The Fox Factory group is right there in the mix and, following the recent release of the lightweight, flippable Race Face TurbineSL stem, today the brand drops two much larger products in the XC/downcountry space: Fox 34 SL fork and Twin Stick remote.
A couple of weeks ago, Fox hosted a media event in Scottsdale, Arizona near where I live. I was able to attend a portion of it where the hosts installed a new 34 SL fork on the Sour Bicycles Cowboy Cookie I was reviewing to gather some initial on-trail impressions at the event, and during the weeks since, that I’ll share below. Fox also presented the new Twin Stick remote lever, which I just got my hands on earlier this week.
Josh Weinberg
To be frank, once I heard the new 34 SL was in the works, I became determined to complete my Cowboy Cookie review ahead of the fork’s release. The fork seemed to fill a downcountry gap among available suspension forks I identified while building up that bike. In my review, I lamented the limited options in the range of 130 mm travel offering a lightweight chassis of a RockShox SID (1,485 g claimed) or Fox 34 Step Cast (SC), which is 1,422 g claimed weight, but both are only available with 120 mm travel.
The closest 130 mm travel options are the regular Fox 34 (1,879 g), Ohlins RFX 34 (1,689 g) and the RockShox Pike (1,885 g), which I used in my review build. But now, here we are. The 34 SL replaces the 34 Step Cast (SC) in Fox’s lineup as a single lightweight (claimed 1,475 g in 130 mm) option catering to both XC and downcountry segments now with three travel options: 110 mm, 120 mm, and 130 mm.
Fox 34 SL fork and Twin Stick remote.
Fox 34 SL
Wheel size compatibility: 29 in
Travel options (mm): 110, 120, 130
Rake: 44 mm offset
Axle: Kabolt SL (with Factory-level)
Rotor size: 180-203 mm
Steerer tube: 1.5” tapered
Max tire size: 29 x 2.5
Claimed weight: 1,475 g with 130 mm Grip SL damper and steerer cut to 165 mm. For shorter dampers, Fox claims that each reduction in travel equates to about 7 g less weight.
Price: US$649-$1099 depending on series level (Performance, Performance Elite, Factory)
Twin Stick Remote
Actual weight: 68 g (without clamp)
Works with: Cable-actuated droppers, forks, shocks
Compatibility: two or three-position lockout systems
Price: US$149
The sharp end of XC mountain bike racing is becoming increasingly demanding. Courses now have sections that would have looked at home in an enduro race just a few years ago. Climbs are steep and sustained with technical obstacle-laden downhills. You could have a circular chicken-or-egg discussion about whether the courses are making the bikes burlier or if more capable bikes are requiring courses to become more challenging.
Fox 34 SL
And then there’s the whole downcountry thing, which might be my favorite tech trend in all of cycling right now, in which brands incorporate elements of trail bike geometry with XC components amounting to efficient pedaling platforms that are also confident descenders. It all amounts to increased demand for lightweight yet burly tech to outfit bikes accordingly. Following a few-year lag in design-to-market timeline, we’re now starting to see more components like the Fox 34 SL that will find their way to everything from XC race bikes to light trail rigs.
According to a Fox press release: “34 SL adds more stiffness, more suppleness and absolute minimal weight gain from the preceding 34 StepCast fork…. The 34 SL uses a full 34 chassis (not step-cast) with a larger volume air spring to allow for a max of 130 mm of travel if you need it, or if you want it. All at a weight that made sense for World Cup XC riders and weekend amateur racers alike.” Plus, the 34 SL can fit up to a 203 mm rotor and 29 x 2.5" tire: two aspects only covered by larger forks in the past.
Grip SL damper. Photos courtesy Fox
Other than the addition of a 130 mm travel option to Fox’s 34 mm stanchion fork, the chassis and air chamber have been redesigned from the previous generation. But before I get into those details, let’s look at one carryover component – the Grip SL damper. Fox revamped its damper lineup last year. From the gravity Grip X2, to the all-mountain Grip X, and the XC Grip SL, each one was designed to reportedly save weight and offer “more traction, speed, and control.”
For the Grip SL specifically, which most riders will choose for the 34 SL (Grip X and Grip are also options in 130 mm travel), Fox got rid of the bladder system used in the previous generation FIT4 and replaced it with a more reliable and predictable coil-based IFP (internal floating piston), while still shaving 60 g from its predecessor (in 100 mm travel). For the most part, IFP is easier to service and offers greater tuning options over bladders that can be made lighter but are prone to tearing. Grip SL optimized for low-speed damping, which is the early part of the fork’s travel where a lot of XC and trail riding inputs occur. While in firm, or “lockout mode,” Fox built in a noticeable “blowoff” to limit energy loss while impacting small obstacles at speed and the damper mode switch is now easier to turn while under load.
The new 34 SL has a completely new chassis and air chamber. So, combined with the Grip SL damper, it’s an entirely new fork from the 34 SC that is being phased out. Both the arch and crown have a completely new design to save weight and increase strength. While we hear this from Fox and other brands each time they release a new product, rampant technology advancements are contributing to the endless quest to, in many cases, create a design that’s lighter and stiffer than before.
Not unlike what's been done with the year-old 32 Step-Cast, Fox explained that its engineers used a generative design process to have the cut-out arch wrap around the fork lowers and increase torsional stiffness by a claimed 17% over the previous 34 SC. Additionally, the aluminum crown contains internal lightening bores and is anodized rather than powdercoated to save additional weight. Further, the full-chassis SL only weighs 40 more grams than the truncated-chassis SC that it replaces.
The 1,475 g weight represents a 404 g and 20 g saving over the regular 34 and 34 Step Cast it replaces, respectively. By comparison, RockShox’s most comparable product is the SID Ultimate at 1,485 grams, but which also tops out at a maximum of 120 mm travel. Meanwhile Fox’s lightest fork, the 32 SC, weighs just 1,276 g, but is also limited to a maximum of 100 mm travel.
Sculpted crown and arch are results of generative design.
If you, like me, were wondering what generative design is and how it can be used for this sort of work, I’ll offer up Wikipedia’s definition of the technology: “An iterative design process that uses software to generate outputs that fulfill a set of constraints iteratively adjusted by a designer … By employing computing power to evaluate more design permutations than a human alone is capable of, the process is capable of producing an optimal design that mimics nature's evolutionary approach to design through genetic variation and selection.” Fox certainly isn’t alone in using such a technology, but it is early days within the cycling industry.
The 34 SL also gets a longer air spring, and there's now more bushing overlap than the 34 SC. Bushings are an interesting aspect of suspension design and don’t get talked about too much because they aren’t a part that typically needs normal servicing. In fact, RockShox doesn’t even sell replacement bushings for their forks. Each lower fork leg has two of these Teflon-lined sleeves that the stanchions move through and are sources of uncontrolled damping. While designers can control suspension damping with springs and dampers, they can only do so much about the friction that builds up with stanchion-to-bushing interaction under sideways loading. The closer together the bushings are to each other (also called “bushing overlap”), more friction can build up. While this isn’t as pronounced in shorter-travel forks as it is in longer ones, Fox increased the bushing overlap in the 34 SL by 20%, which is said to offer riders “additional suppleness at higher speeds when bending loads on the fork are at their greatest.”
Following a few weeks of riding the 34SL, the weight savings over the Pike it replaced on the Cowboy Cookie is quite apparent. In a good way. The sprung vs unsprung weight scenario I touched on in that review proved out when reducing weight of the fork chassis. Riding much of the same terrain as I did with the Pike, the bike seems to handle more efficiently and requires noticeably less effort to maneuver over obstacles both climbing and descending. Bump sensitivity and movement through choosy terrain feels smooth as a result of the GripSL's low-speed damping capabilities.
When I push the fork, though, in fast rocky descents where the bike is prone to side loading through rock gardens and small drops, I can feel the difference in stiffness coming from the beefier chassis of the Pike. Not that this is a bad thing, but expecting everything to be the same just because travel is equal between the two is unrealistic. There will be some tradeoffs based on stanchion diameter and overall chassis construction. More test impressions to come, but let's move on to the other new product Fox announced today.
Twin Stick remote and shock lockout.
Twin Stick remote
The Twin Stick joins Fox’s lightweight XC product lineup as a replacement to the Fit4 lockout remote. Using a similar system as the Fox Transfer lever, the Twin Stick relies on ramps and catches to actuate and release suspension lockouts. It has slots to run two cables and can control a fork or shock individually, or both at the same time. It can be configured in a two- or three-position setup. The three-position format is only compatible with Fox forks and shocks that have compatible compression dials, while the two-position can pair with any remote-controlled Fox products and those from many other brands as well.
Twin Stick in action.
Where it differs from the old remote, however, is in the integrated lever that works with any mechanical dropper post. Separate dropper levers were still needed with the old remote, but the Twin Stick brings it all together for a tidier cockpit that, in my initial usage, is quite convenient to operate. If this sounds familiar, that’s because Scott has had a similar-concept TwinLoc on its Spark bikes for some time.
You can see in the photos of the Twin Stick routed to the Float SL I recently installed on the Cowboy Cookie that a remote lockout might not make sense on all frames with compatible shocks. Vertical mounted shocks like this one require some interesting cable routing that might not be desirable for some users. Certain frames are designed for it; this Sour is not, though a majority of XC bikes have horizontal mounting and should work just fine.
As a system, or what Fox calls their “ecosystem,” the full setup – with the 34 SL, Float SL, Transfer SL dropper, cables and housing – weighs in at 2,232 g. This, again as is claimed, and amounts to 333 g less than RockShox’s equivalent spec with a 120 mm fork vs Fox’s 130 mm Float SL. Now, this number is a bit misleading because we can assume it figures a Reverb AXS vs mechanical Transfer SL, so removing droppers from the equation, the Fox group is still lighter than RockShox, but it’s more like 50 grams difference. Still, the option to have a 130 mm fork in this competitive range is a great move for Fox.
But RockShox is likely close behind and I’m going to be sitting back eating my popcorn watching where these brands push the short travel segment. With Specialized’s 130 mm fork spec on the new Epic, and other brands releasing similar builds, the demand for lightweight longer-travel forks will only increase as XC gets more burly and downcountry spikes in popularity.
As for the Fox 34 SL and Float SL currently on the Cowboy Cookie, I'll be embarking on a longer-term analysis and comparison with similar spec components across other brands. If you have any questions about the project, drop 'em in the comment section.
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