I designed and hand-made my first off-road cars back in 1986, and they dominated the races due to their unbeatable reliability and superior performance. Many years later in 2004, we started our first mass-production XRAY XB8 followed by the 1/10 off-road platform based on our long-term experiences, knowledge, and R&D expertise gained over decades. I carry heritage into the future, always improving along the way.

Dipl. Eng. Juraj Hudy
XRAY Chief Designer

CNC-machined from high-quality Swiss 2mm 7075 T6 aluminum, the chassis is strategically machined in low-stress areas to make it as light as possible without affecting strength or rigidity; and black-coated for increased lifespan.

Weight distribution, chassis width & length, and proper flex have key influences on the handling of the truck. All of these features were incorporated into the design of the chassis.

The side guards allow the motor to be positioned as low as possible on the chassis to improve cornering speed and stability.
Tough composite side guards perfectly fit the chassis to seal against dirt and protect from side impacts.

Molded from a hard composite material, the side guards are an important part of the chassis flex adjustment for the majority of track conditions. For very-low-traction tracks, optional medium stiffness side guards are available.

To improve protection against dust, Velcro® double-sided tape is included to ensure a perfect seal of the body to the side guards, to reduce the noise level of the running car.

The graphite chassis brace – machined from high-grade graphite material – is installed in the lower part of the composite brace connected directly to the chassis. The brace reinforces the rear of the truck and generates more stability while increasing traction.

The chassis brace is a vital part of the Multi-Flex™ setting.

The rear suspension features adjustable rear-upright design, longer CVD drive shafts and longer, rear camber link. The rear suspension offers a vast range of roll-center tuning adjustments for different track conditions.

The XT4 driveshafts are manufactured from world-renowned HUDY Spring Steel™ and feature 2.5mm drive pins for maximum drivetrain efficiency. The drive shafts are some of the thinnest yet most durable drive shafts used in electric off-road cars. Treated with a proprietary hardening process; the drive shafts provide unbeatable lifespan and reliability.

Rear uprights feature multiple set-up options for upper & lower roll centers. The upper roll center is adjusted at the camber linkage via shims (up/down & in/out) while the lower roll center is adjustable to 9 different positions via eccentric inserts (up/down & in/out).

The multi-function uprights have the upper roll center position in the middle-axis of the drive shaft’s connecting joint to help generate more traction and increase stability.

There are three different uprights available: hard (included,) graphite (optional) and aluminum (optional), each suitable for a different range of track conditions.

The XT4 comes equipped with offset hexes to perfectly match the width of the truck to the new suspension arms and hubs.

Ultra-lightweight 12mm wheel hex-drive hubs are CNC-machined from Swiss 7075 T6 black-coated aluminum. These ultra-true hex hubs have a clamping design to ensure ultra-solid mounting of the wheel’s hub.

To adjust track-width, optional offset wheel hex-drive hubs are available.

The suspension arms are rigid enough to provide a responsive feel; yet soft enough for extreme durability. The exclusive composite mixtures used for suspension arms are a perfect balance between reliability and performance.

There are three different rear suspension arms available: medium (optional), hard (included) and graphite (optional), each suitable for particular track conditions.

The aluminum suspension holders feature Integrated Suspension Settings (I.S.S.™) which allows for super-fast & easy suspension geometry setting. This XRAY concept was first introduced in the very first XB8 and now has been carried over to the 1/10 scale XT4.

Using eccentric suspension bushings inserted into aluminum suspension blocks, as well as additional shims, the XT4 suspension geometry can be completely adjusted including:

• caster

• camber

• front & rear toe-in

• front & rear roll-center

• front kick-up

• rear anti-squat

• wheelbase

• track-width

The tiny yet tough steering blocks are molded from a special composite mixture for maximum strength.

Composite steering block inserts allow for very quick & easy lower roll center adjustment. With additional shims and extra inserts, fine tuning the roll center is easily achieved.

For maximum drivetrain reliability, larger 5x12 ball-bearings are used in the outer position with increased dynamic load. On the inner position, the smaller 5x10 ball-bearings are used for minimized unsprung weight.

The 1-piece caster blocks are very lightweight, yet the construction makes them very stiff and rigid. The non-adjustable caster angle is preset to 9°. Roll center position can be quickly & easily adjusted by inserting different thickness of shims atop the caster block (between the block and the vertical ball stud).

The front of the chassis is pre-angled with an integrated 8° caster angle, however the position of the adjustable eccentric bushings in the I.S.S.™ suspension holders influences the caster as well. (For example, if the eccentric bushings have the roll center in middle position, the caster angle is 9° which when added to the 9° caster block gives a total of 18° caster. The total adjustability range for caster is 16-20°.)

Optional caster blocks with 6° and 12° built-in caster angles are available for further suspension geometry adjustment.

There are four different caster blocks available: medium (optional), hard (included), graphite (optional) and aluminum (optional), each suitable for particular track conditions.

Center driveline features universal joints that accommodate the machined bevel drive gears from the proven XB4 platform. The bevel drive gears are machined from special gear steel material that reduces the weight and significantly improves reliability.

The XT4 gear diffs ensure increased on-power steering which is needed on nearly all types of tracks and is ideal for both carpet and clay tracks.

The maintenance-free super-smooth gear diffs includes internal gears which are precision-molded from the tough XRAY developed composite material ensuring a long life time and super-smooth and efficient operation.

To improve the reliability of the differential and to reduce the rotating weight, both front and rear bevel drive gears are CNC-machined. The differential crown gears and bevel drive gears are made from steel which has been additionally hardened to ensure increased lifespan and reliability.

A center gear differential comes as standard equipment in the XT4 and can be tuned for a wide variety of traction conditions.

The maintenance-free diff design will benefit racers of all levels. Once built, the diff assembly should require minimal maintenance for extended intervals…no need for frequent oil changes.

The super-smooth gear diff includes a composite case and cover with a removable spur gear. The kit includes the 81T spur gear and an 78T spur gear is available as an option.

Precision-molded spur gears are made from XRAY's exclusive secret blend of composite material, allowing the gear to run true yet be robust enough to handle high-performance brushless motors. The spur gears are designed to have the lowest possible weight while staying strong and light. Each gear is stamped with the tooth number for easy identification.

The XT4 is equipped with an 81T spur gear which suits the majority of tracks. For additional tuning, optional 78T spur gear is available.

To reduce rotating weight, the super-lightweight diff outdrives are machined from HUDY Spring Steel™ material which allows additional material to be removed on the outer part of the outdrives, further reducing the weight without effecting durability. The inner part of the outdrives is additionally hand-ground for perfect fitment into the diff case.

The outdrives are hardened using XRAY’s own special process to provide extended lifespan and reliability.

The super-strong front & rear bulkheads withstand rigorous impacts and abusive racing conditions. The bulkheads securely position the differentials with minimal play, resulting in increased gear teeth lifespan and minimized gear stripping.

XRAY’s attention to the finest details, R&D and engineering are obvious in the design of the diff bulkheads. These unique bulkheads allow super-fast & easy diff exchange and servicing by dismounting only 4 screws from the front of the bulkhead and bottom of the chassis. This super-fast diff access is available at both front & rear.

The graphite upper deck captures the ball-bearings in the motor mount and central bulkhead assembly. If using the central slipper clutch, the upper deck allows easy access for the slipper spring adjustment.

With the super-low CG design focus, the XT4 uses the same lower profile motor mount and bulkhead from the latest XB4 buggies to keep the motor and gear diff as low in the chassis as possible.

The lowered motor bulkhead reduced the CG of the motor and center diff, improving cornering speed and stability.

Machined from the premium Swiss 7075 T6, the motor bulkhead is strong and lightweight.

With the weight balance adjustment, the XT4 features two different battery straps choices. Using the longer strap, the battery pack can be installed either frontwards or rearwards, using the included foam back spacer to keep the pack secure. Using the short strap positions the battery to the rear and creates some additional space on the chassis for mounting the electronics.

Both front & rear shock towers are machined from premium-grade graphite and are lightweight & strong, with multiple shock positions and roll center adjustment positions. The front shock tower is 3.5mm thick; the rear is also 3.5mm thick and features multiple positions for the ring wing mount.

The shocks are membrane-free, yet they still allow for easy, consistent building and rebound setting using the bleed-screw shock cap design.

The aluminum body and lower cap are machined from premium Swiss 7075 T6 aluminum.

Shock rods are machined from special steel material, precision hand-ground for maximum smooth operation, and additionally hardened for improved lifespan.

Shock pistons are made from Delrin® and are molded using ultra-high precision moulds. All-new 2-hole pistons (1.6mm and 1.7mm holes) are now included in the set.

The XT4 springs have been specifically designed to complement the shocks.

The XT4 springs, like all other XRAY springs, are manually measured, selected, and matched into pairs to guarantee precisely equal length and damping characteristics.

The dual arm steering system is very simple yet effective and features an integrated easily adjustable servo saver. Ackermann adjustments are quick and easily by changing the steering link mounting positions on the steering plate.

Bump steer is easily adjusted for tuning the steering response by inserting a shim between the steering block and steering linkage.

Anti-roll bars are manufactured from special spring steel material and are included to stabilize the front & rear ends of the truck. The roll bars are easily mounted to the diff cases and can be adjusted with the linkages.

Both front & rear anti-roll bars are interchangeable since they have same shape. Anti-roll bar wires of different thickness are optionally available for fine-tuning. The thickness of each anti-roll bar is laser-engraved for easy identification.

The high performance low profile aerodynamic body was designed by XRAY to perfectly fit the XT4 and to work in most track conditions effectively.

The front and rear of the body have been designed to provide downforce for maximum stability of the truck. The body sides as well the cockpit sides are as flat as possible to allow the air flow around the body for the side stability. On the top of roof two flow channels are incorporated for proper air flow.

The body is made from high quality premium Lexan material.

Stylish and effective rear wing works perfectly with the XRAY XT4 body. Made from strong Lexan™ material, the wing is supported on the mounts by extra flat shims to better support and extend the life of the wing.

Optional thicker 1.5mm (#363511) and 2.0mm (#363512) rear wings are highly reliable with less chance of breakage, while at the same time influencing the performance of the truck. The thicker wing gives higher traction and stability but can reduce steering.

The XT4 features greased ball-bearings for front steering blocks & rear uprights to increase lifespan in dusty conditions. The remaining bearings are degreased and oiled with AeroShell® Fluid 12 for maximum smoothness and long life.

A full set of high-speed ball-bearings are used throughout the drivetrain to ensure maximum efficiency.

HUDY Exclusive Silicone Oils are manufactured in Europe and each batch is laboratory tested and calibrated to ensure the highest possible consistency and quality from batch to batch. Based on the industry-standard cSt rating, the new line of oils will be easy to identify, adjust, and feel.

When following any set-up sheets by XRAY or XRAY team drivers, you can be sure that the oils you will get for your truck are exactly same as those used by the factory racing team, thus ensuring very exacting set-ups and handling.

HUDY Chem Series.

The XT4 includes premium #106210 HUDY Graphite Grease which is a high-performance, advanced-technology semi-fluid lubricant which incorporates both extreme pressure additives and finely-dispersed graphite for load carrying. It is intended primarily for the lubrication of rotating parts and loaded gears. In addition to providing outstanding load carrying, it is formulated to have excellent adhesion and resistance to "fling-off" under extreme conditions. The grease reduces wear and increases parts life.

The XT4 is one of the most adjustable electric truggies in the world. Whether you are a hardcore racing fanatic or a club-level sportsman, you can very easily adjust the XT4 to suit your racing style, race track type, and all track conditions. To fully understand the set-up possibilities we recommend the legendary HUDY Set-up Book, loaded with over 40 pages of high-quality pictures and easy-to-understand RC car set-up explanations. Whether you are a novice driver or experienced racer, you can easily learn many set-up tips & tricks and improve your set-up skills, ultimately translating into improved racing performance with your XT4. The HUDY Set-up Book is available for download exclusively at www.hudy.net

XRAY Instruction Manuals have become the industry standard, being simply the best manuals you will ever get with an RC model car. Whether you are a first-time builder or an experienced racer, all the instructions are straight-forward and easy to understand. The full-color instruction manual contains large 3D illustrations that show all assembly details in the clearest possible way.

Owning an XRAY model racing car is an experience on its own. Not only will you own the most premium luxury model racing car in the world, but you will also become a member of the prestigious family of XRAY owners with direct support and service from the XRAY factory. XRAY brings you the most up-to-date RC Web site on the Internet, with daily racing news and latest product developments. If you have any questions, problems or comments, you can ask the XRAY Support Team or any XRAY Factory Team Driver on the XRAY Support Forum. You can even upload your own set-up sheets or download from the thousands of different set-up sheets available from all around the world at the exclusive XRAY Virtual Set-up Sheet Database, the world’s largest set-up sheet database. And that is only the start of the VIP treatment you get by joining Team XRAY.