Fox VanRc/Performance RC and Marzocchi Bomber CR
Speed Sensitive Damper Mods
Best AVA option for custom valving for coil compatible progressive/rising rate linkage designs!
What if my frame has a more linear or only a slightly progressive linkage?
You need to consider your bike's travel and intended use.
If it is a all mountain or enduro bike, you are not a big jumper, are mostly
trail riding and you want that coil feel:
Are you are able to categorize your riding as trail mostly, only do small
drops and
try to avoid high speed g-outs?
Then you could consider replacing your air shock with a coil over shock.
You will need to consider your spring rate carefully and the shock will need
a much more aggressive bottom out system.
We can help you determine if your frame is compatible and determine the extent
of restraint you will need.
We have been offering the coil BomberCR/VanRC shock for custom tuning. This
coil shock chassis with
our tuning and modification provides a plush coil feel which you are looking.
The coil system allows for
independently setting the ride height(sag), with an adjustable preload collar,
without increasing the spring rate
(over pressurizing caused by an air shock) and it resists bottoming with a
tapered bumper system without?
the midstroke ramp caused by an air shock.
Why is this shock your best choice for a custom valved Fox/Marzocchi shock?
Low initial cost (under $350 new)
Larger midvalve style main piston (27 mm same as 11-6)
Shimable compression adjuster design for tuning high speed harshness out.
Compact light weight design that fits nearly all frames.
Compatible with most aftermarket springs as well as Fox's new SLS springs.
Works with all hardware reducer options and RWC needle bearings.
Available in standard sizes, metric sizes and trunnion mount.
Reconfigurable mix and match parts for eye2eye and stroke changes.($89)
Custom Size eye to eye and stroke($125)
Chromed Steel shaft upgrades(124.95)
And many other options listed below
Set it and forget it tuning simplicity.
Custom sized BomberCR 165 x 45mm Trunnion (724 grams with 600 lb spring) for Evil Following (V2-V3)
Why do I need a compatible linkage that will accept a linear
coil shock?
A progressive linkage starts at a much higher leverage which makes the shock
feel softer at the top of the stroke,
as the shock compresses the leverage will make the shock spring feel stiffer
and the shaft speed will also increase
causing the damper to automatically feel firmer to resist bottoming naturally.
This allows us to valve the shock for a plush, supportive feel with no bottoming.
Matching shocks up with the proper leverage allows them to use all the travel
effectively and perform at their best without band-aid solutions,
such as over damping, stiffer springs, larger bumpers and of course position
sensitive bottom out devices in the reservoir or air can.
How do I know if my frame has a compatible progressive linkage?
If your bike lists coil options or uses a very large air can system with no
volume reduction spacers, more than likely its fairly progressive.
Also if you have maximized the air volume and still can't use all the travel
then the rate is very progressive.
or
List of some of compatible bikes with our coil conversion:
Banshee Prime, Spitfire, Titan V3
Canfield One.2/Balance/Lithium/Jedi/Riot
Canyon Sender/Torque/Strive/Spectral On CRF
Commencal Supreme/Clash/Furious/Meta 4.2/ Meta Power Meta TR
Devinci Spartan/Troy/Wilson
Evil Calling/Offering/Insurgent/Wreckoning/Evil Following 165 x 45(V2/V3)
Forbidden Druid, Giant Reign/Trance, GT Fury Team
Guerilla Gravity Gnarvana, Trail Pistol, The Smash
Ibis Rimpo V2 AF, Intense Tracer/Taser
Knolly Fugitive 138/LT/Warden/Lithium
Kona Process Operator/Process 153/167
Mondraker Crafty R/Dust RR
Nukeproof Dessent/Mega V3/V4/275, Oreba Rallon/Rise
Norco Aurum HSP/Range/Sight
Revel Rascal
Rocky Mountain Slayer/Instinct/Altitude/Power Play
Santa Cruz V10/Nomad/ Megatower/Bronson/5010/Hightower(limited by spring dia)
Scott Ransom/Genius/Voltage
Specialized Turbo Levo/Kenevo/Stumpjumper/Demo
Trek Slash/ Rail
Yeti SB130/140/150/165
YT Tues/Decoy/Jeffsy/Capra
2020/21 Specialized
Enduro (with shorter
modified reservoir)
Transition Sentinal, Patrol(2019-20 Carbon requires 10 mm shorter reservoir
or shorter stroke)
($29.95 request via e-mail)
Click here for our current list of Bikes compatible with the BomberCR/Van coil shocks
Some linkages do not provide as much progression typically needed for a coil
conversion.
To allow less progressive linkages(less than 20%) to accommodate a coil shock
we have
engineered our tapered bumper system with various tapered bumper sizes to
increase the resistance needed
to make up for the lack of end progression.
We also use larger 1.50 inch ID springs(std size is 1.38 inch) to allow the
bumper system to fit and to provide more
clearance with the shock body to eliminate wear on the body. It also comes
a with a friction reducing spring collar.
Even progressive linkages(20-35%) can take advantage of the tapered bumper
system. The system allows
the coil spring and damping to be set as soft as possible to provide a smoother
transition
from a softer midstroke to a firm end stroke for better squared edged performance
while providing for increased bottoming resistance.
Without the proper bottoming system, the coil spring rate would have to be
a bit
stiffer and this stiffer spring choice would reduce the small bump performance
as well.
We feel that progressive springs ramp up too fast in the midstroke and prevent
square edged bump
absorption performance. Larger riders have difficultly setting the sag with
the softer initial rate and
the overall result is a stiffer feel in the midstroke.
Not on the list, Just call or e-mail us!
This modification consists of a revalved main piston and modification of the compression adjuster to convert the VanRC/Bomber CR to a true speed sensitive damper.
Includes custom valving and setup for rider, frame leverage and conditions, and printed set-up chart.
Also includes complete rebuild service, new improved seals and dust wiper system, oil, nitrogen charge and typical wear parts* included in price
Available Sizes
We can recommend a spring rate and shock size and you can order here:
Standard: 7.5x2.0”, 7.7875x2.0”, 7.7875x2.25”, 8.5x2.5”,
8.75x2.75”, 10.5x3.5"(custom size)
Metric: 190 x45mm(custom), 210x50mm, 210 x52.5(with 2.5 mm spacer), 210x55mm,
210x60(custom), 210x65(custom),
230x57.5mm(with 7.5mm spacer), 230x60mm(with 5 mm spacer), 230x62.5(with 2.5mm
spacer),
230x65mm, 230 x 70mm(custom), 230 x 75 mm(custom)
250x70mm(with 5 mm spacer), 250x75mm
Trunnion: 165x45mm(custom), 185x50mm(with 5mm spacer), 185x52.5mm(with 2.5mm
spacer), 185x55mm,
205x60mm(with 5 mm spacer), 205x65mm, 225x75mm(with 5 mm spacer), 225x75mm
( For custom sizes please call or e-mail)
*(Typical wear parts: shaft seal, dust scraper, shaft bushing, reducer DU
bushings, and o-rings)
Includes New Interactive Set-Up Chart
Example
Low speed adjustment - Modified low Speed Adjuster system with wider range 22 click low speed adjustment. Midvalve design for supportive low speed compression with plush small bump performance (no need for lock-out lever). High speed adjustment - Internal Shim Stack tuned to leverage curve of linkage and rider needs. Revalvable high speed shimmed compression adjuster system to tune out high speed harshness and dial in bottoming control Low speed rebound adjustment - 16 clicks low speed adjustment and revalved high speed shim stack to match rider weight and spring rate. Suggested spring rate based on rider weight and bike leverage supportive feel and maximized performance
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Optional:
Hard coated aluminum IFP with bleed screw ($29.95)
Hybrid Progressive Bumper with 1.50 inch(38mm) ID adaptor Conversion Kit,
(Reduced Friction, 1.50 collars and Tapered bumper system bottom out control)
($54.95)
Reduced Stroke (2.5, 5, 7.5mm) spacer additional ($24.95)
We stock light weight Avalanche/Rockshox/NukeProof/MRP
springs starting at ($59.00), SL $139
Rockshox/Fox DU style reducer bushings or Fox Flange style starting at ($24.95)
see below to add options:
The Van R requires requires a compression adjuster style new upper for mods
to be performed.
Damper Modifications apply to:
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Performance/Van
RC |
Bomber CR |
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BomberCR 190 x 45 10 mm shorter reservoir and tapered bumper system
VanRc Shape Factor Bottom-out Bumper
Fox VanRC
Modified Compression Adjuster System |
Fox VanRc/Bomber CR Speed
Sensitive
Damper (SSD) Modifications Shock must be sent in to receive modifications. Price $279 options shown below Order Here and Send Shock for Modifications Price $279 Do you have a BomberCR/VanRc with the wrong eye2eye
and stroke Optional Chrome Steel Shaft Upgrade
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VanRc/Bomber CR Modifications The BomberCR/VanRC is Fox's redesigned DHX that has the the Propedal valve removed and replaced with a low speed threshold Belleville spring style valve, this setup limits the high speed tuning and with a very limited low speed adjuster range, it is difficult to find a good setting. We convert the compression adjuster to a shimmed system for infinite tuning options and a smooth transition from low speed to high speed without that harsh feel. This makes the BomberCR/VanRC a true speed sensitive damper but with emphasis on pedal performance with our midvalve shim arrangement on the main piston(what we call supportive low speed compression). We have developed a modified version of BomberCR/VanRC valve that uses shimmed high speed valving, a wider range low speed adjuster for more sensitive low speed performance and more progressive high speed damping feel while still allowing it to blow-off on square edged bumps. This now allows us to revalve the main piston valving to complement the redesigned adjuster system. We also provide a wide range of bottom-out bumpers that match the end stroke needs.
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Advanced Shape
Factor Bottom-Out Bumper Click here for Technical Description Custom sizes that work best with the Price $24.95
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Fox VanRc/Marzocchi Bomber CR/Fox DHX Improved IFP's
The Internal Floating Piston in the BomberCR/Fox are non anodized or plastic, the IFP begins to wear and allows the IFP to tip in the reservoir and allow air and oil to leak between them. The BomberCR/VanRc's IFP are made of plastic and do not provide a bleed screw, these are always recommended to be replaced. This replacement IFP has been redesigned with a wider land and tighter tolerances and prevents this from happening. It is also hard coat anodized to prevent wearing out. We may suggest
you replace the stock IFP when we inspect your internals or Add option here Price $29.95
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Fox VanRc/Marzocchi BomberCR/Fox DHX Fox Upgraded design IFP's with glide band
After
2 or 3 years of riding the Internal Floating Piston The BomberCR/VanRc's IFP are made of plastic and do not provide a bleed screw, these are always recommended to be replaced. This Fox IFP has been redesigned with a glide land and tighter tolerances and prevents this from happening. It is also hard coat anodized to prevent wearing out. Add option here Price
$44.95
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Fox VanRc/Marzocchi BomberCR/Fox DHX Replace rubber squish plug with schrader valve reservoir end cap
This allows for easy charging, leak proof compared to squish plug design and overall nicer flush design. Uses Fox internal Schrader charge adaptor, no need for needle charging system. Add option here Price
$44.95
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It includes:
Improved Bumper Cup Collar replaces the flat
spring retainer and constrains $54.95 Why not use a progressive spring? Well the progression begins as the coils starts to progress and generally creates too much to soon and affects the midstroke absorption of deep square edged bumps. A bumper system can be used to only affect the end of the stoke thus allowing most of the travel to deal with deep edged bumps while preventing bottoming. Even if your frame is progressive you can still benefit from a taller tapered shape factor bumper system. We feel the end stroke still benefits from a tapered bumper system because we are trying to make the valving blow off for square edged deep stroke ledge bumps, so we can keep the valving plusher and rely on the bumper system as well. What most refer to as progressive linkages may not be as progressive
as downhill coil like linkages and if it can still accommodate both
air and coil it may have a linear or regressive end stroke. We make
4 different tapered bumpers and 3 sizes of the reverse shape factor
$16 budget bumpers(more abrupt but provide some protection and less
ramp up) that work with the stock spring.
Bumpers are custom made for stroke and ramp up required for each tune. |
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Optional Chrome Steel Shaft Upgrade
55 mm Chrome Steel Shaft and Arbor Bolt shown
52.5, 57.5, and 62.5 mm require shaft spacers, sold below.
$169.95 |
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Need your shock stroke shortened?
$24.95
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Need your shock reservoir shorter for clearance?
$29.00
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techinfo@avalanchedownhillracing.com