- X-6 CUBED ASSEMBLY INSTRUCTIONS -

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TUNING SECTION

Tuning section in PDF


ABOUT ADJUSTMENTS

R/C race cars, in general, are some of the most adjustable racing machines of any scale. What's really amazing is just how easy and quick it is to make all of our changes: remove a ball stud to change roll center, one screw to change springs, or tape in some weight to change the car's distribution. On top of that, the X-6 Cubed is more adjustable than most R/C cars, adding options like the transmission height and super-easy anti-squat adjustment plus the ability to change rear pivot height..

It's easy to get lost though, and over the years we've learned that at any given track, only a few adjustments will help the car get around the track faster. 90% of set-up changes only change the way the car feels to you. The trick is to find those few changes that really make a difference in lap times, and use the other changes to make the car suit your driving style. If you ever feel lost -- the car isn't working at all and you can't seem to get it back on track -- change completely back to a standard set-up or something that worked previously and start again-it's how we learn!

When there are lap times available, pay attention to both your fastest lap and your consistency (how close the other fast laps are to the fastest one). If your fast lap is significantly quicker than average, work on making the car easier to drive-your third- and fourth-fastest laps will be quicker. If the whole run is within two or three tenths of the fastest lap, add some more steering or power and see if you can go faster.

Finally, don't be afraid to acknowledge if a set-up change seems to have little effect, or even makes things worse. Some adjustments are subtle, and different driving styles are sensitive to various adjustments. Learning that an adjustment didn't work as expected is a valuable result-focus on other things, and perhaps try it again later as your driving experience accumulates and set-up evolves.

DRIVING THE X-6 Cubed

The mid-motor slim-line X-6 Cubed is obviously a lot different than a wide rear-motor car, and it can take a bit of practice to get used to the new characteristics. With its weight more central the X-6 Cubed naturally caries more corner speed. With no "pendulum effect" from the motor hanging off the rear, the car likes taking smoother racing lines, while the rear end stays more planted. Watch out that you don't slam into the motor guards of other cars through the infield!

The initial disadvantage of the mid-motor concept was a lack of forward bite out of corners, especially on slick tracks. X Factory designed the 4-gear transmission to solve this problem: by turning the motor so it rotates in the same direction as the wheels, the motor itself helps transfer weight to the rear under acceleration, dramatically increasing forward bite. Further, the XF Team has put a lot of work into set-ups, developing cars that often have more rear bite than our competitors!

The starting set-up in this manual has several features that add rear traction; these help ease the transition to driving a mid-motor car. As part of this the U.S. starting set-up runs the rear arms and hubs all the way forward. You can also try the 4 toe-in bar for additional forward bite. As you become more familiar with the car, you may find yourself surprised to be searching for steering. Read through the rest of this Tuning Section; check set-ups posted by Team drivers and other Family members on our website, and feel free to post questions about your car on X Factory's FB page. We love talking about this stuff!

TIRES

Tires are the most important tuning element by far: they're the car's only connection to the ground, and all other suspension or chassis changes must act through them. That said, tires are obviously very track- and condition-specific, so there's not much we can tell about them here. If you don't already have the right tires for your local tracks, see what the fast guys there are running. That's usually it.

SLIPPER AND DIFFERENTIAL

In the Race Preparation section we described breaking in your diff, adjusting it, and how to test your slipper clutch. Now, a few words about setting them! The diff and slipper can have a big impact on how your car corners and lays down the power.

The slipper clutch allows some 'give' in the driveline, which both protects the rest of the driveline from shock loads and takes the edge off the car in the high-torque range of the motor's rpm. Off the line and out of corners the slipper will slip some, just as its name implies, which helps prevent wheelspin and lets the car hook up. On slippery or looser tracks, we generally run a 'looser' slipper: back the nut off so that, when checking on the bench, the front end barely rises off the table. As traction comes up, you can tighten the slipper accordingly. On super high-bite surfaces, you'll actually back the slipper off some to prevent the car from pulling hard wheelies. The nice thing about slippers is the ease of adjustment: have a friend take a 1/4 wrench out to the track, and a few brief pit stops later you can have the car completely dialed.

Adjusting the differential for track performance is a tougher science, especially since the adjustment window is pretty small-less than full turn on the diff screw can go from too loose to locked up. The idea is, the looser your diff is, the more corner speed the car will carry. A tighter diff will have more forward bite-similar to a locked diff in a drag car. Diff adjustment isn't changed often but can be useful; always be sure the slipper gives before the differential barks.

FRONT CASTER

The X-6 Cubed Set-Up sheet calls for 30 caster blocks in U.K., 25.on dirt. These make a difference in steering on corner entry, exit, and through the corner. 20 blocks available (ASC #9592); compared to the 30, 25o takes away from turn in while adding exit steering and 20.goes even further. Once you settle on the blocks the suit your driving style, there are other ways to gain steering without losing stability.

STEERING BLOCKS

One way to increase steering is to switch from the stock trailing axles to inline axles (ASC #9623) and inline steering blocks (ASC #9577). When you install these parts, move the spacer from behind the caster blocks to the front, and use the rear Ackerman hole in the steering rack. These axles will give much more aggressive steering in and out of the corner, though they sacrifice straight-line stability: they can make the steering feel twitchy. To combat this twitchy feel, many X Factory drivers have experimented with running the inline axles while leaving the caster blocks forward. This extends the car's wheelbase while taking some weight off the front tires, all of which smoothes out the car's steering. There are so many ways to skin this cat!

ANTI-SQUAT

Rear anti-squat is the angle of the rear hinge pins relative to the ground. Lowering the rear toe-in block by removing spacers increases the amount of anti-squat in the car. With the 2mm shim under the hinge pin brace and no rear spacers, the car has 4 of anti-squat; with approximately 0.120" (3 mm) of rear spacing the car has 0, so every .030" (.74 mm) of spacers is a degree less. The thin white nylon shims included in the kit are .030"; the thicker ones are .060".

More anti-squat (rear of pins down) will generally take away rear side bite, add forward bite, and let the car spring more off jumps, generating a higher arc in the air. A car with more anti-squat will 'rotate' easier in sharp corners. Less anti-squat (pins closer to level) will make the car feel more stable and locked-in. Generally anti-squat is a "feel" adjustment, changing the way the car drives more than the fastest lap. On the X-6 Cubed it's quick and easy to change, so have a play with it and see what you like best.

Your X-6 Cubed also has a 2mm spacer under the hinge pin brace, which sets the height of the rear pivot. Another way to say this is to call it the distance between the outdrives and hinge pins. This distance affects a number of things, including the mix of forward bite and side bite. Adjusting the hinge pin brace shim will affect anti-squat, and your rear spacers should be adjusted accordingly. XF part # 3262 is a set of three CF hinge pin brace shims, 1mm, 2mm, and 3mm. The 2mm shim is standard in your Kit.

Back to Rear Suspension

REAR WHEELBASE

The wheelbase of your X-6 Cubed can be adjusted by moving the shims on the inner or outer rear hinge pins. As the pins are parallel to each other, moving the arm or the hub carrier by the same amount will have the same effect.

Moving the hub carrier forward increases rear traction in two ways: Primarily you are adding more 'angle' to the driveshaft, so there's more scrub between the dog bone and the outdrive as well as in the CVA joint. All this friction locks in the rear end and creates traction. Moving the hub carrier forward also increases the percentage of weight on the rear tires, further increasing bite.

Moving the hub carriers back is probably the easiest way to add steering and corner speed to the X-6 Cubed. It's one of the most commonly used adjustments for Team drivers. Moving the hub carrier or arm back some will increase steering throughout the corner. It also makes the car more stable in bumps, and because the driveshaft isn't as bound up, the car will "pop" better over jumps.

TRANSMISSION HEIGHT

The X-6 Cubed features X Factory's adjustable-height transmission. While not the easiest adjustment, it's a very powerful tuning tool to adapt the car to different surfaces. Included in Bag D (step D7) are several sets of transmission shims, four each of .030", .060", and .090". Counting zero, that's four transmission height positions. When you change transmission height, make sure to re-check rear ride-height (remember the race preparation list?). Keeping the ride height the same will allow you to feel the isolated effect of the transmission height.

Important Note: For the .060" and .090" setting, you'll want to add more shims to the motor plate support bracket. We generally use #4 flat washers for this. Also, as you adjust the transmission height keep an eye on the driveshafts' position in the outdrive: use the small shims between the wheel washer and outer wheel bearing to move the axles in and out, keeping the CVD engaged in the outdrive at full droop without bottoming out on compression.

Adjusting the height of the transmission changes the distance between the inner hinge pins and outdrives which changes several things at once; a greater distance (higher trans) allows the CVD to exert greater force on the suspension. It also changes the car's center of gravity slightly because you're adjusting the height of the motor too.

Raising the transmission will give your car more forward bite. It effectively stiffens the rear of the car, which means the car will break loose sooner in corners and will bounce more over washboards or small bumps. A softer rear shock package is generally recommended when running the transmission high. Lowering the transmission does the opposite: less forward bite, but greater side bite and a smoother, more stable car through rough sections.

FRONT AND REAR TOE ADJUSTMENTS

Toe-in (or out) is the angle of the tires to parallel when viewed from above. At zero degrees of toe the tires are parallel to each other; toe-in is when the front of the tires point toward each other, and toe-out is when the front of the tires point away. Front wheel toe is easily adjusted by turning the steering tie-rods between the steering rack and the steering blocks. Front tires are generally run with zero degrees of toe. Adding some toe-out will increase initial steering, but can feel twitchy and wander-y. Toe-in will stabilize the car, especially out of turns, but slows down the steering response and slightly decreases corner speed.

The rear tires are always run with toe-in, but the amount can be changed. It is adjusted by switching the rear tor-in block (installed in step E12). More rear toe-in (the 4 block) gives the car more forward traction but makes it harder to pivot the car. Less rear toe-in (the 3 block) will let the car flow through corners and pivot well, but at a loss of stability off the line and out of corners. A drag car would use lots of rear toe-in.

CAMBER

Camber describes the angle of the tire from vertical when viewed from the front or back. If the top of the tire leans out past the bottom you have positive camber; if the tire leans in at the top it has negative camber. A good starting point is to have -1 of camber all around; the Team usually runs between 0 and -3. In general, more negative camber will give more traction in the corners, while less gives more bite while the car is level. A good method of adjusting camber is to watch tire wear or dirt build-up: if the tire looks even or uniform coming off the track, then you're close to spot-on.

RIDE HEIGHT

Ride height is how high the car sits off the ground at rest. Pick up the whole car and drop it from a height of 6 inches or so onto a flat surface, letting the shocks settle. To check ride height by eye, look at the molding seams in the middle of the control arms: are they parallel with the ground (called "level") or do they angle up or down? If the center of the car is lower than the hub carriers/caster blocks, so the arms angle up as they go out, that is referred to as 'below level." "Above level is when the seams are angled down at the outside. If you have a ride-height gauge, touch off just behind the front bumper for the front and just under the transmission for the rear. (The chassis will wear underneath the rear toe-in block through the chassis life, so measuring under the transmission will be more consistent.)

The standard ride height is with the front arms level, or about 30 mm off the ground using a gauge (gauge measurement will vary based on the diameter of front tires); and the rear arms just below level, or roughly 29 mm with similar considerations for tires. Raising the whole car up will add traction, feel better on rough tracks, and jump better. It also makes the car more prone to traction-rolls, though. When the traction comes up, it's better to lower the car some; the car will feel more direct, with faster reactions, and it helps prevent roll-overs.

Check the car from the side using the same drop technique. This lets you see the "rake" of the chassis: the angle from front to back. In general you want to keep the car flat front-to-rear, or perhaps a touch higher in the back. Lowering one end of the car will give that end a little more grip, but extreme differences can make it more difficult to control on the track.

CAMBER LINKS

Camber links are a complicated but effective adjustment on any R/C Car, and your X-6 Cubed is no different. The inside hole groups are referred to by numbers, and the outside holes are called by letter. The more inside the hole is, the lower the value. Thus a "2B" rear camber link is in the outside hole of the rear bulkhead (2) and the middle hole in the rear hub carrier (B); a "1A" link would be the inside holes in both.

Camber links adjust the car's roll centers-points critical to understanding how the suspension and chassis will lean or roll through a corner. Without going through the geometry here, remember this: the shorter and more angled down the camber links are (inside lower than the outside), the higher the roll centers are. A higher roll center reacts more quickly but with less overall effect. Thus, removing washers or shortening links makes the car react more quickly but have less total roll. Adding washers or lengthening the link will slow down the reactions but make the car feel stiffer. Changing washers is generally a smaller effect than changing the length of the link. Remember:
Less washers (inside) = shorter link = higher roll center = more aggressive
More washers (inside) = longer link = lower roll center = slower, stiffer
If the above is the theoretical look at camber links, here's a more direct view: In the front, removing washers/shortening the link will quicken steering response but give the front less roll, leading to a possible mid-corner push, or steering which seems to wash out. A longer link will slow the reaction but give you more mid-corner steering. In the rear, removing washers/shortening the link means the back end will roll less and square up out of corners better. A longer link will give more rear traction in corners.

For a more systematic approach: Think about the outside ball studs first. The further out in the hub carrier or caster block you run, the more "square" that end of the car will run. This is especially felt in the rear: the 'C' hole in the rear hub carrier has more side bite in the corner, but when the car does break loose it will spin hard. The 'A' hole will let the rear end slide more, but it's much easier to control with throttle. The inside holes go through bumps a little better, too. Secondly, look at inside ball stud location: the inside hole (longer links) will give more traction and feel safer while the outside hole is more aggressive. Last, find the number of ball stud washers you like: more washers will give that end of the car more corner traction but slow down its response.

A final note about camber links: keep an eye on the balance of the front and rear links. Having a short link up front and a long one in the back can make the car feel less confident and consistent. If you find yourself liking a long rear link, try a longer front one to go with it, and vice versa.

SHOCKS

The shock absorbers on your X-6 Cubed offer much adjustment potential, and with good reason: they're working all the time, through corners, bumps and jumps, even just going straight! On your shocks you can change the spring rate, the damping and pack, mounting locations, and travel limits.

Changing the spring rate is pretty easy: change the springs. AE makes standard shocks, the V2 shocks, and big bores with lots of different springs, which will give you plenty of options. In general, stiffer springs will make the car feel more direct and jump a little better; they're suitable for high traction surfaces. Softer springs are better for bumpier surfaces, and can help generate traction on low-traction tracks. That holds true for each end of the car. Stiffer front springs will take away steering but can make it easier to drive, while soft springs add steering. Too soft will make the car hook spin out mid-corner. Stiff rear springs will add steering, especially in long sweepers, but at a loss of rear traction. Going softer in the rear will add bite, good on bumpy tracks, but take away steering. The big bore shocks & springs generally give a more "plush" feel, especially on rough tracks or those with large jumps. By using spring retainers from other manufacturers, big bore springs can be put on standard shocks; this often works very well on smoother indoor tracks with smaller jumps.

The damping in your shocks is a combination of the pistons inside and the oil they travel through. Heavier damping (thicker shock oil) will make the car smoother on the track, and better landing jumps, but will make the car bouncy in bumpy or choppy sections. Lighter damping makes the car more reactive overall and better through bumps, but it will bottom out more jumping and be slightly harder to drive.

You should also consider the "pack" your shocks have. Due to fluid dynamics, the resistive force of our dampers greatly increases as the piston moves faster. The faster the piston moves, the more it "packs up," and it does this on any stroke, even if there is only one. The smaller the shock piston holes, the more quickly the shock will pack and the greater the force will be. Larger piston holes are the opposite. By adjusting the shock pistons and oil together, you can tune both the static damping and pack separately. To change the pack while leaving the static damping similar, adjust the oil 5 wt for each piston change. So if you started with #2 pistons and 30 wt oil, you could:
Increase pack with #3's and 25 wt
Decrease pack with #1's and 35 wt
and all three shocks would feel very similar on the bench (static damping). Increased pack is good over smooth tracks and very good for big jumps with flat landings; it also carries more corner speed. If your car is bottoming out hard landing jumps, try increasing pack in the rear. Less pack is good for bumpy sections, as the suspension can soak up high speed movement better.

Suspension travel is controlled by adding limiters inside and outside of the shock. Limiting inside the shock (where the oil goes) reduces the amount of downtravel in the suspension: how far down the arms can go. More downtravel (fewer limiters inside) is better for rough tracks, as it goes over bumps and lands jumps better. Less downtravel (more limiters) makes the car corner flatter, change directions quicker, and prevents traction rolls, all at the expense of rough-track handling. In the rear, make sure you limit downtravel enough that the CVAs cannot pop out of the outdrives; especially when using the inside shock hole on the rear arm the X-6 Cubed has quite a bit of travel. Limiting uptravel (adding spacers outside the shock body) is rarely used, usually only in the rear to prevent the CVA bone from hitting the outdrive.

Finally, we discuss shock mounting. Changing the bottom shock mounts affects quite a lot: the further inside the shock is mounted on the arm the softer the suspension feels (because the wheel has longer lever arm on the shock) and the more travel you have. To keep downtravel the same, it's generally recommended to add .060" (1.5mm) of spacers inside the shock for every hole you move in on the arm (and take out spacers when you move out, obviously). Running the front shock on the inside hole will add low speed steering at the expense of stability. The more in the rear shock is mounted, the "safer" the car will feel around the track: it's softer and soaks up bumps better. Moving the rear shocks out on the arm will add steering and is generally recommended for high traction, smoother tracks.

The upper shock mounts are much easier: the shocktowers holes are designed in an arc so that the suspension travel doesn't change as much. Inclined shocks (mounted in on the tower) have a progressive feel to them. They're smoother around the track and provide more side bite. Vertical shocks have more forward bite and are better over jumps.

Back to Rear Shocks Tower

Back to Rear Suspension

THAT BODY AND WOW, IS THAT THE WING?

The body on the X-6 Cubed is different than most other "cab-forward bodies in several respects; it was designed primarily to create traction but still looks great!ll: The rear is upswept like all X Factory bodies to generate rear traction. In the front, the X-6 Cubed's windshield is a bit further forward than most and has a steeper angle to create bite on the front wheels at the end of the straight and help keep the nose down in jumping. Take the body off for practice once-we're pretty sure you'll want it back on before completing the first lap.

X Factory's huge #8101 high downforce wing, standard on the X-6 for years, is a big reason: our cars develop the most rear traction of any car out there. It's good at its job. Air comes off the body and hits that scoop behind the shocktower, the #8101 wing is as wide as legally allowed, and the rake on the back is quite noticeable.

Your Cubed is equipped with our new #8103 medium downforce wing. It is 1/2" narrower than the #8101, and the rear kick-up is 5 less, so it generates less downforce. Both wings fit your Cubed, so if you want more rear traction at the end of the straight, try the #8101 wing.

The key our wing is that it's adjustable: you can always trim it down. Kind of hard to add lexan to a smaller one though...Also, on both wings the side dams are as large as the rules allow; they can be trimmed too.

Most Team drivers have several of both wings with them, each with a different Gurney height (the vertical piece at the back, named after Dan Gurney, American F1 driver and team owner). Obviously, higher Gurney = more force. The downside is that the car loses steering and, more importantly, will begin to jump nose-up over larger jumps. If you experience this problem in the air, cut the wing down until the car flies correctly. At some tracks we've actually cut away some of the back angled section to get the downforce we wanted. Adding a front wing can also help balance the car in the air.

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