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Improving the 2011-2016 Cruze Handling and Suspension
Intro
This post is being created to be a living document that I will be updating over time as options increase for ways to improve the handling of the Chevy Cruze. This post will contain information for new Cruze owners who want to hit the ground running and improve how their car handles. It is not intended to be extremely technical. If you have any input to make on the already existing sections, please comment on this thread and I'll add the information.
Anti-Roll
Anti-roll bars, also anti-sway bars, are designed to reduce the side-to-side leaning of the car during cornering. The Cruze has one in the front from the factory and it's actually tuned pretty well. In addition, the factory already uses polyurethane sway bar bushings on the subframe. There are two known upgrades available:
Anti-roll bar end links. The factory end links are plastic, and they flex. Many aftermarket options (particularly Moog) are solid metal. Upgrading to solid medal end links not only allows you to grease them for longer life, but also noticeably reduces body roll as they no longer flex. You can pick these up fairly cheap for about $18 each on Amazon. It's a cheap, simple modification that everyone should do to their Cruze.
Rear anti-roll bar. The rear of the Cruze does not have an anti-roll bar, which is done for comfort as well as to ensure that your vehicle understeers rather than oversteers. This is dollar for dollar the best handling mod you can make on your vehicle, and will balance out some of the understeer that these cars are known for. BadNewsRacing.net sells one for the Cruzes with a build date of on or after 11/11: Whiteline Rear Cruze Sway Bar
Chassis Reinforcement
One of the more affordable (and arguably one of the first) ways to improve handling is to reinforce the chassis. When turning, going over bumps, and maneuvering your vehicle, the suspension compresses. During this compression, the strut towers have a tendency to "bend" inward as there is no support between them to keep them equidistant. This transfers more energy into the cabin during suspension compression and therefore makes the vehicle less stable. While turning, the chassis also twists, which causes the vehicle to have a sensation of delay when making quick turning maneuvers. If you ever change lanes on the highway quickly, you'll notice the vehicle feels as though the front turns and the rear follows and settles afterward.
The easiest and quickest way to reinforce chassis is through the use of strut tower bars. These bars connect the towers where the top of your struts or shocks connect and provide additional rigidity. The first thing you'll notice after installing the front and rear strut tower bars is steering responsiveness is greatly improved, and the vehicle simply responds more as a solid chassis instead of two parts that twist and flex independently of each other. In addition, a stiffer chassis allows the suspension to more effectively absorb road anomalies, which transfers less energy into the cabin and improves not only stability, but also ride comfort.
For our cars, Ultra Racing makes the following chassis reinforcement bars:
:: Fender braces
:: Front lower bar
:: Front strut bar
:: Middle lower bar
:: Rear member brace
:: Rear lower bar
:: Rear strut bar
:: Rear torsion bar
If you only do one of these, get the front strut bar. The two strut bars can be ordered from the Bad News Racing website, but the rest can also be custom ordered through Bad News Racing as well.
Shocks (also Shock Absorbers, Struts)
The front of this car uses a MacPherson strut, and the rear use basic shocks. The OEM shocks lose their ability to dampen large road anomalies after about 50,000 miles, where excessive reliance on the jounce bumper begins and the frequency of suspension crash-throughs increases. A "crash-through" is a total compression of the suspension, sometimes referred to as "bottoming out." Most people don't notice this as much since the chassis is not particularly stiff from the factory, and the jounce bumper more gracefully transfers energy between the suspension and the body, which then flexes to absorb some of it. It is recommended that you replace OEM shocks at approximately 50,000-60,000 miles depending on driving conditions and driving habits.
Many people have insisted that their shocks work just fine even after 100,000 miles. I would recommend that you visit your dealer and test drive a low-mile Cruze to see the difference in how the suspension behaves. The primary purpose of the shocks is to control the rate of suspension compression. Over time, the shock becomes "softer," and while it still performs its purpose to the extent that your vehicle may not "float" on the highway like some cars with completely worn shocks would, that doesn't mean your shocks have retained their optimal effectiveness.
Stock Replacements: In the past, I've had very good results with KYB shocks. They are inexpensive, reliable, and generally perform better than OEM shocks. Monroe also makes shocks for this vehicle.
Upgrades (stock): For stock springs, Bilstein makes a B6 HD kit for this vehicle, which are available on the BNR Website: Bilstein B6 HD Shocks.
Upgrades (lowered): For lowered springs like HHR or Eibach, Bilstein makes a B8 shock for this vehicle, which are available on the BNR Website: Bilstein B8 Sport Shocks. These shocks are stiffer than stock and are specifically designed to be paired with lowered springs.
The Bilstein shocks are a bit stiffer than stock but still offer reasonable ride comfort. A stiffer shock will reduce pitch and squat during braking and acceleration, and will also reduce body roll during sudden maneuvers. Furthermore, it will make your vehicle significantly more stable on the highway at higher speeds. The Bilstein B8 kit is very strongly recommended if you plan on using lowering springs. For the sake of handling, do not simply install lowering springs on OEM shocks.
For a detailed overview of Bilstein's shock lineup, click here: Understanding BILSTEIN's Product Line
Springs
Springs are a point of contention for me, as I don't necessarily agree with some of compromises made to suspension geometry when a vehicle is lowered (dynamic camber, for instance). For street purposes, the OEM ride height on OE/RS springs is ideal, but I understand that some people place a great deal of value on center of gravity.
OEM: For the most mild lowering, you can simply pull springs off of another Cruze with the Eco or RS package. Be sure the transmission matches the vehicle you are pulling the springs off. The Eco/RS springs are 10mm lower than other Cruzes are.
Lowered Springs: Actual lowering distance will depend on your starting point, transmission, and trim. Weight of the Cruze can very by as much as 250 pounds from one model to another, excluding the Eco Diesel that weighs even more. The following options are available:
:: H&R (1.8L ONLY): Approximately 1.5-2.0" drop. This kit will actually raise a 1.4L turbo due to the weight difference.
:: Eibach (1.4L): Approximately 1.2" drop.
Lowering Spring/Strut Kits: Bilstein makes a B12 kit, which includes their yellow HD shock and a set of lowering springs. This is, in my opinion, the best performance combination of springs and shocks for someone who wants a mild lowering kit.
Coilover Kits: A coilover kit is essentially a kit that includes springs, shocks (usually adjustable), mounts, and any other hardware required to install. Some kits include shorter anti-roll bar end links, and some require you to purchase them separately. These adjustments are performed by turning a nut that serves as a spring perch that sits over a threaded sleeve that is attached to the body of the shock. These kits can vary wildly in quality, performance, reliability, and shock/mount longevity. Coilovers are very popular since they often include adjustable shocks and allow people to drop their car farther than lowering springs can. Since the shock absorber is often adjustable, you will need to know how to adjust them to suit your ride height and driving environment. I will not attempt to grade these by quality, construction, or performance, and will simply list the option so you can decide for yourself.
:: BC Racing BR Kit
:: Bilstein B14 Kit
:: D2 Racing RS Kit
:: DGR Kit
:: CXRacing Coilover Kit
:: ISC Suspension N1 Basic Coilover Kit
:: KSport Kontrol Pro Kit
:: KSport Kontrol Plus
:: KW Speedtech Coilover Kit
:: Pedders XA
:: XYZ Super Sport Kit
For more details on these kits, check out the Ultimate Cruze Coilover Thread. Check out the options available on the Bad News Racing website.
Note: One drawback with coilovers is that the sleeves and nuts are constantly exposed to dirt and even road salt in colder regions. This can cause the adjustment nuts to seize. A good product to keep your coilovers in good shape is to seasonally coat them with AMSOIL MPHD; a heavy duty metal protector.
Tires
This one is going to be a bit open ended, and I won't make many recommendations, but be aware that the tires fitted on this car from the OEM were not done so for performance purposes. They are a compromise between ride quality, cost, tread life, winter performance, noise, and fuel economy. Tires with exceptional fuel economy will be light with a low rolling resistance, but will often have soft sidewalls that flex considerably while cornering and will have very compromised traction. High performance summer tires can weigh more (see unsprung weight), have a lower treadwear rating, and be almost dangerous in snow/ice conditions.
When choosing a replacement tire for handling purposes, check the reviews and find a tire that meets your needs for your driving conditions. In my case, I replaced my Goodyear Assurance FuelMax 215/55/17 tires with Bridgestone Turanza Serenity Plus 235/50/17 tires; two sizes wider at the same diameter. The tires ended up increasing my unsprung weight by 9 pounds due to an exceptionally deep 12/30" of tread, which was noticeable. However, my goal was to improve handling in wet conditions as I occasionally tow a boat with my trailer, and I didn't want to have issues pulling the boat out of the bay on a busy day with a soaked ramp. These tires had a much firmer sidewall and vastly improved traction in wet and dry conditions while still being within the tire width that a 7" wide wheel can accommodate.
At the end of the day, a tire can make or break your driving experience.
Unsprung Weight
The concept of unsprung weight refers to the weight of a vehicle's component that is not suspended by the vehicle's springs. Reducing unsprung weight allows the shock absorbers to function more effectively and allows you to maintain better traction and ride comfort over road anomalies. When a wheel hits a bump on the road, its natural tendency is to compress the suspension. The purpose of the shock is to limit the rate of suspension compression. Greater unsprung weight compress the suspension farther as it carries more momentum, which will also translate into more force applied on the cabin of the vehicle (causing instability) and less force on the road.
Tire Weight: The OE Goodyear FuelMax tires on my Cruze Eco were an exceptionally light 19 pounds per in 215/55/17, but that is highly unusual. My replacements, Bridgestone Turanza Serenity Plus, in 235/50/17 were 28 pounds per. Other options in the same size were available at 2-3 pounds lighter, and tires in the OE size were 1-2 pounds lighter still. An increase in tire weight increases unsprung weight. Be mindful of the weight of the tire you are upgrading to.
Wheel Weight: It may surprise you to learn that one of the best wheel options for this vehicle is the OEM Eco wheel. The Eco wheels are forged and polished aluminum and as a result, are extremely light. The 2LT wheels, also 17" in diameter, weigh a staggering 5.2 pounds more each. That is a very significant increase in unsprung weight. If you're looking for a better handling wheel, the Eco wheels are worth strong consideration; you aren't going to find a cheaper forged wheel for less.
For other aftermarket wheels, be sure to check the per-wheel weight and compare to the OEM wheels listed here: http://www.cruzetalk.com/forum/12-g...suspension/47993-cruze-oem-wheel-options.html. The wider and bigger you go, the more unsprung weight you add. Within a certain budget, you'll have a compromise between wheel weight and sidewall height. While a smaller sidewall will reduce sidewall flex and therefore improve cornering stability, it will also increase unsprung weight.
