Quantum Zero

owner’s Manual
Quantum Zero
owner’s Manual
Quantum Racing Services Ltd.
Station Approach Industrial Estate
Pulborough, West Sussex, RH20 1AQ

quantumracing.co.uk

First published January 2014

© 2014 Quantum Racing Services Ltd.

Text and illustrations

Laurence Wilson
Quantum Racing Services Ltd.

Published by
Quantum Racing Services Ltd.

Printed and bound in Great Britain by

Solopress.com

All rights reserved. No part of this publication

may be reproduced in any form or by any means
without the prior written permission of Quantum
Racing Services Ltd.
 9
10
13
22
27
Introduction
Damping curves
Basic operation
External adjustment
Routine maintenance
Introduction
Congratulations and thank This is doubly important because the
you for purchasing Zero shock effective area is proportional to the
volume of oil that will flow through
absorbers from Quantum. the adjuster and the pressure inside
the shock absorber.
We recommend you read this manual
thoroughly before making any Increasing the volume of oil available
adjustments to your shocks. to the adjuster means the adjuster
can be made bigger, thereby making
Zero is a family of mono-tube shock it less sensitive to manufacturing
absorbers with one or two ways tolerances.
of adjustment—upgrades that can
also be applied to the basic non- Increasing the area the adjuster acts
adjustable. upon reduces the pressure inside
the shock absorber, allowing it to
Quantum was the first to introduce respond quicker to small movements
to Formula 1 a two-way adjustable and high frequencies.
mono-tube shock absorber without
reservoir canister that was entirely All Quantum shock absorbers are
adjustable on the car. based upon this simple idea.
The Quantum Two.Zero is the latest This manual describes the operation
evolution of that game changing and care of Quantum Zero shock
design. absorbers—the Zero, One.Zero and
Two.Zero. They are entirely self-
The Two.Zero offers independent contained and do not require a
external adjustment of compression reservoir canister or base valve for
and rebound damping. This is made the purposes of external adjustment
possible by placing two adjusters or compression damping.
inside the shaft.

Placing the adjusters inside the

shaft puts them in parallel with the
piston. This is the best location for
an effective adjuster.

Any valve or adjuster that acts

across the piston affects an area
with a diameter equal to that of the
piston—unlike the valve or adjuster
inside a base valve or reservoir
canister that affects an area with a
diameter equal to that of the shaft.

Quantum Zero owner’s manual | 9

 Damping curves
When describing the operation of a shock absorber it is often
helpful to understand how information is displayed on a
dyno plot—the force vs. velocity curve produced by a shock
absorber dynamometer.
Shock absorbers are essentially timing devices. They are
unable to support the weight of a vehicle alone but will
influence how quickly the vehicle settles on its springs.

Hydraulic shock absorbers are velocity sensitive. The force

with which they resist movement varies with velocity. How
this force varies is entirely dependent upon the configuration
of the shock absorber.

The force experienced at the shaft is the

result of a pressure differential inside the
shock absorber. A pressure differential occurs
knee
when oil is forced to flow through small
apertures inside the shock absorber.

A simple force vs. velocity curve can be

divided in two: low-speed damping below the
low-speed high-speed knee and high-speed damping above the knee
(Fig. 1-1).
Fig. 1-1
Low-speed damping is
affected by bleed. Bleed occurs through
any orifice that does not vary in size during
operation, such as a drilled hole.

A bleed of fixed diameter will always produce

a progressive damping curve. If there are no
other valves, the force will
increase exponentially and
there will be no knee and no Fig. 1-2
high-speed transition (Fig.
1-2).

Adjusting the bleed or the diameter of the

hole affects the rate at which low-speed
damping force increases in kg/mms 2 between
Fig. 1-3 0kg and the knee (Fig. 1-3).

10 | © 2014 Quantum Racing Services Ltd.

 High-speed damping is affected by flow through a pre-loaded
valve. It begins when the pressure differential inside the
shock absorber is sufficient to open the valve.

If the pre-load applied to the valve can be

adjusted, the force at which the valve opens
can also be adjusted (Fig. 1-4).

The open area of the valve governs the rate

at which high-speed damping force increases
in kg/mms 2—just as it does for low-speed
damping.

A small poppet might only

Fig. 1-4
reduce the rate at which
the damping force continues to increase,

r
ea
whereas a large annular shim seat may cause

lin
the damping curve to ‘flat-line’.
digressive

Damping curves that show little or no

change in rate we refer to as being linear.
Damping curves that fall dramatically we call
digressive (Fig. 1-5). Fig. 1-5

When both axes of the graph are taken out to

low-speed curve
infinity, it can be seen that even a pre-loaded
valve will produce a progressive damping
curve (Fig. 1-6).

The bleeds and valves that define the shape

high-speed curve
of the compression-damping curve do not
need to be the same ones
that define the rebound-
Fig. 1-6 damping curve. This means
the compression and rebound
curves can be different.
compression damping
The two curves will often be illustrated on
the same graph with positive and negative
force and velocity in positive units only (Fig.
1-7).

The shock absorber will also exhibit different rebound damping

characteristics as it accelerates and
decelerates. The accelerating force values will
be lower than the decelerating force values
as the shock absorber changes direction, i.e. Fig. 1-7
at zero velocity (Fig. 1-8).

Quantum Zero owner’s manual | 11

 Separation between the accelerating and
decelerating curves occurs as pressure
equalizes inside the shock absorber. This is
decelerating curve called hysteresis.

It is desirable to reduce hysteresis to a

minimum but where steep low-speed curves
are preferred, hysteresis must be accepted as
accelerating curve
inevitable.

Note: In order to compare hysteresis between

two shock absorbers it is necessary to
replicate test conditions. Peak velocity and
stroke must be the same as well as adjuster
position.
Fig. 1-8
Note: Hysteresis can be characterized as a
delay in build up and release of pressure when the shock
absorber changes direction. It is particularly harmful to high
frequency short stroke operation. If the pressure inside the
shock absorber is unable to equalize sufficiently quickly, the
shock absorber may provide little or no damping immediately
after it has changed direction.

Hysteresis is the result of compressibility in the shock

oil, gases dissolved in the shock oil and even flex in the
components. It is at its worst when the differential pressure
is high—especially if the bleed adjusters are closed.

Shock absorber manufacturers will look to reduce the effects

of hysteresis by increasing the effective area of the valves.
This can be explained by the equation:

Force = Pressure × Area

The pressure inside the shock absorber can be reduced if the

area the valve acts upon is increased. This can be achieved
by increasing the diameter of the piston. Nonetheless,
where a reservoir canister or base valve is used for external
adjustment or compression damping, the shaft becomes
the piston—and because the effective area is so small, the
pressure differential must necessarily be high.

Hysteresis is inevitable but it can be alleviated by good

design. The best solution is to manage all damping across
the piston—as we do at Quantum.

12 | © 2014 Quantum Racing Services Ltd.

Basic operation
The Quantum Zero, One.Zero In compression, pressure inside the
and Two.Zero belong to a rebound chamber will decrease.
In extension, pressure inside the
family of mono-tube shock rebound chamber will increase. At
absorbers with excellent all times the pressure inside the
interchangeability of parts. compression chamber will remain
What follows is a brief consistent with that inside the gas
chamber.
description of the operation
of these shock absorbers. Note: Gas pressure should be greater
than the maximum anticipated
Figures referred to in the text can be operating pressure to ensure proper
found at the end of the chapter. operation.

The inside of the shock absorber

can be divided into three chambers: Compression
the compression chamber (Fig. 2-1.A, As the shock absorber is compressed
Fig. 2-3.A, Fig. 2-5.A), the rebound the shaft moves into the body and
chamber (Fig. 1.B, Fig. 2-3.B, Fig. the piston moves through the oil.
2-5.B) and the gas chamber (Fig. This causes the volume inside each
2-1.C, Fig. 2-3.C, Fig. 2-5.C). of the chambers to change. The
compression chamber and the gas
The piston separates the chamber will reduce in size. The
compression and rebound chambers. rebound chamber will increase in
These contain oil. size.

The gas chamber contains nitrogen. The amount of oil that must flow
This is kept separate from the oil through the piston—and thereby
behind the floating piston. the change in volume inside
the compression and rebound
At rest, the pressure inside all of chambers—is equal to:
the chambers is equal. All the time
the shock absorber is fully extended Change in volume = (Pi × Radius
this will be consistent with the of the piston 2 − Pi × Radius of the
recommended gas pressure. shaft 2) × Travel

When the shock absorber is caused

to move, the piston moves through
the oil. In doing so, oil must flow
through the piston. The restriction
of the valves will cause a pressure
differential either side of the piston.

Quantum Zero owner’s manual | 13

The shaft displaces a volume of its jet (Fig. 2-5.G). The oil enters the
oil. This is compensated for by a rebound chamber via cross-drillings
reduction in size of the gas chamber. in the shaft.
The change in volume of the gas
chamber is equal to: It is possible to adjust the restriction
externally. Turning the CD adjuster
Change in volume = Pi × Radius of the clockwise introduces the CD needle
shaft 2 × Travel further into the jet, increasing the
restriction.
i. Zero: Negative pressure inside the
rebound chamber causes oil to flow ii. All variants: As the velocity of
through the bleed jet. The diameter the shaft increases, so too does the
of the jet causes a restriction. The difference in pressure inside the
jet is of fixed diameter and cannot shock absorber.
be adjusted externally.
When the difference in pressure
Oil flows through the jet (Fig. 2-1.D) becomes sufficient, the
and into the rebound chamber via compression-damping valve stack
cross-drillings in the shaft (Fig. on the backside of the piston opens.
2-1.E). The specific pressure is determined
by the choice of piston and the
i. One.Zero: Negative pressure quantity and thickness of the shims.
inside the rebound chamber causes
oil to flow through the bleed jet. Oil flows around the rebound-
A restriction occurs where the oil damping valve stack and through the
passes between the jet and the piston. A build up of pressure on the
needle. back of the compression-damping
valve stack causes the valve stack
Oil flows through the jet (Fig. 2-3.D) to deflect (Fig. 2-1.F, Fig. 2-3.F, Fig.
and around the needle (Fig. 2-3.E). 2-5.H) and the oil enters the rebound
It enters the rebound chamber via chamber.
cross-drillings in the shaft.

It is possible to adjust the restriction

Rebound
externally. Turning the adjuster As the shock absorber extends the
clockwise introduces the needle shaft moves out of the body and
further into the jet, increasing the the piston moves through the oil.
restriction. This causes the volume inside each
of the chambers to change. The
i. Two.Zero: Negative pressure inside compression chamber and the gas
the rebound chamber causes the chamber will increase in size. The
RD check shim to open (Fig. 2-5.D) rebound chamber will reduce in size.
and the CD check shim to close (Fig.
2-5.E). Oil flows through drillings i. Zero: Positive pressure inside the
in the perimeter of the RD jet (Fig. rebound chamber causes oil to flow
2-5.F), bypassing the RD needle. through the bleed jet. The diameter
A restriction occurs where the oil of the jet causes a restriction. The
passes between the CD needle and jet is fixed diameter and cannot be

14 | © 2014 Quantum Racing Services Ltd.

adjusted externally. difference in pressure inside the
shock absorber.
Oil flows through cross-drillings in
the shaft (Fig. 2-2.D) and into the When the difference in pressure
compression chamber via the jet (Fig. becomes sufficient, the rebound
2-2.E). damping valve stack on the topside
of the piston opens. The specific
i. One.Zero: Positive pressure inside pressure is determined by the choice
the rebound chamber causes oil of piston and the quantity and
to flow through the bleed jet. A thickness of the shims.
restriction occurs where the oil
passes between the jet and the Oil flows around the compression-
needle. damping valve stack and through
the piston. A build up of pressure
Oil flows through cross-drillings in on the back of the rebound-damping
the shaft. It passes between the valve stack causes the valve stack
needle and the jet (Fig. 2-4.D) and to deflect (Fig. 2-2.F, Fig. 2-4.F,
enters the compression chamber via Fig. 2-6.H) and the oil enters the
jet (Fig. 2-4.E). compression chamber.

It is possible to adjust the restriction

externally. Turning the adjuster
clockwise introduces the needle
further into the jet, increasing the
restriction.

i. Two.Zero: Positive pressure inside

the rebound chamber causes the
CD check shim to open (Fig. 2-6.D)
and the RD check shim to close
(Fig. 2-6.E). Oil leaves the rebound
chamber via cross-drillings in the
shaft and flows through drillings
in the perimeter of the CD jet (Fig.
2-6.F), bypassing the CD needle.
A restriction occurs where the oil
passes between the RD needle and
its jet (Fig. 2-6.G). The oil enters the
compression chamber via the RD jet.

It is possible to adjust the restriction

externally. Turning the RD adjuster
clockwise introduces the RD needle
further into the jet, increasing the
restriction.

ii. All variants: As the velocity of

the shaft increases, so too does the

Quantum Zero owner’s manual | 15

Fig. 2-1
Fig 2-2
Fig. 2-3
Fig. 2-4
Fig. 2-5
Fig. 2-6
External adjustment
Quantum One.Zero and Two.Zero shock absorbers are
externally adjustable. Adjustment is made by turning a
knurled collar—or clicker—on the top eye.

Quantum One.Zero
The Quantum One.Zero is one-way
adjustable. It has a single clicker on
the top eye. Adjustment affects both
compression and rebound damping.

Low-speed adjuster
Type: Bleed adjuster
Affects: Bleed across the piston
in both directions
Effective area: 1,185.7mm 2
Number of clicks: 24±1
Full stiff: Position 0, fully
clockwise

Note: The effective area can be calculated

using the following equation:

Effective area = Pi × Radius of the piston 2 −

Pi × Radius of the shaft 2

It is equal to the volume of fluid that will

pass through the adjuster for one unit
length of travel.

22 | © 2014 Quantum Racing Services Ltd.

Quantum Zero owner’s manual | 23
 Quantum Two.Zero
The Quantum Two.Zero is two-way
adjustable. It has two clickers on the top
eye. The clicker nearest the shaft affects
compression. The clicker furthest from
the shaft affects rebound.

Low-speed compression adjuster

Type: Bleed adjuster
Affects: Bleed across the
piston in compression
only
Identification: The clicker nearest the
shaft
Effective area: 1,185.7mm 2
Number of clicks: 24±1
Full stiff: Position 0, fully
clockwise

Low-speed rebound adjuster

Type: Bleed adjuster
Affects: Bleed across the
piston in rebound only
Identification: The clicker furthest
from the shaft
Effective area: 1,185.7mm 2
Number of clicks: 24±1
Full stiff: Position 0, fully
clockwise

24 | © 2014 Quantum Racing Services Ltd.

Quantum Zero owner’s manual | 25
Low-speed adjuster effect on the Note: All adjustment should be made
from position 0, full stiff. At this
damping curve position the needle will bottom out
Quantum One.Zero and Two.Zero in the jet. Full soft is not so clearly
shock absorbers are low-speed defined as the total number of clicks
adjustable. This means the rate at can vary due to manufacturing
which damping force increases in kg/ tolerances.
mms 2 between 0kg and the knee can
be adjusted externally (Fig. 3-1). Note: Do not force the clickers past
full stiff of full soft. Doing so could
Note: The shape of the damping damage the adjuster. Do not use any
curve and the range of adjustment tools to adjust the clicker, e.g. pipe
are heavily influenced by the choice grips, mole grips, etc.
of piston and the internal valving.
The illustration should be considered
an aid to understanding only. tiff
full s
0—
ition
Pos
Adjustment affects the open area
of the bleed jet. The One.Zero has
one bleed jet that affects both oft
ls
ful
compression and rebound damping. 4—
io n2
The Two.Zero has two bleed jets that sit
Po
affect compression and rebound
damping independently.

The adjuster inside the One.Zero

comprises a needle and a jet. The jet
has a hole with a fixed diameter. The
needle is the same diameter as the
hole at its base and tapers to a point
at its tip.
Fig. 3-1
The needle faces into the jet. An
adjuster rod passes through the
shaft and contacts the back of the
needle on one end and a cross-pin
in the clicker on the other. Turning
the clicker clockwise introduces the
needle further into the jet, thereby
reducing the open area and further
restricting flow.

The Two.Zero has two needles and

two jets. Both jets have the same
open area, which is the same as the
single jet in the One.Zero. Each jet
flows in one direction only.

26 | © 2014 Quantum Racing Services Ltd.

Routine maintenance
With proper care and absorber to cool it down.
maintenance, your Quantum
• Periodically inspect the spherical
shocks should prove joints for play. The ball should be
exceptionally durable. tight in the housing.

Service intervals are difficult to • Do not allow the shaft to rust.

predict as environmental conditions The shaft is hard chrome plated
can vary wildly. Shock absorbers and will resist corrosion well
subjected to road dirt and grime and but it is advisable to lubricate
those near the exhaust will require it regularly with WD40 or similar
more regular servicing than those penetrating oil—particularly
protected from the elements on top underneath the bump rubber and
of the pedal box. around the eyelet base where
moisture can collect.
We suggest that you visually inspect
the shocks regularly and observe the • Do not attempt to adjust the
following recommendations: height of the spring platform
without first removing loose dirt
• Keep the shock absorbers clean from the body.
and dry.
Dyno testing your shock absorbers
The shaft bearing is fitted with a is the only acceptable means to
wiper seal but it is effective only determine if they are performing as
in preventing foreign materials expected. Shocks should always be
from being drawn into the shock tested in pairs—where this applies—
absorber. It will not prevent to be sure they match.
dirt from accumulating around
the shaft. If this is allowed to Over a period of time the oil inside
happen the risk of damage to the the shock absorber will degrade.
shaft is increased. As the bore of the shock absorber
wears, microscopically small particles
Keeping the shocks clean and dry of aluminium become suspended
makes it easier to identify leaks. in the oil. If the intervals between
servicing are too great, this can
• Try to keep the shock absorbers cause accelerated wear.
cool. Make every effort to
keep the temperature equal Only by opening the shock absorber
across axle pairs. If one shock can the condition of the oil and the
runs hotter than the other— internal components be assessed. If
be this because it is closer to the oil has blackened or smells bad,
the exhaust or for any other it should be changed.
reason—direct air onto the shock

Quantum Zero owner’s manual | 27

All Quantum shock absorbers are
supplied with Motul 5W shock oil.
This is the only oil we recommend.

With regular servicing there should

be no reason not to expect an
exceptional service life.

28 | © 2014 Quantum Racing Services Ltd.

 Your Quantum shock
absorbers were supplied by:

Quantum is committed to a policy of continuous product development and reserves the right to make changes
to specifications and prices without prior notice. The illustrations contained within depict generic designs. Some
external features and other details may differ from the product supplied. The information in this manual can
therefore be given as guidance only. While Quantum makes every effort to ensure that specifications are accurate at
the time of publication, you should always check with your authorised distributor for up-to-date information.