Understanding RC car suspension is extremely important. Never minded how camber, toe or shocks effect your vehicle handling ? Suspension tuning is one of the most important way to decrease your lap time. Maybe you’re fast, but with a good setup, you’ll be faster. Here’s few good tips to set up your vehicle.
Note: Be sure there is no loose or bending in the suspension or in the steering components before attempting to tune your vehicle.
How to adjust front and rear camber
When you look at the front of the rear of your vehicle, camber represents the vertical angle of your tires. If the top of the tires are leaning toward the chassis (like the letter A), this is negative camber. On the opposite, if the top of the tires are leaning away the chassis (like the letter V) , this is positive camber. Camber is used to adjust the contact patch of the tires. Why adjust the camber ?? Simply because when entering a corner, the inner tires are leaning toward the chassis while the external tires are leaning away the chassis. By tweaking the camber, you can adjust your wheels to have more contact on the track surface and then have more traction. More the suspension is stiff, less camber you’ll need.
Typical camber settings:
Toe-in / Toe-out
Toe represents the horizontal angle of the tires. If the tires are pointing in, this is toe-in. If the tires are pointing out, this is toe-out.
Less toe (toe-out)
More toe (toe-in)
|Caster is the angle of the king pin or the steering block when viewed from the side of the vehicle. If the top of the king pin or steering block leans toward the rear, this is positive caster. In the opposite, if the king pin or steering block leans forward the vehicle, this is negative caster.|
More negative caster
More positive caster
|Shock oil affect damping speed. The thicker the oil is, the slower the shock piston moves inside the shock body. If the shock can’t move fast enough, the tire will loose contact with the ground and by consequence, lose traction. On the opposite, if shock oil is too thin, the shock will not absorb sufficient bumps and can make your vehicle bottom out after landing jumps. Don’t forget that the shock oil also influences the weight transfer when turning, accelerating and braking.Shock oil and shock springs work together, when you drastically change shock oil, don’t forget to replace shock springs according to the oil used. See Shock spring section for more information.|
Lighter shock oil
Heavier shock oil
|Shock springs are paired with shock oil used. If you use thicker oil, you should normally use firmer springs and vice versa. The shock spring should be firm enough to fully extend the shock when fully compressed in a reasonable amount of time. This means that if you use thick oil and the spring is not firmer enough, the spring will have not enough time to fully extend the shock before the next shock compression. On another hand, a shock with thin oil and firm spring will make your vehicle looks like a pogo stick.Shock springs and shock oil work together, this is important to have springs that work with your oil selection. See Shock oil section for more information.|
Stiffer shock spring
Softer shock spring
|By changing the shock piston you will delay or activate the damping action. This is similar to use thicker or thinner shock oil. Basically, the smaller the piston’s holes are, the slower the damping will be because less oil will pass thru the piston.This option is used when you can’t find the right oil density. Ex,: When 40wt oil is too thin and 45wt oil is to thick. The solution is to use 40wt with smaller piston holes or 45wt with larger piston holes.|
More or bigger holes
Less or smaller holes
|Shock position is the angle of the shock. You can adjust the shock position by changing the shock location on the shock tower and/or the a-arm.Changing the shock position can be helpful when you can’t find the correct shock spring/oil combo.|
Don’t forget, by changing shock position, you’ll alter the suspension damping and maybe you’ll have to fine tune shock spring/oil according to your new shock position. Ride height is also affected by the shock position.
Less inclined shock position
More inclined shock position
|Front or rear:||Front or rear:|
|The ride height is the distance between the vehicle and the ground. For off-road, a good starting point is the adjust the suspension to “bone level” which means that the a-arm, the CVD and the ground are parallel. Ride height dramatically modifies weight transfer. If you bash, you can set the ride height higher to prevent chassis bottoming. For racing, you better keep things low for better cornering and lower CG.|
Higher ride height
Lower ride height
|Wheelbase represents the length between the front axles and the rear axles.|
|Shorter wheelbase makes the vehicle good in tight turns but decreases stability on bumpy surfaces. Will also increase weight transfer when accelerating or braking.||Longer wheelbase makes the vehicle more stable on bumpy surfaces but will decrease cornering. Will also decrease weight transfer when accelerating or braking.|
|Anti-squat is visible when the vehicle accelerates or breaks. When accelerating, all the weight of the vehicle is transferred to the rear end causing the rear to lower. This also transfers traction to the rear tires.|