Recommended Height For BMW M Performance Suspension (HAS)

bringbacklsb · 03-06-2018, 11:13 PM

What factors determined BMW's "recommended" height for the HAS, and what downsides are there (other than greater risk of scraping the front end) to lowering the car at the max HAS level? Are the handling and suspension unbalanced when doing so?

MicaCeli · 03-07-2018, 01:05 PM

Most likely shock travel/ tire clearance.

spr · 03-09-2018, 02:12 AM

No, its the performance of the struts and coding. I put them all the way down and they rode like shit. I have them at min front measurement at 625mm all around which is gts street front and it's awesome.

bringbacklsb · 03-09-2018, 02:17 AM

Quote:

Originally Posted by spr

No, its the performance of the struts and coding. I out them all the way down and they rode like shit. I have them at min front measurement at 625mm all around which is gts street front and it's awesome.

So the awesome ride is higher than the BMW recommend drop?

SanchoDivine · 03-09-2018, 11:20 AM

Quote:

Originally Posted by spr

No, its the performance of the struts and coding. I put them all the way down and they rode like shit. I have them at min front measurement at 625mm all around which is gts street front and it's awesome.

I have had my car full drop front and almost full drop rear and the ride has been great.

karbonM3 · 03-12-2018, 11:52 AM

what is the actually recommended height?

spr · 03-12-2018, 05:28 PM

Recommended height for 20s is 633/626mm or 24 7/8 / 24 5/8" from bottom of rim to fender.

Minimum is 350/325mm from center of rim to fender or with 20s 24.5/ 23.5" from bottom of rim to fender.

GTS street height is 24.5/ 24 13/16" from bottom of rim to fender. This is why I did 24.5" f/r. Going below 24.5" rode like shit and was clearly under damped no doubt it will eat the shocks going below min range. I've experienced this before with pss9s.

Brasko · 03-17-2018, 08:44 PM

Quote:

Originally Posted by spr

Recommended height for 20s is 633/626mm or 24 7/8 / 24 5/8" from bottom of rim to fender.

Minimum is 350/325mm from center of rim to fender or with 20s 24.5/ 23.5" from bottom of rim to fender.

GTS street height is 24.5/ 24 13/16" from bottom of rim to fender. This is why I did 24.5" f/r. Going below 24.5" rode like shit and was clearly under damped no doubt it will eat the shocks going below min range. I've experienced this before with pss9s.

What do you mean by bottom of rim? I'm not sure I follow. You don't happen to have pic illustrating this, do you?

x.shell · 03-17-2018, 09:49 PM

Quote:

Originally Posted by Brasko

Quote:

Originally Posted by spr

Recommended height for 20s is 633/626mm or 24 7/8 / 24 5/8" from bottom of rim to fender.

Minimum is 350/325mm from center of rim to fender or with 20s 24.5/ 23.5" from bottom of rim to fender.

GTS street height is 24.5/ 24 13/16" from bottom of rim to fender. This is why I did 24.5" f/r. Going below 24.5" rode like shit and was clearly under damped no doubt it will eat the shocks going below min range. I've experienced this before with pss9s.

What do you mean by bottom of rim? I'm not sure I follow. You don't happen to have pic illustrating this, do you?

Because different tires have different sidewall height. Measuring from the bottom of the rim to the fender ensures a consistent way of measuring ride height across all rims of the same diameter.

This doesn't work on different diameter wheels though. That's why I prefer measuring from the center of the wheel to the fender.

Brasko · 03-18-2018, 10:04 AM

Quote:

Originally Posted by exo-shell

Because different tires have different sidewall height. Measuring from the bottom of the rim to the fender ensures a consistent way of measuring ride height across all rims of the same diameter.

This doesn't work on different diameter wheels though. That's why I prefer measuring from the center of the wheel to the fender.

Thank you for the explanation! Much appreciated! I was wondering about the consistency with using that method. Measuring from the center seems like a much better approach.

SanchoDivine · 03-19-2018, 11:12 PM

Quote:

Originally Posted by bringbacklsb

What factors determined BMW's "recommended" height for the HAS, and what downsides are there (other than greater risk of scraping the front end) to lowering the car at the max HAS level? Are the handling and suspension unbalanced when doing so?

My guess is wheel well clearance plays a part in that recommendation. The kit can be adjusted outside of the "recommended heights" but they did not design the kit to be able to be set in a manner that would damage the car (look how conservative the front max drop is). If you go lower than the recommended height, there is a chance that your wheel can rub the wheel well during turning especially if there is a bump, and even more likely if you have wider tires than OEM. This can rub a hole into the wheel well which also protects one of the radiators from debris.

spr · 04-16-2018, 04:01 PM

If you look at the BMW instructions, all of the measurements are from the bottom of the rim to the fender.

Quote:

Originally Posted by Brasko

What do you mean by bottom of rim? I'm not sure I follow. You don't happen to have pic illustrating this, do you?

spr · 04-16-2018, 04:02 PM

This is exactly right. That's why the BMW instructions given different recommended heights for the different size rims. If you do the math they're the same just take up the difference from rim size. I did the math for you on 20s.

Quote:

Originally Posted by exo-shell

Because different tires have different sidewall height. Measuring from the bottom of the rim to the fender ensures a consistent way of measuring ride height across all rims of the same diameter.

This doesn't work on different diameter wheels though. That's why I prefer measuring from the center of the wheel to the fender.

03-06-2018, 11:13 PM	#1
bringbacklsb First Lieutenant 215 Rep 398 Posts Drives: 2016 LSB M3 (F80) Join Date: May 2014 Location: Lancaster PA iTrader: (0)	Recommended Height For BMW M Performance Suspension (HAS) What factors determined BMW's "recommended" height for the HAS, and what downsides are there (other than greater risk of scraping the front end) to lowering the car at the max HAS level? Are the handling and suspension unbalanced when doing so? __________________ 2018 Atlantis Metallic M3, Manual, 854 miles! - SOLD! http://f80.bimmerpost.com/forums/sho....php?t=1510201
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03-07-2018, 01:05 PM	#2
MicaCeli First Lieutenant 186 Rep 339 Posts Drives: 07 e90 335i Join Date: Jul 2010 Location: Ellicott City, MD iTrader: (0) Garage List 2000 996 C4 [0.00] 2007 335i [0.00] 2001 B5 S4 Avant [0.00]	Most likely shock travel/ tire clearance.
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03-09-2018, 02:12 AM	#3
spr Major 93 Rep 1,089 Posts Drives: F80 M3; e92 ESS650+ M3 Join Date: Nov 2008 Location: San Diego iTrader: (1)	No, its the performance of the struts and coding. I put them all the way down and they rode like shit. I have them at min front measurement at 625mm all around which is gts street front and it's awesome.
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03-12-2018, 11:52 AM	#6
karbonM3 Private First Class 30 Rep 154 Posts Drives: '18 F80 ZCP Join Date: Jul 2017 Location: Jacksonville, FL iTrader: (0)	what is the actually recommended height? __________________ IG: @karbonM3
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03-12-2018, 05:28 PM	#7
spr Major 93 Rep 1,089 Posts Drives: F80 M3; e92 ESS650+ M3 Join Date: Nov 2008 Location: San Diego iTrader: (1)	Recommended height for 20s is 633/626mm or 24 7/8 / 24 5/8" from bottom of rim to fender. Minimum is 350/325mm from center of rim to fender or with 20s 24.5/ 23.5" from bottom of rim to fender. GTS street height is 24.5/ 24 13/16" from bottom of rim to fender. This is why I did 24.5" f/r. Going below 24.5" rode like shit and was clearly under damped no doubt it will eat the shocks going below min range. I've experienced this before with pss9s.
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