In situations where the exit portion of the track provides less traction and/or the corner is more flat, we might need to develop more rear traction upon acceleration. As the rear end rotates on acceleration, the left wheel moves rearward more so than the right wheel, creating a slight amount of rear steer to the left. LEGEND: May use 1 or 2 90/10 Dampening ShocksOver Rear End to Tighten Car on Corner Entry. It's been three years since we discussed the subject of handling fixes. 208 0 obj <> endobj At the end of the day, the springs where rated. Leaf springs perform the following tasks: Due to all the loads leaf springs are under, it is one of the most stressed components on the race car. Leaves that are tapered on the ends are generally used for mass production applications which do not require the close tolerances and consistency in the spring rate that racers demand. Setup With a big-bar Mike Leary of Leary Racing Shocks recommends adding wedge to the car by preloading the bar. Those were salvaged out of the old car and were perfectly fine. Generally the spring rate will increase when the following is done or decrease on the opposite. An inconsistent clip, such as the Kwick Clip or Banding Clips with rubber insulation, will transfer into an inconsistent side bite. The rubber, many times, will fall out due to the rigor of racing. The tapering thicknesses are inconsistent which translates into inconsistent spring rates. Maximum U-bolt torque for 1/2 diameter, plated U-bolts are 45 lbs. This prevents undesirable chassis and rear end movement, thus creating favorable synergy between the chassis, springs and rear end. Increase the Rear Brake Bias. %%EOF The current spring is tagged 2,000#; however, the unknown actual rate is 1,900#s. So, here is, in order of logic and importance, a list of setup parameters we need to address to make our cars fast and consistent. So, there is a limit to how much you can get away with and still have a decent corner entry. 9. When attempting to tune your car's handling balance at the racetrack, always start with the middle phase of the turns. These lightweight clips simply cannot withstand the tremendous forces encountered in racing leaf springs. . You may not be able to find a 16-inch 100 rate spring, so this provides more spring length to use. The advantage of this style is that the spring is lighter than the multi-leaf. This is how the spring segments are clamped together. Decrease RR Trailing Arm length by 1/8 inch. A front wheel offset to the outside will increase leverage of the lower A-frame against the coil spring, and the nose of the car will be lower. Installed rateis another rate all together. Add to cart Details. The basics remain the same, but with a few critical adjustments. If too much of the bias is on the rear brakes, the car will be loose under heavier braking. Neck Mount 1.525in Black ALL14475. Adding or removing as little as 50 pounds can also make a difference. The reason less shackle angle, more preload on each leaf, and a taller resistance line. If a user was to lose their sheets then we should be able to pull the data up at a later date. Here is a typical situation found at any given track. The free rate is generally progressive, meaning that the leaf spring rate does not increase proportional to the rate of deflection. DATA PRINTOUTS:Having springs packaged with data information is crucial to any serious race team. These bushings produce a solid rear housing displacement for added traction. Adjust Cross Weight as changes are made to keep the car neutral. How to raise the cross weight in an iRacing asphalt setup. This leads to bent shackles, warped sliders and misaligned axis points. Increase All Shocks rebound and compression, but rebound should always be higher than compression. The front may be too stiff compared to the rear. Leaf Spring Suspension Performance Tips. Rear Steer Design - Chassis Setup For Improved Cornering - Circle Track Decrease the Pre-Load on the Front Stabilizer Bar. Drag Racing Front Spring Tec. The open-end type springs are required when spring security of location is desired. Using antidive on the RF and prodive on the LF helps square the front end to the racetrack and, along with a softer spring setup, provides an enhanced aero effect. It must show a consistent gain in performance and a logical ideology to the bulk of race teams. Furthermore, the life of the spring will be extended due to the fact it is not under high stress, but more importantly, handling will be consistent. When this occurs, the car will increase spring pre-load and do one of two things. Coil Spring Technical Information. The wedge/bite will be determined by the rear spring split (different spring rate from left to right) combined with the front springs and the size of lowering blocks used. The setup that will stay consistent throughout the race is the one that wins, and balance provides that consistency. Moreover, accurate spring changes will allow teams to be more progressive in their test sessions and eventually reflect in their qualifying efforts and then onto the race. Leaf spring rates can be increased or decreased based on the mounting positions and angles. Tire temperatures can tell a lot about the setup and where we need to look to fix the setup balance problem. Multi-Leaf Spring This type of leaf spring has more than 1 leaf in its assembly. 3. If you lightly brake into the corner and the problem diminishes, then brake bias is the culprit. Therefore, decreasing its long term effectiveness and life. Remove the spring from the car and place it on its side on the floor or a flat surface. This insures properly made springs, guaranteed arch tolerances, access to complete labs for testing and research with technical racing experts to understand your requirements. Furthermore,Landrum Springis recognized as the only company in the racing industry worldwide doing so. The farther to the right of the centerline, the less the front end will want to roll. The spring rates and spring split across each axle help determine the desired attitude, or roll angle of that end of the car. by RCJ Mon Jun 20, 2011 9:28 pm, Post As we use the left-front tire more. When using coil springs on the rear, changes are made with spring rates not the free height of the coil springs. If we have a top view difference in alignment between the transmission output shaft and the pinion shaft and they are parallel, then the angle to the driveshaft created by that misalignment might be sufficient to provide the needed angular differential needed for loading the U-joint bearings and reducing negative harmonics. Leaf spring geometry. Any links to good articles? The shorter upper A-arm decreases in length faster than the lower control arm causing camber loss. A common misconception is that arch affects free spring rate, which it does not. Rear Suspension - Circle Track Supply, Inc. Leaf Spring Overall Length. With setups that use a very stiff right rear spring, the angle of the right trailing arm will need to be less than when using a conventional softer spring because that corner will move less. Remember that drag is an important aspect of aero design. To check if the spring and jack plate is making true contact, simply inspect the contact points. It is possible to have Ackermann in our steering system when we steer left and reverse Ackermann when we steer to the right. Leaf springs possess many desirable suspension features, such as dampening, forward bite, roll over steer, high anti-squat percentage, and high lateral stiffness. A loose or tight car can also be caused by a tight or loose setup. For example, if the main leaves are the same length and one spring has more arch, the spring with the most arch will have a stiffer installed rate. By purchasing springs that are already accurately rated, you will not have to pay your engineer ($$), team manager ($$), or crew chief ($$) to rate springs that you have purchased. Furthermore, with the incorporation of the coil-over spring/shock type suspension, the coil spring and shock ratio is close together and operates as one unit. In the next issue of CT, we will delve into the setup problems for a dirt car. asphalt metric street stock setup asphalt metric street stock setup on March 30, 2023 on March 30, 2023 The once tight condition now switches to loose as the front gains grip from excess steering angle. Published: Mar. Also, excessive torque of the shackle bolts will increase the installed rate. Multi-leaf springs used for racing should incorporate leaves that are diamond trimmed on each end, not leaves that are tapered on the ends. LIT-722 C7 Z06 Corvette Heat Exchanger 80294NDP. The opposite holds true, the shorter the shackle, the faster the rate of change. Same weight, same board, but now let's use a 25 pound spring and a 50 pound spring. These springs tend to stay locked in place when the suspension is unloaded; for instance, changing a tire during a pit stop. Roughly 8-10 degrees of third link angle is sufficient to promote antisquat and not hurt your corner entry. Mid-turn handling problems are caused by a car that is either tight or loose. Furthermore, the fiberglass spring is susceptible to damage from rocks and debris. Furthermore, band clips are frail and tend to break, stretch and fail under minimal contact (opponents right front fender hits your left rear spring). This is an effect that increases the amount of toe-out in our race cars when we turn the steering wheel. Initial camber settings must be revised when changing from conventional to BBSS setups. The RF and LF wheels will always experience changes in camber as the car enters and rolls into the turns. For example, when the leaf springs are toed in (the front eye locations closer together than the rear mounts) the lateral rate or twisting resistance is increased, therefore ones side bite rate is increased. Parabolic Single Leaf Consists of one main leaf with a tapered thickness. Let's stay with the circle track lingo. Plan out changes that could help improve performance or durability. Furthermore, a race team will not have to purchase additional springs to fill the void left by the springs that did not rate properly to the theoretical rate that they were supposed to be. Off-centered adjusters can be very inconsistent. Since the spring promotes rebound and resists compression as inherent properties, then the shock rate of compression control must be less than the rate of rebound control. Free rateis the rate of the spring when it is out of the chassis. In addition, as the spring is put under load the shackle angle increases; therefore, the spring rate decreases under travel. I have had a lot of feedback from teams who did the same with the same results. Circle track leaf spring help - Don Terrill's Speed-Talk by racerx1622 Mon Aug 29, 2011 2:12 am, Post Another negative effect of forged end springs is the fact that the chassis settings may change. Bushingchoice can affect spring rates. 1/2" on RF (5 degree angle of Upper A-Frame mounting bolts), 1/4" on LF, front higher than back, average bolt height the same as before. FYI, the springs shown here are stock ride height for a 1970 Nova. On asphalt, don't make large changes to components that . Pitch is the distance between the wires on any given coil-spring. This system involves riveting the clips onto the leaves; the advantage is in preventing the clips from sliding up the leaf and becoming loose. The same theory applies to leaf springs. This system uses two springs on tip of each other in series. When the car is jacked up during a pit stop for a tire change, the suspension may become completely unloaded leaving the coil spring to rotate in the spring bucket. This happens very quickly and the rear end snaps loose as the throttle is applied. Although the camber change is quick and the wheel returns to normal camber settings a short time later, once the push starts, it is hard to stop it without slowing down. Negative aspects might include excessive bumpsteer (more than 0.030 bump in or out in for each inch of travel is considered negative by most designers), excessive Ackermann (more than a 1/4 degree added steer in either front wheel in 10 degrees of steering input is considered excessive), and incorrect steering quickness. 4. There are several things we can do to help balance the car. Bushing choice will also affect spring life, and more importantly, spring performance. The components that locate the rear end must be evaluated and set correctly. In addition, the leaf spring suspension is more forgiving on chassis set-up errors. Circle Track Setup: Springs 101 - iRacing.com e; As the front brakes are applied, the caliper grabs the rotor and the motion of the wheel/rotor tries to rotate the spindle.