The Shock Lab

Sweet Fox squirts on camera 💦🎥

These 2021-2025 Fox X2 (and other 🦊) have a reputation for getting aerated prematurely, ingesting air pressure from the air can into the damper 👎

The air can is pressurized up to 350psi at full extension, while the damper is only filled to 100psi, this creates a massive pressure difference that's basically asking for air migration 🙅

If that wasn't enough, these used to use a Polyurethane dynamic o-ring at the sealhead, which works good for sealing oil and has amazing abrasion resistance, but these aren't good for sealing air 💨

The issue with these, is that they are too stiff to conform to the microscopic imperfections on the sealing surface, which is exactly where the air creeps through 🫧

Softer compounds (even NBR) work much better for sealing air, but HNBR and FKM can offer improved wear and/or chemical resistance. We use premium FKM seals on our damper service kits, and we'll finally have our air can service kits officially available soon 🤘

While the X2 is now known as one of the least reliable shocks in history, the latest 2026+ version is quite the opposite, at least in some ways. Making it one of the most overbuilt air shocks I've seen in recent years, do you think it can change the reputation of the X2? 🤔

Speaking of the latest X2, I'm working on a full rebuild video with a couple upgrades, dropping soon 🔥

What do you want to see next? 🤔

Fox air spring service 🧈

This Fox 38 uses a tube-in-a-tube air spring design, whos main purpose is to increase the lower leg volume, as the space between the tubes all the way up to the dual o-rings is part of the lowers, decreasing unwanted ramp up 🤘

Interestingly, the latest Fox 38 ditched this smart design for their "Glidecore". And what's even more interesting, is that the Rockshox fork lineup now uses a tube-in-tube air spring design 🙃

I've been thinking...one brand has the tube-in-tube to increase lower leg volume, the other has the Glidecore to (supposedly) maintain better air spring alignment and reduce friction. Is it possible to combine them? 🤔

In fact, it is. And it already exists (kind of) 👀
Using a "cartridge" air spring has several benefits, obviously increasing lower leg volume, but also, being connected only at the top and bottom of the fork, allow it to maintain alignment (relatively) independently from the chassis flex 🔍

And it doesn't stop there, this can be explored much further; making a localized "flex" area (right under the top cap, for example) that reduces/eliminates the flex elsewhere in the air spring would take it to the next level 🤘

I mean...we could probably integrate a buttercups-like system on there...seems like I may be doing some prototyping work on my old Öhlins fork 👀

Yeah, I know...we went off topic a bit there 😅

Another interesting fact, is that the "old" Fox 38 uses the same size air piston as the Fox 34, as the 38 is basically running a 34 stanchion inside it 🔍

The scariest part of the service can be clamping directly against the sealing surfaces (like the air shaft) for disassembly, specially with metal clamps, a bit of slippage or a wrong move and you've scratched the sealing surface ☹️

Our 3D printed clamps are soft and have a "stop" that prevents you from crushing/ovalizing the shaft, they have an outstanding grip at low clamping forces, specially when using a bit of Powerwash soap, in other words, they're great for beginners! But of course, keep in mind they're plastic so keep your distance from the heat 🔥

Affordable tools, premium supplies, and professional service. L

Service your fork 🤌 Now easier than ever 🔥

Suspension can be complicated internally, but a 50h service is normally quite straightforward and something you can do at home with mostly basic tools 🤘

The lower leg service involves just dropping the lowers, cleaning, swapping the seals, changing the oil and reassembly. Sounds easy! 🤙

However, you need to handle the parts carefully as they're relatively delicate and a scratch on a sealing surface can be expensive 💸

Always make sure to check your service manual, specially for oil and torque specs, which are different between brands and models 🔍

Our DIY service kits can include SKF seals, oil, grease, gloves and syringes, they start at $49 and make the service as easy and straightforward as it can be 🤘

Still not sure? No worries, we can take care of it. The basic service is just $49 + parts, usually around $90 including SKF wiper seals.
Our full service is only $99-109 + parts, usually $160-200 including full rebuild kit and SKF seals 🔥

Our mail-in service process is as straightforward as possible, just fill out the service form, you'll get shipping instructions and we'll take care of the rest! Our current turnaround time is ~6-8 days 🔄

Wether you want to do it yourself or send it in for service, we can help! Link in bio 🔗

Looking for the service manuals? Google this:
"Fox bike help center"
"Rockshox Trailhead"
"DVO service guides"
"Öhlins document library"
"Cane Creek suspension service instructions"

Hope that helps, otherwise send me a message! 🤙

The easiest shock to service? 🤔

The Öhlins TTX22 has been around for over a decade with only minor updates. It's an amazing performer, easy to service, and it can be custom tuned/optimized for your setup 🔥

The official 100h service procedure involves replacing the bladder, sealhead and bottom out bumper. That's it! ...although the service kit is ~$90 💸

The service tools you'll need are only a few, but keep in mind that you have to use a vacuum pump in order to get all the air out of the system 🔧

Now, it may be simple to service, but the engineering behind it is absolutely nuts, the twin tube damper featuring low and high speed compression as well as low speed rebound is packaged elegantly within subassemblies in the shock 🤘

Now, adjustment range can be pretty limited, it only has 6 clicks of rebound, but that was certainly done on purpose, as people tend to crank the adjuster in (or out) until it feels "good", often overcompensating with low speed damping what should've been addressed with custom tuning.

Keeping a relatively narrow adjustment range makes it easier to notice when you need (and encourages you) to get the proper tune 🤘

Although this shock was a bad example...these are quite robust and reliable. It's not common to see them fail (unlike 🦊), but they still need some love periodically. Recommended every 100h of use 🤙

What should we cover next? 🤔

Öhlins service guide in 3 minutes ⏰

FULL/SLOWER VIDEO IS UP ON YOUTUBE ▶️

Most of the guide also applies to newer RXF forks and TTX damper variants, make sure to check your service manual, specially for torque values and lower leg volume ⚠️

RXF36 service made simple, this is (pretty much) one of my all-time favorite forks, released around 2015-2016, these were way ahead of their time, so much that other brands are still trying to catch up 🤌

Starting with the air spring, this is a 3-chamber air spring using self-equalizing positive and negative chambers, as well as a ramp up chamber inside the air shaft, which can use a travel/volume reducer, offering an infinite amount of adjustability 🔥

Now you can find similar systems on other fork brands, as well as aftermarket upgrades, although their effect or adjustability may vary 🤘

Similarly, this STX was their "entry level" damper, which may look a lot like (and outperform) many modern dampers. And don't even get me started on the TTX, which, in my opinion is still the most advanced fork damper out there (yes there's a new version now) 👀

Their air spring uses a Silicone o-ring for the main piston, which can be quite draggy, I recommend replacing these with FKM for reduced friction, and we've found that the SG920 grease from Maxima can further boost their performance 🧈

Removing the negative volume reducer is an official upgrade/update on its own, and for some reason the new air spring has/had that spacer again, take it off! 🙅

Now, let's talk service kit prices...WHAT THE F...

SKF (blue) lower leg kit - $60.99
Air spring rebuild kit - $99.99
Damper service kit - $75-85.99

I know making forks that last 10+ years isn't good for business, but come on... 😅

Our built-in-house service kits (and tools) for Öhlins are now available! We're trying to make suspension service more accessible 🤘

Worn forks are not fun; they look and perform horribly, and your friends will judge you (if they don't, I will) 😡

Service your sh*t 🤌 You can do it yourself, or we can do it for you...either way, link in bio! 🔗

Fox X2 "basic" air can service - part 2 🔧

You probably already know: an air can service isn't possible on the X2, not without taking the damper apart 💀

This (and being 🦊) makes it one of the worse MTB shocks to try and DYI. Don't believe me? Let's take a look at the specialty tools (taken from the official service page):

398-00-419: Negative seal head tool - $165
803-01-690: Air can shaft clamps - $83
803-00-805: Damper shaft clamps - $132
398-00-887: Damper sealhead tool - $49
398-00-882: Rebound valve tool - $71
398-01-174: Compression valve tool - $39
803-00-566: Single IFP tool - $144
803-00-969: Damper body clamps - $97
803-01-545: Reservoir clamps - $66
803-01-578: VVC adjustment tool - $529
398-00-280: Standard eyelet tool - $102
398-00-951: Trunnion eyelet tool - $100
803-00-463: Vacuum bleed adapter - $44
803-01-986: IFP fill adapter - $34

That's over $1600 on specialty tools, most of which work ONLY for 2021-2025 X2s. WHAT THE F... 😡

That's ~10 times more expensive than the Vivid tool kit (and no, I'm not biased towards RS, I'm biased against BS) 🤬

Now, these are the parts you "need" to get your X2 updated to the official 2024 Fox spec:

230-45-605: Updated damper shaft - $25
204-18-708: Updated damper body - $56
812-06-118(or 125)-KIT: Updated sealhead - $46
803-01-932: Updated tuning kit - $70
808-14-086-KIT: Updated trunnion eyelet: $180

That's close to $400 in just updates, that doesn't include the ~$55 service kit or the service itself. THAT'S ABOUT $600 🤯

And even after all the 2024 updates, I wouldn't call it a reliable shock...the improvement to aeration was arguably minimal, and they did absolutely nothing to make the air can seals more robust or serviceable 🙃

If you have one of these 2021-2023. TRY TO GET IT REPLACED UNDER WARRANTY, it really makes no sense to pay for all this, for $600 you might as well get a different shock 🙅

But, if you want to keep it running (and have no warranty), better seals is all you need, FKM damper seals alone have worked miraculously to prevent aeration on these, and now the improved air can seals will prevent air leaks for a long time! 🤘

Continued in comments...

Another one bites the dust 💀

Trunnion really sounded like a good idea at the time, right? Reduced eye to eye length allows engineers to save space within the frame and/or get more creative with the designs. HOWEVER...

A Trunnion shock is secured directly at the shock "head", it's bolted straight to the frame which is extremely stiff, it doesn't flex, not even a little bit 🤏

Is that a bad thing? Absolutely, your frame flexes under load (some more than others), and this results in misalignment at the shock, which forces it to flex with the bike 🙅

Normally, the shock is mounted with DU (or polymer) bushings, which allow for a bit of flex to reduce side loads at the shock, the 12.7mm wide eyelets themselves can also flex a little bit with heavy loads 🤘

Now, this bike (won't tell you the brand but it's a GIANT manufacturer that makes bikes for several companies) combines a Trunnion mount at the top, with a direct (no bushing) interface at the bottom, making an extremely stiff connection that is VERY bad for shocks. But hey, at least they didn't add a clevis extension... 😬

And of course, this is not uncommon for the Fox DPS, which uses an Aluminum 9mm damper shaft and breaks even if you look at it wrong... ☠️

What's the moral of the story? Service your sh*t. Specially if you ride a bike using Trunnion mounts, clevis extensions, or both (WHY THE F...)

Back for warranty - WHAT HAPPENED? 🤔

We're taking apart this X2 to figure out what the problem is, it started leaking pressure after 10 months of riding, which is technically outside our current air can warranty, but we don't see warranties often, so we can be quite flexible 🤙

But most importantly, I want to figure out the issue and see if it's something we did wrong or if there's something we can improve 🔍

So, let's take the air can apart real quick...oh wait...the engineers decided air can services are overrated. We need to take apart the whole shock 🙃

Yes, that means to de-pressurize the damper, disassemble, drain, then build it back up, vacuum bleed it...only to access the first seal that gets contaminated, the one that's most likely to leak. Holy sh*t, what were you guys thinking?! 😡

"Calm down bro, they did all they could, maybe it's not even possible to service the air can separately with this layout, right?"
Yeah...that kind of makes sense, IF THERE WEREN'T OTHER BRANDS WHO HAVE DONE IT FOR YEARS 🤬

I don't mean to compare (I actually do), but the Cane Creek DB air has always had a 2 piece sealhead that lets you service the air can. So does the Öhlins STX and TTX shocks, AND THE ROCKSHOX VIVID...

Maybe this wasn't an issue considering most X2s would aerate prematurely and require a full service before the air can even had issues, but that's another thing I want to talk about...

THERE IS NO AERATION. I'm sure you were waiting for me to get showered in shock oil as usual with these, but there was absolutely no air in the system...how?! 🤔

This isn't a $100 upgrade, or $50, not even $10, upgrading your seals to FKM will cost you next to nothing and will dramatically improve the damper reliability of your X2 (or any 🦊 shock).

What about the air can?
We've been using OE (or similar) seals for the air can and I haven't been happy with the soft wiper seals they use

These new wipers are stiffer and provide a much better internal and external seal against contaminants. They will be featured on our custom air can service kits and will allow us to increase our air can warranty to 1 year as well 🔥

Part 2 dropping soon 🔜

TTX Air Service - PART 2

This story is too good not to share: "AI said to turn this gold k**b to adjust compression" 🫪 "And it said it often gets stuck" 🫪🫪🫪

To be fair, the k**bs can be a bit confusing for some, and the "clicks" on these aren't really that noticeable. That said, it's one of my favorite trail shocks, like a mini-X2 (without the premature aeration) 👀

Speaking of which, did you notice the air can is already disassembled, without having to take apart the damper? Just saying 👀

This allows you to service the air can separately as needed and prevent worn/damaged parts, exactly as shown in the video 😢

The damaged damper body is a sealing surface, and scratches/wear can result in pressure leaks, even with fresh seals. Replacements start around $25 for some brands, but the damper body for this puppy is ~$100 💸

And sometimes it goes like...*unavailable at US distributor, 6+ weeks ETA* 🙃🙃🙃

In fact, both the replacement end cap kit and the damper body were unavailable for weeks. Is there something we can do? 🤔

Stay tuned for part 3 👀

Quality control? Never heard of her... 🤔

Have you noticed how, even with fresh bushings, the hardware can be a bit (or very) loose?

Yes, there is 2 OE part numbers for these fl**ge bushings, one of which is supposed to fix this exact issue, but if you've used them before, you know they don't actually help 👎

The "standard" bushing is 0.598" x 0.501", it's a relatively common size and works beautifully for 15.00-15.02mm eyelets
Their "special" bushing has a smaller (WTF?) OD at 0.5925" x 0.498", giving it an interference of only ~0.015mm (~0.0005") against the eyelet. I guess they wanted it to rely more on interference with the hardware, not the eyelet...have you had shocks where the bushing spins against the eyelet? Yeah...that's why 🙃

A lot (or most) of the modern Fox shocks are oversized, pretty consistently, almost like if they were doing it on purpose...there must be a reason then 🤔

Maybe they want to keep the friction low at the eyelets, but I think they may have taken it a bit far(?) 😬

Anyway, I'm not a fan of Fl**ge bushings since they must be removed to securely clamp the shock for service, and they often get stretched/deformed in the process, forcing you to replace them, even if they were in good shape 😢

Sleeve bushings (you don't have to buy them from me) can stay in place during the service, and their continuous contact surface (compared to split fl**ge bushings) improves their durability, even with heavy side loads 💪

For 15.03mm+ eyelets, DU bushings (like those found in Rockshox shocks) are my personal choice, these fit considerably tighter against the eyelet, and are burnished to size after installation for the perfect low friction fit 🧈

For Fox, Öhlins, and DVO hardware, you'll also need to compensate for the missing fl**ges, you can machine or 3D print your own. We actually use 3D printed Igus spacers designed to be used with square cut o-rings to effectively seal off against contaminants and keep the original spacing, I'd be happy to share the 3D file if you need it 🤙

And of course, the Igus bushings, custom spacers, and the installation/burnishing tool are all available on the website. Link in bio 🔗