Most of the top manufactures that build race spec RC cars will provide you with a setup sheet. In the world of RC this is one of the most important documents to have. When you first start out racing it’s best to ignore the setup sheet and just focus on track time. Get as much track time as you can till you have honed your skills and you feel it’s time to start tweaking your RC car.
In short a setup sheet is a record of all the settings on your RC car. Once you have a set-up sheet filled in for a track you have a baseline record. If you change something for the better or worse you are able to see what the previous setting was.
The higher the skill level the more useful a setup sheet is. When Professional racing drivers post their set-up sheets on-line it’s also useful for other up and coming drivers. Using someone else’s setup sheet is a good way to find a baseline. All drivers have different driving styles and what works for one may not work for another.
Disclaimer: I do not claim to be a professional in this field. In RC there is always something new to learn. Over the years I have picked up a few things through experience and this article is constructed to share them with you. If you believe something is wrong or missing please feel free to share them in the comments below.
In this guide I will be using the Tekno EB48.4 Set-up sheet. This is an electric 1/8th scale race spec RC car. Whilst it may look different to your cars specific setup sheet the principles remain the same.
A setup sheet takes into account not only the settings on your RC car but also the conditions of the track. Track conditions play a vital role in how your car will handle and the amount of traction available.
Date is an important factor, race tracks rarely remain the same through either wear and tear or modifications. A new feature added to a track could increase or decrease lap times. If the new feature is a significant change your new set-up sheet could be completely different. What some drivers see as a small track, others may see as a medium size. This is another reason why it is important to fill in your own setup sheet.
Bump Steer – is how much the wheels turn as the cars suspension is going up and down. Bump steer is generally a negative. If the car hits a bump or accelerates/decelerates it can change the direction of the car. You can alter bump steer by adding washes to your steering linkages.
Ackermann – is how your wheels are angled when you turn. As you turn left or right the inside wheel can turn more than the outside wheel. More ackermann increases the angle of the inside wheel. Please excuse the crude paint illustration below, graphics are not one of my strong points. Hopefully you get the idea, the left wheel is at a sharper angle than the right wheel.
Servo Saver – does exactly what it says on the tin! – Inside a servo saver is a spring which controls how tight the servo saver is. As your servo operates the steering the wheels get knocked and bashed about during operation. The initial impact will goes through the servo saver first. You can change how tight the spring is by the threaded adjuster at the bottom of the servo saver. Too tight and the servo saver won’t protect the servo properly. Too loose and your servo won’t be able to control your wheels properly. Your car can also rapidly change direction going over bumps.
Steering Stop – you can limit the amount your wheels turn by adding washes to your C hubs. More washes would equal less steering angle. Not all RC cars have this tuning option, you could also restrict the amount of steering by changing your D/R (Dual rate) on your transmitter.
Suspension changes have a huge effect of the handling of your car. Shock oils come in different thicknesses and are often measured in WT, CST & CPS. Do not mix and match brands as the viscosity varies between measurements. A general rule is the higher the number the thicker the oil. If you add thicker oil to your suspension the dampening effect will be stiffer and slower.
A piston inside your shock is what gives you the dampening effect. They have tiny holes in them which the oil passes through. You can add more holes or make the holes larger. These will effect how much oil can pass through the piston.
Springs are measured on their strength and the length. Manufactures usually color code the springs which makes it easier to identify them based on strength. Longer or heaver springs change the rate at which the suspension operates.
You can adjust the amount of rebound your shocks have when you are adding oil into your shocks. Push the shaft up to your desired position then put the shock bladder on top and screw the cap on. Lets say you pushed the shaft up 50% of the way put your bladder on and your shock cap. You will now have 50% rebound, as the shaft is compressed it will automatically come back out to 50% of the way.
Tekno use 3 different shock types STD (standard), EMUL (emulsion) & VENT (vented). These 3 shock systems operate in different ways. It’s worth making a note of the type of shock you have on your setup sheet. If your chosen manufacturer has multiple shock options.
Front and rear chassis options.
We have allot going on in this section.
- Shock positions – In the illustration we have 4 holes at the top of the shocks and 2 positions on the lower suspension arm labeled A & B. These mounting points are to adjust how close the shocks are to the car and the lean angle of the shocks. Without going into too much detail about fulcrums & angles here are the basics. The further in (closer to the car) the shock is the softer the shocks will be. As you move the shock out it becomes stiffer. You can also adjust the lean angle of the shock a more upright shock will handle bumps better but decrease stability. You can have different settings front to back, its recommended to keep left and right the same as each other.
- Drive shafts – UVD (universal drive shaft) and CVD (constant velocity drive shaft) perform the same job of transferring energy from the differential to the wheels. A CVD is more suited to high grip smooth tracks. UVD’s are more suited to rough tracks with lots of bumps.
- Turnbuckles – are the link between your shock tower and C hub. You can adjust camber, camber rise and chassis roll using the turn buckle. Its worth purchasing a turnbuckle spanner, its very difficult to adjust a turnbuckle with long nose pliers! Start with the manufacturers recommendation on lengths and see what works for you. There are so many variations of length and position, what works for me might be different for someone else.
- Offset – can be changed by he thickness of the wheel hex. More offset will move the wheels out from the car. A wider offset will increase the stance and stability in some circumstances, as with all changes what you gain in one area you could loose in another.
- Sweep – I have not looked into sweep much to understand its effects. Sweep is when you have your front lower suspension arms angled either in or out.
- Kickup – is also a setting at the front of the car. This is the angle of the lower suspension arms with the front edge raised. More kickup will result in the front of the car lifting more under acceleration. This will transfer more weight to the rear of the car. This helps with bumps and rough tracks. Less kickup makes the car more responsive which is better for smooth tracks.
- Anti squat is when the rear of the car resists the weight transfer under acceleration. If you raise the front edge of the rear suspension arms this will add more anti squat. Anti squat is only noticed under breaking and accelerating. More anti squat will increase stability when you accelerate but decrease stability when turning off power.
- Rear toe is the angle the rear wheels on the horizontal axis. When you have more toe in the wheels are pointing in towards the car. More rear toe in increases stability on acceleration but can make the car more likely to flip over when turning. To adjust the toe on the front of your car you adjust the length of your steering linkages. I like to have a little toe in on the rear and a little toe out on the front.
Ride height can easily be altered by adjusting the pre load on your suspension. You measure ride height when your car is resting. I like to drop my off road cars onto a smooth flat surface from approx 12 inches. Let the car settle a little then measure the ride height at the front and rear. Less ride height is better on smooth tracks and more is better for rough/bumpy tracks.
Too much ride height and the car will have a tendency to flip over when turning. Ride height can also be different front to back. You want to ensure there is not too much difference as it will make the car unpredictable.
Camber is adjusted via the turn buckles at the front and rear. If you look at your car at the front or rear head on. When your wheels are perfectly flat on the vertical axis you have 0 camber. If the top part of the wheel is angled towards the car this is negative camber. There is no real need to run positive camber. More negative camber will reduce the chances of your car flipping over. Too much camber and you will loose forward traction.
Caster from what i understand is the angle of your c hub in relation to the rest of the car. To change the caster you usually need to change the C-hubs. I tend to follow the standard caster set by the manufactures on all tracks.
Sweep, Kick up, Anti Squat & Toe In/Out are discussed in the front and rear chassis options above. Enter your measurements in this section.
Sway Bars are also known as anti roll bars. These link the left and right suspension arms together. Thicker sway bars make the car feel stiffer and resist body roll. You can have different thickness sway bars at the front and back. A thinner front sway bar and a thicker rear will increase steering. A thinner sway bar in the rear and thicker in the front will increase rear traction and smooth out the steering.
Droop is the amount of down travel on your suspension. If you lift your car up in the air slowly you will see the wheels remain on the ground as you pick the car up. Eventually the wheels will come off the ground also. The more droop you have the longer your wheels will stay on the ground. Droop also plays a factor in how much your car will roll in corners. More droop is recommended for rough and bumpy tracks. To adjust droop you usually have grub screws in the suspension arms. As you screw them in clockwise it will lift the arm up, which will lower the amount of droop you have.
Tires and Differentials.
Brand/tread – I personally like to use the same brand and tire tread all round. I sometimes like to use different compounds harder/softer but not very often. Events can sometimes have a control tire this is a set tire which is only allowed to be used at the event. Speak with your local track owner or club members on the recommended tire. This is a vital tuning point, more time can be gained by picking the correct tire than any other tuning option.
Compound – this is how hard or soft the tire is. The same tread pattern can perform differently in hard and soft compounds.
Insert – these go between the wheel and the tire. Just like tires these also come in different compounds.
Wheels – are built with different types of plastics. Some are more supple than others, a wheel which is more supple can be less prone to cracks from rough tracks or jumps. Wheels can also have an offset built into them. Some wheels may not fit your car properly due to offset.
Differential oil tuning – is off my favorite tuning options the viscosities are much higher than shock oil. You would not use shock oil in a differential and vise versa. Viscosities can also drastically change in scales and types of RC cars. The general rule I follow for off road racing is thicker or same as the center in the front and thinner oil in the rear. Something like 7k front, 7k center 5k rear or 753 is what I like to use for all types tracks. A thicker oil in the front will increase steering with power but decrease steering when your off the power. A thicker oil in the center increases acceleration. Thicker rear oil will cause the rear to spin out or loose traction on power.
Bodyshell, Wing & Wheel base.
Body shells are not for just looking shiny when you have it professionally painted. They play a role in aerodynamics. That’s about as far as my knowledge goes on body shells and aerodynamics. Some cars have after market body shells which can often have different features to stock.
Wings also play a role in aerodynamics. The tuning options can be limited by the manufacturer. A wing is used to create down force over the back of the car. This increases stability at speed and helps the car glide through the air on jumps. To much down force and the front will lift.
Wheelbase is how far apart your wheels are. A larger wheel base is better for rough tracks and adds stability. A shorter wheel base is better for maneuverability on tight tracks with sharp corners.
Electronics, Drivetrain & Chassis Braces.
ESC’s (Electronic speed controllers) have a whole host of tuning options, for the purpose of the setup sheet its best to put down the make & model of your ESC. If you would like to learn more about ESC tuning options. I wrote and article on speed controller settings.
Battery enter the make and model in this section. If you have space you could also put down the “C” rating and “mah” rating. The C rating is how much current the battery can provide. The mah rating is the total capacity of the battery. Larger mah ratings will give you a longer run time but could be heavier. Larger C ratings will provide more punch.
Motor – you want to record the manufacturer here and the KV rating of the motor. A lower KV motor will provide more torque but less overall top speed. A good balance for 1/8th off road cars is 1900 – 2100kv.
Radio – fairly simple here put down the manufacturer of your radio system. I also like to put down how much D/R (dual rate) I am using. D/R is a setting on transmitters to control how far your wheels turn from left to right. I use it to protect my servo. The wheels will only turn so far before they stop. This is where I set my D/R so the servo will go no further. Setting it higher would only put unwanted stress on the servo.
Servo – apart from the name of the servo, you could also put in here the speed of your servo and the torque rating. I like to use Hitec HS-7950TH which has a speed of 0.13 seconds and a torque rating of 486 oz-in at 7.2v.
Drive trian (pinion size) – You can change how your car accelerates and the top speed simply by changing the pinion gear. A pinion gear with a higher tooth count will increase the top speed but decrease acceleration.
Chassis braces – a chassis brace is a support. However you can remove supports to tweak chassis flex. Be careful when you start removing chassis braces as you will also reduce the over strength of your car. Tekno state on their setup sheet “front brace is always recommended”.
There is a lot of information to take in with setting up an RC car. It’s possible to spend many track days just tweaking one individual option. This is why manufactures start you off with a recommended baseline. Don’t be put off, when you start to understand how to setup your car it’s very rewarding.
Take a pen and some paper to the track with you. Try one thing at a time, I can’t stress enough how important this is. Make notes of how the changes effect your car to your driving style. Have fun on the track and the results will follow.
I would like to thank Matthew Wolter from Tekno RC for letting me use the Tekno Eb48.4 setup sheet in this article.