Another component that promotes rear steer is when the rear trailing arms are angled from a top view, with the front mount closer to the centerline than the rear mounts. The Truck-Arm System - The truck-arm system has been adapted from the design for a 1964 Chevy truck, and is used on many Late Model Stock cars, as well as the three premier divisions of NASCAR (Craftsman Trucks, Busch, and Winston Cup). The Impala spindles are the " hot set up " on a metric chassis. We stated earlier that trailing arms mounted upwards to the front of Rear Suspension - Medieval Chassis In simple terms, it keeps the body from roll rotating on the launch. just ordered the adjustable lowers On extremely dry, slick conditions, use lots of rear steer to the right. 60 offset new reproduction stamping Ford 9 housing with new 3 tubes and GN hub type snouts. using stock coil springs new .have adjustable uppers and 1-1/2 Tube Diameter Clamp For Limit Chains on Chassis Side, 1-3/4 Tube Diameter Clamp For Limit Chains on Chassis Side. Location. $15.75. You are using an out of date browser. LR bracket is 6.75 from axle tube to center of bottom hole. The upper trailing arms are pretty much in the stock location. Decrease the Angle of the Upper Trailing Arm. J-AUTO - Bushings, Suspension, Parts for Mazdas article to determine the correct link lengths for your application. efforts, will provide you with an advantage. How to Determine Over-Amperage on Pulley Size Change. when making this adjustment. In the past, drivers would set up the car for exit off the corners, throwing the car sideways by breaking the rear tires loose. The following examples and illustrations should help you to understand Check Tire temps, if LF is coolest (unbalanced setup): Decrease front springs, maybe even use reverse split (LF stiffer). Trailing arms mounted in this manner cause the rear tires to . Rear steer in this system is caused by chassis movement, which can produce several secondary effects. This action will cause 2- 175-B upper mounts. PDF Design Analysis and Fabrication of Rear Suspension System ability to let the race car turn freely in the middle of the corner Rayburn builds the swing-arm type of rear suspension. Part No. and the right coil-over unit behind the axle. We can reduce The Metric four-link suspension design is a bit different than most other rear suspensions. Simply replace the slug with different combination of offset slugs. Truth!^^^^^. (PDF) Optimization of semi-trailing arm suspension for improving Now you have to compensate with spring change. Decrease the Rear Weight Bias. Adjust Cross Weight as changes are made to keep the car neutral. The company also sells ultra-lightweight rear . I am getting ready to change my lowers out to some better ones that are adjustable. the indexing and the link angle changes during roll or bump. AA-621-B fits 2-5/8 ones $14.95. Your email address will not be published. A racer himself, he was the winner of the Street Stock Nationals in 2019. This induces less rear steer when the car squats on exit. Buy Traxxas 9530: Suspension Arm, Front (Right), Black From RCMA For The Best Deals In Australia, We Also Have Same Day Shipping On All Orders Placed Before 3PM Today! birdcage path and at least 3" of compression movement for the right Phone (07) 31033011 Between - 9:30am - 4:30pm. This caliper mount brackets is built to fit the small GM metric calipers. On a tacky track, the team would do well to limit rear steer on both sides of the car. Triangulated 4-Links: Make Your Stock Suspension Car Work Suspension Rear Trailing Arms - DCA RaceFab LATE MODEL SUSPENSION FRONT-REAR; LATE MODEL DRIVELINE-WHEELS; . We never need our suspension to steer the rear end to the right of centerline on asphalt. Not only does the condition of rear steer affect the entry and middle handling balance, it affects handling under acceleration due to the thrust angle of the rear end being either right or left of the centerline of the car. reducing loose roll steer. Therefore, the rate the car feels is much less, usually around 50 percent, than the actual installed spring rate. At the nose, Id do the same (spherical bearings or Delrin bushings). Required fields are marked *. Under the wrong conditions, it can ruin your handling. Adjust the pinion angle. We can reduce loose roll steer by lowering the bottom links at the Then this trailing arm bracket kit is a must have. Picture does NOT represent all jig options. Im assuming youre referring to the front end more below: Cars with a lot of twist and bind are difficult, if not impossible to tune. When you find the correct amount of rear steer, stay there and tune the handling with the other components. and rearward (R.S.) 3 to 4 degrees nose-down is recommended. roll steer. preceding paragraphs should help you understand why. The entry is more important to design for than the exit as far as rear steer is concerned." The lowest rear RC you can get is with all arms parallel to the ground (no angle) . Bolt On, Clamp-3 Chain Limiter w/ Chain and Adjuster Kit, Bolt On, Trailing Arm Bracket Kit XTREMER LR, Bolt On, Trailing Arm Bracket Kit (2.5 SINGLE HOLE), Bolt On, Trailing Arm Bracket Kit (2.5 SLOTTED), Bolt On, Trailing Arm Bracket Kit Extreme Drop LR, Bolt On, Trailing Arm Bracket Kit HEAVY, Single Hole (Kit), Bolt On, Trailing Arm Bracket Kit HEAVY, Single Hole (LR Only), Bolt On, Trailing Arm Bracket Kit HEAVY, Slotted (Kit), Bolt On, Trailing Arm Bracket Kit HEAVY, Slotted (LR Only), Bolt On, Trailing Arm Bracket Kit Multi Hole, Bolt On, Trailing Arm Bracket Kit XTREMER. Adjust the length of the control arms as needed to achieve the desired pinion angle. it feels as a plank over nude bearings on the road .. Pem 9" Grand National Limited Floater Rear End Housing - Re-ssm-5800 Matt, Trailing Arm Brackets Metric 4 Link Setup For Dirt steve smith autosports tech tips, the home of the jet mod and jet phantom the championship dirt track modified and stock chassis offering a full inventory of high performance racing parts racing safety equipment racing components and more lf 5 1 2 rf 5 3 4 lr 6 rr 6 1 4 our setup manual is the most in depth mod . If the car has OEM style rubber suspension bushings, a pinion angle of minus three to minus four degrees is more appropriate. Oct 12, 2013 #2. 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. If the front is diving under braking then add anti-dive to front suspension. Under the right conditions, rear steer can be beneficial and enhance performance. made to provide such handling, you must first understand a few basics on rough race tracks. The 2-day class is broken down section by section. Where did I run mine? A & A Manufacturing makes a similar trailing arm mounting kit for racers using Ford 9 rear ends in GM Metric chassis (part No. Metric Rear Suspension - Don Terrill's Speed-Talk When the track goes slick, especially dry slick, rear steer is needed. Wehrs Bent Suspension Tubes 5/8"-18 Thread. Unbolt and remove one upper rear control arm using a " wrench. Bump Steer & Bump Stops - JOES Racing Products Adaskaveg got his start working for track photographer Lloyd Burnham at Connecticuts Stafford Motor Speedway in 1970. If you are racing on a rough track or up against the cushion you will need these bushing washers to help hold the rubber from pushing out the end of the bushing housing. My trailing arms are stock triangulation. There are times when we definitely want the rear to steer to the right. $ These tapered profile spring cups are manufactured from high strength steel and are designed to minimize any stretch and bending while still being lightweight. For example, you want the top link to be perpendicular to the rear end housing and parallel to the car. During chassis roll, trailing arm/s mounted upwards will cause the right These new Currie 31-spline axles feature press in studs in a 54 3/4 wheel bolt pattern, , thick heavy duty bearing retainer plates, and tapered wheel bearings pressed on. wenee9w Pit Crew. I am setting up a GM A body 1972 Monte Carlo. springs). We hope the information in this article, combined with your Description : General Motors 64-67 "A-Body" Adjustable/Indestructible Rear Control Arm Upper Cross Member! This is done to add more angle to the lower trailing arms, which adds roll steer to the rear, as the body rolls. forward bite and roll steer. That helps equalize traction to the rear tires. Also, how old are the shocks and have you ever had the valving checked? Thanks . about rear suspensions. shocks and springs. The four holes for adjusting the lower trailing arm angle are all symmetrical, so when you move the trailing arm up or down it does not change the wheelbase of the car, said Tom Nolff, of T&D Custom Fabrication in Grant, Michigan. "High left-rear loading does not increase traction," he said. - Trailing Arm Brackets - Bushings in Upper Mounts - Brake Caliper Mounts (GM Metric) . Undo the two bolts that hold the subframe support arm: the rear of the arm bolts to the front of the rear subframe, and the front of the arm bolts to the trailing arm bracket. AA-621-A fits 3 axle tubes $14.95. Browse Suspension Parts, . This will add Roll Steer as the chassis rolls over in the turn and the LR arm scribes an arc forward and shortens the left side wheel base. bottom link arrangement of illustration 2C on the left side and the The significance of this, for the purpose of this article, is that the chassis travel in a Z-link is enhanced compared to the 4-link suspension when using the same installed spring rate, and this causes quite a bit of chassis travel and related rear steer. We do not necessarily need to know the exact amounts of rear steer our cars are subjected to, but we do need to have a solid understanding of what produces rear steer and what effect rear steer has on the handling in our cars. Notice how this Decrease the Split on the Rear Panhard Bar Heights. Which ones do you recommend? 87 Chevy C10 upper control arms. Wehrs Modular Non-Adjustable T-Bar. try to drive underneath the chassis as the rear axle pushes the race car Has boxed lowers, adjustable uppers , stock springs and shock. suspension. It seems not being an Irak/bu . I'm new at this how do u do that and does it makr a big difference. This condition may You can also check These stamped metric style control arms are great replacements for twisted or worn out rear upper arms on your GM G-Body. the bottom links are lowered but the effect on forward bite is usually From a structural standpoint, tubular trailing arms are much stronger than factory trailing arms. On the left, we have reduced the forward movement of (Sold Individually). acceleration causes the rear axle & chassis to separate. As you can see, the bar ties the upper and lower trailing arm mounting points together, which spreads the load and helps to prevent mounts from tearing out. When Distance from link mounts to transmission output and 3'rd yoke will dictate mount position. 60 MAXIMUM aftermarket Ford 9 housing with new 3 OD tubes and 2.5 GN hub snouts. "Rear steer helps the driver get the rear end around on dry, slick tracks without having to break the rear tires loose," said Garrison. 266. What is wrong ? clamp brackets and ahead of the axle can improve forward bite on adjustment, positioning the lower links 5downhill, causes the bottom of Rear Lower Control Arms : Lower Rear Control Arms : Trailing Arms rear trailing arm mounts frame repair PDF BMS Racecars - Winning's not just a goal it's a tradition! 2). movements of the 1- LZ-13-B lower mounts (pair ) 1- 384-B shock mount (right) 1- 384-C shock mount (left), *LZ-13-B is a laser cut mount that has been welded on the proper angle to fit a GM metric chassis. Decrease the Angle of the Upper Trailing Arm. Anti-squat is a concept used to determine how much the rear of a chassis will squat under acceleration as a result of the rear geometry. 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. traction characteristics desired by the chassis tuner. Spring Motion Ratio Mounting the left coil-over unit ahead of the axle Increase the Angle of the Upper Trailing Arm. 60 GN 1R offset MAXIMUM aftermarket Ford 9 housing with new 3 OD tubes and 2.5 GN hub snouts. right, the left rear tire can become loaded more quickly than the right As a result, we reduced loose 4.0 from axle tube to center of hole. Speedway Stamped GM Metric Upper Rear Control Arm These arms also use rod ends on each end to prevent binding when under load. Custom Part is Non-Returnable and Non-Refundable. The bearing allows for smooth movement without the binding a rubber bushing can cause. Rear ends are straightened after jigging for truer alignment of axles to 3rd member. Tune For The Leave: Drag Suspension Tweaks For A 10-Second Chevelle Dirt Rear Steer correctly. Hotchkis and Global West make similar control arms for Mustangs and GM A- and G-bodies. suspension moves. $ 599.95. This one is made by Hotchkis for GM A-body cars. WEHRS MACHINE & RACING PRODUCT - Performance Bodies birdcage rotates or "indexes" on the axle tube whenever the conditions, bottom links 2 shorter than the upper links work well. Outside Groove Note of Transparency: A&A Manufacturing paid for the production of this article. These conditions call for a driving line that is more straight ahead. Seems that more of an angle equals more traction bit, less angle (ie flatter) more stability in the turns and under braking. Adjustable rear trailing arms are also available for specific applications. Rethink Dirt: Advanced Dirt Track Theory | Hyper Racing note the left rear tire moves to the front in body roll. We should learn to read the conditions of the dirt tracks and tune the amount of rear steer-less for tacky and wet conditions, with more rear steer as the track gets slicker. When using trailing arm angles to help your setup it pays to truly understand the movements at each section of the corner as well as think about any drawbacks that rear steer or understeer might create. Because there is very little slip of the tires on asphalt, the range of useable rear steer is very small. AA-175-B) are constructed from stout 5/8-thick steel. PDF SQUARING A R C - Longacre Racing A well designed 4-link provides good forward bite and the proper Tack weld the slugs to secure them to the trailing arm. the 60 in the low 50s have 505hp 350 460fpt car weight 3400 what is your take on the pinion angle? clamp brackets. initial forward bite. And have fun at SIR! A link length change of 1" or a link angle My lower trailing arm is level. That thought echoed Garrison's point of keeping the rear tires connected to the ground going in and through the middle, helping to provide traction off the corners. The RR lower most will run . In turn, that bite tends to move the car toward the left. Conversely anti-dive is used to describe how much a chassis nose dives under braking. (during acceleration) is quickened and forward bite is enhanced. My upper a arm is at a 10 degree angle pointing down towards the front. The Flying from Ho Chi Minh is hassle-free and convenient when you book with Cathay Pacific. short bottom link arrangement of illustration 2D on the right side. Please Login or Register. loose roll steer tendency caused by the steep angles of the upper links. PDF Metric 4 Link Setup For Dirt - annualreport.psg.fr The only reasons to adjust the upper bars on a triangulated four-link are to set the pinion angle and to center the rear axle side to side in the car. Excess loading of either the left- or right-rear tires decreases traction in most cases. The car was set up and driven more like an asphalt car and it was fast. Anytime you are acting thru an angle, this force is diminished and is not as effective as it could be. 4AN To for 8mm X 1.0 Metric Straight Adapter Vibrant Decrease RR Trailing Arm length by 1/8 inch. Top 8 GM G-Body Suspension Tips - Aldan American Usually, the right-rear corner of the chassis moves more than the left-rear. Tubular arms are constructed of 1 1/4" diameter .120" wall steel tubing, which offers increased strength over other designs and also has the added advantage of lighter weight. On most asphalt 3-link cars, the right-rear trailing arm mostly controls rear steer due to body roll. In a car with a non-triangulated four link, you can shorten the upper right trailing arm to increase the preload on the right rear tire. The setup is balanced when the LF and LR tire temps are similar. To really add over steer at the rear end housing you can mount the front pivot point of the RR trailing arm towards the center of the car. Thanks. Jul 23, 2001. Rear Spring Cups from A&A Holidays Wish List, Shellhammer Dirt Track: 10 Races in Less Than 3 Hours, Tucker Clark: Racing Helps Teen with Autism, Bob and Sandy Garby: Super Fans Recognized, Hayden Cardwell: iRacing Champ to Real-Life Racing Champ, Outside Groove Racing Show a Hit; 24 Date Set, Hayden Ross Motorsports Foundation Started, Michael Lutz: Not the Results Hes Looking For, Lincoln Speedway: Thursday & Sunday Do Well. We usually need to position the angle of the trailing arm so that the front mount is higher than the rear mount by roughly one third of the distance that the front mount will move down during cornering. If excessive, loose roll steer can cause a loose A 200-pound spring in a Z-link car feels more like a 4-link car, where the coilover is mounted to a birdcage with a 100-pound spring installed. If you have a Fox-body or SN95 Mustang, a 1980s GM G-body (Grand National, Malibu, El Camino, etc.) Knowing these basics, we need to look at each type of racing to see how rear steer affects each type of car and how we might improve our performance using rear steer. With adjustable trailing arms (rather than the factory originals), you can adjust the pinion angle by simply changing the length of the upper trailing arm. 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. The sideways attitude of the car does two things: 1) it helps to slow the car down on entry much like an air brake on a Lear jet, allowing deeper entry and 2) it may also help to produce a left-side, lateral force that resists the opposite centrifugal force that tries to take the car to the fence. (Steel). Rear steer can either tighten a car or make it very loose. traveled by the centers of the birdcages during chassis roll. We can see the effect of the Sprint Car wing in the turns-as the cars actually roll left due to the pressure differential developed on the flat wing sides-as the cars go sideways at a high speed. Trailing arm Angle for a 4-Link | race-deZert Some manufacturers have added multiple mounting points on the front and rear chassis mounts. Lowering the car changes the sprung mounting points (body/chassis) but not the unsprung (axle) mounting points. Since then, hes been a columnist, writer, and photographer, in racing and in mainstream media, for several outlets, including the Journal Inquirer, Boston Herald, Stock Car Racing, and Speedway Illustrated. To make it work, Id be inclined to either use spherical bearing upper and lower rear trailing (control) arms or at least a set with Delrin bushings. One fix is to position the links so that the On a Late Model, this air pressure difference may help keep the car on the track by virtue of having the car go through the air at an angle, causing both a high pressure on the leading (right) side and a lower pressure on the trailing (left) side. Many teams use varying amounts of rear steer to adjust to constantly changing track conditions, a product of variations in moisture content so common in dirt racing. Facebook; Twitter; Youtube; Pinterest; contact us . Thanks so much! Lower the Rear Panhard Bar on both sides (frame and rear-end attachment). Your DS length will dictate your lower link length. Kit includes standard 55 GN hubs, hub bearings, seals, brake rotor, drive flange, 31 spline solid axles and all hardware necessary. Not sure if there are any big "Tricks". In dirt racing, it may be advantageous to incorporate a large amount of rear steer under certain conditions. Now with Ten properly positioned holes . extremely short links change their angles radically whenever the There are limits to how far we go in steering the car this way. Allstar GM Metric Trailing Arms - JEGS High Performance it feels as a plank over nude bearings on the road .. on rough race tracks. this important function of the lower links. Whiteline Rear Trailing Arm Upper Bushing - Holden H Series/Monaro HQ Some will say run them as low to the rearend housing as you can. Housings havefill and drain plug installed. NOTE: If installing on a Frankland quick change, the bracket will need to be modified and reinforced to fit. 4-link, wishbone, z-link or trailing arm type design are examples of geometry that affect anti-squat. Heres a look at an adjustable upper trailing arm fitted to a GM G-body. SKU: 64-67ABox. (Try to bounce the rear of a car with a 4-link rear shortening the lower links, is a reduction in loose roll steer. position) instead of forward as in illustrations 2A and 2B. Another option are the double adjustable UMI upper and lowers available at Summit Racing (Part Number 402717-B or 402717-R). To ensure the pinion is in the correct location under power, it is typically set nose down in its at-rest (static) position. Typically, indexing causes the coil-over mounts, if located on the Now on to getting everything adjusted out and working. The live class took place January 22-23, 2022. Three Link Lessons - JOES Racing Products I highly recommend that if your wanting to run coil-overs or something of the sort or long travel that you use a 0 degree dual pivot trailing arm i use it in the designing of all my frames and i think its better for more wheel travel. You should pay close The top links are angled from a top view with the front pivots wider than the rear pivots. Adjustable lower bars are used to center the tires front to back in the wheel well and to make small wheelbase changes. Clamp Brackets are used to mount the If the upper links are shorter than 17", the lower A lot of guys take that to extremes.". A smooth entry provides a faster exit. KT-1A). The GM Metric adjustable rear trailing arms will aid in adjusting pinion angle, centering the rear end and adjusting wheel base. best for tight, flat race tracks or on any track where the chassis tends Click here to remove banner ads from this forum. OUT OF STOCK until appox. (USRA/IMCA Stock Car Legal). My car had 7Deg of angle it. by comparing the different paths drawn on your model. and parallel to each other). of the Wehrs Metric Trailing Arm Bolt. The trailing arms can be mounted parallel to the centerline of the car, or angled with the front mounts closer to centerline. Clamp brackets are sometimes used on short, slick tracks to improve He will be showing the latest tools to enhance your chassis set up. Dirt Late Model cars can be designed with a considerable degree of adjustment for rear steer. Insert the bolts to the ends of the control arm Lower the jack from the transmission Tap the bolt into the control arm Raise the rear suspension to simulate ride height Torque the bolt to 95 foot-pounds Torque the bolt near the rear axle to 103 foot . Other teams may just stick with a fixed location for the mounts in the rear end and adjust handling with other means. On extremely slick race tracks, you That saved the factory some money. This is correct. right and 10 to 15 on the left provide good forward bite. Any of you guys changed any angles on trailing arms etc on a metric to make it faster? Also has a anti roll bar added to it. One of the things we have done, is to raise the rear ride height. If you run the frame side of the J-bar is higher . Raise the Rear Panhard Bar Up on both sides. Black & Red PCE 16A Coupler (400Volt, 3P+E Pin Configuration) 16A Lead Coupler with a current rating of 16, a voltage rating of 400 and a 3P+E pin birdcage. See the text for more information. PEM 9" Grand National Limited Floater Rear End Housing, RE-SSM-5800 is a 58" housing with a 0 pinion angle, stock mounts, and GM Metric caliper mounts. right amount of loose roll steer can help a race car to turn the corner We could reduce loose roll steer even further by combining the long Lower the Rear Panhard Bar on both sides. you to better understand the 4-link suspension. Below you'll find a selection of our flight destinations to spark your interest. These systems only steer to the left and have a limited amount of steer. The idea is to trace the paths actually Looking for increased forward bit and traction? The key to correctly Balance the Front and Rear stiffness. (and tire) are forced towards the race track. Mounting them higher will shorten the instant center point too much, causing violent launches for high horsepower cars. 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. This saves wear and tear on your U-joints while . The upper arms can be used to set the pinion angle by adjusting both arms in the same direction and by the same amount. 1-15 How Important is it to Bump the Left Front? If the Panhard bar is mounted on the right side of the chassis and level to the ground, the rear end will be pulled to the right, and will steer to the left when the chassis moves during cornering. If both sides are configured to move in opposite directions, then rear steer can be extreme. The adjuster is at the front of the bar. shortened bottom link. The 4-link is a relatively complex rear suspension that is very This induces rear steer when the car squats on exit. A drag race style anti-roll bar is a key ingredient to making your triangulated four-link work. move the If you want to insert bushings with a press rather than a mallet, opt for part No. Changes in the height of the front of the trailing arm as small as a 1/4-inch can be felt by the driver. The Metric 4-Link System - The metric 4-link is a widely used system that comes with some models of stock automobiles. Asphalt stock cars have four predominant rear suspension systems and all of them produce some amount of rear steer. The amount of rear steer due to body roll is regulated by the height of the front mounts of the arms, which are always mounted lower than the rear point of rotation (the axle). I like to see a 1" long weld on the top inside of the right side. keep in mind the effect that indexing has on suspension stiffness. You can Watch, Rewind, and Watch Again. Preload is another tuning tool to counteract body roll rotation. RAceman. With this system, the rear end stays located by virtue of the opposing angles of the upper and lower links. A triangulated four-link puts the instant center (I/C) locationthe imaginary point of where the rear suspension components intersect, and the point theyrotate around in a given (instant) positionway out front, often close to the engine.

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