VW Tech Tip VW Suspension Technical Article Tech Tip: by Charles Adams The following is a technical THE TRUTH ABOUT SUSPENSIONS MYTH: Lowering or raising my car will give it greater performance than I article written for better If you want a smooth ride and not just looks, there is more than meets could expect at stock height. For ex- understanding of the rear the eye at a quick glance. Anyone ample if I simply lower my car it will corner better than my friend’s car that air-cooled VW suspension can lower or raise a vehicle and call it good, but just like any good en- is not lowered. Alternatively, if I raise as well as our products. For gine build, if you seek performance, my car it will perform better off road, absorbing bumps and jumps, than my the majority of people, the everything should be prepared in advance and every component’s friend’s car that is not raised. rear VW suspension is little function should be understood. It understood and more is more than just ordering the most FACT: Every suspension rides at its costly parts, assembling them, and greatest potential when it is riding often misunderstood. blowing away the competition. Yet within the parameters that it was suspensions are not a mystery and designed for. This means that facto- they certainly are not rocket science. ry suspensions perform the greatest The truth is that they are simply and when the ride at factory height and easily understood if they are ex- the geometry is not tampered with. plained simply. Unfortunately there Therefore it is of upmost importance is a seemingly infi nite amount of that any part that is purchased is misinformation, which is unneces- actually designed to operate with- sarily complicated, leaving the reader in the altered region, rewriting the bewildered about how to approach chalkboard so to speak. But doing this their own car’s suspension. This is is like hitting the factory reset button, not how we roll, so we encourage as the car is either lowered or raised. you to read on and come to your own It also means that there is not a “one conclusions to piece together the size fi ts all” suspension. If you seek suspension that is just right for you. true performance, safety, and han- It is our hope that you will fi nd the dling then you will carefully need to material easy to read and to grasp. select the parts that are designed to operate at the ride height that you are most often going to drive.

Raise Plates and Drop Plate Drop or raise the rear of your air- cooled VW without loosing ride quality! It seems that there are 101 different things that you can do to the front suspension, but when it comes to the rear, VW owners have been given little choice until now. Figure 1

Benefi ts It is now possible to have a full suspension performance vehicle! Our Drop Plates have been engineered to drop the rear of your VW yet allow your car to ride and feel as the factory intended. While the math and engi- neering may be extensive, the concept is simple: Drop Plates locate the axle up higher, but maintain factory spring plate travel in the lower region (fac- Figure 2 tory articulation region) and maintain torsion in the system. This idea is similar to Drop Spindles in that sense. However with Atomwerk Drop Plates the upward range of travel is extend- ed, which means that you will be able to roll over even taller bumps (assum- ing that your upper stopper has not been cut off). Figure 3 Can’t I just lower or raise my VW with factory plates? plate only has a limited distance that it resistance that is found in the tor- Of course you can lower/raise your was designed to articulate (travel) in be- sion bar. The further up you push the vehicle using your stock spring plates. tween. This space that limits the spring spring plate the more torsion you are People have been doing this for de- plate travel is often referred to as the loading in the system, kind of like a cades. Atomwerk Drop Plates were torsion housing. The travel is limited by heavy duty rat trap! not created so that you can just lower/ a lower stopper and an upper stopper, When you lower your VW’s rear sus- raise your vehicle; they were created in addition to the factory rubber bump pension with factory plates you have as an alternative to a bad, clunky, and stop. When you lower or raise your ve- made it impossible for the spring squirrely ride that you are bound to hicle you literally force your spring plate plate to articulate correctly, and that get when you lower/raise your vehicle to operate outside of its designed travel is why it will smash into the upper with stock plates. range. There are three specifi c factors stopper when going over bumps. Not that affect your ride quality: good! In general, the spring plate should be able to articulate down- Why does my ride quality 1) The spring plate articulation ward about 25% of the total travel change when I lower or raise 2) Torsion in the system range and should be able to articulate with factory spring plates? 3) Toe-in on swing axles about 75% upward, respectively. There are several reasons for this. Torsion in the system changes when The easiest way to think about this is The spring plate articulation is the you lower a VW and the initial torsion that a lowered stock VW is operating factory travel range. It is the angular (pre-load) changes drastically and this outside of the factory geometry in the distance between the lower stopper signifi cantly changes your car’s ride torsion housing. You see, the spring and the upper stopper. Torsion is the characteristics, as we will see later. Mechanics of per. When the vehicle is lowered the think that it is better described as Lowered and Raised spring plates tend to pull the axles, and “bump toe-in” since it is toe-in that thus the wheels, toward the vehicle. is induced. Regardless, this is an inev- Swing Axle Suspensions The dangerous thing is that bad toe-in itable effect of the swing axle suspen- will manifest itself when a person least sion - including stock VWs. However, if Toe-in expects it. This is not something that it can be felt at all - it would only be Toe-in is the effect of the rear wheels I personally like experiencing at high while absorbing very tall bumps. Every turning into the vehicle as a result of speeds, on slippery roads, or with my one of us who has ever driven a swing the rear axles being pulled forward. family in the car. Have you ever driven axle VW has experienced thousands of When using factory plates, toe-in will over a wet surface on one side of the negligible bump steering on practically occur any time the spring plate is at road and felt the rear dart to one side? every trip. any angle other than horizontal, as can Toe-in becomes dangerous, and literally be seen in the adjacent drawings. In a steers the rear of the vehicle when each lowered or raised VW the vehicle’s toe- Why Shouldn’t I Notch my Plate? wheel experiences a different kinetic Figures 4 and 6 demonstrate the in on each rear tire will normally cancel coeffi cient of friction (grip to the road) position of a stock spring plate in a out the other, assuming that the vehicle in respect to each other and at the vehicle that has been both lowered has been lowered evenly and there has same moment in time. The tire that and raised about 2.5 inches. You can been no frame damage. In the adja- has the greatest grip to the road will see how close a factory spring plate cent drawings it is demonstrated by win the grip battle and quite literally rides to the stoppers when a vehicle’s the horizontal (x) distance between the steer the rear end of the vehicle in one height is changed. In extreme cases it center of the torsion bar and the factory direction. NOT GOOD! There have been takes “Notching” (removal of mate- axle location. It is represented by the several documented cases where drivers rial) of a stock spring plate to fi t into vertical line (y). Figure 6 demonstrates have totaled their VWs due to bad toe- these positions. Atomwerk Engineer- the position of a stock spring plate that in surprising them unexpectedly. In ing Inc. does not recommend anyone has been re-indexed to lower a vehicle addition, it should be noted that since to notch a factory spring plate (either about 2.5 inches (note that this is not the spring plates still need to travel in top or bottom) because this creates the distance that an actual spring plate an arc, the toe-in can only drastically a stress concentration in a plate that has been dropped, as they are separate increase as the vehicle absorbs bumps was engineered for economy. calculations). One can see how close it in the road. It can also be seen from rides to the upper stopper. It doesn’t the adjacent fi gures that toe-in also take much of a bump to make the happens in raised applications. spring plate impact on the upper stop- Tire Scrub Sometimes the term “tire scrub” is used as a substitute for the term toe- in. Tire scrub is actually a description of what is happening to the tire that is experiencing toe-in, that is to say that the road is scrubbing away the tire similar to an eraser being used, A stress concentration should be re- although obviously not as drastic. Tire garded as a very bad thing because it scrub is actually a greater source of magnifi es all the forces that are found wear on a tire than camber is. However in the spring plate and concentrates it camber is often blamed for all of that in one tiny area. Think of it like this: tire wear. Unless an additional joint is have you every seen someone lay on added in the axle, tire scrub can only a bed of nails or tried that yourself? be eliminated by elongating the spring I have. It is easily done because your plates so that there is zero toe-in at entire body weight is spread out over the new ride height deviation. a large surface area (the sum of all the nails). But what would happen What is Bump Steer? if all of the nails suddenly retracted “Bump steer” may be defi ned as the except for one? You could consid- toe-in effect that happens as a result er this a giant stress concentration! of a bump. While the term “bump When it comes to a spring plate, all of steer” is the common vernacular, I the forces that are distributed along the spring plate are magnifi ed at the sealed so that they will not corrode. notch. The more jagged the cut it fol- Yet in the end they are considered the Introductory Drop Plates lows that the stress concentration will best solution since they cannot defl ect and Raise Plate Sets be higher. In addition steel is noto- and will allow for rapid movement of These are our introductory Drop/ rious for fatigue under cycling loads, the spring plate. Raise Plates so you can start riding which means that if it takes 5000 ft lbs Secondly, sleeve bearings (bronze at any height in comfort and style to fail your plate now, in two years it bushings), which are less expensive, immediately! These plates are sold in may only take 3000 ft lbs. Fatigue and yet still provide precise pivot point sets and are constructed from laser stress concentrations together are very location. It is important to note that cut, factory thickness, grade 50 tool bad! Even techniques such as rounding these bearings must also be properly steel spring plates, and 1026 carbon it or drilling the notch do not signifi - lubricated so that excessive wear does steel Spline Stubs that are 1.75” in cantly improve the week spot on the not occur and so that corrosion does diameter. We offer these plates with plate. Now consider that the Volkswa- not occur. instructions and all the technical gen spring plate was made for econo- Thirdly, and most commonly, bush- support that is necessary for head- my, after all it was “the people’s car.” ings are used, in particular by Volk- ache-free installation on your classic When someone takes this economy swagen. It can be reasoned that this VW. These Drop/Raise Plates come spring plate and puts a stress concen- was due to the economy nature of standard with a powder coat fi nish, tration in it they are seeking a disaster. the vehicles. When it comes down to which is far more durable and beau- Nobody knows when a notched plate it, bushings get the job done. They tiful than the industry-standard zinc will fail, but when it does you will lose are cheap and they do not need to coatings that you will fi nd on most control of your wheel and disaster will be sealed since they can never rust. suspension components. For swing likely strike. However, when considering bushings it axles you can choose from 1.2” drop, is important to keep in mind that their 2.4” drop, 3.6” drop, or a 1.2” raise, purpose is to act as a bearing, that is and for IRS you have the choice of 1”, to say they should be a pivot point that 2”, or 3” drop or raise. Keep in mind does not defl ect. There are two kinds when making your selection that each of bushings that are most commonly spring plate has a variance of an inch used: rubber and urethane. in either direction. For example if you So which kind of bushings are bet- wanted to drop your VW 3.25” then ter? That question depends on your you should purchase the 3.6” Drop budget. From the discussion above Plates and then index them on your it should be reasoned that harder is VW so that it sits 3.25”. better. In my opinion urethane bush- ings give the best bang for your buck since they defl ect less and are inex- pensive. However, if only the best will do, then rolling element bearings are unsurpassed!

What is a Torsion Bar? A torsion bar is a bar that delivers 326-008 What do Bushings do? spring force (potential energy) in twist. Bushings are actually an inexpensive That is to say that the more you twist bearing. You see spring plates were it, the more it resists you. Volkswagen designed to pivot about a fi xed point, and Porsche used torsion bars very the torsion bar, and this is why bush- successfully for decades. Almost all of ings are located about the spline stub the air-cooled VW models use torsion 326-009 and torsion bar. bars, and the only difference between Ideally rolling element bearings (such them are the lengths, diameters, and as needle bearings) precisely locate the the stiffness. Other than that they are spring plate pivot point, however they dimensionally equal (bus models use prove to be the most expensive way different torsion bars). to do this because of all the processes Every VW torsion bar (buses exclud- that they have to go through and the ed) has 44 teeth (splines) on the outer tolerances that they are manufactured end and 40 teeth on the inner end. Of to. They require grease and must be course the stiffness of the torsion bars How is this possible? on the angle that you want. Ok I know that this seems quite However, those astute mathemati- impossible, after all a spline precisely cians may have noticed that if one were locates the spring plate, so it seems to perform the procedure that I just that you can either locate it at the wrote about, that person would not be given “notches” (or teeth) that are able to hit exactly 20.5 degrees. In fact in the torsion bar and spring plate. one could only fall short to 20.3 degrees For example you can either position or overshoot to 21.1 degrees. This is the spring plate a “click” up or a click nowhere near infi nite, some might say. down, but there is no way to put the The answer - keep rotating. However spring plate in the middle of the two since this is not practical in the real clicks (teeth). Well the reality is even world, back off two clicks on one end of the torsion bar and advance only one vary according to their lengths, diam- though there is a defi nite number of click on the other end. By doing this you eters, and material properties. Stiffness teeth on a torsion bar, there is prac- will now hit an angle in between the is defi ned as the ability of the material tically an infi nite number of positions two that you were at before. And the to resist changes in shape (resistance that a torsion bar can fi t into. procedure can be repeated on and on to twisting in the case of the torsion You see, a torsion bar plays on a and on. bar). It follows that the shorter the mathematical algorithm, otherwise torsion bar the higher its stiffness known as “indexing.” The inside will be. Also transversely, the longer of a torsion bar has 40 teeth, while What makes this happen? the torsion bar the less stiff it will be. the outside has 44 teeth. The VW If you rotate the spring plate only That is why that in general the shorter engineers were no fools when they one spline increment on the outside torsion bars (21 3/4”) are stiffer than designed them that way! Since the splines of the torsion bar, what you the longer torsion bars (26 9/16”) and number of teeth are different with are doing is rotating that spring plate are often sought after for both greater respect to each other, this means precisely 8.1818 degrees. That’s a stiffness for performance, as well as that there is always a position for the rather large angle! That means that wheel clearance issues for buggies. The spring plate that the torsion bar will fi t two clicks changes your vehicle’s exception to this is high performance into. You just have to fi nd it. height by over 4.64” or greater. Of torsion bars that are manufactured at course when you drop a factory spring different diameters and lengths for How can you fi nd this plate that much, the spring plate increased performance. “Magic Position?” operates much closer to the upper As complicated as indexing may be stopper and bump stop if your vehicle mathematically, you don’t have to be still has it - and this is also why many a genius to fi nd it. A given angle can people start notching their spring be found by creeping up on it, so to plates, so that the spring plate will speak. For example, say that you want clear the stopper (NEVER A GOOD IDEA). to install your spring plates at exactly The opposite is also true for raised 20.5 degrees, but your spring plate applications. only fi ts in either at 17 degrees on the If you rotate the spring plate to- one end or at 26 degrees at the other gether with the torsion bar one spline end. Choose the increment that is increment on the inside splines of the What is Indexing? closest to 20.5 degrees, in this case 17 torsion bar, the spring plate is being Well there are a lot of defi nitions degrees, and note where the torsion rotated precisely 9 degrees. That’s an for indexing, but when it comes to bar fi ts with respect to the spring even larger angle. Volkswagens the only defi nition that plate and chassis. Then, while main- However, when you combine the two we are concerned with is indexing taining the torsion bar to the spring above techniques you get the best of spring plates on the torsion bars. This plate, rotate the assembly one click both worlds. You get fi ne tune height procedure is often misunderstood, in the inside splines (in the chassis of adjustment. All you have to do is but is not that diffi cult to master. the car) with respect to the vehicle. rotate the torsion bar alone one spline Indexing is the procedure of changing Once you have done this, disengage increment on the inside splines, and the angular position of a spring plate the spring plate from the torsion bar rotate the spring plate in the other on a torsion bar with respect to the and rotate it back one click. Once you direction on the torsion bar. This is vehicle. Simply put, indexing in a VW put the angle fi nder back on, you will possible because what you are do- means that your torsion bar will fi t in have noticed that that angle has been ing in fact is adding one angle and at any angle that you choose for your advanced to 17.8 degrees. If you keep subtracting the other, or literally (9 spring plate. doing this you will eventually creep up – 8.1818 = 0.8182) degrees. It is this small angular change that makes for repeat the procedure to fi nd the angle this small height change. that you are looking for like you have The real magic happens when you to do with other spring plates. We en- perform this indexing procedure courage our customers to forget about (forward on one end of the torsion all of this indexing nonsense and just bar and backward on the other end) pull the torsion bars out entirely. Then so that the spring plate eventually ro- install the inside bushing along with tates 360 degrees. This is not possible the spring plate and clamp it to the on an enclosed chassis. You see, it bottom stopper, noting the angle that doesn’t return back to the same exact you want (between 18 and 22 degrees position that it started out as when it usually). After this has been done, in- has been indexed exactly 360 degrees stall the torsion bar through the front. - it either falls short or passes it and It will slip in through the spline stub enters into a new set of angulations. and engage fi rst on the inside splines. access of the vehicle, or simply put Keep indexing and guess what? The If you are lucky it will also engage on it is wheel slant. It follows then that same phenomena will happen again, the splines on the spring plate. How- the “cambering effect” is the constant and on and on. ever, chances are that it won’t. But if change in camber as the vehicle drives The bottom line (not literally) is that you keep rotating the torsion bar on down the road. If a vehicle has wheels a torsion bar can fi t any given position the inside splines you will fi nd that that lean inward the vehicle is said to that you want and you are not forced “magic spot” (the spot where both the have negative camber, and if a vehi- to live with a choose of predetermined inside splines and outside splines line cle has wheels that lean outward the “clicks.” Interesting, right?! up at a predetermined angle) without vehicle is said to have positive camber. having to think too much about it. Usually on a performance street car Can I do this an easier way??? Once you fi nd this spot just smack the about 2 degrees is desirable for cor- Yes you can with Atomwerk spring torsion bars in with a soft mallet, in- nering but not much more. plates! Our spring plates are designed stall the bushing housing, tighten the When it comes to a swing axle, with an open end so that the torsion set screw if you have one, and load up cambering is inevitable since each bar can slide through the front. That’s the plate. Done! side of the vehicle uses a straight right, you do not have to put the tor- axle. However, up until this point sion bar in fi rst, take note of its angle, What is Camber? there was practically nothing that then install the spring plate over the Camber may be defi ned as the angle could be done to stop excessive top of it, note its angle and then of the wheel with respect to the vertical negative camber from happening in a lowered vehicle, and transversely excessive positive camber from happening in a raised vehicle.

Will These Plates Fix my Camber? No spring plate will fi x your camber. Spring plates only supply the spring force from the torsion bar to the axles, and then, in turn, to the road. Camber is directly linked to the axle, which is straight. However we are almost ready to launch our full suspension that will include the Adjustable Camber Unit (ACU). A suspension fi tted with this will inevitably raise the bar on swing axle technology and solve a problem that no company has been able to do, which is make an infi nitely adjustable and highly tunable swing axle sus- pension. The ACU is compatible with the Adjustable Plates and defi nitely recommended. The hubs and Drop/ Raise Plates are actually an integral part of the system so when you pur- how the distance between the bottom to want to drop down to excessive- chase them you are actually purchas- stopper on both drawings is the same? ly while cornering and have rear ing a piece of the entire Atomwerk Thus in the same way that VW had in- wheel tuck (dangerous for cornering), performance swing axle suspension. tended, Atomwerk plates are designed whereas the side with the Drop Plate Our entire suspension is more ad- to operate with the same amount of keeps everything in check quite nicely. justable suspension than the IRS and PRELOAD that the factory had intend- An added advantage of the Drop more robust, and therefore will be ed. When properly preloaded, the only Plate was the extra clearance that the a competitor to the mighty IRS, but difference will be the final axle location, shock has. This is because the Drop more importantly it will be an alter- and therefore wheel location. Your ride Plate does not twist the shock under- native to hacking and converting your quality will not lessen, but your car’s neath the axle tube like a re-indexed swing axle to an IRS just because you height will change. factory spring plate does. Factory want performance and you don’t want plates were not designed to ride at excessive camber. Ultimately an IRS So then do Atomwerk Drop any other height than stock location. conversion devalues a vehicle in the and Raise Plates fix all of these This is also true for a Drop or Raise grand scheme of things. Plate. They should only ride at the bad issues? height that they were designed for. Why Do Atomwerk Spring Yes. When installed correctly you What can’t be conveyed without pic- Plates Ride Better than Stock will have restored the factory torsion tures is the difference in ride quality Spring Plates When my Car is in the system, the plates will angulate the side with the Drop Plate had!!! Lowered or Raised? correctly in the torsion housing, and Ok, so if this still seems a little bit toe-in will be zero. This means that The Quality your ride will feel firm, your rear sus- confusing, I completely understand. Quality is a lot more that just nice pension will have full travel to absorb There is a lot of calculation involved. parts for your VW. Quality is engi- tall bumps, and your ride will track However, all you have to do is see neered in. All of our parts have been straight in all weather. the YouTube video to observe my car computer engineered, human engi- easily absorbing all types of terrain. neered, tested in the lab, and then Atomwerk Drop/Raise Plates work The Importance of Alignment proven on the street. We do more well because torsion is retained in It is important after our Drop than “seat of the pants” engineer our the system. Have you ever lowered, Plates are installed that the vehicle stuff, but actually crunch the num- or seen someone lower a VW with is aligned. After aligning the car, first bers. All of our inventions have been factory spring plates? If you haven’t drive it for several miles so that the designed on our own regardless of I encourage you to either google the car has a chance to settle down into some similarities our parts may have procedure or look it up on YouTube. its natural daily driving position. Only to the other guys. This is why our One thing that should stand out in after this can the car be regarded as spring plates look slightly different your mind is that before the spring safe for everyday and track usage. than anything out there, and why we plate could be reindexed, it first had have inventions that are like noth- to be unloaded. Initial torsion is lost. Comparison ing out there! Our plates are the best Unloading a spring plate can be a I recently had a chance to go to the quality that money can buy! This is dangerous process because it is under Mid America Motorworks, Air-Cooled not an exaggeration like a lot of other “preload” or “pretorsion.” This means VW Funfest 2013 in Effingham, Illinois companies claim. Simply put, our that stock spring plates are loaded and set up an open chassis with a Drop Plates are overbuilt. much in the same way a rat trap is Drop Plate on one side and re-index when cocked. This preload is CRITICAL the other side with the factory spring Other Products for VWs to ride correctly. I want to plate. The cal was sitting evenly and Drop Plates are only part of the reemphasis that preload is CRITICAL! at first glance there was nothing un- complete puzzle and alone cannot You see Volkswagen designed the cars usual. Just a lowered car. give you the ride that you are after. so that the instant they touched the The Drop Plates fit into the tor- If you have not already purchased ground the rear wheels already have sion housing just as a factory plate the other parts (Urethane Bushings, a certain amount of force pushing would if it had not been lowered. The Short Shocks, Spring Plate Loader away from the ground (torsion in the problem with a lowered factory plate Tool (323-243) & Fasteners) system). Notice figure 3 (pg.2). A car is that there is not enough upper Mid America Motorworks can help with these raise plates should ride clearance and there is too much lower to complete your suspension. in this position. That is to say that they clearance. There isn’t enough clear- should NOT look this way before the ance on the left side to stick your fin- This article is used with permission from: car is touching the ground, but only ger in. This causes a very harsh ride! Charles Adams - AtomWerk Engineering after. Now notice figure 1 (pg.2). Note This causes the re-indexed side And is reprinted here as a FREE service