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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.

Fender mounting bolts are found on the backside of the arch, and the fender, included with the fork, creates a seamless and sleek look when mounted.

The lower legs optimize torsional stiffness with a wide profile along the top of the arch and a thin profile across the front with ample bracing between the legs and dropouts.
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."
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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.

Unlike most dual crown downhill forks, the steerer tube is tapered, not a straight 1 ⅛. 
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.

Not a sausage.
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. 
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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.

External damper adjustments include high and low-speed compression and low-speed rebound. DVO aimed to widen the range of adjustability to accommodate more riders.
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." 
Side Note: Our test fork likely had an assembly issue. Discovering an additional ten clicks out of the already massive range of 28 HSC clicks made tuning a bit overwhelming, and individual clicks felt indistinguishable.
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 it costs more than both and didn't offer the same level of performance."
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." 
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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 HLR denotation indicates independently adjustable high and low-speed compression as well as low-speed rebound. 
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."
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