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BMW Suspension - Street
Street Suspension Recommendations for BMWs
This page applies to all BMW car models (not SUVs).Assuming you know all of the basics of BMW suspensions (click here for our Basics page), you're now in the market for a suspension replacement or upgrade on your street-driven BMW. This page will cover BMWs that are driven on the street and never used for autocross or track use. Despite having a Championship-winning race team, BimmerWorld employees do not drive race cars to work. We have street cars just like everyone else. And what works on our winning race cars is not what we want during our commute. Below is our recommendations for buying a street suspension. Unlike other sources we're not going to run down a list of everything we sell and declare them all "great". We will actually give you our opinions based on experience and testing, just as if we were buddies.
Scenario A: I only want stock, original parts.
The BimmerWorld View: If you felt the original ride and handling was ideal but the car has become too soft, mushy, or lacks precision there are Original BMW and OEM products to restore the factory feel and performance. There is a reason why BMWs are celebrated for their handling and it earned the Ultimate Driving Machine reputation. And when new and fresh, the factory suspension is hard to fault. It's only when we have a specific complaint that we seek to upgrade. As good as the original suspension may be it was designed for a mass audience with compromises made to performance to make it appeal to a broader audience. BMWs have definitely lost some of their visceral and driver-centric sensations behind the wheel. But given how successful BMW sales have been, who are we to argue how they should feel straight from the dealer?
For recommendations we would almost always seek out the OEM replacement parts. BMW manufactures very few components themselves. Parts like shocks and bushings are made by outside suppliers like Sachs and Lemforder. These Original Equipment Manufacturers are free to sell the same products to the public, outside of the BMW dealer network. You can get the same part for a lot less money only without the BMW logo. Remember to replace worn parts in pairs or sets - both front shocks or both control arm bushings since wear and tear happens equally on both sides of the vehicle. We can also package items together for a discounted price. In some cases we may offer a lower cost alternative from a aftermarket manufacturer. Not all of these are a "you get what you pay for" experience but keep that in mind any time you're considering OEM versus aftermarket versions of the same part.
Scenario B: I wouldn't mind a little extra performance but don't want to lower it.
The BimmerWorld View: As impressive as the original suspension might be, it's engineered for a mass audience. Like tacos don't come with hot sauce already on them. If you want to add a mild spice to your car's handling but don't want the regrets there are several "OEM+" options available. Since this is the mild sauce, not even your passengers will likely complain.
Shocks - both Bilstein and KONI offer shock absorbers that are slightly firmer than original. In both cases you likely won't feel the extra stiffness because of their innovative designs. Bilstein HD and KONI Active shocks are stiffer during slow velocities (ordinary driving, cornering) but actually get softer at fast velocities (bumpy pavement). So you get a firmer ride and better handling but no punishment in ride comfort. In over twenty years we have never had someone say their HD shock was too stiff so these are an excellent mild upgrade if the original ride was a disappointment.. Both Bilstein and KONI have limited lifetime warranties as well. New mounts should be installed with every new shock.
Springs - leave them stock for the original ride height and stiffness but check them for cracks or broken pieces (very common).
Sway Bars - leave them stock. There is a handling advantage to upgrading sway bars but doing them before changing springs can actually hurt your ride comfort.
Bushings and Mounts - Meyle HD makes a firmer rubber bushing for many applications. The stiffer material improves handling, response, and precision, especially in the front end. But since it's still rubber, ride comfort and noise are nearly the same as stock. Meyle HD bushings have a four year warranty, twice as long as OEM bushings. Why didn't BMW use a stiffer material when new? They often do! But these factory bushings are usually reserved for M Sport or full M models (M2/M3/M4, etc). The Meyle HD bushings are like an M bushing but for non-M cars.
We also offer Powerflex urethane bushings. In most cases these will be stiffer than a HD bushing but still acceptable for the street (in our view). Powerflex rigorously tests the suspension as a whole to determine an optimum bushing stiffness for regular street or serious high performance. Urethane requires lubricating grease during the initial install and potentially after years of use (the bushing traps grease for extended service life). Powerflex has a lifetime warranty.
Scenario C: I want more performance but this isn't a race car.
The BimmerWorld View: Hot sauce is the way to go... Maybe we're too familiar with performance or racing suspensions but most of us prefer a street sport setup. For decades BMW enthusiasts have used these sport springs and shocks for a moderate drop in ride height and not a huge punishment in ride comfort. The greater benefits of better handling and looks is worth the tradeoff in ride comfort.
Shocks & Springs - This is a package of sport-tuned springs and matching shocks. There will be a stiffer ride that is less comfortable for some but - make no mistake - these are not race car springs. Both Bilstein and KONI use Eibach PRO-Kit springs in their packages. PRO-Kit is the happy compromise for those that want to lower the ride height a little but don't want to be scraping driveways or have a "slammed" look. H&R also makes high-quality springs that tend to be lower and stiffer than the Eibach PRO-Kit. These are great for an aggressive stance and huge reduction in bodyroll but will be tuned more for performance than even PRO-Kit springs. The Bilstein or KONI shocks are shorter and re-valved to match the new spring rate. New mounts should be installed with every new shock.
Sway Bars - After upgrading the shocks and springs, a sway bar upgrade is a wise choice. A lot of bodyroll can be tuned out with a larger sway bar, which will make the car corner flatter and better manage the weight distribution. There is very little downside to a larger sway bar and the performance gain is huge. New links should be installed with the sway bar.
Bushings and Mounts - At this stage we would really push the Powerflex street urethane mounts over any rubber, although OEM or HD rubber is certainly acceptable as well. Rubber bushings are compatible with sport shocks & springs but you're giving up some performance. Rubber has more deflection and will allow a lot more alignment variation than urethane. Urethane can be nearly as comfortable as stock rubber but the performance benefit is worth any small decrease in comfort.
Alignment - We recommend the stock alignment settings with any street suspension but when lowering with a sport spring there may increase tire wear on the inside shoulder of the tires. To correct increased camber you will need front and rear adjustable camber kits. These are a front upper mount and usually a bushing or new control arm in the rear. The adjustment allows you to reduce the negative camber and set the alignment back to factory settings.
Scenario D: I want more performance and I need to fine-tune the ride height for the best stance.
The BimmerWorld View: This is still the Hot sauce - we haven't gotten into the Fire sauce yet.
Shocks & Springs - For most people a sport shock & spring package like above is all that is necessary. But for those of you who wish to fine-tune the ride height for the perfect look and stance, a street coil over is your best option. Scenario C above uses springs with a fixed ride height. But if you have taller wheels and tires, add-on bodywork, or want a lower-than-usual ride height, the coil over is your solution. Bilstein PSS, H&R, KW Variant, and ISC Street are all sport-tuned coil over kits that offer ride height adjustment on the front and rear. These are sport suspensions designed for street use. Don't mistake them for track or race coil overs. Each varies in features from a basic shock and spring (H&R) to more complex adjustments (ISC) so you have to decide how much you want to tweak the settings. If you're a "set it and forget it" type of enthusiast, the H&R may be your top choice. The most well-rounded and widely praised is the KW Variant 3 kit. It has a robust set of features and we get excellent feedback for its smooth ride.
Sway Bars - After upgrading the shocks and springs, a sway bar upgrade is a wise choice. A lot of bodyroll can be tuned out with a larger sway bar, which will make the car corner flatter and better manage the weight distribution. There is very little downside to a larger sway bar and the performance gain is huge. New links should be installed with the sway bar.
Bushings and Mounts - At this stage we would really push the Powerflex street urethane mounts over any rubber, although OEM or HD rubber is certainly acceptable as well. Rubber bushings are compatible with sport shocks & springs but you're giving up some performance. Rubber has more deflection and will allow a lot more alignment variation than urethane. Urethane can be nearly as comfortable as stock rubber but the performance benefit is worth any small decrease in comfort.
Alignment - We recommend the stock alignment settings with any street suspension but when lowering with a sport spring there may increase tire wear on the inside shoulder of the tires. To correct increased camber you will need front and rear adjustable camber kits. These are a front upper mount and usually a bushing or new control arm in the rear. The adjustment allows you to reduce the negative camber and set the alignment back to factory settings.
Spring & Shock Package versus Coil Overs
The BimmerWorld View: Coil overs are essentially a shock and spring package with the added benefit of height adjustment and shock damper adjustment in some cases. The spring rates and shock rates are very similar and coil over manufacturers engineer them as street products. These would be poor track suspensions based on their settings and most are designed to use only the stock mounts. If you never plan to adjust ride height or make the shock stiffer/softer there is no benefit to buying a coil over. That's really the largest difference but we'll break down their differences and pick winners and losers below.
Price: Packages are typically around $700. Coil overs start at $1,000 but can easily approach $2,000. Advantage: Package.
Install: Packages are a direct 1:1 replacement for the stock OE shocks and springs and use all of the original mounts. Coil overs mainly use original mounts too and install like factory parts. But they require ride height adjustments and measurements post-install. Advantage: Package.
Handling: This is subjective without actual testing data (which we have done but won't muddy the waters with that here). Spring rates are typically close but coil overs typically have slightly stiffer springs that further reduce body roll. And most coil overs include multiple shock settings and you can set the proper ride heights and corner balance (to some extent). Advantage: Coil Over.
Ride: This is subjective and everyone has a different threshold for comfort. Since spring rates are typically very close so any advantage comes from playing with the shock settings. Coil Overs are designed together with the proper travel before bottoming-out. The Package has also been engineered to work together to some extent but you may get into the internal bump stop more often. Advantage: Coil Over.
Features: Not even close. Coil Overs are all about adjustments while Packages are static. Advantage: Coil Over.
Lifespan: Impossible to determine because it depends on where you drive. But this is worth mentioning if you live in the Rust Belt. Coil Overs have exposed threads that can easily be jammed with sand and debris. Locked up height adjusters is a real problem that Packages will never experience. Advantage: Package.
Coil Overs eek out a win but only from their expanded features and most brands have damper adjustments to fine-tune the handling and/or comfort. There are multiple coil over formulas from soft to near-track specs so you have to dig further to make the right decision. The package is geared exclusively for street so if ride height doesn't need to be fiddled with, these may be your best bet. Don't let the coil over features minimize the legitimacy and performance of the traditional Package. On performance alone the Coil Over wins. But if you want most of the performance for 1/2 or 1/3 the cost the Package won't disappoint.
Bump Stop
The bump stop is otherwise known as a "Additional Shock Absorber", "bump rubber", or "Micro Cellular Jounce Bumper" and it plays a more crucial role in your suspension than most people realize. Every shock absorber includes a bump stop and there's a reason why: they are just as important in suspension tuning and ride comfort as the coil spring. The bump stop is made of foam or rubber and acts within the suspension as a low-tech spring. Using the bump stop is not necessarily a bad thing and can be misunderstood. Some cars are designed for the bump stop to play an active role in suspension tuning and will act as a secondary spring. This allows the manufacturer to use a softer main coil spring for a nicer ride. There are usually two or three variations of Bump Stops for a particular BMW model and they are matched to the length and travel of the shock absorber. Shorter and stiffer Bump Stops are often found on Sport and M Sport models and these are also recommended for any aftermarket lowered suspension.
Besides handling, the Bump Stop also protects the shock internals from major damage during bottoming-out. It acts as a cushion so that metal-on-metal contact is avoided. You should never be reaching that point in the shock travel, but if you are please call us so we can discuss your suspension needs. BMW requires a new bump stop any time the shock or spring is changed. Most Bilstein or KONI performance shocks will include one, especially if the shock is inverted to be upside down (Bilstein HD and Sport). But stock or "OEM" versions of shocks will usually not include bump stops. They are cheap and easy to install during the job so don't overlook them.
Wheels & Tires
We would be remiss if we didn't mention the contribution of wheels and tires as a performance upgrade. A better tire will probably contribute more to performance gain than any shock, spring, sway bar, or bushing. If you upgrade the suspension but leave the all-season tires, you just wiped out half of the benefits. Conversely, if you upgrade the tires but leave the stock suspension you will quickly feel its deficiencies. Your plan should include upgrading everything even if you don't do it all at once.
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