Review: Fox 40 vs RockShox Boxxer vs Ohlins DH38 - DH Bike Week

---

If you’re an avid reader of Pinkbike then you’re probably aware of the outcome of this test. But play along and maybe you’ll learn something on the way there. Just don’t forget to act surprised when you get to the end.

For everyone else, we’re continuing our DH Bike Week with a head-to-head-to-head of three of the biggest DH forks out there at the moment. Over the course of the entire summer and autumn seasons, as well as some choice dry spells in the winter season, we tested these three forks across four different DH bikes to find out which one came out on top.

---

There’s a pinch bolt-less Maxle axle system that bolts the axle into the fork from one side and then uses a wedge system to splay the axle end apart to resist undoing. It’s a 20mm diameter axle with a 110mm width and interestingly doesn’t use the Torque Cap system that the rest of the RockShox range uses.

Sag markings are printed on the stanchions, something that RockShox has patented, and make it a doddle to set up the fork if you’re running something different to the recommended settings. In an effort to reduce the friction in the fork, RockShox used SKF wiper seals along with fresh fluids in the damper.

The Boxxer is available in 29” and 27.5” wheel sizes. There’s a 36mm and 46mm offset available for the small wheel version and 46mm and 56mm available for the big wheel version.

There are a few travel options too – 180mm, 190mm and 200mm, which allow the Boxxer to be applicable to not only DH bikes but also some bigger travel bikes that usually sport a single crown. Our 200mm travel Boxxer has a 602mm axle to crown.

It’s a 200mm post mount for the brake with a max rotor size up at 220mm. But that brake mount is following the Boost DH standard, so you might need a 5mm spacer behind the disc if you have an older, non-Boost DH hub.


The Boxxer uses RockShox’s DebonAir air spring system, which is on the face of it a very similar system used in all of RockShox’s forks, with the dual chamber system auto equalising through travel via a moulded dimple on the inside of the stanchion.

The air spring is tunable via screw in volume spacers that use an 8mm hex tool to snug them into one another and the top cap. The max number of tokens is 6 for all the travel options, with only the number of tokens coming installed from the factory changing with travel. Max air pressure is 200psi.


The Boxxer Ultimate uses the latest Charger 2.1 sealed damper cartridge that has externally adjustable high and low speed compression at the top of the fork with low speed rebound adjustment at the bottom. There are 4 clicks of high-speed compression, 18 of low-speed compression and 18 of rebound.

Our Boxxer Ultimate came in at 2,588g, the lightest in the test. It’s 2,071g for the fork and 517g for the crowns. Setup was - 29” / 56mm offset / flat crown / 162mm steerer / no star nut / 1 token.

The Boxxer Ultimate costs €1,890 or $1,699 USD, making it the least expensive if you're paying in USD.

---

Much like the 38 and 36, the 40 saw a redesigned crown to offset it further forwards and more out of the way of the frame. But it carried over the pinch bolt axle and lower leg bleeders from the previous version, which also found their way onto the 38 and 36. There’s also the lower leg channels that allow the bath oil to circulate up to the upper bushing during fork use, keeping everything well lubricated.

That floating axle system tightens the axle up against the brake side lower leg, pinches it off and then allows the opposite leg to float and find its perfect position to align the lowers and stanchions for smooth movement. It’s then pinched to the axle via two 5mm bolts. There are replaceable threaded pars for the axle pinch bolts too.

It’s a 203mm post mount brake with the max rotor size up at 230mm. It follows the Boost DH standard too. The 40 is available in 203mm travel and 29” and 27.5” dedicated forks. But Fox actually offers four different crown offsets, from 44mm to 56mm, along with a flat and drop top crown in every offset.

There’s actually a 190mm air spring assembly available too, giving an option for a slightly shorter 40, if you so wish. Our 203mm travel 40 has an axle to crown of 601.9mm.

There’s a Fox bolt on mudguard available for the 40, that uses the two bolt holes in the back of the crown and forgoes the spacers behind the back of the air bleeders on the lowers.


The EVOL, or extra volume, air spring is again a familiar system from the previous version of the 40 and still uses the two self-equalising chamber system with the ability to snap in volume spacers to change the air spring characteristics. For 2021 it got updated though to have larger positive and negative chamber volumes.

Max volume spacers are 5 for the 200mm travel fork and 7 for the 190mm version. Max air pressure is up at 120psi.


If you’re familiar with Fox, then you’ll recognise the 40 using the company’s latest Grip2 damper, with external adjustments for high and low speed rebound and compression. This latest version of the damper uses a small propeller shaped mechanism to adjust the force on the piston’s shim stack and so adjust the high-speed compression and rebound, dubbed VVC. There are 8 clicks of adjustment on the high-speed circuits and 16 clicks on the low-speed circuits.

Our 40 Factory came in at 2,770g. It’s 2,245g for the forks and 525g for the crowns. Setup was - 29” / 56mm offset / drop crown / 162mm steerer / no star nut / 2 tokens.

The Fox 40 Factory costs a whopping €2,299 or $1,749 USD, making it the most expensive in the test if you're paying in Euros.

---

The DH38 uses the same lowers for for 29” and 27.5” wheels and when you purchase the fork it’s as two separate parts – the fork and the crowns. The latter having four different offsets from 46mm to 58mm in 4mm increments. Flat and drop crowns are available - the flat is associated with a 27.5” wheel and the drop crown with a 29” wheel.

The axle system on the DH38 is the same as the Fox 40, with only the exception of one bolt per leg instead of two. The principle also being the same in allowing good alignment between the lowers and stanchions no matter the tolerance on the hub width. There are replaceable threaded pars for the axle pinch bolts too.

The DH38 is available in 180mm and 200mm travel full fork versions, but there are air spring options for as little as 120mm meaning you can have that dual crown directness on almost any bike you want. It’s also approved for ebikes.

It’s a 200mm post mount for the brake and uses the Boost DH standard. Our 200mm travel version had a minimum axle to crown of 608mm for 29” and 590mm for 27.5”.


While the RockShox and Fox air springs might be somewhat similar in design, the Öhlins one is a little bit different. The two self-equalising chamber design is there, but there’s a third ramp chamber, accessible at the bottom of the fork, that allows the fork’s ramp up characteristics to be changed via air pressure, and so with much more resolution than the fixed volume tokens on the Boxxer and 40. It’s a sealed cartridge too, meaning you can disassemble it from the fork without having to take the air pressure out.

There’s a new ramp chamber tube in the air spring to help with longer service intervals and all three chambers can actually be altered in volume via spacers, but it’s a more involved job to do than on the RockShox and Fox forks and is only something that would need doing if you have some really specific requirements.


The damper in the DH38 takes a lot of inspiration from the RXF36 m.2 trail and enduro fork and benefits from the refinements to the one-way valves that control the oil flow inside the twin tube damper. It also uses the same piston design and low speed damping needle for the compression and rebound circuits to increase adjustability.

There’s externally adjustable high and low speed compression and low speed rebound damping adjustment. Those adjusters now having a bit more of a defined click to them to help identify where you are in the range. There are 3 clicks of high-speed compression, 17 clicks of low-speed compression and 16 clicks of low-speed rebound.

Our DH38 m.1 came in at 2,822g, the heaviest on test. It’s 2,379g for the forks and 443g for the crowns. Setup was - 50mm offset / drop crown / 162mm steerer / no star nut.

The DH38 m.1 retails for €1,443 or $1600 USD for the fork and €316 or $350 USD for the crowns, making it the most expensive in our test if you're paying in USD but the least expensive if you're paying in Euros.

---

Initial Setup

RockShox Boxxer Ultimate
Boxxer setup is pretty quick and easy. Along with that there’s some very good setup and user manuals from RockShox to help with installation, setup, explaining the different adjustments and providing somewhere to note down your setups.

The wheel bolts in fast and there are recommended air spring pressures printed on the side of the fork. There’s also the TrailHead tool online or via the app which uses the fork’s serial number to output the starting pressure and rebound for your weight.

The sticker suggested 118psi, working from the rider weight ranges that it displays. The TrailHead app directly suggested 118psi with 9 clicks of rebound from fully closed.

Lots of the Boxxers on the DH bikes we tested came with 1 volume spacer installed, and I started like this.


Fox 40 Factory
There’s a few more bolts to turn on the 40 to get the wheel in. But it doesn’t take much longer to do. There’s also recommended settings printed on the fork, with air pressure and settings for the low and high speed rebound.

Fox also provides documentation for 40 setup and adjusting along with technical drawings and all relevant part information and numbers should you need any bits and pieces.

Working from the rider weight ranges again, it suggested 70psi for a 75kg rider, half way between the 68-82kg range. Accompanying that was 7 clicks of low and high speed rebound from fully closed.

The 40 came stock with 2 volume spacers installed and that is where I started.


Öhlins DH38 m.1
The DH38 uses the same axle system as the 40, just with 2 less bolts. And it too has printed recommended settings on the side of the fork for the three air chambers.

It suggested 108psi in the main chamber and 215-230psi in the ramp chamber. I started at 215psi.

Öhlins also has a Performance Suspension Guide that uses your bike brand and model along with your weight and suspension preference to output all the applicable components along with suggested starting points in setup. It suggested 110psi in the main chamber and 215psi in the ramp chamber.

There’s also good documentation along with the fork about installation, setup and adjustment along with instructional videos available through the website.

---

Performance


RockShox Boxxer Ultimate

The Boxxer actually came specced on three of the four bikes in our recent DH bike group test, giving me a lot of time in on it.

Set up to the recommended setting of 115psi it became immediately apparent that something needed to change. There’s really a lot of movement in and out of the travel all the time, and this was the character trait that defined the Boxxer throughout testing. Pressure was quickly upped to 130psi and the total number of tokens to 3 from the stock 1. That also warranted more rebound damping to control the bigger spring.

With this setup the fork performed a lot better. It brought more composure to the front of the bike and really helped when riding fast through rough undulating terrain. But that trait is still there and something that needs more arm movement and more thought to account for. Creeping up the compression damping again helped to calm this erratic movement a little more, but did bring a bit more harshness into the equation.

I experimented with even firmer pressures, up at 140 and 145psi, but this was now beginning to be too much. It pushed the harshness of the fork too high from solely the spring and balancing with less compression damping didn’t do the trick. Each time I experimented, I came back to 130psi and the compression not too far from fully closed as the best balance of spring and damping to reduce the big fork oscillations as much as possible.


I’ve received flack in the past from internet comments about too firm settings in suspension. But living in front of a World Cup level race track does demand some meat in the setup, and this over-springing is something that many a friend with a Boxxer has had to do to calm that character trait, along with all the testers that were on the Boxxer equipped DH bikes we tested.

Because it needs that much spring to deal with its main issue, it means that it won’t be the supplest of forks through the impacts. You’re somewhat forced into one of two camps with it. One being to run it softer, in spring and damping, to have a nice supple feel, but then having a lot more fork movement when things get rough and choppy. The other being the camp that I settled in, forgoing that suppleness for some control.

Now the Boxxer is a good fork, it’s easy to adjust, the adjustments result in a noticeable feeling, it’s easy to work on and does perform well. But it’s a fork that requires more of your concentration when riding, to use your arms more in the suspension equation and, if you prefer to run it on the firmer side, grip a little bit harder when you hit through the rough stuff.

Another point to mention is the fork width on the Boxxer. It’s a fair bit narrower than the other forks here and does increase the turning circle on a lot of bikes quite noticeably, especially on bikes with very prominent fork bumpers or wide tubes. For those of you thinking about putting a Boxxer on your enduro bike, god forbid, it might be something to keep in mind. I also had more than one occasion where the whole axle became undone and started to unscrew out of the fork while riding. It never came completely out, and it was pretty quickly recognisable from the wheel rattle at the front, but it prompted me to check the axles on the Boxxers a little more than often.

And while the Boxxer is available in two different offsets for the 29” version, it's only the longest 56mm version that we saw on the bikes and might actually be too long, as we’ll explain more about in the Fox 40 and especially Öhlins DH38.

---

Fox 40 Factory

The 40, in comparison to the Boxxer, is a fork that doesn’t force you into a corner of setup. Although, like any fork, its setup does also depend on how the rear suspension of the bike is working and behaving.

Fitted to the Cube TWO15 that we’ve recently reviewed, it needed a slightly softer setup, closer to the recommended settings, to complement the softer feeling from the rear of the Cube that had generally more suspension movement in it. Running the fork firm on this bike pushed the rider weight too far back and resulted in some issues. In its softer setting it did exhibit obviously a bit more movement but that matched the very progressive rear suspension of the Cube.

Running it on a bike with a lot more chassis support in the rear meant that the fork could be run a bit firmer, to then complement the rear suspension feel more. On the likes of the Canyon Sender, I could run more air in the spring and more tokens while still having a fork that maintained an impressive amount of suppleness. There will often be a trade off in support vs suppleness, but on the 40 that gap is a lot smaller and it’s soft and absorbent when you need it to be and then hard and supportive when you need that.

But its ability to adapt to each of those bikes while still having a high level of performance was noticeable and much appreciated when swapping it from one bike to another.


As I’ve mentioned, I do prefer a slightly stiffer fork. And with the 40 setup a bit firmer it really starts to disappear underneath you on the more demanding tracks, leaving you with only the faint damping schlurp noise to remind you that it’s working. That trait to disappear meaning that you could put your focus more on the riding and not having to ride around any unfavourable traits in the fork’s working.

That firmer setup did put it further away from the recommended settings and is something echoed by friends and other testers on the 40, who were often up at 90psi and with more tokens in there too. But the fork's suppleness and feel weren’t compromised by this up in pressure.

It is a long fork though, especially in the 29” guise, and this is something true of all the 29” downhill forks we tested. Depending on your rider height, headtube length and bar height preferences it can make getting a low bar height tricky.

There are a lot of adjusters on the 40, but if you’re confident in knowing their purpose you have some wonderful windows of adjustability with the 40 both in compression and rebound. On the flip side, if you’re not familiar with what each dial does then it’s an easy process to bracket each one at a time to understand the difference in feeling and how that affects the ride.

There’s also adjustability in the crowns with the 40. Both our test forks had the longest 56mm and as we’ll go into with the Öhlins, where we had the opportunity to test the different offsets, I’d actually prefer the 52mm offset that Fox offers for its balance of cornering grip versus understeer. But it’s another positive for the 40 to offer this level of adjustability.

---

Öhlins DH38 m.1

And then we get to the Öhlins. Those loveable traits exhibited by the Fox 40 almost turned up another notch when you rode the DH38. This really is a suspension product that completely vanishes underneath you, so good is its performance, and it often left me speechless at the bottom of the run. I honestly spent a lot of time staring at this fork wondering how it had not only allowed me to just get away with murder, but somewhat incited me to do it.

Out of the box and with exactly the recommended air pressure settings the fork exhibits brilliant sensitivity that really takes the sting off any hits that would definitely be felt more through the likes of the Boxxer. When the ferocity of the trail increases then so does the composure of the fork. You push it harder on a run, it just gives you more back, and you end up in this constant one-up battle with it to see where its limits are. Spoiler, I don’t think it has any. That transition and build from buttery smooth to creamy supportive is class leading and really addictive.

The DH38 never seems to get flustered, dealing with every impact or scenario just once and then moving on to the next. All the while it providing you with a crystal-clear path of information to what’s going on at the front contact patch. This is something that the Fox 40 also does really well, but on the DH38 it’s like there’s less interference in the phone line. It really is a fork that lifts your gaze when riding, leaving you to focus on nothing but the trail in front of you, which is coming up mightily fast.

Each adjuster definitely does have more of a defined click to it now, to let you know where you are in the range. Each one of those clicks creating a palpable change in fork feel and in the direction that you intended. There’s no second guessing adjustments and even though there are overall less clicks than some of the other forks on test, the range is wonderfully usable.


Another favourable part of the DH38 is its ability to adjust the ramp characteristics of the fork. Using air instead of plastic tokens as the main adjustment gives a finer resolution and even running the ramp chamber up at 220, 230 and 240psi, it still maintains the wonderful sensitivity at the beginning of the travel. That up in ramp pressure providing more support for some of the more demanding tracks, like Morgins, and the hugely sculpted jump trails in Chatel.

That adjustability also extends to the fork’s offset. Öhlins being kind enough to send us a bunch of different crowns to experiment with. Down at the shortest of 46mm, there seems to be a bit more tucking of the front wheel when you turn it. You initiate the turn and the bars keep wanting to turn past the point that you need to make it round the corner.

Out at the other end, with 58mm offset, there’s a tendency of the front wheel to understeer in the turns, especially in high-speed flatter turns. It’s not a snap movement, but there’s more push from the front end which isn’t the nicest of feelings for confidence when you’re riding fast.

Coming into the two middle settings, of 50mm and 54mm, it’s the 50mm that I found to be my favourite. That tucking trait was substantially reduced and so too was the understeer feeling in the fast flat turns. Using the 54mm brought a bit of that feeling back and I found myself coming back to the 50mm.

---

Servicing

RockShox Boxxer Ultimate
The Boxxer is a really easy fork to work on to keep it running well. Lower leg services are a cinch, very similar to every other RockShox fork and advised every 50 hours.

It needs 10ml 0w-30 in both lower legs and 3ml in the air spring, along with a bit of grease around the piston seals.

Every 200 hours RockShox recommends a full fork service, which they do explain how to do in the service manual, but is a little more involved and requires some more specific tools than the lower leg service. You’re directed straight to all relevant service and upgrade parts for your Boxxer through the TrailHead tool.


Fox 40 Factory
Fox says to do a full fork service every 125 hours or yearly, whichever comes first. And if you ride a lot and in extreme conditions a lot then you’re urged to do this earlier.

It’s also not a tricky procedure at all to do a lower leg service, with Fox having online documents for oil volumes for the lower legs along with service manuals for damper and air spring rebuilds.

It needs 35ml of Fox 20wt Gold oil in the air side lower leg and 6ml in the air spring itself. Then 50ml Fox 5wt Teflon Infused oil in the damper side lower leg.


Öhlins DH38 m.1
Öhlins suggest doing a lower leg service every 50 hours and now have the service kits and instructions available to the public. It needs 10ml Renep CGLP 68 fork lube in both lower legs, which is a bit less than the other forks, so it’s advised to stick to that 50-hour service interval to keep it running perfectly.

A full fork rebuild is recommended every 100 hours or yearly, whichever comes first, and this is also something Öhlins now document how to do for the lowers and air spring although it does need some more specific tools. The damper also needs servicing at this interval and this is something that Öhlins still recommends to have done by an official service centre.

---

Verdict

The RockShox Boxxer is the lightest of the forks we tested by quite a margin. And while it is a good fork that a lot of people can get along with, it does have a glaring character trait that can push you to a corner in setup.

The new Fox 40 is sublime and is another step forward from what already was a great previous fork. Its ability to blend together suppleness and support all while being adaptable to how the rear suspension of your bike, or yourself, is behaving is brilliant and easy to do. Every year it seems hard to see how the big brands can improve upon the last version, but Fox have taken the new 40 to be right up there and battling with the very best in the pack.

But what the 40 does so well, the Öhlins DH38 m.1 does just that little bit better and makes this truly a special fork. If you want a dual crown fork that blends smoothness and support like no other, all the while egging you on to ride faster, push harder and pull further, then look no further than the DH38. It is heavier and more expensive than the competition, if you're paying in USD. If you're paying in Euros then it's actually the least expensive. But any concerns on weight and price metrics are out the window when you ride it. And for these reasons it earned the title of Suspension Product of the Year 2020.

---

---

Photos by Kifkat / Shaperideshoot

Posted In:
Reviews and Tech Reviews Suspension Fork Ohlins RockShox Fox Factory Fox 40 Ohlins Dh38 Rockshox Boxxer DH Bike Week