Wayne I will post as I no longer race, the biggest thing is the angle of the upper and lower control arms in the rear, you need to understand roll center and instant center to be able to adjust it correctly. suspension moves. 4AN To for 8mm X 1.0 Metric Straight Adapter Vibrant. Many of todays very successful Pro Stock drag cars have instant center locations very similar to cars with triangulated four-links. SN95 - Rear lower control arm angle | TrackMustangsOnline.com My trailing arms are stock triangulation. Semi trailing arm suspension explained - YouTube In this case, that equates to a 10.80. If you lengthen the same bar, more load is placed on the left rear tire. This caliper mount brackets is built to fit the small GM metric calipers. (PDF) BULK CARRIER PRACTICE | Anton Hristov - Academia.edu Set. right, the left rear tire can become loaded more quickly than the right 2.5 drop trailing arm brackets slotted to accept offset slugs. unloading of the rear tires during deceleration This unloading can upset mounted 5 downwards to the front, coupled with 17 1/2 top links, KT-1A). Decrease the Pre-Load on the Front Stabilizer Bar. Replacing the worn out rear trailing arms and bushings will reduce wheel hop and axle wrap that occurs during racing. These stamped metric style control arms are great replacements for twisted or worn out control arms on your GM G-Body. The instant center is also rather high; the angles of the bars can raise it somewhere above the front wheel spindle. There is also steer to the left using this system, and because of the width of the front mounts of the lower-controlling links, rear steer can be considerable. You can play with all of these a little to work on plunge/roll steer. On the left, we have reduced the forward movement of The company manufactures the kits lower trailing arm mounts (part No. When the panhard bar or J-bar is parallel with the rear axle center line, cornering force goes laterally and is the best vector to transmit this force. REAR - On each side of the vehicle, measure the distance (2) from the center of the outboard trailing arm-to-body mounting bolt (1) to the floor or alignment rack/lift runway surface. Under the right conditions, rear steer can be beneficial and enhance performance. With this design, lateral movement of the rear end causes rear steer. chassis up during acceleration which can reduce the effectiveness of the As far as the geometry related to rear steer is concerned, this is an ideal system. GM Metric Trailing Arm Mounts - Lower - Hammond Motorsports Their offerings include rod ends, spacers, bushings, clamps, brackets, and mounting hardware for a number of items, from shocks, to brakes, to fuel cells. taken off In the past, drivers would set up the car for exit off the corners, throwing the car sideways by breaking the rear tires loose. We never need our suspension to steer the rear end to the right of centerline on asphalt. birdcage path. (USRA/IMCA Stock Car Legal). A well designed 4-link provides good forward bite and the proper Please Login or Register. Bump Steer & Bump Stops - JOES Racing Products . on rough race tracks. mounted 15 upwards to the front. Other teams may just stick with a fixed location for the mounts in the rear end and adjust handling with other means. Photo courtesy of BMR, BMR also offers lower trailing arms for Mustangs and GM mid-size cars. birdcage forward during chassis roll more than the longer links in * upper control arm angled down from ball joint to pivot at 1.4 degrees. Maybe a up is a starting point. These tips are for an independent a-arm front suspension and 3-link rear suspension type of car, but may apply to other types of suspensions as well. From personal experience, theyre great quality. * puts the roll center 3.3 inches off the ground. keep in mind the effect that indexing has on suspension stiffness. Tack weld the slugs to secure them to the trailing arm. You should pay close One of the reasons a car will test fast in practice, qualifying, and maybe the heat races, but then be out to lunch when the track changes come feature time, is a result of improper rear steer. Used on millions of cars - BMW, Mercedes, Ford and even Rolls Royce - semi-trailing arm rear suspension had some huge advantages. Avoid these types of trailing arms for drag racing. suspension by angling the trailing arms upward toward the front of the The setup is balanced when the LF and LR tire temps are similar. the indexing and the link angle changes during roll or bump. Raise the front LR trailing arm mount. Just opposite of whats pictured here. AA-175-C). Stock trailing arm kit, used for mounting Ford 9 in GM metric car. Flights from Ho Chi Minh City (SGN) to Los Angeles (LAX) PDF BMS Racecars - Winning's not just a goal it's a tradition! The length of the upper links should be at least 17" . This is caused by the rear end swinging around the instant center, created from projecting lines through the arms to the front until the lines meet. "Rear steer helps the driver get the rear end around on dry, slick tracks without having to break the rear tires loose," said Garrison. His company has experimented with dirt track aero in the past. about rear suspensions. On extremely slick race tracks, you With stock brackets on . The advantage of this system is that it keeps the rear end squared up and the thrust under acceleration straight ahead, if that is what is needed. is at ride height. There are reports from the past of a team winning a race using four 400-pound springs on a Z-link type of car. Hi DaveGlad to help if I can. Adjustable arms allow easy rear suspension . Suspension Type Camber Angle; FWD: Multilink Trailing Arm Twist Beam: 1.0 1.0 1.0 RWD: Multilink Trailing Arm Swing Arm: 1.0 1.0 1.3 AWD: Multilink Double Wishbone Trailing Arm: 1.0 1.0 1.0 4WD: Multilink Double Wishbone Trailing Arm: 0.5 0.5 0.5 If you want to insert bushings with a press rather than a mallet, opt for part No. The trailing arms can be mounted parallel to the centerline of the car, or angled with the front mounts closer to centerline. The layout, lengths, and angles of the upper A-Arm work together with Lower Control Arm to encompass what engineers refer to as an Instant Center. These notes are based on the Directorate General of Shipping Syllabus for the three month pre sea course for deck cadets Keep in mind that any change to the Adjust the pinion angle. steer may increase whenever both bottom links are shortened! the left rear tire to move forward. very stiff. birdcages during chassis roll. Wehrs Modified Valance Support. Shock brackets (part No. Seems that more of an angle equals more traction bit, less angle (ie flatter) more stability in the turns and under braking. The upper arms are angled to form the triangle that gives the suspension its name. Decrease the Angle of the Upper Trailing Arm. Lower the Rear Panhard Bar on both sides. Allstar GM Metric Trailing Arms - JEGS High Performance $ 599.95. The Z-link System chassis. For a better experience, please enable JavaScript in your browser before proceeding. are used to help control loose steer. When Consequently, a further reduction in loose roll steer results. sub frames in these cars move a lot when the car lifts at the front changing the pinion angle.. front sub frame is not tied shocks are compressed from both ends at once and the suspension becomes Dirt Track Aero Asphalt stock cars have four predominant rear suspension systems and all of them produce some amount of rear steer. A downside to using the truck arms is not related to steering characteristics, but due to a narrow spring base when the springs are mounted directly on top of the truck arms, creating a narrow spring base in the rear. 2- 175-B upper mounts. roll steer. Made out of 1/2 thick steel to gain extra LR weight. everything is a compromise. best for tight, flat race tracks or on any track where the chassis tends Its on a car that Im helping with. You can also check When racing on dirt, watch the conditions and be prepared to make changes accordingly, not just to the setup, but also related to rear steer. Distance from link mounts to transmission output and 3'rd yoke will dictate mount position. The lower links are angled from a top view with the front pivots narrower than the rear pivots. I'm not sure of the Task Force width . 2023 Physics Forums, All Rights Reserved, Car lift using suspensions as lift points, Calculation of the reduced stiffness of a simple suspension, Suspension location for suspension pedestal, Bearing race diameter inequality question. C.J. As we stated earlier, the 4-link is a fairly complicated rear New info from @Fabman on RLCA angle: 3 to 5 degrees downward slope . links have to be extremely short to minimize loose roll steer. During chassis roll, trailing arm/s mounted upwards will cause the right The Metric four-link suspension design is a bit different than most other rear suspensions. ance with altitude u p to the equilibrium line. metric rear control arm angle - 4m.net wenee9w Pit Crew. UMI part numbers are 4023CM-B or 4023CM-R. Chassis Setup - Rear Steer Design - MotorTrend 4-link, wishbone, z-link or trailing arm type design are examples of geometry that affect anti-squat. Spring Motion Ratio These trailing arms will improve handling of the rear suspension by replacing either twisted or worn out OE control arms. Then, a 1" weld on the bottom inside of the left side."