How often should my rear shock be serviced?
Most rear shocks should be serviced annually but if you're a DH racer you might
notice performance advantages of one or two services per year. This is due to the
relatively extreme conditions a bicycle shock has to operate in... mud, wet, cold,
hot & all this with as little as 100 ml of oil (that's 20 teaspoons to you & me).
So the oil has to deal with some pretty harsh conditions & even the best oils
will begin to lose their lubrication abilities & viscosity (thickness). This
can result in wear of shafts/bodies and also a reduction in damping (speed control)
of the shock. An annual service is much cheaper than a repair
or replacement of a trashed shock after 18 months.
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What work is done on a full shock service?
Before any service work is carried out the shock is cleaned & hand dyno'd to
check its operation. It's then stripped & all oil seals/o-rings are removed prior
to cleaning the individual parts in a chemical bath. Once cleaned & dried the
parts are inspected before fitting new Fox/PUSH seals/o-rings. Then we assemble
everything in accordance with the factory/PUSH procedures, put oil in the important
places & charge the shock with nitrogen. On air shox we pop the air can on with
some Float Fluid & pump her up to match your weight/bike. Next we do a leak
test for nitrogen (& air on air shox) before popping it on the hand dyno to
check all the adjusters do what they're meant to do. Next we replace the shock bushes
where necessary, install the mounting hardware/reducers (replacing any worn ones),
pop a small TF Tuned sticker on it & send it back.
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What can Custom Valving of my DHX/Van R achieve?
The oil flow through the piston of the rear shock is controlled by port volume (size
of holes) of the piston, the amount and configuration of shims (very thin washers
that bend under the pressure of oil) and the position of the rebound control needle.
By balancing all these elements you can change the characteristics of the shock
to help match how YOU want your bike to ride. You may want to have more low and
mid speed compression damping to help reduce pedal bob, or perhaps you've been down
the pub a little too much (put on weight) and need to up the compression throughout
the range. Whatever improvement you want, it can usually be achieved, especially if you go for the PUSH Factory Tuning or if it can't
we'll tell you.
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What's the difference between Pro-Pedal & PUSH Factory Tuning?
As with any mass-produced products there's always room for improvement by use of
better components and more customer-specific set-up. Apart from the high quality
of all PUSH components, the function of the PUSH Factory Tuning system has a smoother
transition from the 'Platform' to the bump absorption mode giving a lighter, more
speed-sensitive, less indexed feel. The platform is also varied to suit specific
bike designs and rider weight/style unlike the off-the-shelf Pro-Pedal. Another
benefit is that the dual-stage shim stack reduces the shock blowing through its
travel as well as reducing the mid-stroke wallow, especially in air shocks. Finally,
unlike the Pro-Pedal system, the low-speed rebound circuit can be changed to match
individual needs without affecting the high-speed circuit. This allows increased
low-speed rebound damping rates, which aids in controlling excessive movement, while
at the same time allowing the shock to respond more quickly in high-speed situations.
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What advantages can the PUSH system offer for RP3/23/Septune's?
As with any mass-produced products there's always room for improvement by use of
better components and more customer-specific set-up. The main improvements of the
PUSH RP3/RP23 system are...
- Improved rebound - A new piston is fitted to increase flow during higher velocities
allowing the shock to respond quicker in high-speed situations. The next aspect
of the rebound tuning involves different shim configurations, and is based on spring
rate/air pressure used and the specific bike, rider weight and style. Of course,
the final tuning is put in the hands of you, the rider, with the red Rebound Adjuster.
- As with all PUSH Factory Tuning Systems it has a smoother transition from the 'Platform'
to the bump absorption mode giving a lighter, more speed-sensitive, less indexed
feel. The platform is also varied to suit specific bike designs & rider weight/style.
Unfortunatly we cannot create a lockout feel, infact PUSH tuning usually has a softer
Platform although we can make them pretty firm when requested.
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My Float shox has stuck down (fully compressed) & will not extend - why?
Float Shox, at full extension have a bleed port that allows the air from the front
side of the air piston (main air chamber - positive) to pass into the backside of
the air piston (negative) to create a balance giving a plusher ride. If the air
piston seal for any reason during operation fails, then a large quantity of air
will go from the positive side to negative & prevent the shock from fully extending.
As the shock cannot fully extend it cannot balance itself & will remain stuck down.
The reasons for stuck down can be
- Air Piston Quad failure - usually happens when cold as the quad ring has less elasticity
especially on shocks assembled befor Jan 2007. Replacing the quad seal latest version
during service will normally cure this.
- Dirt/old grease build up in the bleed port - again a service will cure this
- Damage to the air can (usually seat post!) - if the air can is not perfectly round
air swap will occur. A replacement air can will be needed.
Procedure to check for a 'stuck down' shock
- Release air pressure from the shock by removing the air cap and depressing the Schrader
valve. You can use the top of the air cap to press in the Schrader valve.
- Using a High Pressure Pump, pressurize the shock to 250 psi.
- If the shock does not extend, it has become 'stuck down.'
DO NOT attempt to disassemble the outer air sleeve or any other part of the
shock. Air has become trapped in the air negative chamber and can cause serious
injury if the shock is disassembled.
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Why does it take TF Tuned Shox 3-4 days longer to service Float rear shocks with
worn bodies?
If your damper body (shaft) has any signs of wear (the one opposite is very worn)
we have to send your shock to the Fox distributor to get the damper body replaced.
This is because internal, 'exclusive' parts are only supplied to Fox Distributors.
When we get it back we will strip it down, do what we do inside (quite often different
from the Fox distributor) and then send it back. All a bit of a ball ache which
adds 3-4 days to the service cycle time.
Even a small scratch, where some grit has become lodged in the air can wiper seal,
is enough to cause air leakage during use resulting in the need to replace the body.
If your shox holds air whilst left in storage but slowly loses it whilst riding
the air is leaking between the air can seal and damper body. If you can't see any
scratches, replace the air can seal. Then if it still leaks whilst riding then it's
probably time for a new body.
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Why does my DHX make a tapping noise on small bumps?
You may have the 2005 model with the schraeder valve outside of the reservoir. These
shocks have a little shim which opens and closes when the shaft is moved in and
out. This shim adheres to the surface it is sitting on and releases with an audible
click. There isn’t anything that can be done, but it is not a problem. For 2006
onwards (DHX’s with the schraeder valve hidden inside the reservoir) Fox have fixed
this.
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What's the difference between Custom Valving and Push Tuning on my DHX?
Custom valving improves the ride of your DHX to stop it blowing through the travel
and also helps the shock to feel less vague when cornering or riding g-outs. This
is done by adding shims to control oil flow through the
piston. These are configured to rider weight, leverage ratio and riding preference.
This is included with the cost of the standard service on the DHX. Push Tuning removes
the piston bolt, piston assembly and existing bottom out pad. These are replaced
with Push parts to make the ride feel a lot more taught and predictable. It stops
the flat tyre feeling in some situations by stopping the shock packing down on repeated
big hits giving a less harsh feel. It also allows the shock to be set up fairly
linear as the longer, tunable conical bottom out pad controls the end of the stroke.
The improvement is most noticeable when banging it down fast rocky sections where
the smoother feel allows greater control with result that you can to go faster.
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Why does my DHX clunk and bang?
You might want to check your air pressure. The DHX operates between 75psi and 200psi.
If it drops below 75psi the boost valve in the reservoir can’t operate correctly
and will bang back and forth. Other symptoms will be uncontrollable rebound. Air
pressure can be lost through leaks from the air valve. It will be worth removing
the shock and putting it under water to see if air is leaking from the valve housing.
If this doesn’t help then you will have either a loose piston bolt which needs to
be stripped/ serviced. Or there could be a gap in the oil which needs to be serviced
also.
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My rebound adjuster has stopped working, it will only wind out.
It is likely that the back of the eyelet has filled with mud, this needs to be cleaned
out to get more rebound as the mud is clogging the threads stopping the rebound
adjuster being screwed in.
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Why does my RP23 knock in the Platform Off position?
This is the ProPedal valve shuttling between the compression and rebound stroke
and can’t be eliminated.