situated only an hour from New York City, Mountain Creek has hosted multiple world-class events over the years, including the second round of the Monster Energy Downhill series earlier this year. One of the most popular bike parks on the East Coast, they are well known for their impressive variety of trails, featuring a mix of rough, unrelenting rock gardens, high-speed chunder, technical root sections, and flowy jump lines with ripping berms. With a short lift ride that allows multiple runs to be knocked out per hour and accommodations conveniently located at the base, Mountain Creek was the perfect location to test each fork on proper terrain.
Our Picks - Vital Recommended
These are the top three standout performers that earned the "Vital Recommends" badge.
RockShox Zeb Ultimate
Highlights
- Travel options: 150mm // 160mm // 170mm (tested) // 180mm // 190mm
- 27.5-inch // 29-inch wheel sizes
- Offset: 38mm (27.5”) // 44mm (27.5”, 29”)
- 38mm stanchions
- Charger 3.1 damper
- DebonAir+ air spring w/ ButterCups
- External adjustments:
- Positive air chamber w/ volume spacers
- Low and high speed compression adjustments
- Low speed rebound adjustments
- 15mm axle
- Pressure relief valves
- Axle to crown: 586mm
- Fender included
- Rotor size: 203mm direct mount (up to 220mm compatible)
- Weight: 2,380g
- Price: $1,159 USD
The ZEB is the first 38mm stanchion fork from RockShox and is reminiscent of the Totem in years past but with a whole lot more bump-eating tech packed inside. The upper portion of the chassis features a tapered steer tube butted into a machined crown that shave as much weight as possible and gives the ZEB a premium look without sacrificing stiffness. The lower legs represent all that RockShox has learned over the past decade of development in enduro racing and long travel single crown performance.
RockShox is always chasing friction reduction and small bump sensitivity, most of which can be attributed to the DebonAir+ air spring inside the ZEB. The piston runs along the inner wall of the upper tube, and RockShox utilizes a more rigid construction of the internal air spring components to maintain smooth action regardless of forces transmitted through the external chassis. This helps avoid friction normally associated with this style of air spring. A large air volume helps build support naturally throughout travel, and volume can be adjusted through the use of the Bottomless Tokens provided with the fork. Taking small bump absorption even further, two rubber pucks found at the bottom of the air shaft and damper assemblies, referred to as "Buttercups," soak up trail chatter before the air spring even begins to move.
The newly released Charger 3.1 damper is now found across the Ultimate and Select+ levels of the RockShox lineup. This revision creates a larger range of damping force within the same range of adjustment. The compression circuit has been reworked to help oil flow more freely when open for decreased damping support and be more restrictive when closed for increased damping support, meaning each click will result in a greater damping effect than before. While the 3.1 update is quite new, the best attributes of the original Charger 3 still remain. There are still five clicks of HSC, ten clicks of LSC, and 20 clicks of rebound adjustment with the same intuitive user interface to coincide with the rest of the RockShox fork and shock line. These adjustments are designed to eliminate any crossover from one to the next, meaning one damping effect should have no effect on another to allow for the most precise setup possible.
While some of us have had the ZEB on the front of our bikes more often than others since its inception, we had yet to spend any time on the latest Charger 3.1 damper and updated bushings. But as we got into testing, these changes proved to be highly effective, and the results spoke for themselves.
What's The Bottom Line?
Jonny: "Dead silent and supportive in all the right ways. The ZEB creates an intuitive ride experience that builds support in a predictable way and makes the unplanned events on trail easier to handle. The settings I am used to running back home didn’t apply where we tested, but the adjusted settings weren’t far off and the intuitive user interface made making changes a breeze. The standout characteristics were comfort and traction; the fork never skipped a beat, and my front wheel felt settled in every situation tested."
Dennis: "I started with the recommended air pressure of 66 psi and found the Zeb was deflecting under hard/deep compressions and diving off jumps and through g-outs. I bumped the pressure up and settled at 73 psi, which helped with the deflection issue. This gave the fork more support and calmed it down during those deep compression situations. It also gave the Zeb more stability at high speeds, keeping the front end up under braking or bermed-out turns, which translated to more confidence. I played with HSC and LSC and returned to the recommended middle position for both. The Zeb has a lot of tunability, and you can really feel the difference just 1 or 2 clicks make. With fewer clicks between settings, I feel this will help riders find their settings easier and faster as fewer options are almost better at times, so you don't get lost in setup.
I ultimately picked the Zeb as my favorite out of the bunch. It was incredibly plush in the beginning stroke yet had plenty of mid-stroke support to keep from diving or bottoming out too harshly. The standout trait was its small bump sensitivity, which really helped in braking bumps. The fork would eat up bumps and chatter so that my hands didn't have to. I also loved the ease of tunability, as Rockshox made it stupid easy to adjust HSC and LSC on the fly. The long service interval is a plus as well; I'm sure I'm not the only one who pushes the limits on service from time to time. Lastly, the most important reason I picked the Zeb was because it's red and will match my bike perfectly. And red is FAST."
Jason: "If this test were based simply on looks, the Zeb would take the cake, no questions asked. The new red colorway was bright but not obnoxious, the compression dials looked all sophisticated like a clock dial, and the crown had a nice bead-blasted finish reminiscent of a factory-edition dirt bike. In action, the fork performed just as well as it looked, delivering insane levels of comfort and small bump compliance matched with a calm composure through chunk. I've always appreciated how smooth and supple the previous Charger 3 damper remained over chatter, and the new 3.1 damper was a similar story. The ease at which the fork breaks away and begins moving during a compression makes it incredibly easy on the hands. At times, this almost made the fork feel a tad vague because it muted so much ground feel. It's hard to complain about a fork eliminating feedback so well, but there were moments when I wanted more feedback to know how the fork was reacting to the trail.
I like what RockShox has done with external adjustments; they're easy to understand and allow you to visualize the changes you are making. You also don't have a bunch of clicks, and each click makes a considerable difference. I did stray from the stock settings a tad, adding 5 psi to gain more hold-up and maintain a higher average ride height. I also added +1 HSC and +2 LSC to achieve a similar outcome. More HSC improved control during fast-paced, big hits and kept the fork from cycling through its travel as much. I still think FOX and Öhlins offered a more controlled, heavier-damped feel during HSCs, but the Zeb still got the job done. More LSC kept the fork riding higher through berms, rollers and jumps. I only increased rebound by +1 as the fork felt a little fast after a few runs of riding in the 90-degree heat.
Overall, the Zeb was the most comfortable fork across every trail we tested on, and provided a supported, calm ride quality no matter if I was pushing a fast pace through technical sections or just cruising down a flow trail. In the end, the Zeb scored the highest in the test for me. However, I didn't pick it as my take-home fork. Why? Well, it was a toss-up between the Zeb, FOX 38, and Ohlins RXF38. I was really splitting hairs picking one as a winner or favorite, but the RXF38 was my take-home choice because of the performance I felt it still had on tap with some more testing and tuning. I'm sure I would be equally as stoked with the Zeb in the long run, but that was my final answer. Regardless of my decision, there is no denying that the Zeb is one of the best forks out there at this time."
FOX 38 Factory
Highlights
- Travel options: 160mm // 170mm (tested) // 180mm
- 27.5 (170mm only) & 29-inch options
- Grip X2 Damper
- Float EVOL Air spring
- External adjustments:
- Positive air chamber w/ volume spacers
- Low and high-speed compression
- Low and high-speed rebound
- Lower leg bleeders and bypass channels
- Kabolt floating axle
- Elliptical steerer tube
- 44mm offset
- Mudguard sold separately
- Axle to crown: 583.7mm
- Rotor size: 180mm direct mount (up to 230mm compatible)
- Weight (29", 170mm): 2,446g
- MSRP: $1,249 USD
Launched back in 2020, the 38 helped write the blueprints for burly, long-travel, single-crown forks. Upper chassis highlights include a larger CSU with an elliptical steerer tube to improve lateral and torsional stiffness and a rounded arch that curves forward to clear larger head tubes and has methodical cutouts to minimize weight. The lower legs utilize bypass channels that increase the air volume of the lowers, creating less ramp-up and a more linear feel. As the fork compresses, air trapped at the bottom of the fork can escape above the lower bushing, allowing the fork to more easily reach full travel. The channels also provide a pathway for oil to circulate the fork, lubricating the bushings and seals.
The 38 uses FOX's EVOL air spring that places the spring piston inside a floating air sleeve instead of sitting against the inside of the fork stanchions. The air sleeve can move slightly inside the stanchion, allowing the piston to function smoothly regardless of torsional load. Riders can install volume reducers in the positive chamber to create a more progressive spring curve. The positive and negative chambers are also connected via a transfer port that equalizes the pressure between them to improve initial stroke sensitivity.
New for model year 2025 forks is FOX's latest Grip X2 damper that replaces their popular Grip 2 damper. It maintains the same four-way external adjustments but offers a higher degree of compression tunability. It also has a faster response time, resulting in more control and traction when you're really getting after it on rowdy trails. The most significant change from Grip 2 to Grip X2 is that high-speed compression is no longer controlled by FOX's variable valve control (VVC) system.
Ditching VVC in the HSC circuit freed up room in the X2 damper to add a large compression shim stack and base valve. Grip 2 had a 20mm base valve with seven shims; Grip X2 has a 24mm base valve with 23 shims. The additional shims allow the damper to better control oil velocity, creating a more consistent ramp in shim flex at various speeds. This results in consistent damping throughout travel, a more sensitive initial stroke, and good support without feeling harsh. The range of tunability is also more usable, and the change between clicks is more noticeable than before. Now, 'open' still offers some damping, while 'closed' is not completely shut off, making either desirable in the right terrain. Beyond all the new damper goodness, the only other update for 2025 forks is lower friction bushings, which, thanks to a grooveless design, retain a more even coat of oil.
The 38 was the one fork in the test we had all ridden extensively over the years. However, we had minimal time aboard the new X2 damper, which turned out to significantly impact the performance of a fork we thought we had figured out.
What's The Bottom Line?
Jonny: "The standout trait of the 38 was stability. The chassis felt super solid, and the damper felt supportive at every part of travel. In terms of adjustability, I feel like any trait a rider could want out of their suspension can be achieved with the tools FOX provides. This fork had the widest usable range of damper and air spring adjustment in the test, making it adaptable to a multitude of riding styles and terrain."
Dennis: "It feels like FOX made the 38 with Richie Rude in mind. This is a big boy fork made for burly riders that has enough compression damping and hold up to support 200+ lb riders without blowing through its travel. The chassis has very little flex and is super stout, giving you loads of confidence. It did take me longer to arrive at a dialed setup as more external adjustments and lots of clicks = more time twisting knobs. Using the bracketing system, after about six or so runs, I felt like I started to get a good feeling out of the fork. I did not have to change out volume spacers this go around like I often did with Grip 2, and I ended up running HSC a touch open and LSC a touch closed. I also bumped up the pressure by 2 psi. The LSC knob was very soft feeling and incredibly hard to count clicks; I had to restart the process a couple of times to be sure I was getting the proper count. Overall, the updated 38 was in the top running for me. I have MANY years of experience with Fox products, and I was very impressed by the support and stability provided by the new damper. The boys at Fox did an amazing job with this one. You won't be disappointed."
Jason: "I’ve ridden the 38 most of all the forks in the test, and enjoy its stout, definitive feel when you really hit stuff at speeds. It takes a pretty big impact or mistake to fluster the fork which translates to lots of confidence. After spending so many years on FOX’s Grip 2 damper, the new Grip X2 damper has required a shift in my tuning approach. But it has been a change for the better. For this test, I was able to run proper air pressure with no volume reducers and instead use more compression damping to add control and support without fear of adding harshness. I never changed my air pressure, and instead closed HSC and LSC one click past middle to increase support. In contrast, with Grip 2, I probably would have added a few psi to achieve the same outcome instead of turning the compression adjustments much further past mid-way. Grip X2 was one of my favorite dampers as it felt like there was no end to how hard I could push the fork and receive ample support, and the clicks of adjustment made a significant change in performance.
The conditions we tested in were super chattery and hard-packed, and after riding a few other forks, it made me realize the stiff, definitive feel of the 38 is great for reading how the fork is responding to the ground, but it's less comfortable. It wasn’t to a degree that made the fork unrideable or minimized traction, but it did cause more arm/hand fatigue throughout the length of a run.
Overall, I think the 38 is still one of the best enduro forks on the market, and FOX’s new Grip X2 damper continues to keep it at the front of the pack. It provides the confidence needed to charge descents really hard, with way more useful external adjustments compared to before and internals that are familiar and easily serviceable by shops worldwide."
Öhlins RXF38 M.2
Highlights
- Travel options: 160mm // 170mm (tested) // 180mm
- 27.5-inch // 29-inch wheel sizes
- Offset: 44mm // 51mm
- 38mm stanchions
- TTX18 twin-tube damper
- Coil or Three chamber air spring
- External adjustments:
- Positive air chamber w/ ramp adjust
- Low and high-speed compression adjustments
- Low-speed rebound adjustments
- 15mm floating axle
- Rotor size: 200mm direct mount (up to 220mm compatible)
- Max tire size: 29x2.8”
- Axle to crown: 583mm
- Weight: 2,320g
- Price: $1,395 USD
Created to provide the same level of performance as Ölin's World Cup-winning DH38 dual crown fork, the RXF38 was built to meet the demands of enduro racing. It features a chassis that was fine-tuned to achieve a flex profile that blends comfort and control. The control part of the equation starts with the upper crown assembly, which consists of a tapered steer tube, solid crown, and 38mm stanchion tubes. Matching this control with a favorable level of comfort comes from methodically constructed lower legs, which house a set of low-friction dust wipers. Öhlins took their time developing these lower legs for the second generation of the 38mm chassis to create a middle ground between the DH38 and RXF36 chassis.
While the Öhlins setup relies more heavily on the damper than the air spring, the air spring is pretty unique in itself. The three-chamber system uses a cartridge-style design, eliminating the need for volume spacers. It consists of a standard positive chamber, negative chamber, and ramp-up chamber found at the bottom of the fork. The main chamber up top dictates the overall spring curve of the fork through standard air pressure adjustment to control the overall fork feel. Within the main chamber is a negative chamber, which can be tuned with spacers to control the initial breakaway force and feeling at the beginning of the travel. Lastly, the ramp-up chamber provides bottom-out support towards the end of travel independent of the main chamber. This separation is made possible through the use of a small piston housed within the lower half of the air shaft assembly, which provides bottom-out support at the second half of travel without affecting small bump sensitivity early in the stroke.
The TTX 18 damper inside the RXF 38 gets its name from the twin tube design and an 18mm diameter main piston. The piston was 22mm on the first generation but was sized down to help improve sensitivity across bumps of all sizes and speeds. The TTX 18 damper provides external low and high-speed compression adjustments and a single low-speed rebound adjustment. While these are standard adjustments found across most dampers on the market, the clicks are more limited than most. High-speed compression has only three positions (plus a locked 'closed' position), while low-speed compression and rebound have a wider range at 15 clicks. Öhlins does this to prevent things from getting too far from a recommended setup and, instead, suggests having the shim stack re-valved if a different damping characteristic is desired.
While the RXF 38 hasn't undergone any major updates recently, the tech it provides is unique among the group. Our overseas tech guru Johan has spent extensive time aboard the Ohlins forks and has always given them glowing praise, so we were excited to see how our stateside crew would fare with the Swedish brand's top-tier fork.
What's The Bottom Line?
Jonny: "Riding the Öhlins felt like I was floating on a bubble that couldn’t be popped over successive hits with a great combination of sensitivity and support. The ramp control air chamber was beneficial in building bottom-out support without sacrificing small bump sensitivity. Where it lacked a bit of overall comfort, it made up for it in support and stability, which allowed me to push closer to the limit. While it didn’t receive the highest overall score in the test, the RXF 38 came out as my favorite fork in the end."
Dennis: "The RXF38 had a heap of confidence. It was an easy fork to set up and "forget" with not that many usable adjustments up top on the HSC/LSC knob, in my opinion. With only one click of HSC, it felt great; if you went + or -, it was either too "open" or "closed" feeling, so I kept it at one. I really liked the ramp-up chamber feature on the fork, as it was easy to adjust and dial in. I did go 10psi over recommended for my rider weight. The RXF38 was super smooth and supple, coming in just behind the ZEB for comfort and compliance. I actually thought both forks had very similar ride characteristics, with awesome small bump sensitivity and plenty of support deeper in the travel when things got wild. It absolutely railed whooped out berms, providing a level of confidence that some of the other forks lacked. It didn't do anything unexpected when pushing off lips or getting pitted in the rock gardens. I've had issues with Öhlins suspension in the past that left a sour taste, but this go-around with the RXF38 was superb, given the short testing period."
Jason: "Based on Jonny's more extensive time on the fork, I took his advice to run higher than the recommended pressure in the ramp-up chamber and then leave the main chamber at the recommended pressure. I ran LSC compression in the middle, which delivered plenty of hold-up through berms and g-outs. I also ran HSC two clicks from closed to keep the fork from reaching bottom out as abruptly.
The most impressive characteristic of the RXF38 was how much support it provided without feeling harsh. The harder I pushed the fork, the more control and stability it could provide. It excelled at tracking the ground and gliding over holes through rock gardens. I think a lot of this comes down to how well the ramp-up chamber and damper work in unison. You get so much control from the middle to the end of travel that you can charge into compressions, knowing the fork won't get overwhelmed and will recover quickly. At the same time, the support is delivered at a constant rate (more linear vs progressive), with no sudden wall compression or air spring damping. The composure of the fork when smashing into multiple large impacts was a notch above the rest. My only issue with the RXF38 was that it was less supple right off the top. I felt the fork chattering a bit more through flat rock gardens and braking bumps, but not to a degree that significantly took away from its performance or ride quality. I still think the Zeb was the most impressive when it came to absorbing energy and minimizing feedback, and the RXF 38 was tied in second with the FOX 38.
Overall, the RXF38 was my favorite fork in the test because it gave me the most confidence to ride aggressively. I also think it has the most performance still up for grabs with more time and tuning. It might not be as buttery smooth as the Zeb, but its composure when things get rowdy has me sold. And as a bonus, it's damn light."
SR Suntour Durolux 38
Durolux 38 Highlights
- Travel options: 160mm // 170mm (tested) // 180mm
- 27.5-inch // 29-inch wheel sizes
- Offset: 38mm (27.5”) // 44mm (27.5”, 29”)
- 38mm stanchions
- RC+ damper
- EQUALIZER air spring
- External adjustments:
- Positive air chamber w/ volume spacers
- Low-speed compression adjustment
- Low-speed rebound adjustment
- 15mm axle
- Pressure relief set screws
- Fender included
- Axle to crown: 590mm
- Rotor size: 203mm direct mount (up to 220mm compatible)
- Weight: 2,576g
- Price: $849 USD
Steadily improving their platform year after year, the latest offerings from SR Suntour look to be on par with some of the high-end offerings on the market but at a lower price point. Updated for 2025, the Durolux 38 is no exception, and the robust chassis has undergone a few refinements from its predecessor. The goal of the Durolux 38 is to offer uncompromised control and stiffness, and SR Suntour achieved this goal by creating a stiff chassis with a damper that provides a useful range of adjustment. The chassis now sits with a 6mm wider stance between stanchions than before. The upper crown assembly consists of a tapered steer tube and hollow crown butting up to 38mm stanchions to create a rigid foundation for steering precision that shaves as many grams as possible.
Pressed into the lower legs are a set of SKF dust wipers to minimize as much friction possible, and just below them sit a set of ports on the backside with set screws for pressure equalization as well. A standard threaded 15mm axle holds the wheel snug in the dropouts, and a 203mm post mount handles the brake interface.
With several iterations since the inception of the Durolux, the EQ “Equalizer” air spring system denotes a negative chamber inside, which equalizes on its own relative to the positive chamber. It is a standard construction air spring running on the inner wall of the upper tube with a transfer port for negative chamber equalization. Spring curve adjustment is possible by adding or removing volume spacers from the positive chamber. The spacers are made of rubber, unlike most volume reducers on the market, making them a bit easier to add or remove from the air spring top cap. The construction of the air shaft assembly is also slightly different than others; it threads together instead of using a snap ring to contain the air piston assembly within the air chamber.
The all-new RC+ damper, which has been in development over the last four years, minimizes external adjustments for the simplest setup procedure possible. After realizing high-speed compression could be preset to where most riders would prefer it anyway, they chose to ditch the high-speed adjustments altogether. The external adjustments of the RC+ damper include 13 clicks of low-speed compression and 26 clicks of low-speed rebound to keep fine-tuning possible. The damper also has a bleed port at the top to help with blow-off under heavy bottom-out, burping oil out into the lower legs, which now use oil for the first time, whereas previous models only required grease.
A big focus for SR Suntour has always been ease of maintenance, and the internal details of the latest Durolux 38 reflect that. But its capabilities were highly unknown among our group of test forks. So the question remained: Is the Durolux more than just a cost-effective option that's easy to work on? And does it offer the performance to compete with the other high-end and more expensive forks on the market?
What's The Bottom Line?
Jonny: "The rigid chassis and supportive damper gave the Durolux a confidence-inspiring feeling from the first run. Dropping down to one volume spacer from the three pre-installed spacers improved small bump sensitivity from the initial recommended setup. While much more similar than anticipated, the primary difference in feeling compared to the high-end offerings was a slight delay between successive hits that transmitted more feedback through my hands throughout a full lap. I believe going one step lighter on the high-speed compression tune would resolve this. Overall, I felt most comfortable in aggressive terrain or on bigger hits, and I really liked the fit and finish of the fork."
Dennis: "The Durolux had three volume spacers installed out of the box and can take up to 6 max. With just three installed, it was incredibly stiff, and I wasn't utilizing full travel. I aired down to 64.5 psi, which offered an adequate ride quality, but if I were to have spent more time riding the fork, I would lean towards more air and fewer reducers. Regardless, I enjoyed the fork's support and composure through rough terrain. It didn't dive during hard braking situations or in the ledgy rock sections and remained high in its travel while still providing plenty of small bump sensitivity. The new damper performed well on a variety of trails, from smooth flow to rocky nastiness. The crew at SR Suntour has been putting in the work, and it shows. If you're looking for a solid fork for under $1,000, I would highly recommend the Durolux. Adjust the volume spacers to your weight and terrain, and you will be happy with your choice. The performance-to-price ratio was definitely the best in the group."
Jason: "The Durolux 38 was an unexpected standout performer in the test thanks to its balance of support and smooth-off-the-top plushness. That's right, plushness. I added 4 psi and one bottom-out token during my setup runs to increase support during fast, deep compressions. This kept the fork riding higher through the holes in the rock gardens and not seasawing as much. As I increased pressure, I decreased LSC. I tried both ends of the LSC adjustment (both of which are useable in the right conditions) and found that the more open I could get away with riding the fork without losing a platform to push against, the more comfort and grip I received. This was especially true in braking bump-filled bike park berms. I landed at one open from the middle of the adjustments. Speaking of bike park berms—the Durolux was my favorite fork on the flowier trails because it had such a responsive feel. It was easy to pump rollers, generate speed in corners, and push off lips. The Durolux 38 was a fork that took little fussing to get set up well, and then it delivered a good mix of support, control, traction, and lively ride quality. It still lands just behind FOX, Rockshox, and Öhlins due to less comfort and chassis compliance during really harsh impacts and chatter."
Formula Belva
Highlights
- Travel options: 170, 180mm (tested)
- 29-inch only
- 35mm stanchions
- Triple coil air spring
- Drop-in cartridge
- Adjustments:
- Positive air chamber
- Neopos volume spacers
- Low-speed compression
- Rebound
- Replaceable CTS compression valves
- Lockout
- 15mm thru-axle
- 43mm offset
- Axle to crown: 585-595mm
- Rotor size: 180mm direct mount (up to 220mm compatible)
- Weight: 2,465g
- MSRP: $1,949.99 USD
In a sea of 38mm single crown forks lies the Formula Belva with its prominent dual crowns and sleek 35mm stanchions. Dual crown forks have mostly graced downhill bikes throughout the years because they provide the most fore-aft stiffness. However, modern enduro bikes have the geometry and ability to attack trails with the same tenacity as a downhill bike. The Belva is the product of this 'ah-ha' moment for Formula. They felt the current crop of enduro forks still lacked adequate stiffness and decided an enduro-optimized dual crown chassis was the perfect solution to deliver a better handling and stable front end.
The Belva uses beautifully crafted hollow forged aluminum crowns, lightweight double-butted 35mm stanchions, and the same lowers as Formula's Selva all-mountain fork. The only disadvantage Belva presents over its single-crown competitors is its limited turning radius. Our turning range varied between our three test bikes but was less compared to the other forks.
The Belva is only offered with a 43mm offset for 29-inch wheels and comes with 170 or 180mm of travel. We tested the 180mm version, which has an adjustable axle-to-crown height between 585 and 595 mm, depending on how far you slide the stanchions in the crown. This is within a few millimeters of most single crown forks of the same travel, allowing riders to easily toss on the Belva without significantly changing their ride height (if at all). It also offers another point of adjustability beyond bar rise and headset spacers.
Tunability is a common theme with Formula products, and the Belva delivers various points of adjustability. A drop-in cartridge damper features an external rebound knob (18 clicks), a low-speed compression knob (12 clicks), a lockout lever, and a threshold dial to adjust the lockout. Additionally, Formula offers its 'Compression Tuning System' (CTS) that allows riders to swap the compression-valve assembly without having to open up the fork. The valve sits on top of the damper and takes only a few minutes to replace. A creative way to give riders a heightened level of custom tunability by completely altering the damping curve, Formula ships the fork with a lightly damped, linear valve (Gold), and a progressive valve (Blue). Six additional valves are available aftermarket for those seeking specific damping characteristics.
Unlike some of Formula's other forks that feature individually adjustable positive and negative air springs, the Belva offers only an adjustable positive air chamber combined with a triple-coil negative spring. The three springs get stiffer as the fork approaches full extension to help counteract topping out while maintaining smooth, off-the-top performance. The air spring piston also sits on a ball joint to help reduce friction during compressions caused by chassis flex.
The spring curve can be adjusted via Formula's Neopos volume reducers. The compressible foam spacers achieve the same goal as typical plastic spacers: reducing the size of the positive air chamber to increase ending stroke support. However, because they shrink in size as the fork compresses, they create a more linear spring curve. This means that adding Neopos spacers increases mid-stroke support without causing an abrupt ramp-up in support towards the bottom out.
Despite what you might assume, Formula has managed to keep the Belva at a fighting weight, coming in at just 2,465g, which, for reference, is only 20g heavier than FOX's 38. This landed the Belva as the third heaviest fork in the test behind SR Suntour's Durolux and DVO's Onyx 38. Depending on where you live, you can get your hands on the Belva through a few different avenues. Here in the U.S., distribution is handled through BTI, so you can order a fork through your local bike shop. The MSRP does sit at $1,949.99 USD, making the Belva the most expensive fork in our test.
Hands down the most unique fork in our Test Sessions, we were curious to see if the Belva would provide new levels of performance that would outweigh its distinct looks and higher price tag.
What's The Bottom Line?
Jonny: "The Belva chassis was very comfortable, with a notable level of fore and aft flex and the undeniable confidence of a dual crown. Being above the recommended weight range for the fork meant successive larger hits started to add up and transmit a lot of feedback. While external adjustments felt limited, the CTS system makes the tuning possibilities feel limitless. The climb switch that served as an LSC adjustment would benefit from detented clicks rather than a sweep lever to help with fine-tuning. Because of my limitations with the air spring, this would not be an option for me, but the tech inside proved to be very useful for changing the behavior of the fork in a simple and effective way."
Dennis: "Once we figured out the formula for the brake adapters and got the 220s fitted properly with multiple adapters on top of each other, the Belva was super fun to ride. It made my Enduro bike look and feel like a downhill bike, which I'm a fan of! I personally did not notice any increased stiffness in the dual crown setup, though. If there was, it was minimal. The dual crown setup definitely limits your steering ability, as the stanchion stance is narrower than an actual downhill fork. Navigating your local switchback trails might give you a hard time. If you're a bigger rider above the 200 lb range, you might need to look elsewhere, as I was at the top of the recommended air pressure at only 190 lbs. Max air pressure was 85 psi, and I was at 82.5. I was one Thanksgiving dinner away from being outside the max pressure!
I did not dive into the volume spacers or change the valves on the fork. In my eyes, swapping out valves to try different tunes would have eaten up too much time for me. I think it's cool that you have extra tunability at your fingertips, but I'd definitely need lots of extra time to sift through how each compression tune feels. I ran the lockout lever a little more open than the middle. I was not a big fan of this adjustment since there were no definite "clicks" to count or return to. I could see how the lever could easily be moved by accident. I'd like to see them change this down the road for a better user experience. The CNC cutouts on the upper crown were a really nice touch. It was super sharp-looking and had a nice modern feel to it. Overall, I think the Belva is a good mid-tier fork for a park rider on an enduro bike that is just busting out laps. I really do not see someone buying this fork to ride around their local trails, as there are better options out there for that."
Jason: "The Belva was a novel fork to test as its hard to beat the extra confidence a dual crown fork provides. On the trail, I didn't find it rode any stiffer than the rest of the forks. It's definitely geared toward enduro, not downhill. I wasn't too bothered by the compromised turning angle and found the biggest benefit of the dual crown design was the way it elevated my intensity. I wanted to hit things harder and jump a bit further off jumps. The plethora of adjustments was more exciting to play with than the other forks. It did take a couple of extra laps to try different settings and valves, but each adjustment had a noticeable effect that made for a relatively efficient setup process.
I swapped out the stock blue valve to a more progressive orange valve. This increased support through medium and high-speed compressions without changing how supple the fork was in the first 20mm. It also allowed me to run less LSC and still receive awesome mid-stroke support through berms and rollers. Through the rock gardens, I struggled to get the Belva to keep up on successive hits. It felt like damping control needed to hit sooner in the stroke, and I was left riding deeper in the travel through successive hits. I tried speeding up rebound, which did help, but it made the fork less enjoyable through small chatter. There are a few valves that offer more compression support that could help resolve this and calm the fork down during successive, big compressions. I also think adding another Neopos reducer could help as well.
Overall, the Belva was another fork that felt pretty sweet across the board, and the adjustments that are on offer will allow most riders to find a high-performing setup. That said, the Belva didn't deliver a ride quality that was way above the other forks, which makes it tough to justify its high price tag purely based on performance.
DVO Onyx 38
Highlights
- Travel options: 160mm // 170mm (tested) // 180mm
- 29-inch only
- 38mm stanchions
- D1 Damper
- SL Air Spring
- External adjustments:
- Positive air chamber w/ volume spacers
- Low and high-speed compression
- Low-speed rebound
- 15mm floating axle
- 44mm offset
- Axle to crown: 587mm
- Mudguard included
- Rotor size: 203mm direct mount (up to 220mm compatible)
- Weight: 2,616g
- Price: $1,149 USD
The Onyx D1 38 is DVO's first dip into the 38mm chassis realm that began as a project to develop a true e-bike-capable fork. DVO wanted to do more than just offer a stiffer compression tune or measly setup tweaks to achieve the support needed to withstand the weight and demands of an e-bike. The solution was to set aside weight goals and first focus on merging stiffness and flex into an optimized chassis structure. And it turns out, the performance benefits on offer were not limited to just e-bikes, but enduro riding as well.
Beginning at the CSU, an all-new crown uses thicker arms with a dual hollow bore design to improve strength and stiffness while keeping weight within reason. The crown also has an oversized race platform to stabilize the steerer tube during high-load impacts. The arch was intentionally reinforced and relieved in certain areas to provide predictable handling without causing deflection or harshness. As forces increase through the arch, it becomes stiffer, helping it remain compliant and comfortable under small loads and traction supportive and controlled during high-force impacts. The lower legs are thicker than DVO's other forks to improve stiffness and vibration damping. Extra-long bushing overlap within the lowers further reduces flex and the amount of damping force needed because there is less binding as the stanchions cycle through the lowers. Overall, DVO feels the Onyx 38 offers the best combination of stiffness and compliance, predictability, direct steering, and comfort.
Inside the Onyx 38 is the latest version of DVO's D1 damper. It uses their exclusive Compression Bladder System that is now 30% larger than before to increase off-the-top sensitivity and consistency. A new high-flow compression circuit provides support and damping through the middle portion of the stroke but allows for easier compression during fast impacts. There is also a new high-flow rebound circuit to improve the damper's response time during high-speed impacts. Combined, these updates are intended to create supportive damping during the majority of the stroke without any unwanted compression harshness or packing during big hits.
The D1 Damper is paired with DVO's new SL (super light) air spring. Unlike the OTT air spring found in DVO's other models, which uses an externally adjustable negative spring, the SL damper uses a familiar dual air chamber design. This helps keep the fork weight down and allows for a broader range of rider weights to achieve a proper setup. DVO says the SL air spring provides great small bump sensitivity with no mid-stroke hammock while ending stroke progression can be tuned via volume reducers.
With big promises of next-level chassis performance, steering response, and traction, we were all excited to see if the Onyx 38 would outshine the bigger OEM competitors.
What's The Bottom Line?
Jonny: "The Onyx D1 38 had an incredibly light feeling off the top, generating a ton of traction but also eliminating the first part of travel by default. The way the fork sat into its travel made it ride where things begin to ramp almost immediately and feel harsh across chatter. Adding pressure helped counteract this feeling but also made the fork rebound rapidly out of its travel through heavier compressions. Still, the chassis felt great in the most aggressive terrain, and the ability to maintain excellent small bump absorption at higher pressures helped inspire confidence across varied terrain."
Dennis: "The Onyx was immediately comfortable and felt linear throughout its travel. There was a boatload of clicks to choose from, but I enjoyed running compress pretty much wide open. First run out, I sent it a little too hard into a rock section without thinking, but the fork had no issue riding through the impact. This told me the fork was willing to reward those who were willing to put it through its paces. It ate up the awkward square rocks without any hesitation and delivered a very composed ride quality. Overall, the Onyx D1 38 performed well across the board, but I'd have a hard time buying it over the 38 or Zeb since for only a little bit more money, I could get a fork that performed better in my opinion."
Jason: "I started off with DVO's recommended pressure, HSC and rebound. As I got a few runs under my belt, I found the fork was sitting too deep in its travel and reaching the end of its travel too often. At the same time, I was experiencing a lot of feedback through rock gardens, and the fork was bouncing off square edge hits rather than absorbing them. I ended up adding one volume reducer and 5 psi, and backed off HSC from 12 to 21. Going to the other end of the HSC adjustment made a world of difference, as it allowed the fork to compress easier during square edge hits, significantly improving how planted and calm the Onyx 38 remained. It also increased support during bottom outs, making for a more consistent ride height.
DVO's recommended HSC settings are broad (ranging from 8-16 clicks for my air pressure). There were also supposed to be 28 HSC clicks, but our fork had 38. While I did end up with a satisfactory setup with the Onyx 38, the fact that there are so many HSC clicks and only five LSC clicks gives you a bunch of HSC clicks that don't do a lot and a big jump between LSC clicks. This creates a more convoluted setup process than forks like the Zeb or RXF38, which have fewer clicks with greater damping changes between clicks.
Once I had the fork setup, it performed well across the board, but didn't stand out in any particular way. The chassis was generally unphased and held up to a lot of energy, such as pumping through berms or smashing through repetitive curb-sized rocks. The big issue was how much feedback I felt once I got into rougher sections. Through the rock gardens with bumps coming from every which way, I felt the shock of rocks more than some of the other forks. I think part of this was the fork struggling to recover during successive hits that led to a harsher ride, and the chassis being on the stiffer end of the stiffness spectrum. On the faster bike park trails, I still got decent front tire grip, and it never felt like the fork was too firm off the top.
If I were to spend more time on the Onyx 38, I would try more air pressure or volume reducers and continue to open up compression. The air spring did a good job of providing support without minimizing small bump sensitivity. So, reducing compression damping to let the fork move more freely and relying on the air spring seems like the way to go to balance comfort and control."
[Edit: Since our test, DVO informed us that the D1 damper does have 38 clicks of HSC. Unfortunately, the setup guide provided with the Onyx D1 38 was incorrect when we tested but has since been updated. Please refer to this Setup Guide when setting up the fork.]
XFusion Vengeance 38
Highlights
- Travel options: 160mm // 170mm (tested) // 180mm
- 29-inch wheel sizes
- Offset: 44mm
- 38mm stanchions
- Finecut HLR damper
- Positive air spring w/ internal travel adjust
- External adjustments:
- Positive air chamber w/ volume spacers
- Low and high-speed compression adjustments
- Low-speed rebound adjustments
- 15mm axle
- Pressure relief set screws
- Axle to crown:
- Rotor size: 180mm direct mount (up to 220mm compatible)
- Weight: 2,461g
- Price: $999 USD
The Vengeance 38 is the first 38mm single crown fork to come from XFusion. The all-new chassis includes some new tech inside and some refinements to existing features from previous models within the XFusion lineup. Starting with the upper crown assembly, a tapered steer tube is pressed into a solid crown with a wide stance to create a rigid interface with the 38mm stanchions. An easy-to-open top cap and set of color-coded external adjustments on the damper side round out the details of the UCA.
Moving down the fork, the magnesium lowers have a clean look with purposeful bracing around the arch and dropout to create a rigid interface between the wheel and the fork. A set of pressure relief ports are found just below low friction wiper seals with set screws to release lower leg pressure, a feature that has been found on XFusion chassis for over a decade.
The FineCut HLR cartridge damper is all-new for XFusion, and the Vengeance is among the first models to receive the damper. The cartridge-style construction is unique in the way it utilizes the inner stanchion wall as part of its construction rather than in a self-contained inner tube. The damper is a bled system with an overflow port for pressure blowoff at full bottom to maintain an equalized pressure within the system.
On the spring side, the Vengeance 38 uses a cartridge air spring to reduce piston size and improve small bump performance. Another long-running feature of XFusion forks is found in the lower portion of the air spring, which allows for easy internal travel adjustment . A dual lock ring system houses travel-reducing spacers, allowing for 20mm of adjustment in 10mm increments. The upper portion of the air spring also allows the use of volume spacers to fine-tune the spring curve.
With a strong presence in the OEM world for over two decades and all of the knowledge and development that comes with it, we were curious to see what X-Fusion's latest high-end fork would ride like once we hit the trails.
What's The Bottom Line?
Jonny: "The recommended setup muted a ton of trail feedback but felt a bit dead; adding pressure and HSC helped create a more solid platform and get a little more feedback from the trail. Traction was excellent through low-speed chunder, but attacking the same terrain at higher speeds got the fork through its travel easily. Still, bottom out never felt harsh at the end of heavier compressions. The chassis flex helped absorb some feedback from the trail but also generated a binding feeling. The feeling could have been HSC feedback or an LSC wall, but it remained consistent when I experimented with various settings. The Vengeance was comfortable to ride but also made a lot of noise, rattling through compressions towards the end of our test period."
Dennis: "Upon the important parking lot test, I noticed the fork had a significant top out, but only when the front wheel would come off the ground. It was very noticeable when jumping and coming off drops into rocky sections. It did not settle with me, and unfortunately, this did not make me feel comfortable or confident while riding through the rocky sections of the trail. The top out would throw the fork off just enough to make it noticeable, whereas other forks would have a softer return to the top. The Vengeance had a tough time tracking through some of the rougher trails and corners and wanted to deflect. Besides the top-out issue, the fork felt pretty solid, and I think it had some real potential. X-Fusion is known for being a lower price point suspension company, but the Vengeance had quite a bit of adjustability, offering HSC and LSC. For $1,000, it's definitely more budget-friendly. But, assuming the issue I experienced is solvable or an anomaly, the Vengeance would be a decent bang-for-your-buck, middle-of-the-road fork."
Jason: "The Vengeance was a straightforward fork to get on and reach a level of performance that was adequate but with room to improve. The external adjustments on offer are enough to get the job done; however, I found that the 15 HSC and LSC clicks lacked significant change between each click. I had to turn the dials a few times to make a change and eventually settled on 6 clicks out on HSC and 10 clicks out on LSC. I did run 15 psi more than what was recommended and relied more on the air spring for support than the damper.
The standout characteristic of the Vengeance was its ability to remain calm and track the ground over high-frequency chatter bumps. Through the flatter rock gardens, high-speed straightaways, and braking bumps diving into corners, it seemed to sit in its travel and manage the compressions without feeling harsh. During big impacts, like landing deep on jumps or bottoming out off drops, the fork arrived at bottom out smoothly and controlled. Unfortunately, when these large or fast impacts became successive, the fork struggled to recover quickly enough and would begin to pack and feel harsh. I sped up rebound, which did help. I also closed LSC for a run, which did improve overall ride height consistency, but it was a rougher and firmer setup to hold onto, albeit definitely faster.
The other aspect of the Vengeance that was hard to look past was how much feedback it transmitted. I don’t think it was a matter of needing to run less compression or air pressure because the setup I settled on felt good during most compressions. I just think the chassis and slight stiction on the stanchions made for a less refined ride quality. On one hand, I think the damp feel of the fork and its support would allow for some really aggressive riding, but if you are purely seeking comfort, you might have to sacrifice some of that support to make the fork feel more forgiving."
Average Overall Score Per Section
A big shout out to Feedback Sports, Ride Wrap, and Mountain Creek for supporting Test Sessions!
Let us know which fork you'd pick in the test, what performance factors you prioritize from an enduro fork, and your experience with any of the forks tested!
8/27/2024 8:00am
View replies to: What's The Best Enduro Fork in 2024? - Enduro Fork Test Sessions
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