Read Before Posting: Lowering FAQs

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cobalt123

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Q.When lowering you GM what are the things you should know and expect after doing this mod
A. The stock ride will be altered (bumpyness,harshness) depending on how low the drop and how high the spring rates. You may have to go over some bumps and inclines at an angle depending on drop and angle of inclines (steep driveways,etc). Your car will handle better and look better!!!<---------main purpose of this mod. If going any lower than 1.3-1.5in get a camber kit (soon available) to correct neg camber in rear. Over time negitive camber can cause excessive tire wear on the inside of the tire. Stock shocks will be fine, upgrade shocks within a few years tho. Springs do give better handling but your car isnt an elise (dont get to cocky).
-

-Is there any maintenance needed after installation?
-replace shocks with performance shocks within a few years

-Will there be squeaking?
-not if done right-

Will it invalidate the warranty?
not your entire warranty, but if you should have a defective stock suspension part, they might not cover it under warranty, and blame it on springs

-Will passenger and added weight in the car affect the lowering springs and will there be tire rubbing?
- this answer is all relative to drop, spring rate, how much weight (5people 300lbs each+cargo,oh yeah theres more rubbing than just the tires)

Q. Will lowering spring affect up sized wheels in any-way such as 18"s before purchasing wheels or after?
A. Stock 17s are 50 series if you go to an 18 and get a 40 series ,the overall diameter will be exactly the same on 18s as 17s

Q. Do you need an immediate alignment after the spring are installed?
A. Not immediately but the sooner the better.

Q. Is there accelerated wear on any other parts after installing the springs?
A. Shocks, tires(simply because you will most likely drive more aggressively)

Q. Whats the difference between progressive and linear springs?
A. A linear rate spring means that the spring rate is constant throughout it's compression. A progressive spring means the spring rate changes (increasing) the more it is compressed.

Q. Is there any technical information you should know about springs before purchasing to help you make a better decision on what you really want for your car and what you don't want?

A. Yes you can look at the drop, 1.3 in is mild (eiabach prokit, progress) and 2.0 in is very low+aggressive( tiens,eibach sportline) other than that there is but you might have to be an engineer to really understand, general rule go with well known brands (tien,eibach,progress) avoid no name brands/cheaper brands.

Q. Is there disadvantage of having lowering springs on you car?
A. Really steep inclines,snow (if applicable, not me cali baby), Hot chicks swarming you, it gets rid of that beutiful wheel gap.


Q. When it comes to linear and progressive springs is there any advantage or dis-advantage between the two?

A. Quite frankly it really depends on your application generally most lowering springs are progressive since they have different spring rates based apon load which aids in streetablitiy simply because the spring rate isnt that high(stiff) while your cruising down the street but when your slicing up that chicane the load on the spring is increased therefore increasing the spring rate and providing a stiffer spring to negotiate the turn. Think of progressive rate springs as having two settings "normal and sport". Since linear only have "one setting" (in my opinion)its a compromise because softer spring rate=less ride degredation,less performance and the siffer spring rate=more ride degredation,more performance. Heres an example of the difference along with some numbers to compare( lets all thank AUTOXER for these rates he obtained from eibach). FYI spring rate is measured in Lbs/in2 (lbs per sq in)


Eibach spring rates
Pro-Kit
(Linear, single rate)
Front = 160#
Rear = 171#

SportLine
(Progressive, Dual rate)
Front = 97# / 280#
Rear = 114# / 303#


Q. When it comes to spring rates (I guess this means stiffness) is there a sweet spot to get (especially for are Mazda 3's) were it's not overly harsh, and also is there an example numerically (a stiffness measurement) as what is very stiff and whats not so stiff?

A. These large companies spend many hours testing thier products to find that "sweet spot"(the best compromise,model specific of course). Then your next question will be "then why are they all different" well son every body has thier own idea of where that sweet spot is, I know ive used this a couple times already but its all personal preference. you may think the prokit is the best compromise of ride and handing where I think it is way tooo soft. The best handing suspension setup might be too stiff for the street only good for track. Thats why racing teams spend at least a day dialing in thier suspension before the race because all road/track conditions are different and call for different settings to find the sweet spot for the type of corners,avg speed, etc. Oh yeah (stiffness measurement)Lbs per square inch just incase you wernt reading my last paragraph. You can find all the spring rates and compare stiffness Lower number=softer , higher number=stiffer

Whew Im tired now!!! I hope this makes sense to you and I hope it helps.


From an expert:
The following is one of my previous posts:

"...Since ride stiffness is always being described by people using subjective words, it is very difficult to gauge how stiff is too stiff. For engineering type people like myself, we usually talk numbers. The proper way to rate ride stiffness is by using suspension frequency. The measurement is expressed in “cycles per second” (or Hz). The higher the frequency, the stiffer the ride. The higher the frequency, the lower the oscillation amplitude, as in less vertical chassis movement (hence higher transient response which gives the driver that sporty feel). The following list is typical values for different types of cars. To understand where I am coming from, I have driven cars with known suspension frequency values over the years and thus can relate to what a particular set of springs would fall in within this range.

Typical production cars (like Mazda3) - 1.0 to 1.3 Hz.
Typical sports car (Corvettes, Porsches) - 1.5 to 2.0 Hz.
Competitive street-driven autox cars - 1.8 to 2.5 Hz.
Most race cars - 2 to 3 Hz.
Race cars with aero downforce - 3 to 4+ Hz.
Max. tolerable for a street driven car (IMHO) - 2.5 Hz

Most Prokit cars - around 1.5 Hz.
Canuck Motorsport springs (Mazda3) - around 1.8 Hz.


Hope these values give you guys a better sense of where we are operating...."

Very seldom would you find off-the-shelve lowering springs going over 2 Hz. Manufacturers would worry about not selling enough of them since most general public would find the ride too stiff. Same reason why car maufacturers would seldom make their high-performance sports cars ride stiffer than 2 Hz (except my recent drive in a Porsche 996 GT3, which I would say it's somewhere between mid-2 to high-2 Hz, it's that stiff). To go over 2 Hz, you will most likely need to get coil-over units and put in much higher spring rates yourself.
 
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