For 2025, Fox has utterly redesigned their Manufacturing unit-level GRIP fork dampers with an all-new valve structure that makes them concurrently plusher and extra supportive.
With the said function of “Pushing Attainable Additional”, the brand new GRIP SL, GRIP X, and GRIP X2 be offering distinct tuning traits for 3 distinct kinds of riders. With previous generations, they’d a fork chassis (32, 34, 36, 38, 40) for each motorbike class. Now, they have got a damper to possess each class, too.
Right here’s the whole thing you want to understand concerning the subsequent era of GRIP dampers…
2025 Fox GRIP Dampers are all about Drive Balancing
The important thing buzzword on the 2025 GRIP release used to be “Drive Balancing”. It’s a tuning philosophy that, due to the usage of a lot more complex dimension gadgets they’ve began the use of within the fork, permits them to create drive differentials within the damper shaft.
I’ve spent hours speaking with Invoice Brown, Fox’s VP engineering, to are aware of it, and you’ll be able to concentrate to my podcast interview with him for extra. However right here’s a graphic to assist illustrate why drive balancing issues. It’s additionally numerous textual content (sorry, now not sorry), however that’s as it’s so much to give an explanation for.
What’s the TL;DR model?
The brand new GRIP dampers assist you to use extra compression damping whilst nonetheless being much less harsh due to new compression damping valves that allow the fork react extra temporarily to high-speed affects. When you’d love to how they did it, learn on…
Each and every fashionable sealed monotube damper cartridge makes damping at two puts – the compression Base Valve, and the Mid Valve. The Base Valve is the place the compression damping circuits (shims, ports, valves, and so forth.) are positioned and has generally been the one position the place compression damping used to be managed (for all manufacturers, now not simply Fox).
Whilst it’s going to seem like the Mid Valve is a plunger that pushes oil up throughout the Base Valve, the truth is that it’s successfully a sieve that we could oil cross via it freely between spaces B and C within the graphic above. Because the Piston Shaft is driven into the damper, it displaces oil, and that oil has to move someplace…and that someplace is throughout the Base Valve into house A.
That oil in A then compresses the IFP, which has a coil spring in the back of it to push the oil again throughout the Base Valve all through rebound (extra at the IFP later).
So, as a result of oil most commonly* flowed freely throughout the Mid Valve, the oil drive in B and C used to be most commonly the similar. That intended the entire compression damping needed to be treated by means of the Base Valve’s Top (HSC) and Low (LSC) valves.
The issue is, that takes an excessive amount of time & power.
We’re speaking milliseconds right here. Fox says an ordinary whole compression whilst you hit a large bump takes about 30 milliseconds. Reside Valve building taught them that people can discover one thing as temporarily as 5ms (Now not related right here, however as an FYI, Reside Valve can discover and open the valve in 3ms).
So, because it solely takes us about 5ms to note a bump, and about 30ms for a whole HS compression, making the compression circuit react even a couple of milliseconds sooner is the adaptation between a bump feeling harsh as opposed to managed.
The important thing to studying this used to be creating new drive sensors that have been speedy sufficient to seize what used to be taking place within those new dampers. Fox is now measuring right down to sub 1ms, and in accordance with the brand new knowledge, they made a couple of key adjustments:
- They added a compression damping circuit to the Mid Valve
- They made the Base Valve’s diameter a lot greater
- They gave the HSC shim stack dramatically extra tunability
Let’s wreck the ones down:
Mid-Valve compression tuning
The principle factor used to be that since the Base Valve used to be doing the entire paintings, the GRIP 2’s HSC circuit needed to be robust sufficient to withstand minor affects. That intended it took extra power to turn on the HSC, so it took a couple of milliseconds longer to begin controlling an affect. From a rider’s viewpoint, that’s perceived as “harshness”.
So, Fox added some gentle compression damping to the Mid Valve, which is able to react extra temporarily. As it’s reacting extra temporarily to keep an eye on an affect, the whole damping will also be softer initially, so the fork feels much less harsh.
Via calmly proscribing the glide of oil from house B to house C, they’re converting the drive differential between the 2, therefore the time period “drive balancing”. It’s now not an enormous trade, as a result of the rest dramatic would begin to create a vacuum in C, which would scale back or do away with the rebound circuit’s skill to serve as. So, it’s balanced, to create the required impact with out messing up rebound.
Then, because the affect compression forces develop, they begin using the Base Valve’s circuits, however the ones are actually higher, too:
Larger Base Valve = higher glide
Word the adaptation in base valve diameter within the symbol above (GRIP 2 at the left, GRIP X2 at the proper). Via the use of the Mid Valve to care for one of the most damping, Fox may just use a bigger diameter Base Valve with larger ports and extra shim stacks. This additional glide gave them extra keep an eye on over the transition from oil flowing throughout the orifices (low pace) to pushing open the shims (excessive pace).
Smoothing the discontinuity in forces between the ones two is how they handle clean traction all through that transition in order that there’s no unexpected distinction in how the fork behaves because it transitions between gradual and speedy compressions.
For the brand new GRIP X2, that more room additionally allow them to use extra and bigger diameter shims within the high-speed circuit’s shim stack. The picture above presentations the minimum shim stack of the GRIP 2 as opposed to the bigger X2, and I’ll give an explanation for why that issues additional down when discussing the X2 damper particularly.
Not more FIT4 damper
All 3 use their spring-backed IFP, there’s not more FIT4 damper within the lineup. We dive into why within the podcast, test that out, however the wanting it’s this: Eliminating the FIT4’s bladder, which wanted room to make bigger to carry oil overflow because the fork compressed, intended much more room for the damper itself…which is a large a part of how they won the additional diameter to do all that stuff discussed above.
The spring-backed IFP design could also be more effective and extra dependable. It has a bleed port (the little hollow at the aspect of the tube within the symbol above) that we could any damping oil that will get ingested into it to bleed out and flow into into the lowers moderately than get trapped and motive the fork to “pump up”. The damping oil is equal to whats within the decrease legs, so it’s advantageous in the event that they combine.
All of this equals extra keep an eye on, much less harshness
Since each the Mid Valve and the high-speed circuit can react extra temporarily, slowing down the fork as quickly because it begins to compress, you’ll be able to upload extra high-speed compression damping, and but have a much less harsh fork. Principally, you don’t must run the HSC broad open to have a “plush” fork anymore. Or, as they put it: “Make stronger when you want it. Damp extra, harsh much less.”
There’s additionally just about no lag within the transition from the low pace to the high-speed, which a few of their best riders have been delicate to. The forks really feel extra constant and predictable all the way through their shuttle without reference to whether or not you’re swooping via a berm, ripping throughout roots, or each concurrently.
*NOTE: Technically, Fox’s prior GRIP 2 Mid Valves did play a small function within the fork’s music; they weren’t utterly benign. However for sensible functions, the brand new GRIP dampers made them an lively a part of the fork’s compression damping. Oh, and that new sub-1ms trying out apparatus? Brown says they’re seeing extra issues at that point that they suspect they are able to toughen.
2025 Fox GRIP damper choices
The brand new GRIP dampers are category-optimized in accordance with the use case:
- GRIP SL (xc/marathon/downcountry)
- GRIP X (path)
- GRIP X2 (enduro/all-mountain/gravity)
For SL, the focal point used to be weight. For X, the focal point used to be giving the standard mountain biker a candy spot of efficiency and helpful adjustability with out bells and whistles they hardly ever use. For X2, it used to be about maximizing tunability, each internally and externally, for riders pushing the bounds.
Regulate dials are goal constructed for every damper, too, providing you with get right of entry to to just the options you truly want for a given use case.
The brand new dampers are most commonly lighter than earlier than, too:
- GRIP SL is 60 grams lighter than Fit4 in 100mm shuttle.
- GRIP X is 120 grams lighter than Grip X2 in 160mm shuttle
- GRIP X2 is just a 20 gram building up over Grip2 in 160mm shuttle
Right here’s what you want to find out about every damper:
GRIP X2
Coming from the GRIP 2, which used to be excellent, their function used to be to extend tunability. Having spent years customized tuning the forks for his or her best professional riders, they sought after to enable you to do inside customized tuning for the professionals, but in addition upload extra helpful exterior tuning so each rider can have the benefit of it. Mixed with the brand new Mid Valve structure, it delivers “tunability with out penalty.”
Principally, they sought after to offer the motorbike a trophy truck really feel, the place the function is to stay the tires at the floor whilst minimizing vibration and damaging comments from achieving the rider. However you want some comments for a motorcycle, so the rider can sense what the motorbike is doing and assist handle traction.
The compression base valve is way greater (24mm vs 20mm), and there are extra shims. GRIP 2 had 7 shims, the GRIP X2 has 23 shims. That’s greater than a 3x development in tuning vary.
Additionally has a sooner reaction, so it’s appearing at the compression extra in an instant for a extra predictable really feel, they usually say it makes the highest finish of the damping curve extra helpful. Which means, in the event you get right into a truly competitive path, you’ll be able to crank the high-speed compression damping as much as care for it, which isn’t one thing we’d typically do with the outdated machine.
The massive useful distinction is that the HSC ports are actually greater, permitting extra oil glide, in order that they added extra shims to withstand that glide. Principally, they moved the HSC oil glide control from the ports to the shims, which supplies them much more tunability. The wave spring (to the precise of the shim stack within the symbol above) quite a bit an intermediate “pivot shim”, which places extra drive at the heart of the shims. The (black) hat that preloads the pivot shim is a tunable merchandise…that means, it’s an element that they are able to switch out with other designs to customized music the fork internally.
Finally, there’s now higher separation between compression and rebound so there’s much less pass communicate between them. One gained’t impact the opposite.
The GRIP X2 keeps the four-way adjustment of exterior excessive/low pace compression and excessive/low pace rebound. It’s to be had on 36, 38, and 40 sequence Manufacturing unit and Efficiency Elite forks. Some motorcycles might spec this damper in a 34 chassis, however it’s an OEM-only choice.
GRIP X
Fox’s function for the GRIP X damper used to be to “Dominate All-Mountain” by means of providing 4-way adjustable efficiency in a 3-way damper. Which means, it’s going to accomplish like an X2 for many riders, however loses the exterior high-speed rebound adjustment.
Previous to this, you wanted to make a choice from an staying power, XC-focused damper (FIT4) or a gravity-oriented damper (GRIP 2). Now, the GRIP X is goal constructed for what maximum people are driving – path to all-mountain.
It makes use of a simillarly outsized base valve because the GRIP X2, however has it’s personal tips tailor made for riders who climb up trails up to they bomb down them.
The largest distinctive function is a brand new “Tremendous Company” mode blended with a brand new outer HSC bezel with a small indicator nub.
The middle LSC dial acts simply love it did earlier than, providing you with an enormous vary of low-speed compression adjustment. However the brand new HSC knob sweeps 170º and serves a couple of functions. The primary ~90º is solely pushing a spring down at the shim stack, toning up HSC. After that, it begins to press down at the low pace compression valve, sooner or later last it off utterly.
This allows you to use a unmarried dial to company up the fork for hiking, then temporarily open it again up, all with out affecting the low-speed compression circuit. Which means, you’ll be able to depart LSC the place you love it, however nonetheless have one thing like a “hiking” mode. The addition of the tiny nub lever supplies a visible indication of the place it’s at, so you’ll be able to temporarily go back in your most popular HSC environment, too, with no need to depend clicks.
For Rebound, they restricted it to LSR, which allowed them to make a smaller, more effective mid-valve (test the comparability photograph up above, it’s so much smaller than GRIP X2!). In addition they narrowed the adjustment vary a little, so every click on could have a extra nuanced adjustment.
You’ll to find this at the Fox 36, 38, and 40 forks in Manufacturing unit and Efficiency Elite trim ranges.
GRIP SL
For the SL, the function used to be to make the lightest conceivable damper whilst additionally making improvements to efficiency relative to FIT4. Racers need gentle weight, the power to hold extra pace with extra self assurance, and a lockout. The GRIP SL damper supplies all 3.
A three-position compression knob has the standard Company, Medium, and Open modes, however it’s additionally to be had with a far off lockout choice. The lever supplies solely low-speed compression damping controls, and the lockout has a blowoff simply in case.
The GRIP SL damper is made for shuttle from 40-130mm shuttle, for gravel to 34 SC, and all else being equivalent, this plus a brand new Kabolt SL axle (it’s butted at the within to save lots of 12g) makes the 2025 34 Step Forged fork 62g lighter than earlier than.
The Open makes use of a mixture of mid-valve and base-valve (drive balancing!) for a buttery clean really feel over any terrain. The Medium (“pedal”) function provides extra damping into the bottom valve to offer it a little of a platform. And the now-larger lever at the knob makes it more straightforward than ever to achieve down and flick it into the “attack-ready” Company mode, whether or not the fork is loaded or now. It has a 140º sweep from open to closed, with forged detents so that you don’t must bet the place it’s at.
To be had on 32 TC (gravel), 32 SC, and 34 SC forks in Manufacturing unit and Efficiency Elite ranges.
New GRIP dampers are backward suitable
All of those dampers are backwards suitable with all present chassis, providing you with the power so as to add those to all in their present forks way back to 2021-22, relying on type.
The MY25 forks may also have new bushings, which not have bleeder channels to flow into oil above and underneath the bushings. Now, the ones ports are forged into the lowers, so you’ll be able to’t retrofit the brand new bushings into your older fork, however it truly doesn’t subject – The brand new seals do technically have decrease touch drive since there’s extra floor house, which means that much less friction, however even Fox says the adaptation is minimum. Marginal positive factors, despite the fact that…
In addition they have an eMTB music, usually with a somewhat softer compression music that’s useful for managing the quicker hiking speeds.
What concerning the Efficiency-level forks?
The prior GRIP 2 damper carries over at the Efficiency point merchandise, however with up to date music and drive balancing to succeed in one of the most identical efficiency enhancements. It gained’t be Manufacturing unit point, however it’s higher than earlier than.
Are they shuttle adjustable? Do the fork chassis trade?
Every shuttle increment calls for a definite air spring, since the piston must line up with the switch port. So, sure, the forks are shuttle adjustable, however it’s important to purchase a brand new air spring to modify them.
The uppers and lowers for all forks except for the 32 SC raise over unchanged. The 32 will get an entire overhaul, which is roofed in a separate publish. For the remaining, Fox additionally gives e-bike explicit chassis.
Shuttle choices for all chassis are:
- 34 SC – 100-120mm
- 34 – 120-140mm
- 36 – 140-170mm
- 38 : 160-180mm
Whoa, whoa, whoa… what’s up with that Gold fork?
That’s a unique version popping out this summer season to have fun Fox’s fiftieth anniversary. Extra main points will come nearer to its liberate date, but when you need one, communicate in your native motorbike store now in order that they’re on it.
First impressions trip evaluation, coming quickly.