Boxxer Open Bath Cartridge Kit
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Rockshox Boxxer Charger Cartridge Upgrade Piston/Valve Kit

Discontinued

Technology


Keep in mind this kit does not reduce the maintenance issues associated with the sealed charger damper.
 We highly recommend you upgrade your pike using our open bath damper.

Thinking of upgrading your old Boxxer to the new Charger Damper?
Just order our open bath cartridge for your old Boxxer and be done with it.
Available Now!

Boxxer 35mm 2010-2015
Open Bath CustomValved Cartridge Kit

Retail Price $449

Why buy a charger damper when you have to send it to us anyway to get it to work!

 


 

This will make your fork feel like a completely different fork,
Low speed damping that’s firm but still blows-off to be plush on small bumps,
Reduced fork dive that eases the fork through the travel without harshness,
No more high speed compression spikes and no more bottoming with the ABS system.
Low speed compression and rebound adjusters help fine tune the valving as to how it transitions from low to mid and when the high speed kicks in,
Much more effective than the other dampers attempt to add high speed adjustment without the proper shim stack.

 

For those who want to keep the Charger damper and want a lower cost alternative to the complete cartridge replacement

We are offering a replacement compression valve and rebound piston kit for the Boxxer.

This kit will allow you to revalve and add adjustable midvalve to the charger damper. The stock rebound valve does have a midvalve of sorts, it is a 16 mm x .15 shim supported by a check spring with a bit of resistance.

Rockshox is using the same size cartridge as ours, (they use the same 20 mm cartridge and 6 mm ID shims that we use) and our rebound piston and compression valve from our cartridge fits right in and allows us to offer this as a tuning option for the stock internals. This would give riders the option to retain the charger damper system and add features to the internals that create tunable midvalves, compression and rebound ported valving and reshimming options and conversion to hydraulic oil lock ABS system option. The stock piston and valves are very limited as to what you can do to the shims for revalving and midvalve.
We hope to make this a self install kit, with shims to tune with, and a complete tuning guide with instructions.

The Piston/Valve Kit for the Charger Damper

Compression valve and rebound piston

* New Compression valve
retains 12 clicks of low speed adjustment.
* New Rebound valve with adjustable midvalves and 2 stage tapered rebound valving shims
Optional hydraulic oil lock ring and ABS cone
* No drilling, machining or grinding. Fits right in.



The Kit will come with an assortment of shims for revalving.
We will supply a set-up chart with options for tuning, based on air pressure, type of riding, and skill level.

1 - 4 port compression piston with o-ring
1 - 4 port rebound piston with piston band
compression shims
rebound shims
midvalve check plate, spool and spring assembly
Optional hydraulic oil lock ring and ABS cone
midvalve shims
sleeve O-ring
charger o-ring rebuild kit
Optional 5/8 hex tool for servicing bladder available

Optional hydraulic oil lock ring and ABS cone

Converts the new air ramp-up system to hydraulic oil lock system for a more effective bottoming system, the air ramp-up affects the last 1/2 of the travel adding to mid stroke harshness, the oil lock system only affects the last 40 mm. Option Price $89

*Self install kit assumes good working knowledge of internals and service procedures.

Need us to install it for you, just send your fork to us and we will install it for $100 including Spectro 85/150 oil.

Charger Cartridge Upgrade Piston/Valve Kit

 

 

Compression Piston

 

 

 

 

Rebound Piston and Midvalve Assembly

 

 

 

Discontinued

Rockshox Boxxer Charger Cartridge Upgrade Piston/Valve Kit, $229

Custom valved and set-up to rider weight, ability and riding style

Choose the type of riding that you will be doing so we can custom valve it to your specific needs.

Click here for a description of our definitions

Type of Riding

Choose your fork model that the charger kit will be installed in.

Fork Model

Choose rider weight.
Rider weight is without gear, we add 5-7 lbs for DH gear, 7-10 lbs for All-Mtn/Freeride.

Rider Weight

Choose the spring rate/air pressure you will be using which gives you 22% sag.
We need this number to help set-up your fork rebound damping correctly.

Click here for sag setting Tips

Spring
Rate/Pressure

Choose your rider ability for us to set-up the charger kit.

Rider Ability

 

 

 

 

Compression/rebound stock internals for the Charger damper

 

 

Stock Charger Rebound Piston and check plate assembly.

 

Stock Charger Compression Piston, notice the very large 2 port design with the threshold rim loaded valve.
It does not allow for fine tuning of the low speed transition, mid speed and high speed valving because full flow is achieved at very small valve opening making shim combinations feel basically on or off.

 

FAQ'S

The damper seems to have too much slow/low speed comression and feels a bit sBoxxery on slow bumps?
There seems to be too much preload on the check valve plate on the rebound piston. We managed to make a sleeve to space out the check plate but there is not enough room with the wider stock piston. Still has too much preload and this is causing the low speed harshness, sort of like a midvalve with no float. We ended up installing our whole midvalve assembly with our piston.

Just seems extreme ditching the Boxxer bladder for open bath, in that case might as well set up a Lyrik.
We agree, we feel the charger damper is a good but it still has a few areas that could be improved or changed. It needs a way to tune the shim stacks rather than the threshold adjust system it has. Next the rebound piston needs to be able to accommodate midvalves that can be tuned, the charger piston and arbor needs more space and features to be able to do this so since our 20 mm rebound piston fits right in (yes, Rockshox used the same cartridge 20 mm tube size and 6 mm shim arbor as we do, how convenient!) This is why we are offering a replacement piston/valve revalving kit the improves the performance and adds midvalves. For those who want the smoother, reliable and maintenance free open-bath cartridge we offer that too. The same pistons and midvalves that we use in the open bath system.

Will this add high speed adjustment to the Charger damper?
No, this adds a 4 ported compression valve that can be revalved with 2 to 3 stage valving set-ups rather than the regressive blow-off style valving that can only be used with the stock rapid recovery 2 port compression valve.

Are we going to change the low speed needle adjuster flow?
We are leaving the adjuster needles stock, they have a bit more range than we want, but still do a very good job fine tuning, doing this will add too much cost(compression side) and install complexity(rebound side) to the kit.

I assume the nitrogen sleeve is a phase 2 for your mod - yes? I see the ultimate value of the mod over the Open Bath
to be weight, resale appeal (no drilled holes, chassis mods)
Yes, this is an added option, again not required for all, as most riders will never push it hard enough to notice, ie it would be for firmer midvalve options and higher speed compression hits. The sleeve actually is very light, 25 grams essentially a thin tube 105 mm long. The open bath btw does not need and drilling or mods, in fact it would be a very simple self-install. The charger upgrade is a very technical tedious disassembly and reassembly process, the oil needs to be bleed exactly correct and maintenance is very sensitive to the performance. Any shock pump with a needle connection will work it does not need to be nitrogen, it will only need a few pumps to get to 20 psi. If the new owner wanted it would still function wit or without a charge. All properly valved sealed damper systems will always out perform an open bath in the most demanding damping conditions, it just may not be needed for most riders and you get all the complexity and maintenance issues. You also get the high speed adjustment feature, this is a big portion or the weight difference between the dampers.

if you want your shop to do it instead of you (maintain like a stock Boxxer per se). Wouldn't the nitrogen sleeve take away another chunk of the 110g weight savings and limit the ease of maintenance since you need a new nitrogen charge after servicing - leaving just resale appeal? Do you believe the nitrogen sleeve version would outperform the Open Bath in any way? Just seems like sucking up the 110g and going open bath may be the easier path :) Thoughts?

All dampers can cavitate when the pressure behind the piston drops below the vapor pressure of the fluid, this is why shocks are charged with nitrogen to keep the pressure applied to the fluid preventing this from happening. Most forks are filled with oil and have a smaller air volume that gets compressed as the fork compresses, this naturally works well in open bath preventing cavitation. For some reason MTB suspension companies are not aware of this issue and have been designing sealed dampers with no exterior way to increase pressure on the oil, i.e. they don’t put enough outside oil to cause this ramp up. MX suspension companies realize potential cavitation issue exists and design If the free bleed is big enough the pressure does not drop behind the piston. This is all good, but if you don’t create enough damping to hold the fork up on low speed conditions then what is the point. The issue is the addition of midvalves to prevent fork dive, can easily create low pressure behind the piston, especially if the main compression valve is soft or has a lot of free bleed, this is where the nitrogen charged bladder will prevent the pressure from dropping, it does not add any damping force it just adds to the air spring rate so you might run 2-3 psi less than the stock damper.

Would your mod not give me a better damped system and the midstroke support smooth out the rebound system ramp up?
Yes this is what we are trying to do, but it does create lower pressure behind the rebound piston.

So I get less change in forces on the Charger bladder?
Yes, I guess this could be an issue if the compression valve is set to soft and it might try to drive all the oil into the bladder after separation occurs in the oil from cavitation.

I understand that the friction connection and it being a bladder means if the force is too large the bladder can burst or break the connection?
No the bladder is kind of restrained by the fork tube, it expands to about 30 mm when filled properly, the id of the tube is 31.4 mm. The Nitrogen sleeve will be 29.5 mm ID and will also restrain the bladder similar to the shock's piggyback reservoir.


Keep thinking I want to do the mod (sounds like exactly what I want to change) and not just go open bath, but concerned with the longevity of the RS bladder design itself - is it still a weak point that will ultimately fail over time.
Adding the nitrogen sleeve will actually help prevent the bladder from breaking or ripping out of the end clamping sleeves. The bladder generally only fails if over filled and stretches too much causing it to tear at the clamping sleeve. It is not an issue with the failure of the bladder but letting it bulge without resistance therefore not adding any pressure to the oil. The bladder is just a simple piece or rubber tubing made of neoprene rubber, very cheap and easy to replace.

When will it be available? And how much?
Initial pricing will be $229. We will not be selling the kit at first as a self-install kit to the general public until we get a good handle on all the things people can do wrong and have it covered in the install manual. The install manual will the the long pole item in trying to get this kit to market. We will offer to do the install if you send the charger damper to us for service, $89 service fee.

 

techinfo@avalanchedownhillracing.com