09-02-2015, 04:58 PM | #1 |
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Ground Control New Plate Design Failure
Well my ground control plates made it a whopping 20 miles before failure, these are the new design. I will be pulling them off the car, doing a detailed photo explanation of the design (or lack of). So far ground control would like to blame the dinan springs. or me.
So basically if you want to buy and run these, they say they are only for stock suspension. Which really makes no sense since they sell them with multiple perch sizes, and who adds camber plates to a stock car? The design is pretty poor, which will be easier to see in photos, swapping them off the car for a new set of kamc plates that are being overnighted from turner since my old ones got over torqued by an alignment shop. So I will keep you guys updated as it progresses. Below are some photos of the bearing and case they are using to support the spring perch. The plate has some serious design defects. I could spend some pages describing the faults, but in simple terms it is as follows: The plate is designed in such a way that the spring force and load is transmitted via the bearing to the car, the bearing case is thin plastic and will not tolerate that load or transfer. ground control stated over and over it is the same bearing as the BMW carrier, However BMW designed there perch and case to transmit the load to the plate, all that bearing in the bmw design has to do is account for the unsprung weight of the suspension. Furthermore your spring perch gets located by a part of the plate that only extends half way down the bearing and end on the seam of the bearing case (where it failed in the photos). This creates and uneven load on the bearing at the worst possible spot. I honestly have a hard time believing an engineer designed these. |
09-02-2015, 08:52 PM | #2 |
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Wow. Thanks for the detailed write up. Very much appreciated as I was wondering how this design would hold up. I was skeptical as they seemed to get this new design out rather quickly. Talk about poor engineering
Would you happen to have the part number to the kmac plates? I would like to look at that design. |
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09-02-2015, 09:23 PM | #4 |
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09-02-2015, 09:25 PM | #5 | |
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here is a pic before and after http://www.2addicts.com/forums/showp...4&postcount=46 keep in mind he has a modified suspension also so not just LCA's but the before and after are with the same suspension Last edited by pikcachu; 09-02-2015 at 09:45 PM.. |
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09-02-2015, 09:39 PM | #6 |
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I have the m3 control arms as well, they do push you forward, add some camber but not enough for my application. The big benefit is the bushings and that the camber they add is from the bottom which is better from a design perspective.
I will post the kmac info when I get to work, ran those plates for 5k miles prob 2k track with zero issues. They are just a little louder, I figured since ground control did a redesign I would try them. Sad to say they did not work out. Ground control says there design for stock suspension only. They also told me I opened up that bearing and a bunch of other stuff that makes no sense. They are supposedly taking them back so I will leave my thoughts out of it, but will post photos of there design, k Mac design and stock design. |
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09-02-2015, 09:45 PM | #7 | |
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09-03-2015, 08:18 AM | #8 |
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which ones? front or rear? The front are stock from m3 arm which are a hybrid spherical, kind of like a monoball with some extra padding. I went with those arms mainly for that reason, a few hundred less than monoballs, more camber and caster. This helps eliminate some of the squirm in the front of the car under braking with race pads.
Rears I replaced with aftermarket, nothing fancy I think LTQ or something. Prob. no better than stock, but I did change all the arms back there for spherical bearings. There is no aftermarket upgrade yet, but the bushings are only like $15.00 so I will just change as needed no big deal. |
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09-03-2015, 10:38 AM | #10 | |
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what arms did you use for the back? |
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09-03-2015, 10:50 AM | #12 |
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BMW design:
Fixed plate with bearing and carrier. Bearing dia. of 107mm encased in a concave metal jacket with a thickness of 2 mil.
Fixed plate extends the length of the bearing carrier with a diameter of 78 mil and thickness of 4mm Bearing carrier is tapered horizontally 10mm to locate spring. Carrier has a diameter of 126 mm where the plate meets the plate. Ok so what does this mean? Simple explanation, the carrier has a larger surface area to disperse the spring load. It is also designed in a way to allow the horizontal forces to be absorbed into the plate. This is important in McPherson suspension design because the shock and the spring are basically the upper control arm. By designing a round bearing plate this transfers the majority of the weight around the bearing, basically the bearing only needs to account for the unsprung weight and some additional factors depending on how your driving. Pretty clever way to reduce the need for needle bearings or tighter tolerances. |
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09-03-2015, 11:10 AM | #13 | ||||
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This plates did not fail by manufacture defect. You have installed the camber/caster plates incorrectly, just as we spoke about on the phone and via e-mail on 9/1. You had informed me that you did not use the factory upper spring pad because you had torn in on a previous spring install. Quote:
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Trevor Last edited by GCSystems; 09-03-2015 at 11:51 AM.. |
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09-03-2015, 11:17 AM | #14 | |
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Last edited by JM3; 09-03-2015 at 12:57 PM.. |
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09-03-2015, 11:30 AM | #15 | |||||
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click for pic Quote:
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Less expensive to manufacture, Easier to seal and make weatherproof More resistant to debris Allows for more lubricant in the assembly I believe this is why Ground Control buys their F22 bearings directly from the BMW dealer. Last edited by JM3; 09-03-2015 at 11:45 AM.. |
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09-03-2015, 12:19 PM | #19 | |
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You guys are really reaching here in thinking that I would disassemble your bearing. I do not think any reasonable person would come to the conclusion. Why would I order your product and disassemble the bearing. Its nice to see you post that is your companies official thoughts on this, saves me some postings. The point of this post was to discuss the various plates, and differences, the failure of your plate like it or not is part of that discussion. I was not really planning on getting into the customer service on this but seems you guys want to open that can of worms its off to the races. |
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09-03-2015, 12:28 PM | #20 | |
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We say these are for use with stock style springs (which are bent). Many aftermarket springs are not bent , because the bent springs are more expensive to make. The geometry of the front strut / inner fender interface of the F22 is designed to use a bent spring, and reverting to a straight spring causes problems with or without GC parts. Pic: Last edited by JM3; 09-03-2015 at 12:35 PM.. |
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09-03-2015, 12:52 PM | #21 | |
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The part that locates the bearing extends halfway because each side of the bearing extends halfway! The seam is where the two halves of the bearing must rotate! The support has to end there, just like stock BMW. JM3 |
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09-03-2015, 12:59 PM | #22 | |
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Thanks, Phil" (photos at top of post) "Hi Phillip, Thanks for your pictures. I will send two new bearings out this afternoon. Please do use the factory boots. You can trim them them down if the length is too long, however it's recommended to use these with OE style springs. Thanks, Trevor -- Trevor Brown Ground Control Systems, Inc. 3885 Dividend Dr. Shingle Springs, CA 95682" Last edited by Pparana; 09-03-2015 at 01:07 PM.. |
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