Weight transfer, traction, braking, acceleration, and other vital defining traits are heavily influenced by the chassis. By handling we, of course, mean cornering, but it is so much more than that. You can also use this function to compare front and rear suspension although be careful as only the model at the front of the drawing is saved within the url. Second, the calculations made with the Front Suspension Geometry Pro (FSGP) software differ. It’s no secret that not all cars are created equal in terms of handling characteristics. For this reason, the calculated curves were shifted to match the specification of 2 degrees of camber at stock ride height. With 4+3 wheels, that radius would grow to 0.92" due to that extra half inch of rim placement outward.Īfter looking at Shock Therapy's article about this, all three values are within their recommended radius of less than 1.0", and why they say the older 900's geometry works well with 4+3 wheels (whereas newer machines are better with 5+2 and 6+1). First, the calculations cannot give the camber at static conditions they give only camber changes with suspension travel. Figure 1: Suspension and Steering Geometry in LOTUS soft. Going larger to a 30x10 tire with a wheel similar to stock (4.5+2.5) would have a smaller scrub radius of 0.42". All-terrain high-performance tires were chosen with dimensions: 22 X 7 X 10: (external diameter x tire width x rim diameter) (in inches) after market research and understanding the experience of teams in previous competitions. With 27" tires, the radius would be just slightly less. There is a way to visualize roll centre which is why we incorporated lines and points to make it easier to fol. The kingpin inclination angle came out to be 6.2 degrees, and with the stock 26x9R12 Bighorns, the scrub radius is about 0.64". Episode 4 where we talk all about Roll Centre. I used the brake rotor as a reference, and from there measured to the hub's mounting face, and to the estimated centers of the upper and lower rod ends. My stock xp 4 900 came with 26" Bighorn tires, and the wheels are 12x7 (4.5 + 2.5) in front. Revealing suspension geometry design methods in unique detail, John Dixon shows how suspension properties such as bump steer, roll steer, bump camber, compliance steer and roll centres are analysed and controlled by the professional engineer. Take these values as approximate, not exact, since I'm not a Polaris engineer and I was eyeballing things with a level, angle finder, and some patience while crouching on the driveway. and couldn't find anything specific, so I took some measurements. Keep in mind that 100% anti’s can make the wheels unstable so they start to hop.OK, I searched quite a bit for kingpin inclination angle, scrub radius, etc. So if you want more anti-lift and squat, if you have a short-long-arm type independent rear suspension, the forward mounting points of the arms must be raised so that in side view, they point to the center of gravity of the car. The assignment presented below aims to understand the fundamentals of suspension design for a Baja trophy truck or an all-terrain vehicle. The explanation in the book is only one paragraph. Since the independent suspension differential reacts the engine torque, the anti-squat comes from the forward force and is reacted at the tire’s center. The explanation in the book comes down to this: If the control arms react all of the torque from engine or brakes, the anti is calculated from the tire’s contact point on the ground with solid axles. (The chart has an error on it, the angle Theta sub R shown on the drawing is replaced by angle Phi sub R in the equation…) But, notice since the angle is through the wheel center instead of the ground contact point, it is much harder to get the angle large enough to get large amounts of anti-squat. Overview: The Roll Center Calculator lets you input, view, save, analyze and compare either Double A Frame or McPherson Strut front suspension geometry. This problem caused by the lack of space for. You can get some anti-lift from an independent rear suspension but it is harder to achieve. Double wishbone is the independent type of Suspension geometry that allows each wheel to act and react independently from the others. These calculation result the front suspension is still too soft, which the optimal motion ratio should be kept around 1:1 for better handling. Once understood, the design process begins by choosing target values to get to the expected behavior. If there is 100 anti-dive applied on front suspension system, the control arms will absorb all energy, which means suspension system going stiffening and further impact the ride experience, therefore, the percentage of anti-dive geometry needs to be adjusted depending on the type of the car. Good choice, it corrects some of my thinking. Abstract: When it comes to design suspension geometry from scratch, you need to understand every suspension parameter influence to get a good result. This diagram is out of a book called Race Car Vehicle Dynamics by Milliken and Milliken.
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