BimmerWorld's 2cents on H&R spring lowering in association with our runflats.

BMW0 · 12-18-2005, 12:50 AM

http://www.bimmerworld.com/Projects/...t_hrspring.htm

Drop It!

There has been a lot of discussion centered around one claim by BMW about the new E90 3 Series - "suspension designed around run-flat tires". What does this mean? Are run-flats the only acceptable tire that can be used on this car? If you work on the suspension, are you going to destroy the delicate balance the the folks in Germany worked so hard to create? No and no!!!

That phrase seems to be very much a marketing phrase to me. Run-flats since their release have a bad connotation of "rough ride". And if they are put on a car in a back to back comparison test against a normal tire, they would feel rough. By design, the sidewalls on these tires are incredibly stiff to support the car with no air pressure.

So a little quick suspension design theory: Tires have a spring rate. Typically this spring rate is stiffer than the actual springs on the car, but still on the order of magnitude to feel its effect on handling. This is why increasing this spring rate (stiffer, less flex) with larger diameter wheels generally increases handling performance. When designing a suspension, the total spring rate is a combination of the actual springs and the additional factors (tires, etc). So when you design a suspension to be used with run-flat tires, you take the stiffer tire spring rate into account when determining car spring rate and damping. And when we modify this suspension to be stiffer and perform better, we are just getting closer to the "rough ride" that BMW engineers "designed around" because it would turn away so many luxury car owners.

In search of better performance, on with the modifications! We finally received our shipment of H&R springs with the new E90 parts on board. More importantly, we found an hour break in the race schedule to actually install a set on the project car! The H&R spring is a very quality piece. They do not sag over time and the durable powdercoat finish keeps them looking good. Install is straightforward and the car requires an alignment afterward because lowering the car changes the suspension geometry.

Initial impression - the car looks much more like a performance sedan 1.5" lower. The gaps above the tires have closed up nicely. On the initial test drive, I immediately noticed the stiffer spring rates. The struts on the car seem well-suited to handle the bigger springs and the car is very controlled - not bouncy. The sport package that this car was delivered with was already tight, but the new springs seem to have taken out some of the body roll and the car is now quicker through quick left/right transitions as well. There is no harshness added, just the confidence of even more sure footing as the car winds through the Virginia mountain roads.

http://www.bimmerworld.com/Projects/...t_hrspring.htm

H&R Sport Springs, 2006 E90 325/330 BMW, Performance street springs, 1.3" drop $259.00

D-Rock · 12-18-2005, 10:22 AM

Do you have the HR racing springs ?

tightie · 12-18-2005, 01:42 PM

race springs homiee.
drop it 2" .
look how sick mine is

AW330i · 12-18-2005, 02:10 PM

So let me get this straight the sport springs droped a 330i with sport suspension by 1.3"? Or do you subtract the drop that you get out of the sport suspension from bmw from the drop you get out of the H&R's to find the difference in ride hight?

BMW0 · 12-18-2005, 02:40 PM

Quote:

Originally Posted by paintball pete

Do you have the HR racing springs ?

Nope, just Sports Package, but in the market for some high quality springs.

BMW0 · 12-18-2005, 02:47 PM

Quote:

Originally Posted by AW330i

So let me get this straight the sport springs droped a 330i with sport suspension by 1.3"? Or do you subtract the drop that you get out of the sport suspension from bmw from the drop you get out of the H&R's to find the difference in ride hight?

Quote:

Originally Posted by BimmerWorld

...The sport package that this car was delivered with was already tight....

According to BimmerWorld this car that they installed the H&R springs has Sports Package and ultimately dropped their car 1.5", read the last paragragh. Does this answer your question AW330i?

khoda355 · 12-25-2005, 07:33 PM

i wonted to drop my baby 2 in and the parents said "its so low now dont screw the car up" so dor me i got to go threw them and bmw to get anything for it...pretty gay...but they got me the car what can i say got to have the love for them...

12-18-2005, 12:50 AM	#1
BMW0 Colonel 241 Rep 2,059 Posts Drives: AW E90 330i Join Date: Nov 2005 Location: Spokane, WA iTrader: (0) Garage List 2006 330i [0.00]	BimmerWorld's 2cents on H&R spring lowering in association with our runflats. http://www.bimmerworld.com/Projects/...t_hrspring.htm Drop It! There has been a lot of discussion centered around one claim by BMW about the new E90 3 Series - "suspension designed around run-flat tires". What does this mean? Are run-flats the only acceptable tire that can be used on this car? If you work on the suspension, are you going to destroy the delicate balance the the folks in Germany worked so hard to create? No and no!!! That phrase seems to be very much a marketing phrase to me. Run-flats since their release have a bad connotation of "rough ride". And if they are put on a car in a back to back comparison test against a normal tire, they would feel rough. By design, the sidewalls on these tires are incredibly stiff to support the car with no air pressure. So a little quick suspension design theory: Tires have a spring rate. Typically this spring rate is stiffer than the actual springs on the car, but still on the order of magnitude to feel its effect on handling. This is why increasing this spring rate (stiffer, less flex) with larger diameter wheels generally increases handling performance. When designing a suspension, the total spring rate is a combination of the actual springs and the additional factors (tires, etc). So when you design a suspension to be used with run-flat tires, you take the stiffer tire spring rate into account when determining car spring rate and damping. And when we modify this suspension to be stiffer and perform better, we are just getting closer to the "rough ride" that BMW engineers "designed around" because it would turn away so many luxury car owners. In search of better performance, on with the modifications! We finally received our shipment of H&R springs with the new E90 parts on board. More importantly, we found an hour break in the race schedule to actually install a set on the project car! The H&R spring is a very quality piece. They do not sag over time and the durable powdercoat finish keeps them looking good. Install is straightforward and the car requires an alignment afterward because lowering the car changes the suspension geometry. Initial impression - the car looks much more like a performance sedan 1.5" lower. The gaps above the tires have closed up nicely. On the initial test drive, I immediately noticed the stiffer spring rates. The struts on the car seem well-suited to handle the bigger springs and the car is very controlled - not bouncy. The sport package that this car was delivered with was already tight, but the new springs seem to have taken out some of the body roll and the car is now quicker through quick left/right transitions as well. There is no harshness added, just the confidence of even more sure footing as the car winds through the Virginia mountain roads. http://www.bimmerworld.com/Projects/...t_hrspring.htm H&R Sport Springs, 2006 E90 325/330 BMW, Performance street springs, 1.3" drop $259.00 __________________ 330i 6MT l 255 HP @ 5900 rpm 214 lb-ft Torque @ 3500 rpm l Alpine White l Beige l Aluminum l ZSP l 494 l PDC "Freude am Fahren" = "Joy to Drive"
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12-18-2005, 10:22 AM	#2
D-Rock Lieutenant Colonel 189 Rep 1,855 Posts Drives: 325i Join Date: Jul 2005 Location: miami iTrader: (2)	Do you have the HR racing springs ? __________________
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12-18-2005, 01:42 PM	#3
tightie JOSH SHOKRI. 524 Rep 5,881 Posts Drives: 991 GT3RS, 964, Raptor Join Date: Aug 2005 Location: los angeles, california. iTrader: (7) Garage List 2008 BMW M3 [7.90]	race springs homiee. drop it 2" . look how sick mine is __________________ Current: 16 991 GT3RS , 91 964 C2, 17 Raptor \| Past: 2015 991 GT3, 2015 i3,15 YMB F80 M3, 13 E92 M3 DCT, 08 E92 M3 6MT, 07 E60 M5, 02 E46 M3 Instagram: @josh_speeddistrict #SpeedDistrict @SpeedDistrict
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12-18-2005, 02:10 PM	#4
AW330i Captain 79 Rep 876 Posts Drives: Alpine White 330i Join Date: Jun 2005 Location: Houston, Tx iTrader: (0)	So let me get this straight the sport springs droped a 330i with sport suspension by 1.3"? Or do you subtract the drop that you get out of the sport suspension from bmw from the drop you get out of the H&R's to find the difference in ride hight? __________________
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12-25-2005, 07:33 PM	#7
khoda355 Captain 26 Rep 862 Posts Drives: EG hatch/ E90 Join Date: Oct 2005 Location: Bay iTrader: (2)	i wonted to drop my baby 2 in and the parents said "its so low now dont screw the car up" so dor me i got to go threw them and bmw to get anything for it...pretty gay...but they got me the car what can i say got to have the love for them...
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