For many years now, the 34 Step Cast was the go-to XC fork for a lot of brands–it was stiffer than the 32, and had 120mm of travel to match up with most modern XC bikes.
But Fox wanted to take that lightweight feel and make it stronger, stiffer, and increase the travel, all without adding weight. The result is the all-new Fox 34 SL–XC bred, Downcountry ready.
The 34 SL is truly an entirely new fork, from the ground up. Nothing about it carries over from the 34 SC. Here are the key features, all explained below:
- Generative arch & crown
- Full-size chassis (no Step Cast)
- Increased bushing overlap
- Inboard bypass channels
- More travel
The really impressive thing is they didn’t stop with strength and stiffness. It’s also markedly smoother, thanks to small but important design changes. Combined with the new dampers introduced in 2024, this truly is the best 34 fork ever. I’ll have a separate review, but first, here’s the tech:
Generative Design
The 34 SL borrows the same generative design philosophy from the new 32 SC, with a punctured arch to save weight, and dramatic sculpting and machining of both the arch and crown.
Why no reverse arch? Because over 100mm travel, it becomes less practical for frame clearance reasons because of how the fork rake is achieved … the 32 SC does this by angling the crown more than the axle offset, but the others use more traditional angles and axle dropout positioning.
It’s 29er only, and is only available with a 44mm offset.
Full Size Chassis, Basically the Same Weight
The new 34 SL replaces the 34 SC, using a standard-width chassis rather than the narrower SC design.
This opens up tire clearance and improves torsional stiffness. Overall stiffness is 17% better, travel goes up to 130mm now, and it fits 2.5″ tires:
Best of all, all of these improvements come with just a 3.5% weight increase over the 34 Step Cast.
To do that, Fox applied all the tricks, like black anodizing the crown rather than powder coating, saving 7-8 grams. And internally butting the damper-side stanchion, because it doesn’t need straight internal walls like the air spring side. And they skipped the pressure bleeders.
The result? A claimed weight of 1,475g. That’s only 33g heavier than the outgoing 34 SC’s weight of 1,442g. Oh, and that’s for a 130mm travel 34 SL versus a 120mm 34 SC.
Bigger Brakes
Another change is it now fits a minimum 180mm rotor. OK, but if this is their new XCO race fork, why 180mm rotors? Because it’s also their downcountry race fork, and some of those folks want 200mm rotors. They say many of their XCO pros were running 180mm rotors anyway, so why not reduce the number of adapters?
Smoother Than Ever
Here’s where it gets really interesting. To make the fork smoother, Fox made three major redesigns:
Longer Stanchions = More Bushing Overlap
First, they gave the fork longer upper tubes (stanchions). This allowed for more bushing overlap (20mm more!), which means lower binding forces (friction) under fore-aft loading.
Internal Bypass Channels
Ever noticed those graduated ridges on the backs of Fox’s fork legs? Those are bypass channels, allowing the air from under the damper or air spring to access the space between the bushings.
They’re important because that air is trapped inside the fork, and it’s not a tunable element like your normal air spring. Yet it is basically a second air spring, because it gets compressed every time your fork compresses. So it, too, ramps up and affects suspension performance.
Yes, Fox (and likely every other brand) tunes the fork based on this, because it’s a known quantity. But anytime they can make that air volume bigger, they can lessen its effect on performance.
For example, in a Fox 36, without those bypass channels, at bottom out, there would be about 45psi in the lower legs, on each side. But with the bypass channels, that drops to about 15psi, which has much less impact on your fork’s performance.
Which is great, buuuuuuut……
Fox upgraded their FEA software and found new hotspots on the bushings around those channels. Forks see much higher fore-aft loads than lateral loads, and so the bushings could deform ever so slightly over that channel, which created pressure points and thus friction.
So moving the bypass channels to the sides provided more support for the lower bushing where it needed it, yielding more even contact pressure with the stanchions. Boom, less friction.
Longer Air Springs
Lastly, the air springs are now longer, so there’s more negative volume, which makes for a plusher fork.
But wait, there’s more… or, not
There are actually other technologies they developed to further improve smoothness, but found that for this fork and its shorter travel application, those ideas didn’t move the needle enough to offset the small weight gain. But, you might see those later… I just can’t tell you about them yet.
Dampers & Other Upgrades
They’ve switched the air spring cap to a Shimano Cassette Lock Ring interface. Until now their forks used an extremely low profile socket, requiring special flat-faced sockets to avoid rounding it off. Now, they’ve joined Rockshox in using the cassette tool interface for more secure, easier servicing with a common tool.
Options & Specs
The 34 SL will be available with the following options:
- 110 / 120 / 130 mm travel options
- Travel changes require swapping the air spring
- Trim Levels
- Factory – Kashima, Kabolt SL thru axle
- Performance Elite level – OE only
- Performance – Kabolt SL or QR thru axles
- Damper Options
- Grip Damper (Performance only)
- Grip SL Damper (lightest damper, all travel options)
- Grip X Damper (more tuning, 130mm travel only)
Fox 34 SL Pricing
- $649-$1099 USD
- $869-$1469 CAD
- €869 – €1469 EUR
- 1149-1899 AUS
- £749 – £1259
It’ll be available with or without Remote lockout (Grip SL damper only), and to operate it there’s an all-new…
Fox Twin Stick Remote
Dual function remotes are often big and clunky, but the new Fox Twin Stick does a pretty good job on both aesthetics and ergonomics. Two small paddles give you easy operation of both a dropper post (larger, lower lever) and your suspension’s lockout.
The lockout portion is compatible with either 2-position (Open/Firm) or 3-position (Open/Medium/Firm) suspension setups. Push it to lock it, then push it again to release it. It can be set up for fork only, shock only, or fork and shock simultaneously. Weight is 66g (76g with clamp), and price is $149 USD ($199 CAD / €199 EUR / 269 AUS / £184.95).
Videos & Bold Claims
Fox says this new fork gives the lightest XC ecosystem, in their words:
“When you combine Fox SL parts – 34 SL, Float SL, Transfer SL – you get the lightest overall complete XC suspension and dropper system from any leading brand, 333 grams lighter than our closest competitor with equivalent spec, and 489 grams lighter than the competition’s electronic XC system, both of which offer a maximum 120mm travel fork vs. Fox’s 130mm max travel.”
Stay tuned for the ride review…and more.
