Off-road suspension tuning guide
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.
Camber |
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| Description: 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 settings: |
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Negative camber |
Positive camber |
| Front:
Increases steering Rear: Increases traction when entering corners Makes the vehicle more forgiving |
Front:
Decreases steering Rear: Decreases traction when entering corners
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Toe-in / Toe-out |
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| Description: 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.
Typical settings: |
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Less toe (toe-out) |
More toe (toe-in) |
| Front:
Decreases straight line stability Increases cornering when exiting corners Rear: This is not recommended to use toe-out |
Front:
Increases straight line stability Increases initial cornering Rear: Increases rear end stability on power Makes the rear end feel more "tight" Increases rear end traction Decreases steering |
Caster |
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| Description: 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 |
Increases off power steering Decreases on power steering Decreases straight line stability |
Increases on power steering Increases straight line stability Decreases off power steering |
Shock oil |
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| Description: 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. |
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Lighter shock oil |
Heavier shock oil |
| Front:
Increases front traction on bumpy surface Increases body roll on high traction surface
Rear: Increases rear traction on bumpy surface Increases body roll on high traction surface |
Front:
Decreases front traction on bumpy surface Decreases body roll on high traction surface Will make the vehicle less prone to bottoming out Can make the vehicle jumps better and higher Rear: Decreases rear traction on bumpy surface Decreases body roll on high traction surface Will make vehicle less prone to bottoming out Decreases the rear end to squat under hard acceleration Can make the vehicle jumps better and higher |
Shock spring |
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| Description: 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. |
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Stiffer shock spring |
Softer shock spring |
| Front:
Decreases traction and steering on bumpy surfaces Decreases body roll on high traction surfaces Can make the vehicle jumps better and higher Rear: Decreases rear traction Decreases rear squat effect Can make the vehicle jumps better and higher |
Front:
Increases traction and steering on bumpy surfaces Increases body roll on high traction surfaces Rear: Increases rear traction Increases rear squat effect |
Shock piston |
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| Description: 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. |
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More or bigger holes |
Less or smaller holes |
| Front:
Increases front traction on bumpy surface Increases body roll on high traction surface Rear: Increases rear traction on bumpy surface Increases body roll on high traction surface |
Front:
Decreases front traction on bumpy surface Decreases body roll on high traction surface Will make the vehicle less prone to bottoming out Can make the vehicle jumps better and higher Rear: Decreases rear traction on bumpy surface Decreases body roll on high traction surface Will make vehicle less prone to bottoming out Decreases the rear end to squat under hard acceleration Can make the vehicle jumps better and higher |
Shock position |
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| Description: 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. |
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Less inclined shock position |
More inclined shock position |
| Front or rear:
Makes the initial shock damping stiffer Decreases lateral traction Makes the vehicle more responsive Makes the vehicle less forgiving and less stable |
Front or rear:
Softens initial shock damping Makes shocks more progressive Makes the vehicle more stable Makes the vehicle more forgiving Increases lateral traction |
Ride height |
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| Description: 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 |
| Front:
Decreases steering Increases rear traction Increases CG and chassis roll Increases weight transfer Rear: Decreases rear traction Increases steering Increases CG and chassis roll Increases weight transfer |
Front:
Increases steering Decreases rear traction Decreases CG and chassis roll Decreases weight transfer Rear: Increases rear traction Decreases steering Decreases CG and chassis roll Decreases weight transfer |
Wheelbase |
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| Description: Wheelbase represents the length between the front axles and the rear axles. | |
Shorter wheelbase |
Longer wheelbase |
| 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 |
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| Description: 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. | |
More anti-squat |
Less anti-squat |
Makes the vehicle more sensitive to throttle inputs Increases rear tires traction because more weight is transferred under accelerating Decreases steering under acceleration |
Increases rear traction while accelerating on loose surface Increases side-bite Makes the vehicle accelerate faster through bumpy surface
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