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Technical Topics Suspension / Chassis / Brakes M340i - Free Rear Lowering Mod?

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      06-15-2023, 03:19 PM   #1
CRBWS6
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M340i - Free Rear Lowering Mod?

It looks like one could potentially lower the rear without replacing the springs; but by modifying (or replacing) the upper and/or lower spring pads.

I've done this on other cars with a divorced spring/shock setup to get extra lowering above & beyond what springs provided.

For now I prefer not to lower the front; and replacing just rear springs would be too much of a squat look.

My goal would be to lower the rear about 1/2" (currently is 1/4" higher than front).

Just wondering if anyone has tried this? The parts are cheap, so I might end up being the guinea pig.

Name:  Rear Susp Parts RealOEM_01.JPG
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Upper:Name:  Top mount_04.JPG
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Lower:Name:  Bott Mount_04.JPG
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      06-19-2023, 05:01 PM   #2
skroonigan
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Honestly that just seems a bit sketchy to me. Those two rubber mounts provide a nice seat for the spring (the springs snap into those). You might be able to get away with not running the lower mount, I imagine that would give you 1/4" lower? Either way I'd probably not risk it. You may as well just replace your springs if you're going to go this far into the rear suspension.
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      06-20-2023, 07:30 PM   #3
RCKYMTN M34OI
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Quote:
Originally Posted by CRBWS6 View Post
It looks like one could potentially lower the rear without replacing the springs; but by modifying (or replacing) the upper and/or lower spring pads.

I've done this on other cars with a divorced spring/shock setup to get extra lowering above & beyond what springs provided.

For now I prefer not to lower the front; and replacing just rear springs would be too much of a squat look.

My goal would be to lower the rear about 1/2" (currently is 1/4" higher than front).

Just wondering if anyone has tried this? The parts are cheap, so I might end up being the guinea pig.

Attachment 3206229

Upper:Attachment 3206238
Lower:Attachment 3206239
How would you go about modifying or replacing them?
Maybe if you could find a company that would replicate them but make them shorter it could work. Personally i wouldn't just go hacking them up. Keep us up to date though
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      06-28-2023, 04:30 PM   #4
CRBWS6
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On previous cars, I was able to completely remove the upper pad and replace it with small diameter hose wrapped around the top coil. Many cars come with no lower pad, as long as there is something else there to hold the spring in place laterally. I am thinking complete removal would result in too much lowering.

My thought is to cut/trim, probably just the lower one, since replacement OEM parts are cheap.
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      06-30-2023, 01:31 PM   #5
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Why would you put negative rake in the car? There is a reason the front is lower than the rear.
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      07-01-2023, 08:16 PM   #6
CRBWS6
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Good question. The goal is to achieve a slightly more lowered look without dropping the front for clearance reasons. In my case, a bit of negative rake is a minor consequence (would be going from +1/4" to -1/4"). I do understand the suspension tuning affects of less rake and have actually used it on a past race car to reduce oversteer.

As a point of reference, my E46 M3 actually has a 1/2" negative rake and it's stock. Although this based on fender measurements which doesn't imply the car is actually negative raked.

Last edited by CRBWS6; 07-01-2023 at 08:24 PM..
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      07-04-2023, 01:41 PM   #7
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Quote:
Originally Posted by CRBWS6 View Post
Good question. The goal is to achieve a slightly more lowered look without dropping the front for clearance reasons. In my case, a bit of negative rake is a minor consequence (would be going from +1/4" to -1/4"). I do understand the suspension tuning affects of less rake and have actually used it on a past race car to reduce oversteer.

As a point of reference, my E46 M3 actually has a 1/2" negative rake and it's stock. Although this based on fender measurements which doesn't imply the car is actually negative raked.
Really you have to measure rake from the chassis hard points at the front and rear, measuring from the fenders is only going to tell you relative if you change it. No BMW comes with negative rake from the factory. Only cars that are running negative rake are drag cars and rarely some race cars. Personally what you are doing sounds like it has only downsides to me, but to each their own. If you want a mild drop put DINAN springs on with their handling kit.
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