The Fox 38, a fork we have all long suspected, and one that is now finally official! Here is our first look at the beefiest single crown Fox fork on the market.
Fans of the EWS won’t be shocked to see the new Fox 38 fork. For months now, pro riders have been spotted with stout 38 upfront but stickered up with RAD prototype decals to not give too much of the game away.
But, we all knew a Fox 38 would launch, and now that it’s here we can give you a hands-on first look and rundown of the newcomer and all of its new 2021 suspension features.
Video: Fox 38 Heritage Edition First Look
Fox 38 Range
The Fox 38 range consists of 4 models, the budget Fox 38 Performance Grip in matte black, Fox 38 Performance Elite GRIP2 in matte black and Fox 38 Factory GRIP2 with Kashima coated stanchions available in gloss black and orange.
There is also a limited-edition Heritage version of the Fox 38 Factory GRIP2, which only comes in this limited Pistachio green colour and the Kabolt-X 110mm bolt-on axle. The rest of the range has a QR axle as standard, but the Kabolt-X is available aftermarket.
Each fork in the Fox 38 range comes in either 27.5in or 29in/27.5+ wheel options, with travel ranging from 160-180mm although some of the more affordable versions only come in 170mm.
Smooth, Stiff and Tunable
For 2021 Fox promises that the 36, 38 and 40 will be smooth, stiff and tunable, and many of the following features we see on the new Fox 38 also appear on the 2021 Fox 36 and Fox 40.
All these updates aim to create forks that run smooth and square to prevent binding on the seals, while also adding new tuning and performance features too.
New Fox 38 CSU
The CSU of a fork consists of the steerer tube, crown and the stanchions, and in the Fox 38, it’s all larger and burlier than ever.
Kicking off Fox’s plan to build a stiffer fork, the team decided to over-engineer the steerer to aid strength and stiffness, but rather than going down the new 1.8 standard paths, Fox has done something unique.
The steerer on the Fox 38 is still a tapered tube and looks a lot like any steerer on the market, but at the end where it meets the crown, the internal shape changes from round to oval. This adds more material to the steerer and helps to keep the front end flex-free.
The name of the Fox 38 obviously comes from the larger 38mm stanchions. On our Heritage edition test fork, these are treated to a Kashima coating for frictionless free movement and are pressed to a new larger crown.
For the OEM market, Fox will offer 2 crown sizes, but the company stresses that there are no performance advantages from one crown to the other, and the choice is purely for aesthetics. A larger crown will be offered for bikes with a larger headtube and chunkier design, such as an eMTB, while a smaller crown is available and looks more at home on a regular enduro bike.
New Fox 38 Chassis
The chassis of the Fox 38 is where we see a lot of changes and many of these improvements are present on the new 2021 Fox 36 and 40.
For starters, the Fox 38 has a new leg arch that sits further forward from the fork stanchions than before and is also a much larger diameter too. The larger size is to aid with fork stiffness, but the stepped design is to improve frame clearance.
At full compression, the new arch is now far enough forward that it offers plenty of headtube clearance even for bike frames that use oversize or chunky designs. It also offers maximum clearance when running an offset headset too, giving frame designers more scope to build in reach and head angle adjustment to their bikes.
This new arch design now comes with integrated bosses for a new Fox mud-guard and is webbed to ensure a balance of low-weight and stiffness.
The backside of the new Fox 38 (and 36 and 40) forks also have a new air channel design, and Factory forks will come fitted with air bleed ports as standard too.
The air channels are there to improve air volume in the lower legs, reduce pressure buildup near bottom out and allow oil to move up through the fork to lubricate the form rings, seals and bushings more effectively.
Bleeders on the backside of the leg are their to equalise air pressure and can also be used to help tune the forks. In a tech briefing with Fox, we were told that lighter riders can press the bleeders while compressing the forks to create a vacuum effect that can help to improve small bump sensitivity, not something I personally need to worry about.
Air Bleeders come fitted to Factory and Heritage forks as standard and as long as a 38 comes with the bosses on the rear they can be added as an aftermarket upgrade to models that don’t ship with them.
At the very bottom of the new Fox 38 chassis, we get to the dropouts and just as we saw on the 36, Fox has kept to a 15mm axle. 2 versions of axle are available and users can swap from one to the other, and actually the new options are pretty clever.
Each new axle is designed to ensure that the fork legs are perfectly square with the front wheel installed. This prevents binding of the legs and ensures better small bump performance.
Fox had found that not all front hub manufacturers build their hubs to the same tolerances, so while some fit perfectly others are a little out and that means the fork legs are pulled slightly while installing the front wheel.
To solve this, Fox has moved to a floating axle design that presses up against the hub and then locked in position, once the hub spacing is set a lock nut is tightened to prevent the axle moving.
The Kabolt-X axle on Heritage forks is the most time-consuming axle, and Fox recommends this option for riders who don’t remove their front wheel that often and those riders who want optimal front end stiffness. Installing the Kabolt-X requires the front wheel to be installed, the axle tightened against the hub, and the fork compressed to 50% to ensure there’s no binding before nipping it all up. It’s a fiddle, but it is stiffer and saves 75g over the QR.
For the QR axle, there’s a floating shim that is adjusted in the same fashion as the Kabolt-X then locked with the 6mm nut. The QR then passes through that shim to secure the wheel in place. The QR axle only needs to be set once, unless you change your front wheel to another brand/model, whereas the Kabolt-X needs to be reset each time you install your wheel.
VVC in Compression and Rebound
Until the 2021 range of Fox forks, VVC (Variable Valve Control) was only available in rebound circuits, but it has now been added to the compression side of the suspension system.
VVC offers a more accurate adjustment of the shim stacks inside the fork to adjust flow and change the performance of the fork. It also offers a more gradual feel to the damping circuits so that the system functions gradually with no sudden changes.
VVC has also been added to Fox rear shocks for 2021, to help make setup of front and rear suspension more similar and simpler than before.
Fox 38 Air Spring Cartridge
While many of the features we see on the Fox 38 have been shared across to the 36, there is one feature that isn’t and that’s the move to an air cartridge inside the air spring side of the fork
Whereas the Fox 36 uses the inside of the stanchion as an air spring, the 38 uses an air cartridge instead, and with it, it brings a few performance advantages for the racer/hardcore rider.
Fox says that to achieve an optimum air spring function and progressivity they needed to reduce the air volume in the fork. Using a cartridge inside the stanchion actually makes the piston area smaller than the 36 which adds the progression that Fox was after, but does require the use of higher air pressures. Personally, this means I’m running around 95psi in the 38 whereas I’d be nearer 75 psi in a 36.
Using a separate cartridge also helps small bump sensitivity in fast, rough, off-camber sections of trail. Normally a fork would be under so much force there might be some binding in the air spring, but as the 38 uses a cartridge the binding is isolated and small bump performance remains unaffected.
Fox 38 First Ride Review
While I have ridden the Fox 38, I haven’t been riding technical and challenging terrain due to the COVID-19 restrictions. As much as I would love to hit our local downhills, I think it is wiser at this time to play it safe and not take any risks that could add strain to the NHS.
So I hope you can understand that I’m not able to give you a full-ride review at this time, but as soon as the world is back to normal, the Fox 38 review will become my top priority.
If you have any questions about the Fox 38 and it’s features then please let me know in the comments section below.
All 2021 Fox products are available through Silverfish in the UK and Ireland.
If you like what we do - if you like our independence then the best way to support us is by joining us. Every penny of your membership goes back into Singletrack to pay the bills and the wages of the people who work here. No shareholders to pay, just the people who create the content you love to read and watch.