attention to how the lower link adjustments change the paths traveled by You can play with all of these a little to work on plunge/roll steer. The company offers a wide array of quality chassis components at reasonable prices. right amount of loose roll steer can help a race car to turn the corner coil-over units directly to the axle housing. His company has experimented with dirt track aero in the past. Then this trailing arm bracket kit is a must have. Most of the Z-link systems utilize a spring mounting system that attaches the coilover spring to the front link. A well designed 4-link provides good forward bite and the proper Picture does NOT represent all jig options. This was encouraging. Loose roll steer causes the rear axle to steer towards the outside of Spring Motion Ratio Indexing is greatest when there is a lot of Ask me how I knowL-O-L. Hope that gets you sorted out. I am looking for a bit more traction and less wheel spin, but primarly want better handling for road . The trailing arm side will be rusty and wont remove easily, I had to unscrew mine with a 3' breaker bar! These arms also use rod ends on each end to prevent binding when under load. 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. The Standard 4-Bar System Get your shocks addressed (tested by someone with a shock dyno who knows what theyre doing) and then go back and work on the pinion angle, using the guidelines from the article. We use the upper links on a 4-link suspension Required fields are marked *. 60 MAXIMUM aftermarket Ford 9 housing with new 3 OD tubes and 2.5 GN hub snouts. AA-175-B) are constructed from stout 5/8-thick steel. wood, aluminum strips, etc. Kit includes required Custom length Double Adjustable upper control arms. Keep in mind that trailing arm angles can become This kit includes two Pull bushings, two steel spools, a rectangular mount tube and side gusset bracket. A smooth entry provides a faster exit. You should pay close The upper arms is where many very in opinion. Specifically designed to increase LR drive off the corner and corner entry adjustability with multiple hole adjustments on the RR. All we had to do now was work on consistency. I am setting up a GM A body 1972 Monte Carlo. 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. Housings havefill and drain plug installed. Use this kit to build your own custom rear end. Suspension Parts, Front & Rear parts . tire loadings. Basically, we've position the bottom links to counteract the Most Street Stock rules wont let you change the frame mounting positions so all you have left is the rear end mounts. 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 . 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. These new Superior 28 or 31-spline axles feature screw in studs in a 55 wheel bolt pattern, , thick heavy duty bearing retainer plates, and tapered wheel bearings pressed on. shocks are compressed from both ends at once and the suspension becomes positioned ahead of the axle and attached to I have a blown 71 Chevelle. [3] Advantages of Trailing Arm with Camber Links Thanks so much! When the rear links are too short forward bite and If it had angle, as it moved up it would lengthen the wheelbase then pass level and start shortening the wheel base as it moves upward. Short links( from 3 to 4 shorter than the upper links) generally work and parallel to each other). Heres a better look at a trailing arm mounting brace. 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). 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. Simply replace the LR bracket and have increase drive and adjustability. We can reduce loose roll steer further by lowering the Hes owned his own speed shop, built race cars, street rods, and custom motorcycles, and restored muscle cars. gained by running the trailing arms upward to the front of the race car. 2-12 Checking to Make Sure Your Rear End is Straight, 3-2 Distributor & Electronics Maintenance, 5-18 Counting Your Rounds & Brake Problems, 6-14 Wrapping Tires & Chemical Treatments, 8-13 How Driving Style Affects Shock Builds, 8-17 Starting Point for Off-the-Shelf Shocks. 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 . How Much is Too Much? birdcage does lose some of its rearward movement because of the 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. the race car upon corner entry -especially when both coil-over units are Photo courtesy of BMR, BMR also offers lower trailing arms for Mustangs and GM mid-size cars. coil-over units on The company also sells ultra-lightweight rear . For example, in illustration 2A, both the top and the bottom links Mounts J-Bar to 9 third-member 4 3/8 offset from pinion. In short Part No. Simply replace the slug with different combination of offset slugs. So, teams need to take this rate difference into account. cause a gas pedal push. illustration 2A. I would like know what the ic would be on a g body with a 9 inch in the rear with stock suspension. change of 5 can make a noticeable change to handling. Trailing arms must also be running forward at the correct car builder design angle. The upper arms are angled to form the triangle that gives the suspension its name. The company manufactures the kits lower trailing arm mounts (part No. I want just for street use, nothing but just Soft Ride, floating kind of .. What is wrong ? If its working correctly, a G Body will drag the back bumper on the track with those pieces, on small drag radials. handling condition that negates the benefits of the forward bite gained race car. Compare the measurements to specifications. $149.99; 149 - Reward points. Many of todays very successful Pro Stock drag cars have instant center locations very similar to cars with triangulated four-links. A 4-link lowered the bottom links to a level position and now the bottom of the currently using 4.5 down and it picked up 60. This trailing arm bracket use common offset slugs (sold separately) to allow you to change the amount of lead or trail in the rear end. KT-1A ). This clamp on trailing arm mount is for the GM metric chassis lower bars. Changes in the height of the front of the trailing arm as small as a 1/4-inch can be felt by the driver. With this design, lateral movement of the rear end causes rear steer. (Sold Individually). $64.00. Decrease the Angle of the Upper Trailing Arm. We can reduce The car was set up and driven more like an asphalt car and it was fast. 2-3 Starting Points for Bar Angles. Usually, the right-rear corner of the chassis moves more than the left-rear. These trailing arms will improve handling of the rear suspension by replacing either twisted or worn out OE control arms. Our services include: Bushing overhauls, suspension repairs . Thanks. A & A Manufacturing makes a similar trailing arm mounting kit for racers using Ford 9 rear ends in GM Metric chassis (part No. My rear end is a nine inch ford with the large pinion. Spring Perchs & Brake Caliper Brackets are now Bolt-On Accessories (not included in Rear End Housing Price). These trailing arms have fluted greasable, graphite/polyurethane bushings, which are superior to the stock rubber bushings. My car was level, As the chassis loads the RR in the turn you want it scribing an arc in one direction only. 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. or something like an early Chevelle or a GTO, it has a triangulated four-link rear suspension.This type of suspension has coil springs and upper and lower trailing arms (also called control arms).The upper arms are angled to form the triangle that gives the suspension its name. The 4-bar suspension is highly adjustable and can be made to steer both directions. without compromising forward bite. (and tire) are forced towards the race track. See all 6 photos. Keep in mind that any change to the bottom link arrangement of illustration 2C on the left side and the designing and tuning a 4 link is to understand the significance of these Trailing Arms, Mono Balls and Mounting Brackets; Rod Ends, Clevis & Spacers; Safety Equipment. This 1/2-13 threaded bolt extends the hex end of the bolt out of the frame rail, allowing you to remove the bolt without losing your socket or fighting the frame rail. In the past, drivers would set up the car for exit off the corners, throwing the car sideways by breaking the rear tires loose. Notice how this Great info! Wehrs Body Bolt Panel Inserts. Increase All Shocks rebound and compression, but rebound should always be higher than compression. 4AN To for 8mm X 1.0 Metric Straight Adapter Vibrant. For a better experience, please enable JavaScript in your browser before proceeding. I am getting ready to change my lowers out to some better ones that are adjustable. Has gone 1.29 60 ft on spray, has 28 10.5 et street tires on it also. AA-175-C). LZ-13-B) from 3/16-thick steel. When At the nose, Id do the same (spherical bearings or Delrin bushings). Increase Left Rear Spring Rate. birdcages, to rotate against the shocks and springs during But since left side amount of roll steer. Dirt Rear Steer Hotchkis and Global West make similar control arms for Mustangs and GM A- and G-bodies. Copyright Racelogic Chassis School 2023. When one wheel moves more than the other, we have a certain amount of rear steer. New info from @Fabman on RLCA angle: 3 to 5 degrees downward slope . 1-15 How Important is it to Bump the Left Front? The lower links are angled from a top view with the front pivots narrower than the rear pivots. roll steer are overly affected and handling becomes inconsistent. (USRA/IMCA Stock Car Legal). have qa1 adjustable coil over shocks without the coil have a tube welded across the frame at the back to mount the shocks like a ladder bar Browse Suspension Parts, . Part No. links have to be extremely short to minimize loose roll steer. This has been confirmed by studying data from onboard computer systems during testing that show shock travel amounts in the turns. conditions, bottom links 2 shorter than the upper links work well. link lengths and angles and how the relationship affects roll steer and Rayburn of Rayburn Race Cars, a driver as well as a car builder, echoed much of what the other buiders had to say. Cf: a c t i v i t . The track in this case was banked and had a lot of grip. Pinion angle is measured between the pinion gear flange and the driveshaft. "loose roll steer". We could reduce loose roll steer even further by combining the long A level panhard bar ( same mounting height on both sides) means force is vectored laterally to the tires. The bars can be mounted on one side of the car so that only that wheel moves to create the rear steer. Also, how old are the shocks and have you ever had the valving checked? 2- 175-C bushing for upper mounts. Compared to the 4-bar cars, it has more limited adjustment for rear steer and historically has worked well on the tighter and more highly banked race tracks because the rear end is pointed more straight ahead. keep in mind the effect that indexing has on suspension stiffness. Those cars have multiple holes, allowing the angles of the control links to be altered to produce more or less rear steer. You can evaluate the roll steer characteristics of different set-ups 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. movements of the and rearward (R.S.) Since we cannot lump them together, we will analyze them separately. C.J. We hope the information in this article, combined with your 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. DCA RaceFab : Suspension Rear Trailing Arms - Chassis Exhaust Misc Linkage / Spacers Rear End Suspension Transmission Engine / Fuel Cooling Steering Brakes Shop Solutions racing, sportsman, hobby stock, street stock, chassis, control arm, bushing, spherical, spherical bushing, delrin . These bars are used to center the wheels in the wheel well and to set the wheelbase from side to side. rear tire to move rearward (until the arm/s reach a level position) and A/C Condenser APDI 7013457 fits 2006 Mitsubishi Eclipse, Mevotech TTX Front Lower Suspension Ball Joint for 1998-2018 Subaru Forester vc. OUT OF STOCK until appox. Tuning With Rear Steer These arms are longer then stock to help lessen pinion angle changing during suspension travel. Masters added, "Any time we can press air against the sides of the car, we can help the car to turn." loose roll steer by making the lower links shorter than the upper links Your email address will not be published. of a 4 link suspension are the link lengths designed into the suspension If you run the frame side of the J-bar is higher . Remove only one control arm at a time. 266. Made out of 1/2 thick steel to gain extra LR weight. 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. or something like an early Chevelle or a GTO, it has a triangulated four-link rear suspension. Third and fourth generation Camaros and Firebirds with torque arm suspensions also have a long instant center and are known to hook up on pretty much anything. Welcome to J-AUTO! Wehrs Modified Valance Support Weld On Clevis. Wehrs Modified Valance Support. The trailing arm with camber links also called as three link trailing arm suspension is a modified configuration of a trailing arm suspension. 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. This induces less rear steer when the car squats on exit. Just opposite of whats pictured here. Decrease the Split on the Rear Panhard Bar Heights. We also talked with Sandy Goddard of Warrior Race Cars and he said his group of racers work with rear steer less than some other dirt teams, although he feels that using a degree of rear steer is very important at times. Custom Part is Non-Returnable and Non-Refundable. BRACKET, CHASSIS PANHARD, BOLT ON 3 INCH OFFSET (PAIR). On a tacky track, the team would do well to limit rear steer on both sides of the car. clamp brackets. Raise the front LR trailing arm mount. My upper a arm is at a 10 degree angle pointing down towards the front. As a result, loose roll steer is reduced. Stronger is Better. This year marks the Outside Groove Director of Photographys 51st year of covering auto racing. To help understand the Instant Center you can visualize a triangle (Fig. Flying from Ho Chi Minh is hassle-free and convenient when you book with Cathay Pacific. They are angled to fit GM Metric chassis and have four holes for racers to adjust their trailing arm position. If the upper links are shorter than 17", the lower Adjustable arms allow easy rear suspension . We can use the lower links of a 4-link suspension to help offset the 9-5 Upper A-Arm Mounting Points Metric. made to provide such handling, you must first understand a few basics Housings have fill and drain plug installed. A & A Manufacturing makes 95% of their product line in Michigan, including the stock trailing arm mounting kit. Followed your advice and got a set of adjustable lowers. AA-175-D. . (Steel). Photo courtesy of Hotchkis Suspension. 60 offset new reproduction stamping Ford 9 housing with new 3 tubes and GN hub type snouts. . Brand new Stamped steel, C-channel arms are strong and sturdy Improve the handling of your '78-'88 GM Metric rear suspension by replacing twisted or worn out rear control arms 11" center to center Sold each IMCA Approved. One theory related to having the attitude of the car sideways involves the use of the aerodynamic aspects of the car. The live class took place January 22-23, 2022. If you lengthen the same bar, more load is placed on the left rear tire. Looking for increased forward bit and traction? Decrease LR Shock rebound and/or increase RF Shock compresion. KT-1A). The 2-day class is broken down section by section. and the right coil-over unit behind the axle. Adjustable rear trailing arms are also available for specific applications. The Metric 4-Link System - The metric 4-link is a widely used system that comes with some models of stock automobiles. Most will run the LR angled down in the back. 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. Tack weld the slugs to secure them to the trailing arm. Check Tire temps, if LF is coolest (unbalanced setup): Decrease front springs, maybe even use reverse split (LF stiffer). the left rear tire to move forward. Adjustable 73 - 77 . AA-621-C is an offset spring cup, which sits 2-1/2 off center of a 3 axle tube $14.95. Specialize in complete bushing overhauls and suspension upgrades to enhance the driving experience for your Mazda RX-7, Mazda RX-8, and Classic Mazdas (R100, RX-2, RX-3) but are more than capable of servicing all cars with the same care and attention to detail. 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. Not sure if there are any big "Tricks". All driving train actually repalced with Moog components.. tuning a 4-link, it is important to understand the relationship between I use the H&R parts stuff anti roll bar * upper control arm angled down from ball joint to pivot at 1.4 degrees. short bottom link arrangement of illustration 2D on the right side. The instant center is also rather high; the angles of the bars can raise it somewhere above the front wheel spindle. The lowest rear RC you can get is with all arms parallel to the ground (no angle) . 3 to 4 degrees nose-down is recommended. Lowering the car changes the sprung mounting points (body/chassis) but not the unsprung (axle) mounting points. Mounting the left coil-over unit ahead of the axle I was looking for more info on stock rear 4 link trailing arm angles. Lower the Rear Panhard Bar on both sides. The Z-link rear suspension, or swing arm as it is also known, is another system used on dirt cars. 4. That gray-colored bar that goes up from the forward trailing arm mount is an aftermarket mounting brace that ties the upper and lower mounting points together. 2-5 Rear Spring Table. Designed for the Wissota street stocks, these trailing arm brackets have the lowest mounting hole position possible. 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. starting point for both links is 15 upwards (to the front). The company also sells ultra-lightweight rear spring cups (see Rear Spring Cups from A&A Holidays Wish List). Avoid these types of trailing arms for drag racing. two factors. Putting the stock "W" style suspension into a bind is your biggest enemy. Emirates offers flights to Ho Chi Minh City (SGN) and 139 other destinations. 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. (more on this later). CTS Upper Metric Trailing Arm Mounts for Ford 9 inch housings. to be loose. The bearing allows for smooth movement without the binding a rubber bushing can cause. When selecting springs for your 4-link, you should Bars like this are typically welded into the chassis and tied to the housing by adjustable links. In the last pass of the night, the Chevelle delivered a 1.629-second 60-foot time on the way to a 7.014 / 99.71 mph pass. The system works well enough on the street, but not so well when it comes to hooking up at the drag strip, especially with big horsepower. Justin is the owner of High Roller Race Cars. forward(L.S.) 88 metric lower trailing arm $65.00. When you add more horsepower, bigger and stickier tires, and start pushing the car, then the flex in these arms becomes even more apparent. In Stock . The Z-link System ~ index. length and/or angle difference in the upper and lower links. That way, the car will stay as fast and balanced as it can be throughout all of the changing conditions. The upper arms on a triangulated four-link are used to center the rear axle housing from side to side; you shift the rear axle housing left or right, depending upon which bar you adjust. The stock trailing arm mounting kit (part No. 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. Now with Ten properly positioned holes . extremely short links change their angles radically whenever the Also pinion angle with stock bushings. move the We never need our suspension to steer the rear end to the right of centerline on asphalt. priority to have the trailing arm brackets and top link hardware to be located in the proper location. 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. Make small adjustments if you feel a need. and the angles to which the links are adjusted. Another method used to reduce the loose roll steer of a 4-link The setup is balanced when the LF and LR tire temps are similar. SportMod jigged. SEALS, FRONT TRAILING ARMS, SET OF 4 *GERMAN* STD BUG / THING / GHIA 1966-77. US $239.9 This product greatly reduces bushing deflection that occurs during acceleration Each bushing is designed to exact tolerances Reduce deflection with minimal changes in NVH and braking The SuperPro elastomer bushings greatly increase the rigidity and stability of the chassis to provide maximum control and consistency which is known for its high stiffness SuperPro bushings are made from . This kit is affordable for most street stock racers, and it is both easy-to-install and easy-to-use, Nolff said. Posts: 5 Metric Rear suspension tricks Dec 31, 2012 20:24:48 GMT -6 . AC A/C Compressor for Honda Civic L4 1.6L 1.5L 1994-2000 & CR-V 2.0L 97-01. 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. on rough race tracks. The trailing arms can be mounted parallel to the centerline of the car, or angled with the front mounts closer to centerline. 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. "High left-rear loading does not increase traction," he said. The bottom trailing arms are adjusted at the back end of the bar near the rear axle housing. Facebook; Twitter; Youtube; Pinterest; contact us . Adaskaveg got his start working for track photographer Lloyd Burnham at Connecticuts Stafford Motor Speedway in 1970. I hear of 305 cid stockers running in the high 1.40s far less hp I have adjustable qa1 shocks Notice, in illustration 2D, The following examples and illustrations should help you to understand The Asphalt 3-Link - The 3-link rear suspension system has two trailing arms mounted near the rear tires, and one third link mounted atop the rear differential that controls rear end wrap-up. Youll find that an instant location similar to stock is actually close to optimum, provided you dont jack the body way up in the air. This helps make the rear steer characteristics more adjustable for the changing conditions. minor relative to the overall handling improvement that is realized by We can reduce loose roll steer by lowering the bottom links at the I also have a trz weld in style arb. Part No. If you dont do anythinig else. Instead of using some form of track locator or Watts linkage, the trailing arm triangluation keeps the rear end properly located in the car. This is your problem, (sprung v. unsprung) your rear lower control arms (body mount to axle mount) must be in a 2.0-3.0 degrees (max) downward slope to the rear axle. Im converting a Pro-Challenge car for road racing, ad Id like to get rid of the Panhard bar, and go to triangulated upper links. In racing, we have the maximum amount of traction from a pair of equally loaded tires on the same axle. everything is a compromise. The roll angles and vertical movement on a dirt car can be very pronounced. are used to help control loose steer. Rear steer in a circle track race car is a condition caused by suspension movement. shortened bottom link. The first element to understand about rear steer is that it is caused by rear suspension movement. efforts, will provide you with an advantage. A & A Manufacturing makes a similar trailing arm mounting kit for racers using Ford 9 rear ends in GM Metric chassis (part No. Has a 1/4 hole on bottom to allow bolting to your weight jack bolt. Depending on the angles of the trailing arms or bars, each rear wheel can be made to move to the front or rear. Skip to main content. Please Login or Register. 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. The popularity of the 4-link suspension is due primarily to its These stamped metric style control arms are great replacements for twisted or worn out control arms on your GM G-Body. The side bite trade off is a big one. I have edelbrock adjustable uppers with non adjustable boxed lowers. Add a good weld-on ARB out back. Clamp Brackets are used to mount the 2,224. (on a clamp bracket) generally tightens corner handling. I had 17 Deg of angle in my car, down in front and up in back. 3. These stamped metric style control arms are great replacements for twisted or worn out rear upper arms on your GM G-Body. Description. This induces rear steer when the car squats on exit. reducing loose roll steer. Perfect for the guys that already have or Extreme or Xtrmer Drop brackets. Suspension movement usually increases when the coil-over units are how the shortened bottom link pulls the bottom of the right side Can be used on both 9" Ford and quick change rear end tubes. Decrease the Rear Weight Bias. Can I convert a combustion engine car to a hybrid car? suspension). Seems that more of an angle equals more traction bit, less angle (ie flatter) more stability in the turns and under braking. If we mount the left-side trailing arm lower than the right-side trailing arm, then as the rear end rotates under acceleration due to the pull bar extending, the left-rear wheel will move rearward more so than the right-rear wheel, causing rear steer to the left to a small degree.