Fox 36 SL Review: Want vs. Need

From our sponsor; more content below...

From our sponsor; more content below...

From our sponsor; more content below...

From our sponsor; more content below...

From our sponsor; more content below...

By Logan Watts

Founding Editor & Routes Director

2,183 Posts

Just announced, the all-new Fox 36 SL replaces the Fox 34 as the brand’s centerpiece “trail” mountain bike fork, blending lightweight internals with a redesigned chassis and bigger 36mm stanchions. The result is a suspension fork that weighs about the same but with improved stiffness. What’s not to like? We had the chance to give the 36 SL a try for this first-ride review…

Action shots by TJ Kearns

It’s rare that a new product launch—especially a high-tech bike component—feels like it has me in its crosshairs. I guess that means the marketing team dialed in their target audience. Or maybe the product development department simply listened. Then again, marketing is just that. Its purpose is to weave a complex web designed to capture specific wants and needs, all in effort to sell, persuade, and fuel our obsession with upgrades. I’m not dismissing genuine innovation and product improvement, but let’s be real: across all industries, including bikes, it’s often the tail (marketing) wagging the dog (engineering and innovation) in pursuit of sales.

Sometimes that can lead to better products, but that’s not always the case. Either way, when I heard that Fox was essentially replacing the versatile 34 trail-oriented fork with the new short-travel-specific Fox 36 SL, the “that’s exactly what I’ve been waiting for” part of my brain was triggered. Fortunately, I had the chance to try one and find out first-hand if it’s indeed an upgrade or merely a marketing ploy. Read on for thoughts and photos after a handful of rides on the all-new Fox 36 SL in this first-ride review.

Where the Fox 36 SL Fits

When weighing out suspension fork options for short/mid-travel mountain bikes, there are basically three tiers to choose from: lightweight XC/race forks like Fox’s StepCast series and the RockShox SID, mid-weight “trail” forks like the Fox 34 and Rockshox Pike, and heavier-duty “all-mountain” or “enduro” forks like the Fox 36 and Rockshox Lyrik. With these lineup delineations comes different travel length recommendations (or travel lengths out of the box), although the bigger Fox 36 and Rockshox Lyrik can each be dialed down to 130mm of travel by swapping out the air spring, further complicating the decision.

The fork crowns and lowers of each of these types of forks also have varying degrees of robustness, and sometimes they have different stanchion diameters. For those unfamiliar, the stanchions on Fox’s short/mid-travel forks range from 32mm to 36mm, and Fox bases the model number on the stanchion diameter. To add a little more context, this is how Fox’s latest lineup breaks down and how they categorize each one:

Shored Up or Trimmed Down?

Today’s release of the Fox 36 SL marks a slight sidestep for the brand. Over the past few years, they’ve made a number of tweaks to trim the fat off some of their forks, effectively paring them down to be more race-ready and arguably less versatile. With the 36 SL, Fox replaced the previous 34 with a larger 36mm stanchion-equipped model that’s slightly heavier by comparison—the last generation 140mm Fox 34 weighs roughly 1,680 grams, and this 36 SL registered 1,778 grams on my scale. The idea is that the 36 SL is a fork with a very similar intent in a theoretically stiffer and sturdier package. Fox claims that the larger stanchions and redesigned chassis adds 20 percent more torsional stiffness to that of the 34 while still only being 100 grams heavier.

Of course, the 36 SL could also be looked at as a trimmed-down version of the Fox 36—the elephant in the room being that pesky “SL” in the model name. One might assume it means Super Light, a term usually reserved for race-oriented products, but Fox makes no claims. Instead, they call it a “hard-hitting all trail fork,” and it occupies the “trail” category in their lineup, which, for all intents and purposes, is supposed to pretty much just represent the age-old practice of semi-casually riding mountain bikes on rough singletrack in the woods. Perhaps 36 TR would have been a better name. So, does “SL” mean something was removed from the 36? Kind of.

Randy Collette, a friend of mine and local suspension technician (MTB Suspension Service), and I don’t see eye to eye on some things. He rides big, long-travel, full-suspension bikes fast, and I mostly ride short-travel hardtails and rigid 29+ “torture devices” at a far slower pace. When I was chatting with him about this fork and how it compares to the Fox 34 it replaces, he kept insisting that I’m comparing apples to oranges and that it should be compared to the Fox 36 instead.

Fox 36 SL vs. Fox 36

I don’t completely disagree with him, but the reason I dove into this review process comparing Fox 36 SL to the Fox 34 isn’t because Fox positions it as such in their marketing. It’s because the 34 is my frame of reference, which is why I’m probably the 36 SL’s target audience. To me it’s an upgrade, not a downgrade. I’ve put countless miles on various versions of the 34 over the last several years, even cracking one open after a couple thousand miles to see the resulting wear and tear.

I’ve always favored relatively lightweight suspension forks. Being on the lighter side myself and preferring short-travel hardtails, I never thought I needed a bigger fork. I typically opted for a RockShox Pike or a Fox 34 (or even a 32 not too long ago) to keep the weight down—I generally don’t like a heavy front end, I don’t ride overly aggressive, and I prefer to keep my hardtails at or under 140mm of travel for the sake of geometry consistency and personal riding preferences. However, after trying a Fox 36 while testing the Pivot Trail 429 a few of years ago, I quickly realized the benefits of a sturdier and stiffer chassis (and a more robust damper). While a one- or two-millimeter increase in stanchion diameter might seem minor, the difference in the larger tubes, heftier crown, and the internals that come with it was immediately noticeable. The 36 felt significantly more stable and composed, particularly when descending. It also didn’t morph into a harsh jackhammer on longer descents, and it simply performed better when pushed. And when I loaded that bike up for bikepacking, the added solidity shone even brighter.

That pretty much sums up why Fox decided to rebuild their trail-specific fork around bigger stanchions. But it’s still a middle child. Looking at the 36 SL (left) next to the latest 36 (right), there are some notable structural differences. They both have the same dimensions—axle-to-crown—and the lowers are largely the same, although the SL has a slight angle at the bottom which removes material and weight. And of course, the stanchions on the SL are 20mm shorter to limit it to 140mm of travel. The 36 SL crown also has a few Geiger-esque recesses carved into it to match that beautiful amorphic lower bridge, and that means it too is less bulky.

GRIP X vs. X2

Still, what truly separates the two forks are the dampers. The 36 SL is only available with the GRIP X damper, and you can get the new Fox 36 with GRIP X, the highly tunable GRIP X2, which adds about 120 grams to the bottom line. The new Fox 36/X2 weighs in at around 2,060 grams, that’s about 290 grams (0.64 pounds) more than the 1,778-gram Fox 36 SL. While that might not seem like a big deal to some, over half a pound extra bulk up front is apparent if you’re sensitive to weight, or if you’re a smaller rider, or if you’re doing any sort of race-like activity. That’s something to consider.

The GRIP X does make a couple of sacrifices that are also worth considering. As many of you may know, the GRIP X damper replaced the FIT4 (and GRIP 2, kind of) last year and was designed to offer the best of both worlds with high-speed and low-speed compression adjustability like the GRIP 2 and a firm compression setting that resembles the lockout on the FIT4—you can now simply rotate the high-speed compression adjuster clockwise until you feel the final, distinct click, which simultaneously closes both high and low-speed compression, providing a firm feel for efficient climbing. That setup on the GRIP X offers a simple way for riders to tune it for their desired long-term ride quality with inner LSC knob, then use the outer blue HSC dial to quickly tweak it during the ride, depending on the terrain.

It’s also a significantly smaller damper than the X2 (or the GRIP 2 that preceeded it)—this was one of Fox’s “cuts” to be able to offer a lighter fork. As a result of its smaller size, GRIP X uses much less oil than the GRIP X2, which also reduces weight. However, that introduces a couple of tradeoffs.

The X2 (and the Fox 36 in general) is built to handle heavier demands, featuring more internal shim stack for better fluid regulation, bigger seals that prevent oil and air from mixing, and a greater oil volume to enhance performance. In short, it’s more robust and designed to absorb bigger hits more efficiently, especially in rapid succession, improving control for longer durations.

As Randy mentioned, “Oil is your friend in suspension. That’s why the best [and most tuneable] products are high volume and the racy ones aren’t structurally much lighter, they simply have smaller dampers and less oil.” As it pertains to durability and maintenance—specifically from a bikepacking and long-distance riding perspective—the reduction in oil volume can result in more frequent service intervals as the oil gets dirtier faster. Randy mentioned that the GRIP 2/X2 uses around three times the oil as GRIP X, “Let’s just say I fill Grip X with a small syringe, and I fill Grip 2 straight off the oil jug.”

But, it’s all a tradeoff, right? 290 grams is nothing to brush under the rug. And stouter forks are harder on the hands—larger tubes and a chunkier crown mean less flex, which inherently results in less vibration reduction.

On the Trail

That said, I’ve also logged hundreds of miles on the latest Fox 34 model featuring the same GRIP X damper as the 36 SL. I put it through its paces on a mix of challenging trails and dirt roads in Oaxaca this winter, dialing in the settings to my preference and getting a pretty good feel for it along the way. In general, I find Fox’s recommended settings a bit too harsh for my liking. Their suggested PSI yielded about 18% sag, whereas I prefer closer to 22%. The recommended rebound works well, and I typically run around 5 or 6 clicks (out of 15) of Low-Speed Compression.

Riding several of Oaxaca’s challenging “long trails,” I was impressed with the 34 and GRIP X once I had it dialed in. The distinct whooshing sound over larger bumps makes it clear the GRIP X is working hard with less oil moving through a smaller circuit. However, it does an admirable job of maintaining performance without ramping up to be overly harsh as it heats up—at least when riding at my skill level and speed. It remains fairly consistent, though I swear there was a break-in period of four or five rides, which may have just been in my head.

Right out of the gate, the Fox 36 SL felt very familiar in terms of damper feel and suspension performance. Like the 34, it’s predictable, tracks well, and has a nicely rounded feel—the first centimeter or so of travel is pillowy and soft, smoothing out the small stuff, yet it absorbs medium-sized bumps without feeling overly progressive or harsh. It also doesn’t feel undergunned on larger hits—at least for the level of terrain I consider big enough to get the adrenaline going without venturing into truly terrifying territory.

On the first couple of rides, I noticed the 36 SL seems to have better traction and composure overall, particularly when punching into bumpy corners or at speed on rough terrain. There’s a corner on one of my favorite trails that you can rail into, but there’s not much room for error as you’re plowing over roots in a relatively tight arc. Riding that the other day was kind of a lightbulb moment with this fork as it felt particularly grounded and calculated.

Part of this might be due to its stature, which is why many of you might still be reading this. I noticed right away that the 36 SL is stiffer than its predecessor. The 34 I got to know over the winter has a discernible amount of flex that’s even visible while riding. The 36 SL has some, but certainly not as much. It’s not as stiff and sturdy as the true 36, but Fox seems to have found a middle ground. Even without riding the three back to back on the same bike, I’d confidently say that the Fox 36 SL sits squarely between the 34 and 36 in terms of general sturdiness and rigidity. On my first few rides, it came across as noticeably more sturdy and confident than my 34.

There are a couple of other improvements that Fox made to the 36 SL that may have some bearing on its performance. One is the Inboard Bypass Channels that Fox says were moved to enhance small bump sensitivity and reduce pressure buildup. Fox also claims the new Float air spring in the 36 SL was designed to be compliant, decoupling the stanchion from the air shaft, allowing the piston to move with the fork while under bending loads, rather than resisting them. Another “upgrade” from the 34 is that the 36 SL features 20mm more bushing overlap, which refers to the distance between the upper and lower Teflon-lined bushings within each fork leg. When a fork experiences lateral forces—like hitting an obstacle on the trail—increased overlap theoretically helps minimize friction from that bending force. Of course, you could also consider this a downgrade as the 36 has even more overlap. And I suppose that’s the ultimate question.

• Model/Size Tested: Fox 36 SL, GRIP X
• Actual Weight: 1,778 grams
• Place of Manufacture: Taiwan
• Price: $1,149 USD
• Manufacturer’s Details: Fox

Further Reading

Make sure to dig into these related articles for more info...

71

Bikepacking Guides

Bikepacking with a Suspension Fork: Setup, Service, and Reliability

36

Bikepacking Gear

Rockshox SID Ultimate Review

31

Bikepacking Bikes

Bird Forge Review

25

Bikepacking Gear Lists

Other People’s Lines + Our Baja Divide Rigs