R/C Tips & Tricks

Set-up

64. Change Only One Thing at a Time

    If you dial in an extra degree of camber, shorten the wheelbase and install stiffer front springs all during the same visit to the pits, you’ll have no idea which adjustment has made your car handle better or worse. Take the car out for a few laps after each adjustment; if performance decreases, it’s easy to "undo" the last adjustment.

65. Make Only Small Adjustments

    Touring-car set-up isn’t a game of inches; it’s a game of TENTHS of inches. Make small adjustments, or you may overshoot the perfect setting. Test the car frequently as you dial it in.

66. Know When to Say "ENOUGH"

    Question: How long does it take to get the perfect set-up? Answer: How much time you got? It’s easy to fall into the trap of chasing set-up all day, all week, or all season. Though you should always be looking for ways to go faster, you should not be altering your car so often that you never get used to one set-up. It’s more important to be able to drive your car at 100% of your ability, even if it’s only 80% dialled in.

67. Keep Notes

    You’ll notice that the fast guys all have greasy little notebooks on which they jot all their set-up info. You should follow suit; write down all the set-up info you can stand - even the stuff that didn’t work! It doesn’t take long to acquire a lot of useful data, and you’ll save a lot of practice laps when you need to tune your car for conditions you’ve encountered previously.

68. Ride Height

    The ride height of your car is basically the distance between the surface of the track and the bottom of your car’s chassis. The best time (really the only time) to measure this is when you have EVERYTHING INSIDE YOUR CAR including electronics and batteries. By not having everything in your car, the weight drastically changes and therefore your ride height changes when you get all the necessary items into your car.
    It is best to set-up your ride height in similar conditions as the track you will be running on, if not on the track you are running on. This particular setting can be adjusted in many different ways, but the easiest and best way to do this is by using preload spacers (which are basically collars and spacers that snap onto the shock to raise and lower the pressure the shock exhibits) or threaded shock bodies. If you race on carpet, the conditions might enable you to go as low as a 3mm ride height. The lower your ride height is, the better your car can corner. Having your car lower to the ground allows the car to corner "flatter" by having a lower centre of gravity. Right height can also affect how much traction you have; the end of the car that is lower will have more traction than the other. Another way to lower ride height (if you use foam tires) is to cut them down. For more tips on tires, go the TIRE TIPS section on this page.

69. Shock Travel

    The title is pretty self-explanatory; it is the shock’s full range of motion from full compression to full extenuation.
    If you are running on a fairly smooth track, then you don’t need as much shock travel as if you were running on a bumpy track. The less shock travel you have the better the overall performance of you car. I recommend having the least possible shock travel you can get away with at your track. Shock travel is adjusted by placing shock limiter/ internal spacers/ O-ring/ shock piston (whatever you wish to call them) on the shock shaft. Just make sure that when you put these spacers into your shock that they are PLASTIC, not metal. Some cars have suspension arms that allow them to adjust shock travel by adjusting the threaded inserts. These threaded inserts may be handy for quick shock travel tuning; they aren’t good because they put a lot of strain on the chassis of the vehicle. Threaded inserts may be used to figure out the best shock travel distance, but final adjustments should be made by the spacers that go inside the shock body. To limit the upward travel of a shock, place any number of spacers onto the shock shaft between the spring perch and the shock body. Make sure you don’t put too many in or the shock will be too short and you will have major problems. You should be able to adjust your shock travel before you hit your local track, unless of course you have no idea what the track you are going to is like. Carpet racing can allow you to lower your shock around 3-5mm lower than the stock setting. Paved road racing may need more shock travel or even possible less; it all depends on how bumpy the track surface is. One important thing to know about touring car shock travel is that touring cars usually work best when there is no "sag" (when the suspension compresses at rest). The shocks should be fully extended when the car has all of the required electronics and parts/accessories in is and a ride height that is proper for conditions. A little big of "sag" might help you if the track is really bumpy, but it usually is not recommended or required.

70. Spring Rate

    This one isn’t an adjustment; it’s a choice. Contrary to popular belief, cranking down on a spring’s preload does not affect its rate. Just about every touring car maker offers an optional set of tuning springs (usually "soft", "medium" and "hard"). Buy two sets so that you can have duplicate springs on all corners if necessary.
    Spring rate must be matched to the car’s need to resist roll in the turns and to its need to absorb bumps. Softer is better for bumps; stiffer is better for turns. If your track is bumpy and has lots of sweepers, you can go soft; if it’s smooth and there are lots of sharp turns, go hard - especially if there’s plenty of traction. Spring rate can also be used to tailor front and rear grip: use a softer spring on the end of the car where you need more traction. Note: spring rate and damping go hand in hand, so be prepared to make some shock-fluid/piston changes if you make a radical change to your spring rate.

71. Shock Angle

    The name states it all. Most TCs have a selection of holes on the shock towers and on the suspension arms that can be used to alter the angle of the shocks
    The shock position suggested by the vehicle’s manual is typically the best set-up for most tracks, but it pays to experiment. Shock angle is easy to change by mounting the shock arm in different holes, so it’s not tragedy if your car changes don’t help the car; just remount the shock in the hole you started with, and you’re back to square one.
    Lower mount: as you move the shock to the outer holes in the suspension arm, the arm has less leverage to activate the shock, and its actions becomes "stiffer". This is useful to counter body roll. If you use holes that are farther inboard, the arm has more leverage, and suspension action is "softer". Upper mount: changes here do not affect the suspension arm’s leverage, but they do affect the shock’s compression rate. If you move the upper mount farther outboard, the angle formed by the suspension arm and the shock will change less as the arm moves through its travel range. This means that the shock’s compression rate is more consistent from full extension to full compression. If the top of the shock is moved inboard, the suspension action will feel progressively "stiffer" because the angle formed by the suspension arm and the shock becomes closer to 90 degrees as the suspension is compressed. The effects described here are quite subtle but are worth experimenting with. Be sure to check ride height when you change shock angle.

72. Damping

    What most racers call "shock absorbers" are actually dampers; all "shock absorbing" on TCs is done by springs. Dampers keep the springs in check by controlling the release of the energy stored in the spring after it has been compressed; without dampers, the car would go "pogo" all around the track. The dampers used on all but the least expensive TCs control spring action with the resistance generated when silicone "oil" is forced through the holes in a piston.
    There are two ways to adjust damping: change the viscosity of the damping fluid, or change the size of the openings in the damper piston. Most shocks use holes of various diameters to control the flow of fluid through the piston. Smaller holes offer more resistance as the piston is pushed and pulled through the oil; larger holes allow the fluid to pass more easily. Likewise, "thicker" fluids pass through a piston hole of a given diameter with great difficulty than "thinner" fluids. Assuming you selected the appropriate springs for your car, less damping will allow the suspension to compress and extend more quickly, and this will result in increased control on bumpy tracks; however, the car is likely to show more body roll when cornering. Stiffer damping will increase smooth-surface traction but will inhibit traction and control on bumpy tracks.

73. Anti-Squat

    Anti-squat is known as the angle of the plane formed by the arms’ inboard pivots as viewed from the side of the chassis. When you have the hinge pins angled further up, the less the car will sink the rear of the car at acceleration. When the hinge pins are parallel with the chassis the cars is considered to have zero anti-squat.
    Almost every sedan has their rear arms mounted on fixed bulkheads so anti-squat is not adjustable. The SHUMACHER SST ’99 PRO is one car that uses independent rear arm mounts in which spacers may be added under the front mounting screw so that the hinge-pin angle may be altered. It is not recommended to adjust the anti-squat from the stock setting, but experimenting might lead to better performance. If you lose a lot of traction while accelerating or feel that the car is wiggling when you are accelerating, you might want to try and adjust the anti-squat (add a degree of anti-squat).

74. Camber

    Whenever you look at your sedan directly from the front or the rear, the wheels should lean slightly inward toward the chassis centre-line. This is known as camber. When the wheels are perfectly vertical, the car is said to have zero camber. If the wheels lean outward (away from the chassis centre-line) the car is said to have positive camber; if they lean inward, the car is said to have negative camber. Camber is used to compensate for chassis roll while cornering. Basically, as the chassis "leans" in the corners, so do the wheels; this reduces the contact patch between the tire and the roadway surface. Giving your sedan negative makes the tires flatten out in the corners and therefore increasing the contact patch. This will also increase cornering ability, better handling, and more even tire wear.
    The camber may be adjust by way of a turnbuckle upper linkage, by adjusting a threaded-rod camber link (one end of the camber needs to popped off), or by threading a pivot ball into or out of the suspension arm (this is quite rare). Touring cars usually don’t need more than 1 or 2 degrees of negative camber thanks to the fact that TC’s have such short-travel suspension systems and do not need to compensate for excessive chassis roll. Higher camber angles can be used to reduce the wheels’ contact area as a way to dial out traction, but that is hack tuning. Adjust your camber if you want even tire wear and try and stick to angles between 0 and 3 degrees negative camber. You can accurately measure this number with a gauge from RPM or RACEtech.

75. Caster

    This is the angle of the steering hub’s kingpin, or the angle of the plane formed by the hub’s pivots. Like camber, caster is measured in degrees and may be "positive" and "negative". If the kingpin is perpendicular to the chassis, it has zero caster. If it leans toward the front of the chassis, it has negative caster; if it leans toward the rear, that is known as positive caster. Caster and camber work together to control the tires’ contact patches as the car turns. When set at zero, caster has no effect on camber. Add positive caster, however, and it’s easy to visualise how camber and caster interact. The Tamiya TA03 has a 10-degree positive caster. The tyre’s contact patch moves to the outside of the tread when the hub is turned toward the rear of the chassis. Correspondingly, the contact patch moves to the inside of the tread when the hub is turned to the front of the car. Now, imagine the TA03 is taking a turn: the inside hub swings the wheels towards the rear of the chassis, and the caster setting helps move the tyre’s contact patch from the inside of the tread toward the outside (decreasing camber). Meanwhile, the outside hub swings its wheel toward the front of the car, and the caster setting moves the tyre’s contact patch farther inward (increased camber) You may have heard that greater positive caster angles increase turn-in steering but decrease steering when exiting a turn. How discernible this is to the average racer is debatable, but it does make sense that the sudden change in camber could cause the car to react quickly to steering input but then "settle down" as chassis lean counters the effects of the camber change.
    Most cars us separate steering hubs and hub carriers that do not allow caster to be adjusted (optional hub carriers with different caster settings are available for some kits however). Also be aware that caster always refers to kingpin angle, not hingepin angle. Some kits, such as the Team Losi Street Weapon, do use optional bulkheads to alter the angle of the front suspension arms' hingepins as a means of changing the angle of the kingpins, but caster angle refers ONLY to the kingpins. Kits that have adjustable caster usually use a turnbuckle to adjust it (GHI Xpress series), or they have variable-position upper-arm spacers (Traxxas 4-Tec). If you are pleased with your car's handling but find it turns too hard (or not hard enough), try altering the caster setting; increasing positive caster will increase turn-in and vice versa.

76. Ackermann

    Ackermann refers to the difference in front wheel angles required for a touring car to steer more effectively. When cornering, a car's inside wheels describe a smaller circle that the outside wheels; therefore, the inside and outside front wheels must turn at different angles to negotiate a turn without encountering "scrub" - the friction caused by a tire that is not correctly aligned with the arc of the turn. Ideally, a car's steering geometry will cause the front wheels to maintain an angle that is perpendicular to the radius of the turn, regardless of how sharp or sweeping the corner is. Associated claims the TC3 has "perfect Ackermann" as described above.
    Ackermann is usually "selectable" rather than "adjustable". In the case of the Team Losi Street Weapon, two bellcrank pivot locations allow the car to be set for more Ackermann (greater difference between left and right wheel turn angle) or less Ackermann (less difference). Some cars have and adjustable drag link between the bellcranks; changing the length of the drag link will alter Ackermann. If your track has lots of tight turns, more Ackermann might suit your car; conversely, less will work well on tracks that have sweeping turns.

77. Track

    This is often confused with width, as any change in width also changes track. But to be precise, track is the distance between the right and left tires, measured from the centre of each tyre’s tread. This is important because two cars with the same total width may have different track measurements because of the width of their tires.
    To alter track, some cars offer a choice of hub mounting holes in the suspension arm, and on a few pivot-ball-supported hub designs; track can be adjusted by threading the balls into and out of the arms. But on most cars, the only way to alter track is to put spacers between the wheels and hubs or mount wheels with more or less offset (which is the distance from the centre of the rim to the face of the mounting hex). Kawada and HPI both offer a line of rims with different offsets. Go with the widest track you can (190mm is usually the maximum width allowed for electric TCs), as width promotes stability. If your local track allows you to run a 200mm car, go for it.

78. Wheelbase

    The distance from the centre of the front axle to the centre of the rear axle represents the car’s wheelbase. Be sure the front axles are perpendicular to the chassis’ centreline for accurate measurements!
    The longer the wheelbase, the more straight-line stability a car has, but long-wheelbase cars do not corner as tightly as short-wheelbase cars - imaging a limo on a slalom course. If your track has sweeping turns and long straights, try a long-wheelbase set-up; for tight, twisting tracks, shorter is better. On most cars, wheelbase can be adjusted by changing the locations of the spacers on the rear of the hubs’ hinge pins. Some cars have rear suspension arms that can be flipped to match the chassis to short-wheelbase body sets, but this is too dramatic a change in wheelbase for tuning purposes.

79. Toe Angle

    This refers to the angle of the wheels as viewed from above. The wheels have toe-in if the front wheels point inward toward the front of the car; and if their fronts point outward...you guessed it: toeout.
    Front toe is fully adjustable on all but the least expensive cars, and it’s adjusted by altering the length of the steering tie rods by twisting a turnbuckle or by adjusting a threaded link. Rear toe is rarely adjustable, but optional hubs with various degrees of toe-in may be available. Most cars benefit from a degree or two of front toe-in to help stability on the straights. Toe-out can be used if you need extremely aggressive turn-in. For most cars on most tracks, the stock setting for rear toe is fine, but running zero rear toe can help efficiency and straightaway speed - but at expense of some stability. Rear toe-out is never used. Avoid extreme toe-in settings (4 degrees or more) at either end of the car, as this will cause the tires to "scrub", and that limits speed and increases tire wear. If stability on the straights in an issue, toe angle should be your first adjustment.

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