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Strut & Spring Guide - Vorshlag Camber Plates

Vorshlag sells camber plates for various cars including E30, E36, E46, E90/92, and E82 chassis BMWs; GC, GD and GR chassis Subarus; EVO 5-9 and EVO X Mitsubishis; R53 and R56 Minis; S197 chassis Ford Muistangs; and several others. Each model has many strut configurations and spring styles to choose from for our matching upper spring perches. Vorshlag camber plates must include new upper spring perches with an integral radial bearing, for a perfect noise-free fit and extremely long service life. The first section of this page shows the common strut end types that are available, sometimes multiple types for the same car model from the same shock manufacturer (which is where it gets tricky). The next section shows the various spring styles and sizes that are available, mainly coilover versus OEM sized. Lastly, we show the basic upper spring perch designs we offer that are further configured to work with the various strut shaft profiles and diameters.

This web page may seem a bit overwhelming to a buyer of camber plates - but imagine designing and building parts to precisely fit all of these variations. Instead of making one camber plate to work with all struts (one-size-fits-all), we accept nothing less than a perfect fit. Perfect fits mean no slop, no noise, no unnecessary wear, and no problems. Due to this, we make customized spring perches with matched bushings to work with each different strut manufacturers' mating surfaces and diameters. This ensures that you have the right parts for your car, and many thousands of worry free miles of use. Vorshlag upper spring perches all have a heavy duty, sealed radial bearing and the appropriate press-in adapters for the diameter, length and shoulder for the struts you are using. The extra effort to verify this strut information is well worth your time in the long run, as this gets you the right parts. The end result is a customized spring perch assembly that works with all of these variables. There is no 100% fool proof way for us to know what you have on your car without seeing your suspension up close and apart, so we hope this page helps our buyers become better informed when they are buying our camber plates.

Exploded views of the main Vorshlag spring/strut camber plate set-ups (click to enlarge):

Bilstein w/ OEM Springs
Koni w/ OEM Springs
Koni w/ 60mm Springs

Note: If you are putting a new set of springs and/or struts on your car before installing camber plates, then please take a look at the parts before you begin to verify strut shaft diameter, shoulder style, and spring type/size. If you do not have your suspension apart to verify these issues, and are about to order camber plates - don't worry. We make it relatively painless to order and you can pick the car model, strut brand, and spring size and 95% of the time that's all you need to know. Still have questions? Contact us and we will likely know exactly what you need. We have sold thousands of sets of camber plates and know what works almost every time just from strut brand and car model. This guide is mainly to verify those handful of cases where there are potential unknowns or unusual components.

BMW Strut Styles

Strut design has a lot to do with the spring perch selection, namely: inverted strut or non-inverted, what diameter upper strut shaft is used, what type of strut end "shoulder" the perch will land on, and upper strut nut diameter. The first variable to determine is the brand of strut you have, which helps determine many variables (sometimes everything). In some situations it helps to know the upper strut shaft diameter and strut end shoulder style. There have been a few changes over the years within the same strut manufacturer, and in rare instances a visual verification is still needed in order to get the right spring perch. The pictures below show you exactly what to look for.

BMW Koni Square style strut end. 14mm diameter shaft with square shoulder. Similar to many Moton and AST non-inverted struts. This is usually what is found on Konis made for BMWs purchased before 2006. Pic 2 - Pic 3
(similar to above) BMW Koni Square Strut End with 16mm diameter shaft and square shoulder. Somewhat rare, GC's Advanced Design struts use these larger 16mm square shouldered shafts. Please note this in your order. All of Ground Control's coilovers are made to work with 2.5" diameter coilover springs.

B&G Coil-Over with 12mm diameter upper shaft and square shoulder fits B&G "PS2" coil-over struts for BMWs. B&G is one of many Chinese built brands that use this small upper stem diameter.
BMW OEM (or some BMW Koni) Tapered Strut End. 14mm diameter shaft with tapered shoulder. Similar to most stock BMW struts, these are easily spotted by the tapered top washer that is used with the stock struts. BMW (OEM), Sachs, Boge, and even some newer Konis typically have this shoulder. If you purchased Konis after 2005 you need to double check your struts to see what you have (or contact us if you cannot disassemble your strut before ordering camber plates).
Bilstein Sport Inverted struts (non-adj/non-PSS9) with 14mm Strut End. Inverted struts with a very short 14mm diameter shaft and Bilstein specific square shoulder. Bilstein, H&R, and other "inverted style" coil-over kit struts will usually have these ends. We have perches to work with these struts and OEM style springs or those that have been modified for use with 2.5" or 60mm coilover springs (a somewhat common conversion). There are also a few 16mm shaft Bilsteins out there (rare). We sell a LOT of kits for Bilstein Sports...
Bilstein E36 PSS9 (adjustable valving, not Bilstein Sport) coil-over struts are fairly common (read: cheap) and made for several generations of BMWs. The E36 models have a 14mm diameter shaft with a square shoulder (similar to Koni square shoulder) and use a "unique" coil-over spring from Bilstein that has a 60mm lower diameter but the upper spring diameter is made for an OEM style upper perch. If you want to keep the included tapered springs Bilstein provides in these kits, order the camber plates with an OEM-style Vorshlag upper spring perch option for your appropriate year car. You can also take the extra step and convert to real 60mm coilover springs and ditch tapered Bilstein supplied springs. Using real coilover springs gives you hundreds of rate and length options to choose from, lowers unsprung weight, and allows more negative camber adjustment (larger diameter springs limit camber travel to the strut tower). See entry below for more.


Many if not most of the E46 PSS, PSS9 & PSS10 applications and some KW coilover kits all use an a similar "tapered" spring design as the E36 PSS kits, which again has a 60mm inner diameter at the bottom but grows to fit into the large OEM upper spring perch/bushing at the top (see picture above). This is not a true "coilover" spring design, which would have a constant 60mm or 2.5" inner diameter. This "big headed spring" causes problems in both sourcing alternate spring rates (there are none in this style) as well as for limiting camber travel, but we can and do make OEM style upper perches for use with Vorshlag camber plates. Remember: The E46 M3 and E46 non-M cars use a different upper perch, but we make models for both. The E46 M3 PSS series uses a taller spool piece, but we'll know how to build it when you order your camber plates - just make sure to mark the model of strut and style of upper perch set-up car has (OEM non-M, OEM M3, or 60mm upper - we've seen these struts sold various ways).

If you would like to convert your PSS/PSS9/PSS10 or KW struts that came with a "tapered" spring to a true 60mm coilover spring, we can also help you source springs plus point you to the correct upper perch that can work with Vorshlag plates. This is a very popular and common upgrade for our customers with PSS series struts.

As you can see there are a number of options for struts, just for 3 series BMWs. For Subarus and EVOs it is much simipler - only a few choices and we have them broken down by brand on the catalog Product Page entries for those cars.

BMW Spring Styles

The other part of the camber plate formula is the spring style and diameter. By spring "style" we mean stock or stock style (with "pig-tailed" or tapered spring ends) versus coil-over style springs (which have a constant spring winding diameter). Vorshlag's camber plate design uses a sealed bearing in the upper spring perch, making a specific Vorshlag upper spring perch assembly be sold with our plates. We make upper spring perches to fit the 3 main spring types sold for most 3 series BMWs, including:

60mm ID Coil-Over Springs

Here is a picture of a commonly available 60mm "coil-over" style spring. This 60mm measurement is of the inner diameter, and is usually part of a spring makers part number. If you ever measure a 60mm spring it could be more like 61-61.5mm - there is a fudge factor to account for several variables, and springs inner diameters always run bigger rather than stated, not smaller. Being metric, the spring rate is usually shown in Newtons/mm (this one is rated "70" N/mm) or Kg/m. To convert N/mm to pounds/inch just multiply by 5.7. Lastly, the free (uncompressed) spring length is shown in millimeters, with the spring shown at left being 170mm long (6.7"). To get mm lengths into to inches, divide by 25.4. We tend to sell mostly springs from Hyperco, and their 60mm ID springs which are unusual in that they are 60mm ID but rated in pounds per inch and made in inch lengths. Hyperco springs are made in Ameirca and they make them this way just for us non-Metric Americans! This 60mm size is very common for use on european struts, like Holland built ASTs. These are the most common sized springs commonly found on modified BMWs with coilovers, and come in a huge array of spring rate and free length choices. Vorshlag stocks and sells a large number of Hyperco 60mm ID springs, and can source Swift springs in this size as well.


2.5", 2.25" & 2" ID Coil-Over Springs




Here are pictures of some other "coil-over" style springs, including 2.25, 2.25" and 2" (2.5" looks very similar to a 60mm spring). This 2.5" measurement is also of the inner diameter (which is about 63.5 mm). This is the other very popular aftermarket coil-over spring commonly available (almost all 2.5" ID springs are built in the USA; those built overseas in this size are usually marked "64mm"). Being a non-metric size, the spring rate is usually expressed in pounds-per-inch of travel, such as 500 pounds/inch. This is commonly referred to as a "500 pound" spring. No, the spring doesn't weigh 500 pounds, but it would take 500 pounds of force to compress the spring by 1 inch. The proper way to order springs like this would be to know the free length of the spring (5, 6 or 7" is common), the diameter (such as 2.5"), and the spring rate (such as 500 pounds-per-inch). Vorshlag tends to only stock a few 2.5" ID Hyperco springs, which we use in certain applications where a 60mm spring doesn't exist. We can sell you adapters to use the larger 2.5" ID on AST struts, which are made for 60mm.

There is another, slightly less common coilover spring inner diameter - 2.25". These are almost exclusively domestically built, and we stock a few sizes and rates from Hyperco. These tend to be the lightest and smallest ID springs commonly used on coilover shocks, but being smaller than 60mm, they don't fit on certain struts (like ASTs) without some perch machining/rework. Moton coilover shocks and struts are usually set-up for this sized spring, however, so we will be stocking more of this size now that we are a Moton dealer. Hyperco makes a staggering array of lengths and rates in 2.25" ID, because the circle track and other professional racing teams have flocked to this size. For some reason they charge more for them than 60mm, so beware the slight cost penalty with 2.25" springs. We use them on certain sports car applications where there is not a good 60mm ID selection, like on the back of BMW E30s (which usually needs a 5" long spring when used with an AST rear adjustable spring platform). We stock a number of these at Vorshlag, and of course can get any Hyperco spring - we are a WD distributor for Hyperco.

An even less common coilover spring is the 50mm or 2" ID, which is used on coilover shocks only (not struts). We stock a few of these from Hyperco here at Vorshlag, for use on BMW rear coilover shock conversion kits. If you have a race car with the rear shock towers tied into a roll cage, this is an option. Otherwise, for 99% of BMW owners reading this, you don't want or need true coilover rear shocks.


OEM Style Springs


Here are pictures of some of the various perches we make for use with stock BMW and Subaru springs, including "stock style" aftermarket lowering springs. The upper spring perch needed is either a modified OEM perch or a CNC perch we've designed, made to use a press-fit, sealed radial bearing (which is typically at least twice as strong as the stock bearing); see the perch section below. Stock Style aftermarket springs include dozens of popular lowering springs that many BMW owners tend to go to "first", before they get serious about racing and/or feel the need for higher spring rates (and the larger number of rate choices) that coil-over style springs allow.

Being a stock style spring, they typically do not work with adjustable height spring perches and take up more room under the fender (slightly less camber adjustment range). These types of springs also tend to come in much softer spring rates, and are often variable rate (the first inch of travel is soft, and they stiffen as they compress). There are dozens of brands, rates and free lengths to choose from, and several pig-tail end sizes for the factory springs made for BMWs (and the aftermarket has lots more), but most are covered by the "stock style" perches manufactured by Vorshlag, as shown in the perch section below. We have OEM perch coverage for E30/E34, E36, E46 non-M, E46 M3, E90/E82 non-M, MINI R53 & R56, and Subaru GR & Subaru GD chassis - among others.






Above are a few more pictures showing various stock style and coil-over springs and struts, for relative sizing. The picture at the far right shows rear springs and shocks as well. Now you can figure out what springs you have - it is easy to visually check and/or measure, even while still mounted onto the car.

Vorshlag Spring Perches

As stated above, Vorshlag Camber Plates require a very specific upper spring perch be used, with its integral radial bearing to isolate turning loads away from the spherical bearing. This is partly why our camber plates tend to outlast the car, and all other designs on the market. The perch choice depends on the type of spring and strut design you have - we make adapter bushings that press into the specific spring perches to fit your strut perfectly. If you have followed the sections above, hopefully you know what strut brand/shaft diameter/end style you have as well as the spring size and type used. We make the upper spring perches below to work with most struts and spring combinations, and there are a lot. The year and model of your BMW can also dictate the style of the spring perch (stock style springs, 60mm or 2.5" coil-overs) as well as the spool piece that adapts our spherical bearing with the strut shaft's shoulder and diameter. As usual, pictures tend to help. Here are the seven basic Vorshlag upper spring perches, each having several optional bushing inserts (spools) to work with the various strut diameters and strut shoulders:

95 M3 OEM style - fits 1995 M3, all E30s, and MIN R53 and R56, among others. The upper perch kit is sold with the necessary axial bearing and spool pieces pressed into place, as well as upper spool pieces.
96 M3 OEM style - fits 1996-99 M3 with stock style springs. The upper perch kit is sold with the necessary axial bearing and spool pieces pressed into place, as well as upper spool pieces.
E36 non-M OEM style - fits E36 318, 325, 328 (1992-1998), and some Z3 models, with OEM style springs. We stock and sell these regularly, but many people that race non-M E36 cars tend to use M3 style struts & springs (which has a different swaybar mount) or go right to coil-overs.
E46 M3 OEM style - This works with all 2000-2006 E46 chassis M3 models, with stock or stock style springs (H&R, etc). This uses a modified OEM steel E46 M3 perch and our bearing. We stock and sell these regularly. As mentioned elsewhere, the OEM style upper spring perch is used on various Bilstein PSS and KW coilover kits.
E46 non-M OEM style - This works with all '99-04 E46 chassis 323, 325, 330 non-M models, with stock or stock style springs (H&R, etc). This uses a modified OEM aluminum E46 perch and our bearing. We stock and sell these regularly. As mentioned elsewhere, the OEM style upper spring perch is used on various Bilstein PSS and KW coilover kits.
The E82 and E90/92 non-M cars use an aluminum OEM spring that we weld a bearing retainer ring to, redrill, and install our radial bearing. This works on the E90/92 3 series non-Ms and the 128/135i E82 chassis, but does NOT work with the E90/92 M3 (we do not have an OEM perch solution for the M versions). E46 non-M OEM style - This works with all '99-04 E46 chassis 323, 325, 330 non-M models, with stock or stock style springs (H&R, etc). This uses a modified OEM aluminum E46 perch and our bearing. We stock and sell these regularly. As mentioned elsewhere, the OEM style upper spring perch is used on various Bilstein PSS and KW coilover kits.
Vorshlag 60mm ID upper spring perches are made to fit non-inverted strut coil over applications using the 60mm diameter coilover springs. These can be made to fit struts with 14mm square shoulders (Koni, AST, others), 14mm tapered shoulder (OEM struts, Boge, Sachs, newer Koni), 16mm square shoulders, or 12mm square (B&G), with various press-fit spool piece adapters.
Vorshlag 2.5" upper spring perches are made to fit non-inverted strut coil over applications using the 2.5" diameter coilover springs. These can be made to fit struts with 14mm square shoulders (Koni, AST, others), 14mm tapered shoulder (OEM struts, Boge, Sachs, newer Koni), 16mm square shoulders (GC Advanced Design), or 12mm square, with various press-fit spool piece adapters.
Subaru GD chassis OEM spring perches were a bit trickier to design and implement with our camber plates, but we made a solution. These use a single row radial bearing instead of a double row, due to clearance issues.
Subaru GR chassis OEM spring perches were also tricky to design and implement with our camber plates, but we made a solution for this chassis as well. These also use a single row radial bearing instead of a double row, due to clearance issues.

Once you know what you need, head on over to the Online Catalog and order up a set of camber plates!