When it comes to extreme sports heritage, few can match Californian suspension manufacturer Fox with its background in motorcycle, ATV and off-road racing.
Fox has been delivering cutting-edge mountain bike suspension forks since 2001 and shows no signs of slowing down, locked in a battle of innovation with its main competitor, RockShox.
Let’s take a look at the latest crop of Fox forks and their applications and differences.
Fox suspension fork hierarchy explained
Fox’s MTB fork line-up is split into the following tiers, based on performance and budget.
- Fox Factory Series
- Fox Performance Elite
- Fox Performance
- Fox Rhythm
- Fox ebike
Fox Factory Series
Fox’s Factory Series is the cream of the crop, offering the highest level of performance. Characterised by their golden Kashima-coated stanchions, Fox Factory forks get the GRIP2 or FIT4 damper. They are also available with the newer GRIP X2 or GRIP X dampers. They feature Float EVOL air springs.
The 36, 38 and 40 also boast push-button bleeders.
Fox Factory forks are most commonly seen on top-spec bikes costing upwards of approximately £4,500/$4,500.
Fox Performance Elite
Performance Elite is Fox’s next-best offering, boasting the same GRIP2/FIT4 or GRP X dampers and Float EVOL air spring as the flagship series.
They also share the same chassis, apart from the gold Kashima coating, which is replaced by black anodised stanchions.
Fox Performance
The Performance tier is Fox’s entry-level aftermarket offering, sharing the same chassis and air spring as the more premium options, but relying on a less sophisticated GRIP damper.
The stanchions are black anodised and the push-button bleeders have to be purchased separately and retrofitted (only available on 36, 38 and 40 models).
Fox Rhythm
Fox Rhythm forks are only found on complete bikes and cannot be bought aftermarket.
Designed to be budget-friendly, these forks use a less adjustable FIT damper and have a heavier chassis that is cast from a more affordable grade of aluminium.
Fox Step-Cast
Available as part of the 32 and 34 series, Fox’s Step-Cast forks are all about saving weight. Narrower than their standard counterparts and with a stepped design that allows for a hollow lower section, these forks are for riders and racers looking to shed every last gram.
They're commonly specced on cross-country bikes and some lighter downcountry bikes.
Fox ebike
Fox also offers the 34, 36 and 38 in a special ebike-ready configuration. These forks look identical to their non-electric bike counterparts, however, there are some differences under the hood.
Fox’s E-Optimized forks get a custom damper tune and progressive air spring, maximising traction for the heavier system weight.
The 34 and 36 also get beefed-up CSU (crown, steerer and upper tube) assemblies to boost their stiffness and strength. The E-Tuned 38 only gets the internal upgrades, because Fox claims it's already stiff enough in its standard guise.
Fox suspension fork models explained
Fox’s suspension fork line-up consists of five main models, named after their stanchion diameter, covering all ranges of suspension travel from cross-country to enduro and downhill.
Fox 32
- Intended use: XC
- Travel: 100mm
- Damper: GRIP
- Wheel sizes: 29in
The Fox 32 is a budget-oriented cross-country workhorse, delivering 100mm of travel in a 29er-only chassis. It’s available at a Performance series level, with a three-position GRIP damper.
Fox 32 fork Step-Cast
- Intended use: XC
- Travel: 100mm
- Damper: GRIP, Grip SL
- Wheel sizes: 29in
The Fox 32 Step-Cast had a complete overhaul in April 2024, adopting a reverse arch and a new damper.
It has 100mm of travel and it is for XC racing, specifically XC marathon events.
Fox says the fork is also its lightest ever XC fork, which is partly due to the weight-saving reverse arch design.
Fox 34
- Intended use: Trail
- Travel: 130 or 140mm
- Damper: GRIP, GRIP X, GRIP SL
- Wheel sizes: 29in
The Fox 34 is a versatile trail riding fork, designed to be light and tuneable with enough stiffness and support to tackle anything your local trail centre could throw at it.
The fork offers 130 or 140mm of travel and is available in three models – Factory, Performance Elite and Performance – which are all 29in only.
Fox 34 Step-Cast
- Intended use: XC
- Travel: 100 or 120mm
- Damper: GRIP, GRIP SL
- Wheel sizes: 29in
The 34 Step-Cast is made for the modern breed of burly XC racecourses. As with the 32 Step-Cast, it features a stripped-down, 29er-only chassis for maximum weight savings.
The 34 Step-Cast Factory is available with 100 or 120mm of travel and the GRIP SL damper.
The 34 Step-Cast Performance gets 120mm of travel and a three-position GRIP damper.
Fox 36
- Intended use: All-mountain
- Travel: 150 or 160mm
- Damper: GRIP2, GRIP X
- Wheel sizes: 27.5in and 29in
Bridging the gap between trail and enduro is the Fox 36. Offering 150 or 160mm of travel, the 36 gets treated to pressure-release valves to maximise its performance on big descents.
The 36 Factory is available with a choice of GRIP2 and GRIP X damper. Also available is the 36 Performance Elite, which gets a GRIP X damper.
Both models are available with 150 or 160mm of travel in 27.5in and 29in options.
Fox 38
- Intended use: Enduro
- Travel: 160, 170 or 180mm
- Damper: GRIP2, GRIP, GRIP X2
- Wheel sizes: 27.5in and 29in
The Fox 38 is a hard-hitting enduro fork, designed for the roughest enduro race stages and gnarliest bike park trails. Designed for maximum performance, the 38 gets pressure-release valves and is only available with the tunable GRIP2 damper (Factory and Performance Elite models).
The flagship 38 Factory is available with 160, 170 or 180mm of travel in 27.5in and 29in options. It boasts the GRIP X2 damper and pressure-release valves.
The 38 Performance Elite shares the same chassis as the 38 Factory (save the Kashima stanchions) but with a GRIP2 damper and is available with 170mm of travel for 27.5in and 29in wheels.
The entry-level 38 Performance is available with 170mm of travel for both 27.5in and 29in wheel sizes. It gets a simpler, three-position GRIP damper and is compatible with the retrofittable pressure-release valve upgrade kit.
Fox 40
- Intended use: DH
- Travel: 203mm
- Damper: GRIP X2
- Wheel sizes: 27.5in and 29in
The Fox 40 is a triple-clamp fork designed for the world’s fastest downhill racers. It boasts a huge 203mm of travel and is available for both 27.5in and 29in downhill bikes.
Designed for ultimate performance, only the Fox 40 Factory is available to buy in the aftermarket. It gets a GRIP X2 damper, Kashima stanchions and pressure-release valves.
Fox suspension fork technology
Kashima coating
Kashima is the name of the stanchion coating used on all Fox Factory series forks. The coating is claimed to reduce friction and wear as the fork moves through its travel, increasing sensitivity and traction.
Fox's dampers explained
Fox’s range of dampers has always been a little bit confusing, with GRIP2, FIT4, FIT and more to choose from. These dampers offer a variety of compression and rebound adjustment.
| Name | Adjustability |
|---|---|
| GRIP2 | Maximum adjustability, high- and low-speed compression and rebound. |
| FIT4 | Three-position (open, medium, firm) compression lever, additional low-speed compression adjustment, low-speed rebound. |
| GRIP | Three-position (open, medium, firm) compression lever, low-speed rebound. |
| FIT | Three-position (open, medium, firm) compression lever, low-speed rebound. |
Fox’s 2025 GRIP dampers: GRIP X2, GRIP X and GRIP SL
For its 2025 model year, Fox has updated its range of fork dampers across the range.
The Grip X2, Grip X, and Grip SL dampers are designed for gravity, trail and XC riding respectively.
The new range aims to help riders determine the most suitable fork for their riding style, terrain and preferences.
All three dampers are based on Fox’s GRIP system, but each is built to meet the needs of the different disciplines.
Fox GRIP X2
The Grip X2 is said to be Fox’s most capable damper and features external high and low-speed compression and rebound adjustment for riders to fine-tune their setup.
Fox has increased internal tunability, especially on the compression damping circuit, providing more control over the damping curve and response.
Fox GRIP X
Providing the middle ground between the gravity-focussed GRIP X2 and the lighter GRIP SL dampers, GRIP X is Fox’s versatile trail damper.
GRIP X saves weight over the burlier X2 version and offers adjustments that are more usable on the fly. The trail damper still features a large 24mm base valve (just like the GRIP X2) to retain as much downhill performance as possible.
GRIP SL
The GRIP SL damper is all about being super-lightweight. Fox has ditched a few grams over the FIT4 system by replacing the external low-speed compression adjustment with a three-position lever for easy use on the trail.
Float EVOL air spring
The Float EVOL air spring is used across the entire Fox fork range. The EVOL name stands for ‘extra volume’ and indicates a large negative air chamber for more small-bump sensitivity.
Push-button bleeders
Push-button bleeders, which are located on the rear of the fork’s lower legs, are found on the Fox 36, 38 and 40. These pressure-release valves enable you to easily expel pressure built up in the fork lowers. The pressure build-up can be caused by rapid changes in temperature or altitude and negatively affect suspension performance.
Kabolt axle
The Kabolt axle is an optional replacement for Fox’s standard flip-lever axle. It’s lighter than the standard version, but requires a 6mm Allen key for installation and removal.
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