Why we fix them!

Comparison Chart

 

Brand/Model

Fox / RC4

 

Features

Coil over Shock
High/Low Compression adjuster
Boost/Bottoming Control
Rebound adjuster
Preload/Spring Rate Options

Short Comings
Details
Fix
Larger shock shaft moves too much oil through reservoir
5/8" vs 1/2"
Modify internals to accommodate more flow
High speed adjuster creates too much harshness when increased

stiff adjuster spring rim loads shim stack, creates too much mid speed damping
Change piston design to be a shimmed blow-off valve, increasing high speed compression is now independent of mid speed damping
Boost valve is position sensitive
(gets stiffer when shaft is deeper in stroke, good for bottoming bad for square edged)

Reservoir pressure assisted end of stroke position sensitive compression pop it valve

Replace with the SSD speed sensitive custom valved shimmed four port piston valve, prevents bottoming without high speed harshness
High speed rebound too slow
(generically valved)
Generically valve to best compromise all spring rates
Revalve with 2 stage custom shimmed for stoke and spring rate.
Low speed compression adjuster has limited range
(can't set soft enough)
Low speed bleed is too small to soften the LS compression
Low speed bleed is increased and a longer tapered needle is installed to double the LS adjustment range
Shaft seals have too much stiction
Bottom-out bumper in effective for end of stoke ramp-up
(anti-clunk only)

squats outwardly with no constraint, no ramp-up resistance

Shape factor, ramps-up progressively as it conforms and fills the shape of the spring inner diameter

Brand/Model

Fox / DHX 5.0/4.0

 

Features

Coil over Shock
Propedal adjuster
Boost/Bottoming Control
Rebound adjuster
Preload/Spring Rate Options

Short Comings
Details
Fix
Propedal system is position sensitive, not speed sensitive
As pressure increases in the reservoir the valve gets stiffer
Replace with the SSD speed sensitive custom valved shimmed four port piston valve, prevents bottoming without high speed harshness
Propedal adjuster creates too much harshness when increased
Too much reservoir pressure force on valve creates low to mid speed harshness when increased
Remove Propedal and replace with low speed adjuster needle and SSD valve.
Boost valve is position sensitive
(gets stiffer when shaft is deeper in stroke, good for bottoming bad for square edged)
Reservoir pressure assisted end of stroke position sensitive compression pop it valve
Replace with the SSD speed sensitive custom valved shimmed four port piston valve, prevents bottoming without high speed harshness
High speed rebound too slow
(generically valved)
Generically valve to best compromise all spring rates
Revalve with 2 stage custom shimmed for stoke and spring rate.
No Low speed compression adjuster
Propedal valve only provides high speed damping
Use the Propedal knob to control the newly installed low speed needle to provide low speed adjustment, 15 clicks
Reservoir volume too small, causes pressure ramp-up in middle and end of stroke
Pressure can ramp-up to nearly 1500 psi, this is what controls the boost valve!
Modified reservoir reduces pressure ramp-up to under 400 psi, extended reservoir keeps it around 200 psi
Shaft seals have too much stiction

Standard buna o-ring with high friction urethane grip dust seal

Double lip Viton oil seal, oil wiper barrier and mud and dust scraper system

Bottom-out bumper in effective for end of stoke ramp-up
(anti-clunk only)

squats outwardly with no constraint, no ramp-up resistance

Shape factor, ramps-up progressively as it conforms and fills the shape of the spring inner diameter

Brand/Model

Fox / VanRc

 

Features

Coil over Shock
Low speed compression adjuster
Rebound adjuster
Preload/Spring Rate Options

Short Comings
Details
Fix
Low speed compression adjuster has limited range (can't be set soft enough)
Low speed bleed is too small to soften the LS compression
Low speed bleed is increased and a longer tapered needle is installed to double the LS adjustment range
High speed rebound too slow
(generically valved for all spring rates)
Generically valve to best compromise all spring rates
Revalve with 2 stage custom shimmed for stoke and spring rate.
High speed compression adjuster has regressive/threshold
(too firm then blows thru)
Uses belleville washers that snap over to open on high speed hits, creates no progression in high speed valving, i.e. blows through the stroke to easily
Replaced with high speed tapered shim valve stack to prevent bottoming but allow for blow-ff on square edged high speed hits
Reservoir volume too small, causes pressure ramp-up in middle and end of stroke
Longer strokes created to much ramp-up in reservoir pressure
Replace with extended reservoir to reduce pressure to keep it around 200 psi
Shaft seals have too much stiction

Standard Buna o-ring with high friction urethane grip dust seal

Double lip Viton oil seal, oil wiper barrier and mud and dust scraper system

Bottom-out bumper in effective for end of stoke ramp-up
(anti-clunk only)

squats outwardly with no constraint, no ramp-up resistance

Shape factor, ramps-up progressively as it conforms and fills the shape of the spring inner diameter

 

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techinfo@avalanchedownhillracing.com