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BMW F22 Camber Plates for Coilover and OEM springs

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  • BMW F22 Camber Plates for Coilover and OEM springs

    Want to learn more about the camber plate design for the BMW F22 series? Read on...

    Like virtually every BMW ever made, the F20/21/F22 series of 1 and 2 series BMWs have McPherson strut front suspensions, and these models have zero camber adjustment from the factory. Like all "McStrut" designs, that usually shows itself as adverse tire wear when you use your BMW on track or in autocross situations. The outer shoulder of the front tires can wear severely in no time, like this BMW 1M tire below shown after one track weekend.



    The BMW F22 chassis had a unique upper strut mount + upper spring perch design which added some new challenges to our typical design parameters. Nothing like we had ever seen before - very thin and with integral mounts for other structural components.



    Unfortunately, these BMWs don't have enough negative front camber to allow them to be driven on a road course or in an autocross event without shredding the outside shoulders of the front tires. The need to add negative camber was something we noticed when these cars were first introduced but there didn't seem to be a way to do it with our traditional Vorshlag spherical top mount designs.



    In early 2016 we had already taken 50+ phone calls from BMW 1/2/3/4 series owners who tracked their cars and were killing tires. From this obvious need we decided to invest the time and money into making a prototype camber plate design for use with OEM springs (+ "OEM style" lowering springs) and coilover springs. This was one of our most challenging designs yet.



    We have been making our unique camber plate designs for 15 years and have sold tends of thousands of units for coilover and OEM style spring use. We started with BMWs and our first OEM spring perch solutions were for BMWs.



    One of the most unique aspects of our design is that we always include an upper spring perch with our camber plates which incorporate an integral, sealed radial bearing. This is more difficult than a "one size fits all" design where we could slap a flat radial bearing on top of your existing perch. We have seen that over a fairly short period of time any unsealed radial bearing gets rain and dirt inside that washes out the grease and the radial bearing locks up.



    If we didn't have this radial bearing, or used an un-sealed radial bearing design like so many others companies do, it would quickly wear out from road grit and rain. Then the spherical bearing in the camber plate (the metal bearing that pivots when the suspension cycles) has to deal with these rotational loads, which wears it out very quickly. Wear in the spherical bearing makes a "knocking" noise over bumps. That noise is distinctive and the only way to fix it is to replace the spherical bearings.



    When a car is equipped with aftermarket height adjustable "coilover" struts we can make our camber plate + upper spring perch solution either thicker or thinner than the factory parts, since you can raise or lower the ride height on the coilover perches to compensate. We normally make our coilover solutions as thin as possible to increase total strut stroke, but this F22 top mount design was exceptionally thin. On the OEM spring setups we have to MATCH the thickness of the factory top mount and perch, otherwise we could raise or lower the ride height of the front end with our camber plate solution. That isn't an option.



    We still use our massive spherical bearing (larger than most competitors; see below) that is Teflon lined and made in the USA to our specs in big batches. Even buying thousands a year they are still costly, but worth the expense when you see how long they last.



    We go to great lengths to make sure this bearing NEVER sees radial or turning loads (the strut shaft rotates as the steering wheel is turned). We also try to help train our customers to make sure the components not only fit when they arrive (we can build the same camber plate 200+ different ways, depending on strut brand / model and spring size), but to make sure that the strut top nut gets installed correctly.



    To make the F22 perch design we had to come up with a new Large Diameter radial bearing, which we found. This design was fitted around the lower portion of the spherical bearing holder, which reduced stack-up height of the assembly when using it.



    The F22 had a huge strut tower opening, which normally makes it easier to get a lot of camber and caster adjustment without having the strut shaft "run into" the circular opening.



    But unlike all BMWs of the past, this factory strut top mount had a strut tower brace that bolted to the mount itself. Very very unusual, and this limited our design path massively.



    The very short "stack up height" of the F22 top mount and perch required us to take an all new approach to our solution that worked with the OEM style spring. We had to make our first "non-articulating spring perch" design, where the strut shaft articulates through the spherical bearing but the perch does not. It was the only way we could see to keep the stack up very short (to avoid raising the ride height) and keep our crucial sealed radial bearing.



    When we made this F22 design a new radial bearing was used (thin with a larger diameter) to decrease the stack-up height. This made for a very thin OEM style upper spring perch...



    When you see the F22 upper perch next to other designs (below) you can see how different this design ended up being. This still uses a large diameter spring, so the perch has to be machined for large diameter billet (more expensive), but it uses the thin design for the unique radial bearing, so it is thin enough to keep the stack-up height of the total top mount assembly low.



    We also put the main spherical bearing holder on TOP of the main camber plate, instead of below. This meant we had to have a matching portion under the plate for the upper bearing holder to bolt to, which adds cost to this design.



    Obviously this design only has camber adjustment, as the necessary room to adjust caster as well was eaten up but the strange strut tower brace that is incorporated into the camber plate / OEM top mount. You can see this below. If we would have added some caster adjustment it would have been so small as to be insignificant.



    Luckily these F22 chassis BMWs already have a lot of positive caster built into the suspension, so that adjustment was not critical. Camber is impossible to live without on a McStrut car like this, and the camber adjustment itself is easy to adjust and offers a wide range to choose from.



    On our tester's M235i we saw nearly -4° of camber at max adjustment, but settled on a compromise street/track setting of -2.5° camber, which is a common setting we will use on dual purpose cars.



    This section of underhood weather strip has to be removed with this (or any other) camber plate design, as we need room for the spherical bearing holder to move inboard and outboard, when adjusting camber. Millions of BMWs have been built for decades without this piece of rubber "Tupperware", so we feel it isn't a big loss - when you can gain tire-saving camber.



    We left this prototype design on this testers daily driven M235i for six months before we moved into production. We wanted to make sure we had eliminated every squeak and rattle before releasing these to the public. After a handful were sent we did make one small change to the F22 upper perch, to allow for the OEM rubber isolator to fit above the spring. This makes the camber plate design complete and worthy of a new $50K+ BMW.


    Non-articulating perch and F22 bearing holder assembly used on Subaru 86 chassis with OEM springs

    Hopefully this forum post explains the "why and how" of our F22 camber plate design. After using this new arrangement on the F22 we have adapted it to work with other chassis, like the BRZ/FR-S design above for OEM spring use.
    Last edited by Fair!; 08-24-2018, 09:45 AM.
    Terry Fair - www.vorshlag.com
    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev
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