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      10-17-2019, 02:53 PM   #1
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Options to raise rear ride height ~0.5" - 0.75"? - F80 M3

I know... BLASPHEMY!!

I lowered the front on Eibach v1's and I've been very happy with the overall performance and general appearance. I purposely went with the v1's over the v2's to keep a slight fender gap in the front for just that little extra ground clearance. Also, I'm personally not a fan of the slammed look, especially on my daily driver.

With that said, I didn't bother installing the Eibach springs in the rear because the OEM rear suspension already sits very low and I absolutely did not want to go any lower. On a flat surface the rear sits with less than a 0.25" fender gap. On even the slightest uneven surface, the rear tires tuck into the fenders.

I know most will think I'm crazy but this is something that drives me bonkers about the car. Especially since it's rarely on a perfectly even surface outside of my garage.

I think the front gap is perfect at exactly 1". I'd love to get the rear to 0.75" to 1" gap, to match. I know this will exacerbate the front rake a bit but I'm willing to do that to achieve the goal. Anyway, I'm curious as to what options I have to achieve something like this without degrading performance noticeably. My first thought is thicker bump stops in the rear. Is that an option?

Anyway, just curious to hear thoughts on the matter. Open to opinions.

And a quick pic of the current setup, for reference...
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      10-17-2019, 03:57 PM   #2
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Quote:
Originally Posted by S4toM3 View Post
I know... BLASPHEMY!!

I lowered the front on Eibach v1's and I've been very happy with the overall performance and general appearance. I purposely went with the v1's over the v2's to keep a slight fender gap in the front for just that little extra ground clearance. Also, I'm personally not a fan of the slammed look, especially on my daily driver.

With that said, I didn't bother installing the Eibach springs in the rear because the OEM rear suspension already sits very low and I absolutely did not want to go any lower. On a flat surface the rear sits with less than a 0.25" fender gap. On even the slightest uneven surface, the rear tires tuck into the fenders.

I know most will think I'm crazy but this is something that drives me bonkers about the car. Especially since it's rarely on a perfectly even surface outside of my garage.

I think the front gap is perfect at exactly 1". I'd love to get the rear to 0.75" to 1" gap, to match. I know this will exacerbate the front rake a bit but I'm willing to do that to achieve the goal. Anyway, I'm curious as to what options I have to achieve something like this without degrading performance noticeably. My first thought is thicker bump stops in the rear. Is that an option?

Anyway, just curious to hear thoughts on the matter. Open to opinions.

And a quick pic of the current setup, for reference...
I get what you're trying to do and it's your car so do as you please but it maybe quite hard to find someone who's done this.
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      10-17-2019, 05:07 PM   #3
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Thicker bump stops will not work. They'd have to basically be solid blocks that lock out the suspension. You need a spacer made to match the shape of the coil spring to spring seat interface. Changing the ride height that significantly will hurt the ride and handling of the car significantly and may negatively effect the cars safety and stability in an emergency situation.

You may not care, but most people will think it looks stupid as well.
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      10-17-2019, 05:11 PM   #4
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Quote:
Originally Posted by Racer20 View Post
Thicker bump stops will not work. They'd have to basically be solid blocks that lock out the suspension. You need a spacer made to match the shape of the coil spring to spring seat interface. Changing the ride height that significantly will hurt the ride and handling of the car significantly and may negatively effect the cars safety and stability in an emergency situation.

You may not care, but most people will think it looks stupid as well.
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      10-17-2019, 07:08 PM   #5
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I've modified my rear ride height with 0.1" thick kydex spacers/shims placed in/on the upper spring cups. The concept is similar to the spacer/shims Macht Schnell uses.

Here's a pic where you can see the two shims I put on top of the spring cup (there are an additional 3 inside the spring cup, which is why the rubber lip isn't flush with the cup lip).


For the range of lifting you want (an additional .5-.75" at the wheel) you'd need 3-4 0.1" shims. I can make you some for pretty cheap.

Additionally, if you want to make your own rear HAS setup you can do that too for ~$250.

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      10-17-2019, 10:57 PM   #6
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I think it looks great as is and you shouldn't change a thing!
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      10-18-2019, 01:36 AM   #7
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Get a piece of 5mm thick rubber mat and cut a circular piece that fits above the upper spring seat. That should raise the car about 1/4 inch.
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      10-18-2019, 06:45 AM   #8
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OP. I may be able to help.

As long as you're mixing and matching springs, I have an extra set of rear springs and mounts from my Bilstein B16 kit. The threads will allow you to lift the height with the stock spring if it fits, or the Bilstein rear spring to higher than stock height.

Do I recommend this? No. But I also don't recommend what you're trying to accomplish either. But I can sell these rear springs and mounts to you, brand new and unused, for cheaper than probably any solution you're going to try. At least this was built for the car.

PM me if you're interested and I can have them shipped out to you.
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      10-18-2019, 07:06 AM   #9
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Looks perfect as-is and both front and rear look even.
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      10-18-2019, 08:15 AM   #10
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Thanks for the input everyone. I spoke with a local M3 owner that I've known for a while, who often tracks his. He mirrored some of the comments here in that he highly recommends against raising the rear at all because it would negatively impact handling in a noticeable manner.

While I'd prefer to eliminate that tucked look, I'm not willing to negatively impact performance to do it.

Thanks again guys!
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      10-23-2019, 05:08 PM   #11
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Macht Schnell provides billet perch spacers for their spring kit for installing on an F80 instead of F82. Those might be a great option and simple solution. i installed a set of them on a friends F80 ZCP and id say they'd be worth right at .4-.5" raise in the rear. Hope this helps.
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      11-04-2019, 11:37 AM   #12
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I know the OP has decided not to raise the rear. With that said, I wonder why everyone is so fixated on matching the rear and front gaps. As it stands, even with the rear at .75" gap and front at 1" gap, the car still looks way raked forward. You can easily see this by just looking at the side skirt as it definitely angles forward. Do people understand that most cars have front wheel wells that are cut naturally higher than rear qtr panels because there's a need to for more tire clearance since the front wheels need to turn left and right?

Additionally, do people realize that the rear tires are noticeably taller than the front tires? Stock 275-35-19 rears vs. stock 255-35-19 fronts are a good .6" or so taller in the rear. Half of that is .3" which means if you measure from the center of the rim to the top of the wheel well (both front and rear) it will measure virtually the same front and rear - in fact, the rear will be even taller.

I guess my point is people should stop fixating on the front and rear wheel gaps and look at the car overall and they will see that virtually all of our lowered cars are leaning/raking forward significantly already. You really don't want to further upset the weight distribution and handling balance by forcing an even steeper forward rake.
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      11-04-2019, 02:32 PM   #13
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Quote:
Originally Posted by AlterZgo View Post
I know the OP has decided not to raise the rear. With that said, I wonder why everyone is so fixated on matching the rear and front gaps. As it stands, even with the rear at .75" gap and front at 1" gap, the car still looks way raked forward. You can easily see this by just looking at the side skirt as it definitely angles forward. Do people understand that most cars have front wheel wells that are cut naturally higher than rear qtr panels because there's a need to for more tire clearance since the front wheels need to turn left and right?

Additionally, do people realize that the rear tires are noticeably taller than the front tires? Stock 275-35-19 rears vs. stock 255-35-19 fronts are a good .6" or so taller in the rear. Half of that is .3" which means if you measure from the center of the rim to the top of the wheel well (both front and rear) it will measure virtually the same front and rear - in fact, the rear will be even taller.

I guess my point is people should stop fixating on the front and rear wheel gaps and look at the car overall and they will see that virtually all of our lowered cars are leaning/raking forward significantly already. You really don't want to further upset the weight distribution and handling balance by forcing an even steeper forward rake.
Took the words out of my mouth.

Case in point, E36 STW.

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      11-04-2019, 02:56 PM   #14
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Quote:
Originally Posted by AlterZgo View Post
I know the OP has decided not to raise the rear. With that said, I wonder why everyone is so fixated on matching the rear and front gaps. As it stands, even with the rear at .75" gap and front at 1" gap, the car still looks way raked forward. You can easily see this by just looking at the side skirt as it definitely angles forward. Do people understand that most cars have front wheel wells that are cut naturally higher than rear qtr panels because there's a need to for more tire clearance since the front wheels need to turn left and right?

Additionally, do people realize that the rear tires are noticeably taller than the front tires? Stock 275-35-19 rears vs. stock 255-35-19 fronts are a good .6" or so taller in the rear. Half of that is .3" which means if you measure from the center of the rim to the top of the wheel well (both front and rear) it will measure virtually the same front and rear - in fact, the rear will be even taller.

I guess my point is people should stop fixating on the front and rear wheel gaps and look at the car overall and they will see that virtually all of our lowered cars are leaning/raking forward significantly already. You really don't want to further upset the weight distribution and handling balance by forcing an even steeper forward rake.
I agree with much that is said here.

However, I fail to see how changing the front-to-rear ride height proportion affects weight distribution in a significant manner?
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      11-04-2019, 04:22 PM   #15
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Find a friend or shop that has vehicle scales and corner balance your car. You'll notice the difference. Performance > esthetics imo.
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      11-06-2019, 09:50 AM   #16
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Quote:
Originally Posted by AlterZgo View Post
I know the OP has decided not to raise the rear. With that said, I wonder why everyone is so fixated on matching the rear and front gaps. As it stands, even with the rear at .75" gap and front at 1" gap, the car still looks way raked forward. You can easily see this by just looking at the side skirt as it definitely angles forward. Do people understand that most cars have front wheel wells that are cut naturally higher than rear qtr panels because there's a need to for more tire clearance since the front wheels need to turn left and right?

Additionally, do people realize that the rear tires are noticeably taller than the front tires? Stock 275-35-19 rears vs. stock 255-35-19 fronts are a good .6" or so taller in the rear. Half of that is .3" which means if you measure from the center of the rim to the top of the wheel well (both front and rear) it will measure virtually the same front and rear - in fact, the rear will be even taller.

I guess my point is people should stop fixating on the front and rear wheel gaps and look at the car overall and they will see that virtually all of our lowered cars are leaning/raking forward significantly already. You really don't want to further upset the weight distribution and handling balance by forcing an even steeper forward rake.

Even though I previously decided against going the initial planned route, this post still resonated well with me. I definitely wasn't considering this, as this is the first car I've ever owned that has different sized wheels/tires front/back. I haven't taken the notably taller tires into account.

And I do agree. Even with the current setup, there is some significant front rake. Pushing the front any lower would make that notably more apparent.
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      11-06-2019, 11:53 AM   #17
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I know you initially asked about raising the rear, but have you considered increasing your front tire size to 265/35 instead of the factory 255/35? With a slightly taller overall diameter, this would help fill out the front gap a bit to visually look more similar to the rear and will not have a drastic change on rake/handling. Probably only worth while if you are due for new front tires IMO since the change is minimal, but something to consider.
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      11-07-2019, 12:38 PM   #18
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Originally Posted by MannyM5 View Post
I know you initially asked about raising the rear, but have you considered increasing your front tire size to 265/35 instead of the factory 255/35? With a slightly taller overall diameter, this would help fill out the front gap a bit to visually look more similar to the rear and will not have a drastic change on rake/handling. Probably only worth while if you are due for new front tires IMO since the change is minimal, but something to consider.
I previously switched to 285 rear and 265 front, already. I'll just get used to the front gap being larger than the rear gap with the current setup. The car performs/handles beautifully, as is.
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      11-07-2019, 07:54 PM   #19
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Quote:
Originally Posted by Kev608 View Post
Find a friend or shop that has vehicle scales and corner balance your car. You'll notice the difference. Performance > esthetics imo.
The first thing your friend or shop will say to you is this... "I can't corner-balance your lowering springs".
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      11-09-2019, 07:03 AM   #20
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Originally Posted by Kev608 View Post
Find a friend or shop that has vehicle scales and corner balance your car. You'll notice the difference. Performance > esthetics imo.
Corner balancing is about adjusting the diagonal weight sharing, not front-to-rear...
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      11-09-2019, 11:46 AM   #21
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Quote:
Originally Posted by CanAutM3 View Post
I agree with much that is said here.

However, I fail to see how changing the front-to-rear ride height proportion affects weight distribution in a significant manner?
Changing the rake angle of the car will tilt the CG forward or backward slightly, which will shift a small amount of weight fore/aft. Quick back of the napkin calcs:

110" wheelbase for M3
20" CG height (my best guess)

Lifting the back of the car 1" will move the CG forward by 0.36", which will shift about 11lbs from the rear to the front.

So yeah, not zero, but also probably not significant in the context of a 3500lb car.
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      11-09-2019, 02:51 PM   #22
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Quote:
Originally Posted by Racer20 View Post
Changing the rake angle of the car will tilt the CG forward or backward slightly, which will shift a small amount of weight fore/aft. Quick back of the napkin calcs:

110" wheelbase for M3
20" CG height (my best guess)

Lifting the back of the car 1" will move the CG forward by 0.36", which will shift about 11lbs from the rear to the front.

So yeah, not zero, but also probably not significant in the context of a 3500lb car.
Agreed, the only effect I saw was the slight Cg forward displacement from the tilting, hence why I specified "significant". However, my napkin gives me half your number using your assumptions (0.18" forward for ~6lb or 0.3%). But I think we can agree that it is not significant .
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