Installed lowering springs and now struggling with bumps!

TJ7 · 12-24-2021, 03:51 PM

I purchased some lowering springs for my Z4 3.0i SE roadster as the stock springs were too soft for the track and the car sat a bit too high (the arch gaps were too much for a car like this). The springs are rated at 30mm, which was the only size available from 4 different manufacturers on Demon Tweeks.

The little roadster now handles a lot better and feels more responsive! However..... the front wheels are now hitting inside the arches when going over the smallest of bumps and making a lot of speed bumps unbearable.

Has anybody else had this experience or have any ideas on how to simply rectify without having to change everything again?
I've been considering replacing spring pads with some thicker ones.

P.S. I already went through the effort and cost of replacing all the shocks last year and didn't have time to consider alternative options before the first track day booked for it, hence why I haven't done coilovers.

Murf993 · 12-24-2021, 03:54 PM

This is often the problem with many after market mods.

maupineda · 12-24-2021, 04:01 PM

No surprise, lol

Our03z4 · 12-24-2021, 04:05 PM

Have you checked the control arm bushings? Sometimes that can cause it to rub on the back arches since your springs can't give as much. I blew one of my struts this year while tracking, caused my front right to hit often.

tomjonesBT33 · 12-25-2021, 11:11 AM

Quote:

Originally Posted by TJ7

I purchased some lowering springs for my Z4 3.0i SE roadster as the stock springs were too soft for the track and the car sat a bit too high (the arch gaps were too much for a car like this). The springs are rated at 30mm, which was the only size available from 4 different manufacturers on Demon Tweeks.

The little roadster now handles a lot better and feels more responsive! However..... the front wheels are now hitting inside the arches when going over the smallest of bumps and making a lot of speed bumps unbearable.

Has anybody else had this experience or have any ideas on how to simply rectify without having to change everything again?
I've been considering replacing spring pads with some thicker ones.

P.S. I already went through the effort and cost of replacing all the shocks last year and didn't have time to consider alternative options before the first track day booked for it, hence why I haven't done coilovers.

Are you running stock rims and tire widths? If not, try a narrower tire. Could also adjust camber.

ToddBlack88 · 12-25-2021, 11:28 AM

Pick up some camber shims. Cheap and effective

wdb · 12-25-2021, 03:17 PM

tl;dr version -- tell us more about your car and it's setup.

3002 tii · 12-28-2021, 10:54 AM

Quote:

Originally Posted by ToddBlack88

Pick up some camber shims. Cheap and effective

Don’t think camber shims work on non-m.

OP - you need to tell us your wheel and tire sizes along with alignment settings.

12-24-2021, 03:51 PM	#1
TJ7 Registered 0 Rep 1 Posts Drives: BMW M3(E46) & BMW Z4(E85) 3.0i Join Date: Dec 2021 Location: Surrey iTrader: (0)	Installed lowering springs and now struggling with bumps! I purchased some lowering springs for my Z4 3.0i SE roadster as the stock springs were too soft for the track and the car sat a bit too high (the arch gaps were too much for a car like this). The springs are rated at 30mm, which was the only size available from 4 different manufacturers on Demon Tweeks. The little roadster now handles a lot better and feels more responsive! However..... the front wheels are now hitting inside the arches when going over the smallest of bumps and making a lot of speed bumps unbearable. Has anybody else had this experience or have any ideas on how to simply rectify without having to change everything again? I've been considering replacing spring pads with some thicker ones. P.S. I already went through the effort and cost of replacing all the shocks last year and didn't have time to consider alternative options before the first track day booked for it, hence why I haven't done coilovers.
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12-24-2021, 03:54 PM	#2
Murf993 Major 14114 Rep 1,336 Posts Drives: Porsche 993 Join Date: Mar 2020 Location: Dog Lake, South Frontenac, Ontario Canada iTrader: (0)	This is often the problem with many after market mods.
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12-24-2021, 04:01 PM	#3
maupineda Captain 456 Rep 972 Posts Drives: E86 Z4MC Join Date: Jul 2012 Location: Detroit, MI iTrader: (3)	No surprise, lol
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12-24-2021, 04:05 PM	#4
Our03z4 Captain 1682 Rep 684 Posts Drives: 2008 BMW Z4 3.0si Coupe, Join Date: Nov 2016 Location: USA iTrader: (0)	Have you checked the control arm bushings? Sometimes that can cause it to rub on the back arches since your springs can't give as much. I blew one of my struts this year while tracking, caused my front right to hit often.
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12-25-2021, 11:28 AM	#6
ToddBlack88 Private First Class 595 Rep 145 Posts Drives: 2007 Z4MC 2010 F650GS Join Date: Jul 2019 Location: North Vancouver iTrader: (0)	Pick up some camber shims. Cheap and effective __________________ Current : 2007 Z4MC, 2010 F650gs, 2018 340i M Performance Edition, 2020 G310gs, 2009 128i Past : 2001 325 cab, 2002 325xit, 1992 325 M tech ll appearance pack cab, 1990 325is, 1988 M3, 2012 328xit, 2009 M135i cab, 2016 M235i cab,
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12-25-2021, 03:17 PM	#7
wdb dances with roads 4714 Rep 4,094 Posts Drives: '07 E86, '02 996, '95 Seven Join Date: Jul 2015 Location: the perimeter iTrader: (4)	tl;dr version -- tell us more about your car and it's setup.
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