Wil reviews the 2025 Fox 34 Step-Cast vs RockShox SID

The final instalment of our 2025 Fox and RockShox head-to-head review series follows on from the battle of the 36 vs Lyrik, and the 34 vs Pike. This time it’s their lighter and shorter travel counterparts that have stepped into the ring; the RockShox SID and Fox 34 SC (Step-Cast). These are both new-school cross country forks that are optimised around 120mm of travel, and you’ll typically find them fitted to modern XC race bikes like the Scott Spark, Orbea Oiz and Specialized Epic 8.

While the SID and 34 SC aren’t the absolute lightest forks in the range (those accolades go to the shorter travel SID SL and 32 Step-Cast), we’re big fans of their extra travel, sturdier handling and plusher ride quality. That makes them the better choice for riders who value grip, comfort and big-hit control, even on their XC bike.

Last time we pitched these two forks against one another back in 2023 it was the SID that came out on top thanks to its supple and progressive performance. Both forks have been overhauled since then, so we figured it was about time for a rematch.

An overview of the RockShox SID

The RockShox SID underwent a significant update for 2024, receiving a new chassis, air spring and damper. It still features 35mm diameter upper tubes like its predecessor, but everything else is new.

With the aim of improving off-the-top sensitivity and mid-stroke support, RockShox developed the DebonAir+ spring. Total volume has increased 16% thanks to a longer air spring, which was made possible by extending the base to sit closer to the axle. Along with a 50% larger negative chamber, the latest SID is claimed to deliver a plusher feel with a flatter spring curve. A large bottom-out bumper is then used to cushion the final 10% of the travel.

Also new is the addition of a coil top-out spring. This is said to be smoother and more consistent than the rubber used before, which could apparently display some hysteresis when skipping across high-speed chatter.

Inside the other leg is the Charger Race Day 2 damper that’s offered in 2P (Open/Lock) and 3P (Open/Pedal/Lock) variants. The main update for the damper is a redesigned seal head made by SKF that aims to elevate durability while maintaining low friction. To prove its new damper RockShox built a machine that simulated dropping to flat with the fork locked out. Even after 50,000 cycles on this torture device, there was purportedly no degradation in the function of the lockout, which had been an issue with the previous SID.

Speaking of, there were also numerous reports online of users encountering bushing knock with the old fork. As with the latest Pike, Lyrik and Zeb, RockShox has updated the bushings used in the SID with improvements to manufacturing tolerances and quality control. The new bushings are fitted to the lowers and sized at the factory to ensure they’re tight enough to minimise play while still allowing for a thin layer of lubricant across the stanchion’s surface. Furthermore, the upper tubes have been extended by 25mm to increase bushing overlap. This stiffens the fork structure and reduces binding during harder impacts, which should lead to less stiction under load.

2025 RockShox SID Ultimate 3P Specifications

• Travel | 110 & 120mm
• Wheelsize | 29in
• Stanchions | 35mm Tapered Alloy, Black Anodised
• Spring | DebonAir+
• Damper | Charger Race Day 2
• Adjustments | Air Pressure, Air Volume (Bottomless Tokens), Rebound, 3-Position Compression Lever w/Lockout
• Axle | 15x110mm Maxle (Torque Cap compatible)
• Rotor size | 180-220mm
• Max tyre clearance | 2.6in
• Claimed Weight | 1,480g
• Confirmed Weight | 1,516g
• Price | $1,715 AUD

An overview of the Fox 34 Step-Cast

The Fox 34 SC was updated alongside the 2025 fork lineup, though the changes aren’t quite as comprehensive as the SID.

That’s because the 34 SC carries over exactly the same EVOL air spring and chassis from its predecessor. This includes 34mm diameter upper tubes and magnesium one-piece lowers that incorporate oil channels down the back of the legs. Thanks to the improved lubrication these channels provide, Fox found it was able to implement solid bushings rather than the split-style of old. The result is said to be less stiction and improved durability.

The bigger news for the 34 SC is the arrival of the all-new GRIP SL damper. This is the lightest option from Fox, and as such you’ll find it in short-travel forks including the 32 TC gravel fork, as well as the 32 SC and 34 SC.

Replacing the old FIT4 bladder-based cartridge, the GRIP SL damper moves to a coil-backed IFP design that resembles a shrunken-down version of the heavy duty GRIP X and GRIP X2 dampers. Thanks to its minimalist approach and thin-walled alloy construction the GRIP SL damper is 65g lighter than the FIT4 it supersedes.

At the top of the fork is a 3-position compression adjuster with Open/Medium/Firm settings. There is no longer a separate low-speed compression dial, which helps to simplify things and further reduce weight.

2025 Fox 34 Step-Cast Factory Series Specifications

• Travel | 100, 110 & 120mm
• Wheelsize | 29in
• Stanchions | 34mm Tapered Alloy, Kashima Coat
• Spring | Float EVOL
• Damper | GRIP SL
• Adjustments | Air Pressure, Air Volume (Spacers), Rebound, 3-Position Compression Lever w/Lockout
• Lowers | Magnesium Lowers w/Bypass Channels
• Axle | 15x110mm Kabolt SL
• Rotor size | 160-180mm
• Max tyre clearance | 2.4in
• Claimed Weight | 1,422g
• Confirmed Weight | 1,427g
• Price | $1,799 AUD

Price | Fox 34 Step-Cast vs RockShox SID

Like a lot of products across the bike industry, the latest Fox 34 SC and RockShox SID have gone up in price compared to previous versions.

In the case of the SID there has been a notable increase for both the Ultimate ($206 AUD) and Select ($165 AUD) models. The Factory Series version of the 34 SC has gone up by $160 AUD, but interestingly the Performance Series fork has actually gone down in price by $190 AUD, making it the value-pick out of the four available options;

• Fox 34 Step-Cast Factory Series – $1,799 AUD
• RockShox SID Ultimate – $1,715 AUD
• RockShox SID Select – $1,355 AUD
• Fox 34 Step-Cast Performance Series – $1,099 AUD

Weight | Fox 34 Step-Cast vs RockShox SID

Despite all of the durability and stiffness-enhancing features of the latest RockShox SID, its weight remains much the same as the old version. The Fox 34 SC on the other hand has dropped significant mass thanks to its lighter GRIP SL damper and new Kabolt SL thru-axle, putting it ahead of the SID by almost 100g. In the world of weight weenie-ism, that’s a lot!

Shown here are the confirmed weights for both forks with a star nut installed and the steerer tube cut to 165mm;

• Fox 34 Step-Cast Factory Series – 1,427g
• RockShox SID Ultimate – 1,516g
• Fox 34 Factory Series – 1,751g
• RockShox Pike Ultimate – 1,908g

You’ll notice that I’ve also listed weights for the Fox 34 and RockShox Pike. That’s because those forks are also available with 120mm of travel, which is the crossover point with the 34 SC and SID. If you’ve got one of those bigger forks and are looking to drop some weight from your bike, there are clearly significant savings to be had.

Installation

Installing the RockShox SID and Fox 34 SC is much the same, with the key point of difference being the minimum rotor size. Riders looking for the lightest possible configuration will prefer the 34 SC as it can take a 160mm rotor. On the other hand, if you’re going to be using a 180mm front rotor anyway then the SID will look neater as it won’t require a separate adapter.

Another aspect worth considering is tyre clearance. The narrower stance of the 34 SC means 2.4in is as wide as you can go, while the SID can take up to a 2.6in tyre. The extra clearance might not be of any use to serious racers, but it will be appealing for hardtail riders and bikepackers who are using higher volume rubber.

I also like that the SID features Torque Cap compatible dropouts. It’ll fit a regular Boost hub with bolt-in adapters, but it can also accommodate hubs fitted with the oversized Torque Caps that help to increase torsional stiffness for a negligible weight gain.

Setup & adjustability

When it comes to setting up, the SID and 34 SC share identical adjustments. Along with air pressure and volume, each fork features a single rebound dial at the bottom and a 3-position compression lever at the top.

To help get you started, the RockShox Trailhead calculator offers suggested pressure and rebound settings. For my 68kg riding weight I started out with the recommended 69psi and positioned the rebound damping halfway at 9/18 clicks. The SID felt fantastic right out of the box, and despite not having any Bottomless Tokens fitted from the factory I felt no need to add any since there was sufficient ramp-up at the end of the travel.

Dialling in the 34 SC took a bit longer. The recommended pressure via the guide on the back of the fork lowers was too high for me, which seems to be a theme with the Fox forks I’ve tested lately. I gradually dropped the pressure down from 74psi to 65psi, which helped but still left the latter portion of the travel feeling a bit firm. I then removed the one solitary volume spacer to free up the end of the travel, and that proved to be the ticket. The 34 SC felt smoother and there was still enough progression that I’ve not had any issues with bottoming out.

Adjusting rebound is a little tricky due to the way the dial is partially hidden inside the lower leg, though once set to the halfway point (9/18 clicks) I haven’t needed to touch it again.

Testing

I first rode the latest RockShox SID on a Canyon Lux World Cup and more recently on my Trek Top Fuel long-term test bike. I also spent a load of time on the fancy Flight Attendant version fitted to a Specialized S-Works Epic 8. Check out my separate Flight Attendant XC review for a deep dive on the electronic suspension system.

I’ve not had quite the same breadth of experience with the latest Fox 34 SC, which seems to have taken longer to show up on complete bikes for 2025. I have ridden this particular test fork extensively on both the Top Fuel and my custom-built Specialized Chisel, and I’ll also note that I’ve reviewed the insanely lightweight 32 Step-Cast fork that features the same GRIP SL damper. The behaviour is very similar between the two forks, making it a useful point of reference.

As well as riding the SID and 34 SC individually, I also embarked on some back-to-back testing in preparation for this review. It’s a process that takes some effort to do, but riding the same loop on the same bike is always the best way to accurately evaluate two competing products.

On the trail with the RockShox SID

When the previous RockShox SID launched in 2020, it redefined what riders could expect from such a lightweight XC fork. The new version continues on that same path while taking things up a notch.

It still gives off a distinct mini-Pike vibe thanks to its sturdy 35mm chassis, which offers noticeably better torsional rigidity compared to the skinnier Fox 34 SC. That’s especially the case when you’re hammering along at speed on trails littered with rocks and roots, where the SID feels beefier and more substantial. Steering precision is excellent, and that only improves if you make use of the oversized Torque Caps. I wish Fox and others would adopt this standard as it’s a no-brainer for stiffening up the interface between the fork and hub.

Thanks to the new DebonAir+ spring and updated bushings, the SID delivers excellent sensitivity across small and medium-size trail debris. It’s a plush and active fork, with the coil top-out spring allowing it to hover smoothly in the initial part of the travel to maintain grip when skipping over the top of rubble.

On rowdier trails the SID doesn’t offer quite the same level of high-speed control as the Pike with its superior Charger 3.1 damper. The SID is a substantially lighter fork though, and with that in mind it soaks up hard landings admirably with the huge bottom-out bumper doing a lot of the legwork to soften bigger hits. It makes it virtually impossible to fully bottom out, and that gives you a lot of confidence to push your XC bike surprisingly hard.

For racing applications, the 3P damper that I’ve been testing is a nice addition to the SID range. The Pedal mode adds some compression damping to firm up the travel and keep the fork riding higher in its stroke, which is useful on buff sections of trail. It remains reasonably active so it’ll still absorb bigger hits if you forget to open it back up for a descent. Switching modes is a pleasure thanks to the light action of the crown-mounted lever and its positive indents.

On the trail with the Fox 34 Step-Cast

The previous Fox 34 SC had always impressed us with its low weight and consistent performance, but it could never quite match the plushness of the SID. That changes with the new 34 SC, which is a significantly smoother fork on the trail.

Compared to the old FIT4 version, the GRIP SL damper provides radically improved small-bump sensitivity. Compression damping is very light in the Open mode and the coil-backed IFP also helps to minimise stiction. Combined with the updated bushings, the 34 SC requires little force to engage the first portion of its travel, allowing it absorb trail chatter with supreme efficacy.

This newfound suppleness results in better traction along with a noticeable reduction in feedback through your wrists. I’ve had a similar experience with the shorter travel 32 SC, which shares the same GRIP SL damper. Both forks are stupendously plush, representing a hefty step up in performance over the FIT4 versions they replace.

Not only that, the new 34 SC is also smoother and more responsive than the SID. It isn’t as divey either, with the highly refined EVOL air spring providing a linear and supportive feel throughout the travel. Fox has gotten the balance spot-on, with the 34 SC providing just enough ramp-up to prevent harsh bottom outs while still remaining active deeper in its stroke.

There is a touch of squirm upon harder landings, with the slimmer chassis exhibiting more flex than the chunkier SID. It’s no different to the previous 34 SC, and for typical XC applications it’ll be fine for most riders. Still, I think there’s some room to improve stiffness for future versions.

One quirk of the new GRIP SL damper is the squishy noise it makes when engaging the high-speed rebound circuit. The SID isn’t exactly silent either, but the 34 SC is quite a bit louder, mimicking our experience with the GRIP X damper in the Fox 34 and 36. I found I got used to it after a couple of rides, but the noise may be more bothersome to others.

Flipping the blue compression lever into the Medium position provides a hefty boost in low-speed compression damping that helps to resist diving when you’re pedalling out of the saddle. The platform it provides is firmer than the SID, but the GRIP SL damper is much smoother when breaking through its threshold, allowing the fork to open up easily on medium-size impacts. That makes it a really usable setting on rolling singletrack, which is handy because the compression lever’s light action and long lever means it can accidentally get tugged from the Open to Medium position by wayward tree branches. This has happened to me at least once a ride, so I’d like to see a more positive indent for each of the three compression settings to help keep the lever in the desired position.

Is it worth upgrading from the previous SID and 34 SC?

In the case of the Fox 34 SC, absolutely. It’s a significantly plusher fork that offers better comfort and traction, while also being lighter too.

For those who own the previous 34 SC, it’s worth noting that you wouldn’t necessarily need to buy a whole new fork. You could purchase a standalone GRIP SL damper, which like the new solid bushings, is retrofittable. For the cost of the parts and labour, you could effectively build a 2025 fork for less money.

As for the SID, I think it depends on your experience with the previous fork. Those who have encountered issues with the bushings and lockout will see value in the improvements that RockShox has made to durability and consistency with the new version. Lighter riders will also find better performance with the more linear DebonAir+ spring that allows you to make better use of the travel without having to drop pressures really low. The addition of the 3P damper will also appeal to racers, especially if you’re using a remote system (more on that below).

That said, the latest SID isn’t any lighter than its predecessor and I wouldn’t say the performance is a night and day difference. It is a little more sensitive while retaining excellent support on bigger hits, but the changes are mostly about making a more durable and consistent fork. If you’ve not had any issues with your current SID then I’d suggest putting your money into routine servicing. And if you really wanted the 3P option, you could always purchase the Charger Race Day 2 damper on its own.

Remote lockouts

Both the Fox 34 SC and RockShox SID are available in a remote-activated option that utilises a standard 7mm cable pull ratio. That means they’re cross-compatible with different handlebar remotes from other brands, including Scott’s TwinLoc and Orbea’s Squidlock levers.

Of course Fox and RockShox produce their own remotes, and out of the two it’s the RockShox TwistLoc Ultimate that gets my pick. It comes in 2P and 3P versions and can be linked to just a fork or shock, or it can activate both simultaneously.

Like an old-school grip shifter, you twist the mechanism forwards and backwards using a throttle-action. The engagement is positive and audible, with a satisfying ‘clack’ each time you switch modes. I also like the low profile design, which allows you to easily fit an under-the-bar dropper lever. It makes for an ergonomic setup that’s about as neat as you can get using two cables. The elongated barrel does mean you need to run the specific push-on grip from RockShox, unless you’re happy to modify one of your existing left-hand grips.

In comparison, the Fox remote lockout is somewhat rudimentary. The design has remained unchanged for a few years, and while the lever works well enough the plastic construction is a bit flimsy. It’s also quite fiddly to replace the cables.

The bigger issue is combining it with a dropper post lever. My preferred configuration is using a vertical over-the-bar dropper post lever as shown in the photo above. If you’ve got a conventional under-the-bar dropper lever, it is possible to stack it alongside the Fox lockout, though it forces your thumb to do some cockpit gymnastics to be able to reach all of the paddles.

Alternatively, you can flip the remote lockout to the top-side of the bars. This isn’t ideal from an ergonomic perspective and it just looks plain terrible. Given the quality performance and construction of the 34 SC fork itself, Fox really needs to do it justice and design a proper remote lockout to work with modern setups.

Servicing & warranty

As with the bigger travel forks from Fox and RockShox we’ve reviewed previously, the servicing intervals and warranty support is the same for the 34 SC and SID.

Generally speaking, we’ve found RockShox forks are easier to work on. The online manuals are detailed but straightforward, and the fact that you don’t require a lot of specialist tools makes it easier for home mechanics to service their forks. This is important because RockShox recommends a lower leg service every 50 hours of ride time to keep the internals clean and properly lubricated. A full service is then recommended every 200 hours, and RockShox backs it all up with a 2-year warranty.

In contrast, Fox only provides a 12-month warranty and it recommends just the one service every 125 hours of ride time. On the topic of servicing, it’s worth noting that the bushings in the 34 SC are replaceable and backwards compatible with older forks. This differs to RockShox, where the bushings are pressed into the lowers at the factory and are not designed to be replaced. We’re told this shouldn’t be an issue providing you stay on top of servicing, but it is still worth mentioning.

Flow’s Verdict

The latest Fox 34 SC and RockShox SID are two exceptionally high performing XC forks.

Taking what we liked about the previous iteration and elevating both performance and durability, the RockShox SID is a smooth and sturdy operator. It offers class-leading stiffness and a burly feel on the trail that belies its low weight, making it more than just a pure World Cup level race fork. With its 180mm rotor mount and 2.6in tyre clearance it’s also a great option for hardtails and short travel trail bikes.

It just gets pipped by the 2025 Fox 34 SC, which has taken a greater leap in performance thanks to its new GRIP SL damper and updated bushings. The 34 SC is incredibly plush and responsive, delivering a more comfortable ride over rough terrain while generating better traction. It manages to achieve this while being even lighter, and the 3-position compression dial provides three very usable settings. While we would like to see some stiffness gains in future versions, for XC riding and racing this is currently the best fork you can buy.

ABOUT THE REVIEWER - Wil Barrett

Hometown

Bendigo, Victoria

Height

175cm

Weight65kg