03-21-2021, 06:14 PM | #1 |
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Mild lowering for adaptive cars?
The Eibach Pro-Kit is just a little too much drop for me in the front, but I would very much like to slightly lower my 2019 M240i with adaptive suspension.
Can anyone tell me what my actual options are? The Dinan drops the rear a bit more than I really want — I want to stay at around 15 mm drop max. The MPerformance springs apparently aren’t available for adaptive cars? (at least not through dealer) I heard there were some H&R 15mm drop springs in existence, but I don’t see them on the H&R web site or for sale anywhere. Can anyone advise on what my actual options might be? |
03-22-2021, 12:48 AM | #2 |
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Dinan sells 10mm spring spacers. This takes the 1 inch rear drop down to a new drop of .6 inch which is about the 15mm your looking for.
https://www.2addicts.com/forums/show...8&postcount=34 |
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03-22-2021, 01:29 AM | #3 |
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Triple S Springs apparently provide lowering of 10-15mm. I haven't used them and don't know anyone who has. I'm also unsure as to why there would be compatibility issues between the adaptive dampers and any of the springs currently on the market.
A shorter spring relative to the stock damper will result in a decrease in droop (extended) and bump (compressed) travel. Correct me if I'm wrong, anybody, but it is my understanding that operating outside the bump/droop travel range causes the dampers to bear the weight of the car rather than the springs as intended. This extra force acting on the damper can cause stress on the dampers that may make it leak, or break mounting brackets, bind on other parts, etc. However, it should be noted that this also applies to the stock damper/spring combo. Hitting potholes and nailing curbs - realistically the only time you're going to exceed the droop/bump travel with a properly engineered system - will even screw up the dampers when paired with stock springs as well. Most aftermarket spring kits make up for the reduced droop/bump travel by re-engineering the system to be stiffer, progressive, and/or include new bumpstops to compensate for the reduced suspension travel. So you'll only run into a problem if you're using significantly shorter springs and/or making significant spring rate changes. And that's the origin of this modern "myth" - damaged dampers were common in the 90's when punk kids were cutting their springs (significantly shorter, greatly reducing bump/droop travel) or using innapropriate spring rates (too soft = bump problems; too stiff = droop problems). They exceeded their new and reduced suspension travel parameters, the dampers had to bear loads they were never designed for, and they'd break. But it's not an issue with modern spring kits because they don't lower your car way too much or make wild changes to the spring rates. |
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03-22-2021, 11:58 AM | #5 | |
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I would go with the Dinan springs and add the spacer in the rear. That's what I did. I also didn't add the front Dinan springs as I felt the front was low enough and the OEM spring rates fine. The Dinan springs only add a marginal increase in spring rate in the front (something like 8%), thus the front drop is cosmetic. The rear Dinan springs are 30% stiffer. I wanted the higher spring rate and a mild drop as I always felt the rear axle felt at odds with the front and the gap too large. With the rear springs only, I've got a one finger gap in the rear and a two finder gap in the front. The look is consistent with prior BMWs where they visually looked like they sat lower in the rear. The reality is that the front wheel wells on all cars are larger to compensate for the wheels turning. With the front Dinan springs installed and spacers in the rear, the gaps are pretty much equal. When doing springs (any kind), you really also replace the front and rear bumpstops with OEM BMW parts 31331138814 (front) and 33536762722 (rear). These bumpstops are slightly shorter and help the springs achieve the appropriate progressive spring rate as they compress.
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03-22-2021, 12:03 PM | #6 |
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03-22-2021, 12:05 PM | #7 | |
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03-22-2021, 12:07 PM | #8 | |
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03-22-2021, 08:48 PM | #9 |
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Yea, they are quite pricey. I did find a random sale on them through ECS tuning one day, so I grabbed them. I paired them with the Bilstein B6 damptronic struts, so I can't just speak to the springs, but I love the way the car feels now. No issues with daily driving (comfort mode is still good), and it's much more planted in the rear when accelerating. No floaty back end anymore.
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03-23-2021, 09:43 AM | #10 | |
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03-23-2021, 09:45 AM | #11 | |
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Last edited by radio3; 03-23-2021 at 02:46 PM.. |
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03-23-2021, 03:34 PM | #12 | ||
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03-24-2021, 08:01 PM | #13 |
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It looks like there are H&R springs that lower the M240i 15mm front and rear. The part number is 28896-2.
Does anyone know how the spring rates on the springs compare to the Dinan? I wonder if the Dinan springs have more optimal spring rates. |
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