Xray XB4 User manual

2
The XRAY XB4 is a modern, high-competition premium luxury racing 1/10
electric 4WD off-road buggy that is the epitome of high-performance and
fine distinctive design. Your XB4 offers highest performance, responsive
handling, and traditionally exceptional XRAY quality, engineering, and
design. The superb craftsmanship and attention to detail are clearly evident
everywhere on the XRAY XB4.
XB4 was designed around a no compromise platform; the attention to detail
creates a low maintenance, extra long life nitro buggy. The ultra-low center
of gravity (CG) and optimized weight balance makes set-up, driving, and
maintenance easy and quick.
The XRAY XB4 was created by blending highest-quality materials and
excellent design. On high-speed flat tracks or bumpy tracks, whether driving
for fun or racing to win, the XB4 delivers outstanding performance, speed,
and precision handling.
We have made every effort to make these instructions as easy to understand as
possible. However, if you have any difficulties, problems, or questions, please
do not hesitate to contact the XRAY support team at [e-mail].
Also, please visit our web site at www.teamxray.com to find the latest
updates, set-up information, option parts, and many other goodies. We
pride ourselves on taking excellent care of our customers.
Failure to follow these instructions will be considered as abuse and/or neglect.
CUSTOMER SUPPORT
XRAY Europe
K Výstavisku 6992
91101 Trenčín
Slovakia, EUROPE
Phone: [phone]
Fax: [phone]
Email: [e-mail]
We have made every effort to make these instructions as easy to understand as possible.
However, if you have any difficulties, problems, or questions, please do not hesitate to
contact the XRAY support team at [e-mail]. Also, please visit our Web site
at www.teamxray.com to find the latest updates, set-up information, option parts, and
many other goodies. We pride ourselves on taking excellent care of our customers.
You can join thousands of XRAY fans and enthusiasts in our online community at:
www.teamxray.com
XRAY USA
RC America, 2030 Century Center Blvd #15
Irving, TX 75062
USA
Phone: [phone] * [phone]
Fax: [phone]
Email: [email protected]
SAFETY PRECAUTIONS
Contains:
LEAD (CAS 7439-92-1) ANTIMONY (CAS 7440-36-0)
WARNING: This product contains a chemical known to the state of California to
cause cancer and birth defects or other reproductive harm.
CAUTION: CANCER HAZARD
Contains lead, a listed carcinogen. Lead is harmful if ingested. Wash thoroughly
after using. DO NOT use product while eating, drinking or using tobacco
products. May cause chronic effects to gastrointestinal tract, CNS, kidneys, and
blood. MAY CAUSE BIRTH DEFECTS.
When building, using and/or operating this model always wear protective
glasses and gloves.
Take appropriate safety precautions prior to operating this model. You are
responsible for this model‘s assembly and safe operation! Please read the
instruction manual before building and operating this model and follow
all safety precautions. Always keep the instruction manual at hand for quick
reference, even after completing the assembly. Use only genuine and original
authentic XRAY parts for maximum performance. Using any third party parts on
this model will void guaranty immediately.
Improper operation may cause personal and/or property damage. XRAY and
its distributors have no control over damage resulting from shipping, improper
construction, or improper usage. XRAY assumes and accepts no responsibility for
personal and/or property damages resulting from the use of improper building
materials, equipment and operations. By purchasing any item produced by XRAY,
the buyer expressly warrants that he/she is in compliance with all applicable
federal, state and local laws and regulation regarding the purchase, ownership
and use of the item. The buyer expressly agrees to indemnify and hold harmless
XRAY for all claims resulting directly or indirectly from the purchase, ownership
or use of the product. By the act of assembling or operating this product, the
user accepts all resulting liability. If the buyer is not prepared to accept this
liability, then he/she should return this kit in new, unassembled, and unused
condition to the place of purchase.
IMPORTANT NOTES – GENERAL
• This product is not suitable for children under 16 years of age without the
direct supervision of a responsible and knowledgeable adult.
• Carefully read all manufacturers warnings and cautions for any parts used in
the construction and use of your model.
• Assemble this kit only in places away from the reach of very small children.
• First-time builders and users should seek advice from people who have
building experience in order to assemble the model correctly and to allow the
model to reach its performance potential.
• Exercise care when using tools and sharp instruments.
• Take care when building, as some parts may have sharp edges.
• Keep small parts out of reach of small children. Children must not be allowed
to put any parts in their mouth, or pull vinyl bag over their head.
• Read and follow instructions supplied with paints and/or cement, if used (not
included in kit).
• Immediately after using your model, do NOT touch equipment on the
model such as the motor and speed controller, because they generate high
temperatures. You may seriously burn yourself seriously touching them.
• Follow the operating instructions for the radio equipment at all times.
• Do not put fingers or any objects inside rotating and moving parts, as this
may cause damage or serious injury as your finger, hair, clothes, etc. may get
caught.
• Be sure that your operating frequency is clear before turning on or running
your model, and never share the same frequency with somebody else at the
same time. Ensure that others are aware of the operating frequency you are
using and when you are using it.
• Use a transmitter designed for ground use with RC cars. Make sure that no
one else is using the same frequency as yours in your operating area. Using
the same frequency at the same time, whether it is driving, flying or sailing,
can cause loss of control of the RC model, resulting in a serious accident.
• Always turn on your transmitter before you turn on the receiver in the car.
Always turn off the receiver before turning your transmitter off.
• Keep the wheels of the model off the ground when checking the operation of
the radio equipment.
• Disconnect the battery pack before storing your model.
• When learning to operate your model, go to an area that has no obstacles
that can damage your model if your model suffers a collision.
• Remove any sand, mud, dirt, grass or water before putting your model away.
• If the model behaves strangely, immediately stop the model, check and clear
the problem.
• To prevent any serious personal injury and/or damage to property, be
responsible when operating all remote controlled models.
• The model car is not intended for use on public places and roads or areas where
its operation can conflict with or disrupt pedestrian or vehicular traffic.
• Because the model car is controlled by radio, it is subject to radio interference
from many sources that are beyond your control. Since radio interference can
cause momentary loss of control, always allow a safety margin in all directions
around the model in order to prevent collisions.
• Do not use your model:
- Near real cars, animals, or people that are unaware that an RC car is being
driven.
- In places where children and people gather
- In residential districts and parks
- In limited indoor spaces
- In wet conditions
- In the street
- In areas where loud noises can disturb others, such as hospitals and
residential areas.
- At night or anytime your line of sight to the model may be obstructed or
impaired in any way.
To prevent any serious personal injury and/or damage to property, please be
responsible when operating all remote controlled models.
INTRODUCTION

3
IMPORTANT NOTES – ELECTRICAL
• Insulate any exposed electrical wiring (using heat shrink tubing or electrical
tape) to prevent dangerous short circuits. Take maximum care in wiring,
connecting and insulating cables. Make sure cables are always connected
securely. Check connectors for if they become loose. And if so, reconnect
them securely. Never use R/C models with damaged wires. A damaged wire
is extremely dangerous, and can cause short-circuits resulting in fire. Please
have wires repaired at your local hobby shop.
• Low battery power will result in loss of control. Loss of control can occur due to
a weak battery in either the transmitter or the receiver. Weak running battery
may also result in an out of control car if your car‘s receiver power is supplied
by the running battery. Stop operation immediately if the car starts to slow
down.
• When not using RC model, always disconnect and remove battery.
• Do not disassemble battery or cut battery cables. If the running battery short-
circuits, approximately 300W of electricity can be discharged, leading to fire
or burns. Never disassemble battery or cut battery cables.
• Use a recommended charger for the receiver and transmitter batteries
and follow the instructions correctly. Over-charging, incorrect charging, or
using inferior chargers can cause the batteries to become dangerously hot.
Recharge battery when necessary. Continual recharging may damage battery
and, in the worst case, could build up heat leading to fire. If battery becomes
extremely hot during recharging, please ask your local hobby shop for check
and/or repair and/or replacement.
• Regularly check the charger for potential hazards such as damage to the
cable, plug, casing or other defects. Ensure that any damage is rectified
before using the charger again. Modifying the charger may cause short-circuit
or overcharging leading to a serious accident. Therefore do not modify the
charger.
• Always unplug charger when recharging is finished.
• Do not recharge battery while battery is still warm. After use, battery retains
heat. Wait until it cools down before charging.
• Do not allow any metal part to short circuit the receiver batteries or other
electrical/electronic device on the model.
• Immediately stop running if your RC model gets wet as may cause short circuit.
• Please dispose of batteries responsibly. Never put batteries into fire.
WARRANTY
XRAY guarantees this model kit to be free from defects in both material and
workmanship within 30 days of purchase. The total monetary value under
warranty will in no case exceed the cost of the original kit purchased. This
warranty does not cover any components damaged by use or modification or
as a result of wear. Part or parts missing from this kit must be reported within
30 days of purchase. No part or parts will be sent under warranty without proof
of purchase. Should you find a defective or missing part, contact the local
distributor. Service and customer support will be provided through local hobby
store where you have purchased the kit, therefore make sure to purchase any
XRAY products at your local hobby store. This model racing car is considered
to be a high-performance racing vehicle. As such this vehicle will be used in
an extreme range of conditions and situations, all which may cause premature
wear or failure of any component. XRAY has no control over usage of vehicles
once they leave the dealer, therefore XRAY can only offer warranty against all
manufacturer‘s defects in materials, workmanship, and assembly at point of
sale and before use. No warranties are expressed or implied that cover damage
caused by what is considered normal use, or cover or imply how long any
model cars‘ components or electronic components will last before requiring
replacement.
Due to the high performance level of this model car you will need to periodically
maintain and replace consumable components. Any and all warranty coverage
will not cover replacement of any part or component damaged by neglect,
abuse, or improper or unreasonable use. This includes but is not limited to
damage from crashing, chemical and/or water damage, excessive moisture,
improper or no maintenance, or user modifications which compromise the
integrity of components. Warranty will not cover components that are considered
consumable on RC vehicles. XRAY does not pay nor refund shipping on any
component sent to XRAY or its distributors for warranty. XRAY reserves the right
to make the final determination of the warranty status of any component or part.
Limitations of Liability
XRAY makes no other warranties expressed or implied. XRAY shall not be liable
for any loss, injury or damages, whether direct, indirect, special, incidental, or
consequential, arising from the use, misuse, or abuse of this product and/or any
product or accessory required to operate this product. In no case shall XRAY‘s
liability excess the monetary value of this product.
Take adequate safety precautions prior to operating this model. You
are responsible for this model’s assembly and safe operation.
Disregard of the any of the above cautions may lead to accidents,
personal injury, or property damage. XRAY MODEL RACING CARS
assumes no responsibility for any injury, damage, or misuse of this
product during assembly or operation, nor any addictions that may
arise from the use of this product.
All rights reserved.
QUALITY CERTIFICATE
XRAY MODEL RACING CARS uses only the highest quality materials, the best
compounds for molded parts and the most sophisticated manufacturing processes
of TQM (Total Quality Management). We guarantee that all parts of a newly-
purchased kit are manufactured with the highest regard to quality. However, due
to the many factors inherent in model racecar competition, we cannot guarantee
any parts once you start racing the car. Products which have been worn out,
abused, neglected or improperly operated will not be covered under warranty.
We wish you enjoyment of this high-quality and high-performance RC car and
wish you best success on the track!
In line with our policy of continuous product development, the exact specifications of the kit may
vary. In the unlikely event of any problems with your new kit, you should contact the model shop
where you purchased it, quoting the part number.
We do reserve all rights to change any specification without prior notice. All rights reserved.
R/C & BUILDING TIPS
• Make sure all fasteners are properly tightened. Check them periodically.
• Make sure that chassis screws do not protrude from the chassis.
• For the best performance, it is very important that great care is taken to ensure
the free movement of all parts.
• Clean all ball-bearings so they move very easily and freely.
• Tap or pre-thread the plastic parts when threading screws.
• Self-tapping screws cut threads into the parts when being tightened. Do not use
excessive force when tightening the self-tapping screws because you may strip
out the thread in the plastic. We recommended you stop tightening a screw
when you feel some resistance.
• Ask your local hobby shop for any advice.
Please support your local hobby shop. We at XRAY Model Racing Cars support
all local hobby dealers. Therefore we ask you, if at all possible, to purchase
XRAY products at your hobby dealer and give them your support like we do. If
you have difficulty finding XRAY products, please check out www.teamxray.com
to get advice, or contact us via email at [e-mail], or contact the XRAY
distributor in your country.

4
Arm Reamer 3.0mm
NOT
INCLUDED
To ensure that you always have access to
the most up-to-date version of the Set-up
Book you can download the HUDY Set-up
Book from their web site at www.hudy.net.
By offering this online version instead of
including a hardcopy printed version in
kits, you will always be assured of having
the most current updated version.
XRAY offers wide range of optional
tuning parts which are listed in a
table like this. Please refer to the
exploded view of each main section
to verify which part is included in
the kit while all other parts are
available only as an optional part
and must be purchased separately.
SYMBOLS USED
L=R
2x
CORRECT WRONG
Overtightened The threads
are stripped.
Part bags used Assemble left and right
sides the same way
Assemble in the specified
order
Pay attention here Assemble as many times
as specified (here twice)
Apply CA glue
TOOLS REQUIRED
EQUIPMENT REQUIRED
EQUIPMENT
INCLUDED
Apply oil Apply cleaner
XRAY Premium Silicone Oils
Side Cutters
(HUDY #189010)
Hobby Knife Turnbuckle Wrench
3mm (HUDY #181030)
Reamer
(HUDY #107600)
or
(HUDY #107601)
Combination Pliers
(HUDY #189020)
HUDY TOOLS:
Transmitter Steering ServoReceiver
05
Tighten screw
gently
Apply thread lock
Lexan™ Paint Battery Charger Tires & Inserts
Apply grease Ensure smooth
non-binding movement
Graphite Grease
(HUDY #106210)
Bearing Oil
(HUDY #106230)
Follow Set-Up Book
FRONT & REAR AXLES
Scissors
(HUDY #188990)
3.0 mm
SAMPLE OF
OPTIONAL PARTS
#36XXXX OPTION 1
#36XXXX OPTION 2
#36XXXX OPTION 3
Speed Controller LiPo Battery
Pinion Gear and Setscrew Electric Motor
Double-sided Tape
Special Tool for turnbuckles,
nuts (HUDY #181090)
OIL
Socket 5.5mm
Socket 7.0mm
Allen 2.0mm
Allen 1.5mm

5
XB4 TECH TIPS
MOTOR POSITION ALTERNATIVES
SHOCK TOWER PROTECTION
Please follow the instruction manual and seal the edges of the shock towers with CA to reinforce them and help
prevent delamination.
Fine sandpaper
Use fine sandpaper to
sand smooth the edges of
all graphite parts.
Apply CA glue to all edges
of the graphite parts.
DRIVE SHAFT PIN SERVICING
TIP
To enjoy the longest possible lifespan of the drive shafts and diff outdrives, it is extremely important to properly service the drive shaft pins.
Inspect the pins after every 3 hours of runtime. If the pins show any wear, replace them with new pins.
For easy and comfortable drive pin replacements use
#106000 HUDY Drive Pin Replacement Tool.
To replace the worn pins use only
premium HUDY drive pins #106051.
GRAPHITE PARTS PROTECTION
TIP
Follow this tech tip to protect the following graphite parts:
Protect all XB4
Graphite Parts:
• Front shock tower
• Rear shock tower
Do not use drive shafts when
the pins are worn.
Press out the worn pins. Press in new pins and
regularly inspect for wear.
The XB4 can be assembled to fit either the saddle battery pack or short battery pack. Depending on the version you choose to build you have to follow the assembly instructions. The Instruction Manual shows the
assembly of saddle pack batteries. If you want to build the car with the alternative short battery pack (rearward motor position), follow the supplementary instructions starting on page 39 (using parts from Bag 09).
INITIAL ASSEMBLY
PAGES 6~38.
INITIAL ASSEMBLY
PAGES 39~44.
FORWARD MOTOR POSITION
SADDLE PACK BATTERIES
REARWARD MOTOR POSITION
SHORT BATTERY PACK

6
BEVEL GEARS
#364935 GRAPHITE (OPTION)
#364945 ALU
(OPTION)
#364955 STEEL (STANDARD)
BEVEL & SATELITTE GEARS + PINS
#304930 + #304980 COMPOSITE (STANDARD)
#335030 + #335080 STEEL (OPTION)
Suggested to use with #365114 Graphite
Composite Bevel Drive Gear 14T.
1. FRONT & REAR DIFFERENTIAL
2x
2x
STEP DETAIL
STEP DETAIL
Use tweezers to
insert pin
➊
➊
➋
➋
➌
➌
➍
➍
➍
➎
➎
➎
➍➎
➍
30 4930 COMPOSITE GEAR DIFF BEVEL & SATELLITE GEARS (2+4)
30 4980 COMPOSITE GEAR DIFF CROSS PIN
30 4990 DIFF GASKET (4)
36 4900 GEAR DIFFERENTIAL - SET
36 4910 COMPOSITE GEAR DIFFERENTIAL CASE
36 4955 STEEL DIFFERENTIAL BEVEL GEAR 35T
36 4960 GEAR DIFF OUTDRIVE ADAPTER - HUDY SPRING STEEL™ (2)
36 4990 COMPOSITE BEVEL GEAR BUSHING (2)
90 3258 HEX SCREW SFH M2.5x8 (10)
94 1015 HIGH-SPEED BALL-BEARING 10x15x4 RUBBER SEALED (2)
96 4031 WASHER S 3.5x10x0.2 (10)
96 4050 WASHER S 5x15x0.3 (10)
97 2050 SILICONE O-RING 5x2 (10)
98 1210 PIN 2x10 (10)
BAG
364960
364910
964050
964031
972050
364955
903258
364960
OPTIONAL:
#365000 BALL ADJUSTABLE DIFFERENTIAL
SET - HUDY SPRING STEEL™
304930
941015
981210
972050
964031
964050
304990
364990
981210
941015
304930
304980
972050
O 5x2
972050
O 5x2
964050
S 5x15x0.3
964050
S 5x15x0.3
981210
P 2x10
981210
P 2x10
CUTAWAY VIEW
NOTE ORIENTATION
OIL
OIL
OIL
OIL
DO NOT USE for ALU or GRAPHITE gears

7
DIFFERENTIAL OIL
Fill differential up to the top of the
diff pin. DO NOT fill the diff to the
top of the housing.
TO ENSURE YOU HAVE THE SAME AMOUNT OF OIL FROM REBUILD TO REBUILD, DO THE FOLLOWING:
➊ Put the diff (without oil) on the scale and check the
weight (approximately 9.80g)
➋ Slowly pour oil into the diff and watch the weight. Add
1.32g of oil into the diff. The approximate weight of the diff
including oil is 11.12g.
LOW TRACTION 5 000cSt (HUDY #106450)
MEDIUM-HIGH TRACTION 8 000cSt (HUDY #106480)
SUPER-HIGH TRACTION 10 000cSt (HUDY #106510)
NOTE:
Softer oil increases rear traction, harder oil increases on-power steering.
LOW TRACTION 5 000cSt (HUDY #106450)
MEDIUM-HIGH TRACTION 8 000cSt (HUDY #106480)
SUPER-HIGH TRACTION 10 000cSt (HUDY #106510)
NOTE:
Softer oil increases steering, harder oil increases stability.
TIPS FOR DIFFERENTIALS
REAR DIFERENTIALFRONT DIFERENTIAL
9.80g + 1.32g = 11.12g
9.80g 11.12g
#107865
HUDY Ultimate Digital Pocket
Scale 300g±0.01g
Tighten the screws equally but do NOT
tighten them completely.
Finish tightening in
this order.
FRONT & REAR DIFFERENTIAL
➊
➋
➌
➍
964031
S 3.5x10x0.2
903258
SFH M2.5x8
941015
BB 10x15x4
2x
2x 2x 2x
OIL
OIL
Rear diff
Silicone oil 8 000cSt
Fill just above the
satellite gears.
Front diff
Silicone oil 8 000cSt
Fill just above the
satellite gears.
OIL
PROPER AMOUNT OF OIL IN THE DIFFS
Use a digital scale to measure the exact amount
of oil in the diff. Remember that during operation
the diff gets hotter and the heat may allow the oil
to expand. If there is too much oil inside it may
interfere with the diff operation and damage the
internal gears.

8
2. REAR CENTRAL TRANSMISSION
GRAPHITE GREASE
(HUDY #106210)
BEVEL DRIVE GEARS
#365114 GRAPHITE (OPTION)
#365134 STEEL (STANDARD)
MARKED “R“
DRIVE SHAFT COVER CAPS
Lubricate the drive shaft connecting joint properly so the drive shaft turns
freely. In the event that not enough grease is used, the connecting pin may lock
and may even, in extreme situations, push through the drive shaft cover cap.
DRIVE SHAFT COLLAR
#365470 COMPOSITE (STANDARD)
#365471-K ALU - BLACK (OPTION)
#365471-O ALU - ORANGE (OPTION)
➊
➋
➌
➍
36 2001 DIFF BULKHEAD BLOCK SET REAR - V2
36 3080 GRAPHITE SHOCK TOWER REAR 3.0MM - V3
36 5134 STEEL BEVEL DRIVE GEAR 14T
36 5230 DRIVE SHAFT COUPLING - HUDY SPRING STEEL™
36 5423 CENTRAL DRIVE SHAFT 64MM - HUDY SPRING STEEL™
36 5440 CENTRAL SHAFT UNIVERSAL JOINT
36 5470 COMPOSITE DRIVE SHAFT SAFETY COLLAR - V2 (3)
90 2306 HEX SCREW SH M3x6 (10)
90 2310 HEX SCREW SH M3x10 (10)
94 0510 HIGH-SPEED BALL-BEARING 5x10x4 RUBBER SEALED (2)
94 0815 HIGH-SPEED BALL-BEARING 8x14x4 RUBBER SEALED (2)
98 0210 PIN 2x10 (10)
36 4900 GEAR DIFFERENTIAL - SET
36 4955 STEEL DIFFERENTIAL BEVEL GEAR 35T
BAG
362001
902306
940815
940510
365440
365230
902310
364900+364955
365134
362001
365470
980210
365423
363080
902310
980210
P 2x10
REAR BLOCK
IMPORTANT
CENTRAL DRIVE SHAFT (64MM)

9
REAR CENTRAL TRANSMISSION
GRAPHITE GREASE
(HUDY #106210)
➊
➋
➌
➍
➎
Follow the TECH TIP on page 5
to protect graphite parts
REAR DIFF 8 000 cSt
DETAIL
When installing the gear on the axle, make sure the
flat spot of the gear sits on the flat spot of the axle.
NOTE ORIENTATION
NOTE ORIENTATION
NOTE ORIENTATION
OIL
OIL
THREAD LOCK
NOTE ORIENTATION
940510
BB 5x10x4
940815
BB 8x14x4
902310
SH M3x10
902306
SH M3x6
902310
SH M3x10
REAR BLOCK
IMPORTANT

10
2. FRONT CENTRAL TRANSMISSION
Graphite Grease
(HUDY #106210)
MARKED “F“
BEVEL DRIVE GEARS
#365114 GRAPHITE (OPTION)
#365134 STEEL (STANDARD)
DRIVE SHAFT COLLAR
#365470 COMPOSITE (STANDARD)
#365471-K ALU - BLACK (OPTION)
#365471-O ALU - ORANGE (OPTION)
DRIVE SHAFT COVER CAPS
Lubricate the drive shaft connecting joint properly so the drive shaft turns
freely. In the event that not enough grease is used, the connecting pin may lock
and may even, in extreme situations, push through the drive shaft cover cap.
➊
➋
➌
➍
36 2000 DIFF BULKHEAD BLOCK SET FRONT - V2
36 2081 GRAPHITE SHOCK TOWER FRONT 3.5MM
36 5134 STEEL BEVEL DRIVE GEAR 14T
36 5230 DRIVE SHAFT COUPLING - HUDY SPRING STEEL™
36 5422 CENTRAL DRIVE SHAFT 116MM - HUDY SPRING STEEL™
36 5440 CENTRAL SHAFT UNIVERSAL JOINT
36 5470 COMPOSITE DRIVE SHAFT SAFETY COLLAR - V2 (3)
90 2306 HEX SCREW SH M3x6 (10)
90 2310 HEX SCREW SH M3x10 (10)
94 0510 HIGH-SPEED BALL-BEARING 5x10x4 RUBBER SEALED (2)
94 0815 HIGH-SPEED BALL-BEARING 8x14x4 RUBBER SEALED (2)
98 0210 PIN 2x10 (10)
36 4900 GEAR DIFFERENTIAL - SET
36 4955 STEEL DIFFERENTIAL BEVEL GEAR 35T
BAG
365230
365470
362000
940815
902306
362081
902310
902310
365422
980210
365440
940510
365134
FRONT BLOCK
364900+ 364955
362000
IMPORTANT
980210
P 2x10
CENTRAL DRIVE SHAFT (116MM)

11
FRONT CENTRAL TRANSMISSION
➊
➋
➌
➍
➎
Follow the TECH TIP on page 5
to protect graphite parts
FRONT DIFF 8 000 cSt
FRONT BLOCK
DETAIL
IMPORTANT
When installing the gear on the axle, make sure the
flat spot of the gear sits on the flat spot of the axle.
THREAD LOCK
NOTE ORIENTATION
OIL
OIL
940510
BB 5x10x4
940815
BB 8x14x4
902310
SH M3x10
902310
SH M3x10
902306
SH M3x6
NOTE ORIENTATION
NOTE ORIENTATION
NOTE ORIENTATION
GRAPHITE GREASE
(HUDY #106210)

12
OPTIONAL
2x
For better stability and to make the car easier to drive, optional #362190 and #363190 graphite stiffeners may be used. Using only 4 screws, the
graphite stiffener can be installed or removed which would completely change the characteristics of the car. Stiffeners may be used independently at
front and/or rear.
IMPORTANT! Install / remove stiffeners equally on left & right sides.
#363190
GRAPHITE REAR LOWER ARM PLATE 1.6MM (2) (OPTION)
ANTI-ROLL BARS
#362470 1.0mm
(OPTION)
#362471 1.1mm (OPTION)
#362472 1.2mm (STANDARD)
#362473 1.3mm
(OPTION)
#362474 1.4mm (OPTION)
#362476 1.6mm (OPTION)
#362478 1.8mm (OPTION)
3. REAR SUSPENSION
363111
306219
363321
362315
367210
362315
363311 903312
901304
362001
903312
902308
363121
901303
303431-K
303454
901308
303454
30 3431-K ALU 4.9MM BALL END - BLACK (2)
30 3454 BALL JOINT 4.9MM - OPEN (4)
30 6219 COMPOSITE SET OF SERVO SHIMS (4)
36 2001 DIFF BULKHEAD BLOCK SET REAR - V2
36 2315 ECCENTRIC BUSHING SET (2)
36 2470 ANTI-ROLL BAR 1.0 MM (OPTION)
36 2471 ANTI-ROLL BAR 1.1 MM (OPTION)
36 2472 ANTI-ROLL BAR 1.2 MM
36 2473 ANTI-ROLL BAR 1.3 MM (OPTION)
36 2474 ANTI-ROLL BAR 1.4 MM (OPTION)
36 2476 ANTI-ROLL BAR 1.6 MM (OPTION)
36 2478 ANTI-ROLL BAR 1.8 MM (OPTION)
36 3111 COMPOSITE SUSPENSION ARM REAR LOWER RIGHT
36 3121 COMPOSITE SUSPENSION ARM REAR LOWER LEFT
36 3311 ALU REAR LOWER SUSP. HOLDER +2 - FRONT - 7075 T6 (5MM)
36 3313 BRASS REAR LOWER SUSPENSION HOLDER SET +2 - RR+RF (OPTION)
36 3321 ALU REAR LOWER SUSP. HOLDER +2 - REAR - 7075 T6 (5MM)
36 7210 SUSPENSION PIVOT PIN (2)
90 1303 HEX SCREW SB M3x3 (10)
90 1304 HEX SCREW SB M3x4 (10)
90 1308 HEX SCREW SB M3x8 (10)
90 2308 HEX SCREW SH M3x8 (10)
90 3312 HEX SCREW SFH M3x12 (10))
BAG
Remove the 3x6.5x2mm shim from each rear arm, this shim
will be used in Rear Transmition section on page 19, step 1.

13
TOE-IN
ANTI-SQUAT
ROLL CENTER
TRACK WIDTH
REAR SUSPENSION
ECCENTRIC BUSHINGS HAVE TWO DIFFERENT OFFSETS FROM THE CENTER.
Middle position = 0.5° or 0.375mm from center.
Outer position = 1° or 0.75mm from center.
The XRAY rear alu lower suspension holders provide great range of adjustment for the rear suspension. Using different combinations of eccentric bushings, fine adjustment of rear anti-squat, rear toe-in, rear
roll center, and rear track-width can be obtained. For more information about the influence of rear anti-squat, rear toe-in, rear roll center and rear track width on car handling, please refer to HUDY Set-up Book
(#209100).
The tables describe the amounts of adjustment using the center and outside positions of
the eccentric bushings.
The middle position eccentric bushings allow for finer adjustment increments.
Example:
The track width is directly influenced by the size of
the wheels and tires used.
0(RR) - 0 (RF) = 2°
0(RR) - 0.5 (RF) = 2.5°
0(RR) - 1 (RF) = 3°
ANTI-SQUAT ROLL-CENTER TRACK WIDTH TOE-IN
RR RR RR RRRF RF RF RF(°) (mm) (mm) (°)
=2°
=3°
=1°
=3°
=2°
=4°
=1°
=2°
=0°= 2°
= 2.5°
= 3°
=3°
=4°
=2°
=2°
=3°
=1°
=4°
=5°
=3°
=
+1.5mm
= 0mm
=
-1.5mm
=
+0.75mm
= 0mm
=
-0.75mm
Check for free movement
Marked “L”
Marked “R”
3x6x2mm
ARMARM
Arm Reamer 3.0mm (HUDY #107633)
If the suspension arm does not move freely use a
HUDY Arm Reamer to size the holes of the arms
➊
➋
➌
➌
➍
➍
RR
RF
All possible mounting
alternatives of eccentric bushings
➊
Composite eccentric bushings
INITIAL POSITION
1º 1º0.5º 0.5º0º
Composite eccentric bushings
INITIAL POSITION
1º 1º0.5º 0.5º0º
903312
SFH M3x12
REAR BLOCK
IMPORTANT
306219
SHIM 3x6x2

14
REAR SUSPENSION
ANTI-ROLL BAR
➊
➋
➌
3x4
3x8
3x3
L=R
2x
1.5mm
4mm
L=R
0mm
STEP DETAIL
➌
Step check for free movement
➊
DETAIL DETAIL
Loosen the 3x4 setscrew if
the anti-roll bar does not
turn freely
Step
➊
ASSEMBLY VIEW
901308
SB M3x8
901303
SB M3x3
901304
SB M3x4
902308
SH M3x8

15
OPTIONAL
2x
For better stability and to make the car easier to drive, optional #362190 and #363190 graphite stiffeners may be used. Using only 4 screws, the
graphite stiffener can be installed or removed which would completely change the characteristics of the car. Stiffeners may be used independently at
front and/or rear.
IMPORTANT! Install / remove stiffeners equally on left & right sides.
3. FRONT SUSPENSION
30 3431-K ALU 4.9MM BALL END - BLACK (2)
30 3454 BALL JOINT 4.9MM - OPEN (4)
30 6219 COMPOSITE SET OF SERVO SHIMS (4)
36 1200 COMPOSITE BUMPER - V2
36 2000 DIFF BULKHEAD BLOCK SET FRONT - V2
36 2111 COMPOSITE SUSPENSION ARM FRONT LOWER
36 2310 ALU FRONT LOWER SUSP. HOLDER - FRONT - 7075 T6 (5MM)
36 2315 ECCENTRIC BUSHING SET (2)
36 2320 ALU FRONT LOWER SUSP. HOLDER - REAR - 7075 T6 (5MM)
36 2470 ANTI-ROLL BAR 1.0 MM (OPTION)
36 2471 ANTI-ROLL BAR 1.1 MM (OPTION)
36 2472 ANTI-ROLL BAR 1.2 MM
36 2473 ANTI-ROLL BAR 1.3 MM (OPTION)
36 2474 ANTI-ROLL BAR 1.4 MM (OPTION)
36 2476 ANTI-ROLL BAR 1.6 MM (OPTION)
36 2478 ANTI-ROLL BAR 1.8 MM (OPTION)
36 7210 SUSPENSION PIVOT PIN (2)
90 1303 HEX SCREW SB M3x3 (10)
90 1304 HEX SCREW SB M3x4 (10)
90 1308 HEX SCREW SB M3x8 (10)
90 2308 HEX SCREW SH M3x8 (10)
90 3312 HEX SCREW SFH M3x12 (10))
303431-K
362320
362315
362310 903312
361200 902308
362111
903312
367210
306219
901304
902308
362000
362315
303454
901308
303454
901303 ANTI-ROLL BARS
#362470 1.0mm (OPTION)
#362471 1.1mm (OPTION)
#362472 1.2mm (STANDARD)
#362473 1.3mm
(OPTION)
#362474 1.4mm (OPTION)
#362476 1.6mm (OPTION)
#362478 1.8mm (OPTION)
BAG
#362190
GRAPHITE FRONT LOWER ARM PLATE 1.6MM (2) (OPTION)

16
FRONT SUSPENSION
KICK UP
ROLL CENTER
TRACK WIDTH
All possible mounting alternatives
of eccentric bushings
The tables describe the amounts of adjustment using the center and outside positions of the eccentric bushings.
The middle position eccentric bushings allow for finer adjustment increments.
The track width is directly influenced by the size of the
wheels and tires used.
Example:
KICK-UP TRACK WIDTHROLL-CENTER
FF FFFF FR FRFR (°) (mm) (mm)
=9°
=8°
=10°
=8°
=7°
=9°
=10°
=9°
=11°
=
+0.75mm
= 0mm
= - 0.75mm
=
+1.5mm
= 0mm
= - 1.5mm
KICK-UP
C-HUB CASTER 7° 8° 9° 10° 11°
6° 13° 14° 15° 16° 17°
9° 16° 17° 18° 19° 20°
Caster is the angle between the steering pivot
axis and the vertical plane. Caster is affected not
only by the C-Hub caster, but also by the front
kick-up angle relative to the flat chassis bottom.
The table indicates how kick up angle effects
total caster.
The XB4’s stock caster blocks are 9°, but 6°
blocks are available as an option.
TOTAL CASTER = C-HUB CASTER+KICK UP
0(FF) - 0(FR) = 9°
0.5(FF) - 0(FR) = 9.5°
1(FF) - 0(FR) = 10°
= 9°
= 9.5°
= 10°
The XRAY alu front lower suspension holders provide great range of adjustment for the front suspension. Using different combinations of eccentric bushings, fine adjustment of front kick-up, roll-center, and front
track-width can be obtained. For more information about the influence of kick-up, front track-width, and roll centers on car handling, please refer to HUDY Set-up Book (#209100).
➊
➊
➋
➌
➌
➍
➍
FR
FF
Composite eccentric bushings
INITIAL POSITION
1º 1º0.5º 0.5º0º
Composite eccentric bushings
INITIAL POSITION
1º 1º0.5º 0.5º0º
Check for free movement
If the suspension arm does not move freely use a
HUDY Arm Reamer to size the holes of the arms
FRONT ARM
L=R
903312
SFH M3x12
Arm Reamer 3.0mm (HUDY #107633)
FRONT BLOCK
IMPORTANT
ECCENTRIC BUSHINGS HAVE TWO DIFFERENT OFFSETS FROM THE CENTER.
Middle position = 0.5° or 0.375mm from center.
Outer position = 1° or 0.75mm from center.
306219
SHIM 3x6x2
3x6x2mm

17
FRONT SUSPENSION
ANTI-ROLL BAR
L=R
2x
1.5mm
4mm
➊
➋
➌
L=R
0mm
STEP DETAIL
➌
Step check for free movement
➊
DETAIL DETAIL
Loosen the 3x4 setscrew if
the anti-roll bar does not
turn freely
Step
➊
3x4
3x3
3x8
901308
SB M3x8
901303
SB M3x3
901304
SB M3x4
902308
SH M3x8
902308
SH M3x8
ASSEMBLY VIEW

18
DRIVE SHAFT COLLAR
#365470 COMPOSITE (STANDARD)
#365471-K ALU - BLACK (OPTION)
#365471-O ALU - ORANGE (OPTION)
REAR UPRIGHTS
#363350 COMPOSITE (STANDARD)
#363351 ALU (OPTION)
4. REAR TRANSMISSION
30 2665 COMPOSITE BALL JOINT 4.9MM - CLOSED WITH HOLE (4)
36 2610 ADJ. TURNBUCKLE M3 L/R 50 MM - SPRING STEEL (2)
36 2650 BALL END 4.9MM WITH THREAD 6MM (2)
36 2651 BALL END 4.9MM WITH THREAD 8MM (2)
36 3111 REAR SUSPENSION ARM - RIGHT
36 3121 REAR SUSPENSION ARM - LEFT
36 3350 COMPOSITE UPRIGHT REAR - V2
36 3520 REAR WING POST - V2 (2)
36 5230 DRIVE SHAFT COUPLING - HUDY SPRING STEEL™
36 5320 REAR DRIVE SHAFT 68MM - HUDY SPRING STEEL™
36 5340 REAR DRIVE AXLE - HUDY SPRING STEEL™
36 5350 ALU WHEEL HUB 14MM (2)
BAG
36 5351 ALU WHEEL HUB 14MM - OFFSET “-0.75MM” (2) (OPTION)
36 5352 ALU WHEEL HUB 14MM - OFFSET “+0.75MM” (2) (OPTION)
36 5470 COMPOSITE DRIVE SHAFT SAFETY COLLAR (3)
36 7320 REAR ARM PIVOT PIN (2)
90 1306 HEX SCREW SB M3x6 (10)
90 2205 HEX SCREW SH M2x5 (10)
90 2310 HEX SCREW SH M3x10 (10)
94 0510 HIGH-SPEED BALL-BEARING 5x10x4 RUBBER SEALED (2)
94 0512 HIGH-SPEED BALL-BEARING 5x12x4 RUBBER SEALED (2)
96 0030 NUT M3 (10)
98 0210 PIN 2x10 (10)
2x 2x
2x
L=R L=R
L=R
Graphite Grease
(HUDY #106210)
Bearing Oil
(HUDY #106230)
LONG AXLE
OPTIONAL HEX HUB EFFECTS
Different off-set hex hubs are used to
increase or decrease the track-width.
LESS OFF-SET
Rear - more traction
Front - more steering
MORE OFF-SET
Rear - less traction
Front - less steering
➊
➋
➌
➍
OIL
➊
➋
➌
902310
365230
365340
940510
363111
363121
901306
302665
362610
940512
365350
362650
960030
362651
365320
363520
980210
365470
363350
302665
902205
367320
940512
BB 5x12x4
940510
BB 5x10x4
902205
SH M2x5
980210
P 2x10
980210
P 2x10
5x12x4
5x10x4
WHEEL HUBS 14MM
#365352 +0.75mm (OPTION)
#365350 0mm (STANDARD)
#365351 -0.75mm (OPTION)
WHEEL HUBS 12MM
#365357 +2.25mm (OPTION)
#365356 +1.5mm (OPTION)
#365355 +0.75mm (OPTION)
#365353 0mm (OPTION)
#365354 -0.75mm (OPTION)
DRIVE SHAFT (68mm)

19
CAMBER
ROLL CENTER
WHEELBASE
REAR TRANSMISSION
DO NOT OVERTIGHTEN
33.5 mm
2x
2x
2x
2x
L=R
L=R
L=R
L=R
L=R
L=R
When using OUTSIDE position on the hub,
use only outside position on the arm.
When using INSIDE position on the hub,
use only inside position on the arm.
Check for free
movement
Ensure that the rear upright moves freely.
If it does not move freely, use sandpaper to
thin both wheelbase adjustment shims.
SHORT LONG
IMPORTANT!
NOTE
ORIENTATION
INITIAL POSITION
NOTE
ORIENTATION
NOTE
ORIENTATION
Alternative Shim
IN FRONT OF HUB
SHORT
SHORT
LONG
LONG
VIEW
VIEW
Alternative Shim
BEHIND HUB
SHORTER WHEELBASE
LONGER WHEELBASE
ARM
ARM
NOTE
ORIENTATION
The outside hole offers great stability and is
recommended for bumpy open tracks.
Inside hole offers great amount of steering
and is recommended for flat, technical tracks.
RIGHT
THREAD
INITIAL POSITION
INITIAL POSITION
LEFT
THREAD
901306
SB M3x6
From Rear Arm
SHIM 3x6.5x2
960030
N M3
6mm thread 8mm thread
6mm
THREAD
8mm
THREAD
902310
SH M3x10
Use shim 3x6.5x2mm from rear arm (Bag 3)
1:1
1:1

20
CASTER
ROLL-CENTER
DRIVE SHAFT COLLAR
#365470 COMPOSITE (STANDARD)
#365471-K ALU - BLACK (OPTION)
#365471-O ALU - ORANGE (OPTION)
4. FRONT TRANSMISSION
30 2665 COMPOSITE BALL JOINT 4.9MM - CLOSED WITH HOLE (4)
30 3122 ALU SHIM 3x6x1.0MM (10)
36 2210 COMPOSITE C-HUB 9° DEG. RIGHT
36 2211 COMPOSITE C-HUB 6° DEG. RIGHT (OPTION)
36 2220 COMPOSITE C-HUB 9° DEG. LEFT
36 2221 COMPOSITE C-HUB 6° DEG. LEFT (OPTION)
36 2250 COMPOSITE STEERING BLOCK
36 2280 ALU CONICAL SHIM 3x6x2.0MM (10)
36 2290 STEEL STEERING BUSHING - SHORT (2)
36 2291 STEEL STEERING BUSHING - LONG (2)
36 2610 ADJ. TURNBUCKLE M3 L/R 50 MM - SPRING STEEL (2)
36 2651 BALL END 4.9MM WITH THREAD 8MM (2)
36 2652 BALL END 4.9MM WITH THREAD 10MM (2)
36 5220 FRONT DRIVE SHAFT 81MM - HUDY SPRING STEEL™
36 5230 DRIVE SHAFT COUPLING - HUDY SPRING STEEL™
36 5240 FRONT DRIVE AXLE - HUDY SPRING STEEL™
36 5350 ALU WHEEL HUB 14MM (2)
36 5351 ALU WHEEL HUB 14MM - OFFSET “-0.75MM” (2) (OPTION)
36 5352 ALU WHEEL HUB 14MM - OFFSET “+0.75MM” (2) (OPTION)
36 5470 COMPOSITE DRIVE SHAFT SAFETY COLLAR (3)
36 7220 FRONT ARM PIVOT PIN (2)
90 1306 HEX SCREW SB M3x6 (10)
90 2205 HEX SCREW SH M2x5 (10)
90 2312 HEX SCREW SH M3x12 (10)
90 2314 HEX SCREW SH M3x14 (10)
94 0510 HIGH-SPEED BALL-BEARING 5x10x4 RUBBER SEALED (2)
94 0512 HIGH-SPEED BALL-BEARING 5x12x4 RUBBER SEALED (2)
96 0030 NUT M3 (10)
98 0210 PIN 2x10 (10)
2x
2x
L=R
L=R
GRAPHITE GREASE
(HUDY #106210)
BEARING OIL
(HUDY #106230)
Effects of option hex hubs - see page 18/step 2.
SHORT AXLE
DRIVE SHAFT (81mm)
DETAIL
LOWER ROLL CENTER
TOP = LONGER bushing & 3x14 screw
BOTTOM = SHORTER bushing & 3x12 screw
Recommended for rough tracks to improve
stability.
HIGHER ROLL CENTER
TOP = SHORTER bushing & 3x12 screw
BOTTOM = LONGER bushing & 3x14 screw
Recommended for smooth tracks to gain
more steering.
CONICAL SHIM
3x6x2
Steel steering bushings allow
roll-center adjustment.
Longer
Shorter
DETAIL
➊
➋
➌
➍
OIL
➊
➊
➋
➌
➌
➊
➋
➌
When inserting the bushings,
make sure that bushings are
inserted equally on both
right and left hub to make
the same roll center position.
IMPORTANT
NOTE
ORIENTATION
362610
365220
365350 362250
362290
362220
940510
365470
367220
362651
960030
901306
902312
365230
362291
940512
362280
362651
365240
980210
362210
902314
303122
362280
362652
302665
902205
BAG
940512
BB 5x12x4
940510
BB 5x10x4
902205
SH M2x5
362280
CON. SHIM 3x6x2
902312
SH M3x12 902314
SH M3x14
980210
P 2x10
C-HUBS
#362210 RIGHT 9° (STANDARD)
#362211 RIGHT 6° (OPTION)
#362220 LEFT 9° (STANDARD)
#362221 LEFT 6° (OPTION)
5x12x4
5x10x4
8mm
THREAD