Automatic checking of a range of design parameters to find the best solution. How your bikes suspension design affects its performance on. Automatically optimize the location of certain components for roll center. Dsp suspension design software for automobile springs and. Click on blue link for a pic of these front suspension layout details. Stop guessing and start winning learn the facts of front suspension geometry with this informative cdrom computer software.
Suspension design software faq suspension by design. For many applications, a 100% anti dive front end may be a desirable starting point or default setting, especially if the 4link. Both systems are used to help control or minimise longitudinal vehicle load transfer, in an aid to either retain suspension compliance, or improve aerodynamic stability. Suspension calculations and suspension simulations. My suspension textbooks are pretty slim on the downsides of anti dive, but also note that most racecars dont use anti dive. Upper lateral link, lower parallel links, twin trailing link rear a variation of the reversed lower aarm style. The suspension system is a device connecting the body with wheels. Now you can get all the racewise chassis school material in an easytouse software program for your home computer. Now, the excel exports item antidive, antilift and brakeanti all refer to the front suspension braking anti dive, and the rear suspension braking anti lift values. Antidive is a suspension parameter that affects the amount of suspension. Aug 21, 2015 this week i did some work to determine the roll center height of the car and decided on switching from rod end bearings to spherical bearings to improve the tilt angle, while still leaving me with. This can be achieved by tilting the upper front control arm a arm so the rear.
These details better locate the exact frame mount for the a arms andor struts, and will calculate anti dive a suspension tuning parameter. Racewise provides the technical understanding of suspension and tire performance that racers must have in order to make no guesswork decisions. The amount of anti dive or anti lift in a suspension system is controlled by the position of the castor pole relative to wheel centre see the post on bump castor for an. These characteristics make the vehicle neutral and keep the power and suspension dynamics independent. Setting anti features is a matter of experience and is generally kept between 020 percent. David hodgson this thesis outlines the process of designing a three link front, and four link rear suspension system. The program is compatible with windows xp, vista, win 7, win 8, or win 10 which means it is easy to use and you will be able to print the results on most any printer, usually in color if your printer supports it. The software will analyze most forms of ffe suspension. How your bikes suspension design affects its performance. We have 5 programs that work with anti dive when conducting suspension simulation.
Antidive suspension tech parameters circle track magazine. On most chassis, the lower control arms are level front to back. When building a 4link suspension, the lengths of the links, their positioning, and the angles at which they are mounted, will all determine how the suspension affects the vehicle chassis under acceleration, braking, and cornering. All kinds of forces and movements between the wheels and the ground passes to the body through the suspension. There are many thick textbooks, expensive software, and hundredpage internet forums out there on the subject of 4link geometry and it is very. How to decide if i need prodive or antidive suspension. An effective way of increasing the antidive of the wedges front suspension is to add an additional factory spacer under the front antiroll bar mount, however this may be a case of less being more and the 1 inch thick aftermarket blocks currently available may be a bit too much of a good thing. As anti dive is added, a portion of the load transfer is resisted by the suspension arms.
The main reason for the difference is due to the different design goals between front and rear suspension, whereas suspension is usually symmetrical between the left and right of the vehicle. Anti squat geometry takes some of the acceleration weight transfer load off the springs and puts it through the links. This can be achieved by tilting the upper front control arm a arm so the rear mount is lower than the forward mount. Antisquat refers to the amount of antisquat built into the rear suspension of rearwheeldrive cars relies on drive torque. Anti squat, dive and lift geometry 18 aug 2018 suspension secrets anti squat, anti dive and anti lift geometry which will be referred to as anti geometry when discussing them as a whole is a form of geometry at the front and rear wheels that alters and controls the amount that a car will compress the springs due to acceleration. Antidive front suspension can be used to limit this characteristic. Autowares racing and performance tech site software for auto racing and high performance cars data acquisition systems new and used engineering services and live seminars on performance and racing technology all types of tech info on racecar engines, chassis and suspension setup for road.
Anti dive and anti squat suspension systems have come in and out of designers and engineers attention over the years. Anti dive is dependant on the vehicles center of gravity, the percentage of braking force developed at the front tires vs the rear, and the design of the front suspension. Ive got some decent rate front springs on the car, and dont know how much the anti dive is doing for me. Pdf influence of antidive and antisquat geometry in combined. Anti dive and anti squat they can be thought of as the counterparts for braking and acceleration as roll center height is to cornering. Anti dive and anti squat are expressed in terms of percentage and refer to the front diving under braking and the rear squatting under acceleration. For the very common double a arm suspension, antidive is designed into the. If a point is reached called 100percent anti dive, all of the load transfer is resisted by the suspension arms and none is carried through the springs.
Antisquat and accelanti both refer to the front suspension. This screen also lets you calculate anti dive, and important handling parameter. Personally i see squats and dives as extreme fine tuning for the driving experience read comfort and i dont really see it relevant in baja sae. Figure 3 independant front suspension on the 2017 ford raptor frontend fued ifs vs. Oversteerundersteer rating to estimate the handling of the vehicle at any corner on the track. The anti lift in the suspension generates a negative vertical force on the suspension which helps to reduce the front suspension lift and as a result the vehicle pitch. The suspension system comprises antisquat and antidive element. Apr 01, 2020 suspension calculations and suspension simulations. Because anti lift can apply to either front braking or rear acceleration, this was changed in v4. In this article well cover what we consider to be the three most important elements. When a car is decelerating due to braking there is a load transfer off the rear. Lower lateral link, upper reversed aarm, twin trailing links rear a variation on the above. Complete graphs and reports are included, and several new.
Suspension systems with 100% anti squat values will have no effect on the chassis under braking or acceleration. The main reason for the difference is due to the different design goals between front and rear suspension. Dec 30, 2014 the leading link front suspension system for the akira bike project, a prototype for a fully functional high performance recumbent motorcycle inspired by kanedas ride in akira see more about. We can reduce understeer and oversteer characteristics with the adjustments of anti roll bar sway bars, bump and rebound, ride height, spring rates, corner and static weights. The more antidive, the less the front of the car will compress during braking, at a cost to comfort and increased chance of brake lockup. So sit back and relax and read on while we go through the az of anti. For the rare case where brakes are not mounted on on the suspended wheel, like inboard brakes, this definition does not apply. Wishbone pivot axes may be tapered in both plan view and for anti dive anti squat in side view, and for any chassis location point for suspension spring units. Suspension design for other vehicles is similar, though the process may not be as well established. Antisquat, antidive and antilift geometry which will be referred to as antigeometry when discussing them as a whole is a form of geometry at the front and rear wheels that alters and controls the amount that a car will compress the springs due to acceleration, deceleration or braking conditions.
Anti dive and anti lift are anti motion effects, not anti force mechanisms. More anti percentage simply means that more load is going to the a. There are many software company sponsoring baja sae participants among them the most commonly used are 1. However, this will stiffen the suspension, since the load is not on the springs.
Suspension analyser to calculate suspension geometry for fast road and circuit cars, including anti squat %, anti dive %, dynamic toe change, dynamic camber change, dynamic castor change etc. Usually the intuitive reactions are builtin to aid traction under accelerating and braking respectively but we can circumnavigate these all together with the black magic of the anti. The suspension analyzer does a complete 3d suspension analysis, including bump steer, ackerman, caster gain, anti dive, tire scrub, camber gain and much more. For analysing suspension geometry we use susprog 3d ie roll centres, camber curves, scrub etc. Finite element analysis to analyse our designs, minimising high stressstrain areas and evaluating them for production. Anti dive front suspension can be used to limit this characteristic.
The basics of anti squat, anti dive, and roll center. These systems are commonly found on vehicles used for the sport of rock. Oct 04, 2018 whether youre seeing the term antirise or antidive opposite way of measuring the same basic thing, all suspension systems with rear brakes have it. Racewise rwfront front suspension geometry software. In order to measure your anti geometry, the side view swing arm for your front and rear suspension systems must first be established. Antidive suspensions are used to reduce body dive by altering the front suspension so that the forces resulting from braking pass through the. Now these anti dive shocks are nothing but regular conventional shock absorbers with some additions to them which we are going to cover in this article. As we all know, a car has a tendency to compress the front suspension under braking. Leading linke antidive front suspension system youtube. It goes well beyond our simpler roll center calculator to include steering inputs, bump steer toe change, ackerman, caster, anti dive and much more. So to counter this, some of the bike manufacturers have come up with a good solution for this called the anti dive shocks. From the side view of your front suspension you have pivot points for the.
Anti dive is is the forces of inertia and mechanical resistance that the brakes create thru the front suspension. One bike will have more antirise than another, but if your wheel goes up and down when you hit stuff and you have a rear brake, youre in on the party. Design and optimization of formula sae suspension system. How to decide if i need prodive or antidive suspension for. Analyse suspension geometry for weight transfer issues eg calculating springs and anti roll bars well use the weight transfer worksheet. Automotive suspension design is an aspect of automotive engineering, concerned with designing the suspension for cars and trucks. Suspension key performance indicators kpi suspension designer. As for anti dive, it is there on basically every double wishbone suspension and should be included, but no one really talks about it. This measurement is again mostly specific to your vehicle. Design of three and four link suspensions for off road use. Antidive suspension geometry explained engineering explained. Susprog3d designer supports full 3d specification of all points.
An effective way of increasing the anti dive of the wedges front suspension is to add an additional factory spacer under the front anti roll bar mount, however this may be a case of less being more and the 1 inch thick aftermarket blocks currently available may be a bit too much of a good thing. The suspension system comprises antisquat and anti dive element. Suspension key performance indicators kpi suspension. Davis, benjamin design of three and four link suspensions for off road motorsports. Anti dive anti squat roll centre migration chassis design. A definition of anti dive as it pertains to motorsports suspensions. Design of a suspension system and determining suspension. Designs which fit into this category include, hub centre steered designs such as difazio, bimota etc. Chassis design is a very black art, but most sources ive found still seem to suggest the following some maybe fact, some myth. It can increase traction, as the load transfer is instant, rather than taking time to compress the springs. Which steering and suspension software should i use for. Mar 01, 2002 anti dive is a suspension parameter that affects the amount of suspension deflection when the brakes are applied. Autoware autoware inc front suspension geometry software.
The classis 60s sports and racing car rear suspension. They can be thought of as the counterparts for braking and acceleration as roll center height is to cornering. All synergy products are designed with the use of the latest cad engineering software to ensure the highest level of fit, finish, and performance. The spring and the suspension arms are sharing the load in some proportion. Department of mechanical engineering, union college advisor. Front suspension ffe software motochassis by tony foale. Like anti squat, anti rise is also measured in percentages. One of the most common questions we get about suspension setup and tuning is how 4link geometry affects the performance and handling of a vehicle. This suspension design software lets you take into account various characteristics of your car, such as corner weights, the suspension type, the suspension geometry, wheel widths and offsets, and wheelbase to intelligently select springs coil, leaf, and torsion bar springs and sway bars also called swaybars, anti sway bars, or anti roll bars. Anti dive suspension geometry with inboard or outboard brakes anti lift suspension geometry with inboard or outboard brakes anti squat suspension geometry with independent suspension or solid axle anti roll bar anti sway bar stiffness calculation for tubular or solid bars.
Anti dive and anti squat the inclination of suspension members dictates what a car does when you step on the gas or stomp on the brakes. Foreaft load transfer is essentially fixed for any given acceleration or deceleration, so the greater the amount of the associated load transfer that is carried through the suspension linkage the less is left over to go through the elastic path springs and dampers, hence suspension compressionextension is reduced. Im also curious if id see any handling benefit from reducing the amount of anti dive in the front suspension. Typical rear suspension screen, here analyzing an angled 4 link rear suspension and driveshaft movement and u joint angles. Anti squat, dive and lift geometry suspension secrets. Design of a suspension system and determining suspension parameters. Nov, 20 1 full floater suspension suzukis mono shock system. Mar 20, 2020 looking forward to the anti dive article as this is a little less clear to me. As the inboard pickup points affect the side view geometry the percent anti dive also gives a fair idea about the placement of the inboard pickup points.
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