Stock Charger Rebound Piston and check plate assembly.
Stock Charger Compression Piston with Pedal Lock-out plate, notice
the very large 2 port design with the threshold rim loaded valve.
Makes for a good on off switch for pedal and lockout but does not
allow for fine tuning of mid and high speed adjustment and valving.
The damper seems to have too much slow/low speed compression
and feels a bit spikey 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 Pike 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. Firstly it has a
pedal/lock-out knob that is useful for some but most seem to want
more tuneability for the downhill or open mode. Secondly it needs
a way to tune the shim stacks rather than the threshold adjust system
it has. By converting the pedal/lock-out knob, changing the piston
and threshold system to a independent high speed adjuster it now
can be adjusted in all positions for increased adjustment range
for descend riding. Essentially 3 clicks of high speed with 12 clicks
of low speed for each high speed setting. Thirdly 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, adds midvalves
and converts the pedal/lock-out knob to a high speed adjuster. 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 RC?
The RC does will not have the high speed adjust as it does
not have the lock/pedal knob, this knob is what we are converting
when we make the high speed adjustable, all other features will
be added including the ability to preset the high speed spring rate.
How is the HSC range with just the 3 settings?
The HSC has a wide range with the standard HSC adjuster spring,
we also provide a softer and firmer optional spring that could be
installed for finer tuning or even wider range. We convert their
threshold adjuster into the HSC adjuster, we are using this mechanism
to change how it controls the stiffness of the high speed shims,
so when converted it uses the same 3 positions as before, we would
call them soft, med and hard settings rather than the open, pedal
and lock. Soft has no preload from the HSC spring, medium uses about
4 mm of preload and hard uses about 8 mm. The goal is to provide
more useful range of adjustment rather than settling for one or
two clicks that sort of work.
I'd bet most riders on a Pike spend almost all their
time in the Open mode. To bad to have 2/3 of a shock's settings
barely being used.
Yes, we feel the lock is completely worthless for
this kind of fork and the trail or pedal mode is still way too stiff
for most, so why not convert it to a more usable setting, this is
what our kit addresses. The trail setting or pedal mode with the
low speed set at 6 out becomes the standard setting or midpoint
between harder and softer overall compression. Click it to lock-out
and it is firmer high speed compression with the same low speed
or click it to open and it it will be softer high speed compression.
This high speed compression range is controlled by one of the 3
high speed springs and the shim stack arrangement options we provide
with the kit. When lighter low speed settings are selected the dive
will be addressed with the midvalve system added as part of the
kit, this comes with adjustable shimming options too.
Are we going to change the low speed needle adjuster
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'm not OK with 2/3rds of the fork's setting being
unusable because the Trail is too harsh, the Lockout is useless
on a trailbike.
Yes, other the past year we have been following the complaints about
the Pike charger damper and have developed a bunch of design changes
to address them, overall a much better damper than the mission control,
but it should be since they used our cartridge dampers as guidelines
to make a mass production version with their own twist on it. We
are just converting it to a more useful adjuster system, adding
our finishing touches and custom tuning it for you.
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 Pike 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.
But I keep seeing the lockout and existing rebound system
system introducing larger deltas/spikeness which should be worst
case - no?
The lockout is upstream of the valves and pistons and does not create
cavitation or any extra pressure on the bladder, it is all taken
out at the compression valve.
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