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Discussion Starter · #1 · (Edited)
I've had the opportunity to put about 100 miles on the Bilstein B6 HD shocks that I purchased for my 2012 Cruze Eco MT6, and feel that I can give a good review. For those who are unfamiliar with these, Bilstein has three shock replacement options for the Cruze; the Bilstein B4 (OE Replacements), Bilstein B6 HD (a heavy duty shock), and the Bilstein B8 (a heavy duty shock designed to be used with lowering springs). Since I have no desire to reduce my ride height with the roads we have around here but did want to upgrade, I went with the Bilstein B6 HD.


Introduction

The reason I began looking for a replacement set of shocks is that I began to notice a degradation in vehicle stability and comfort. When driving over a highway overpass, for example, I'd hit uneven pavement that sometimes had lane-wide gaps or bumps, and the suspension in the front would bottom out. Most people might not notice what I did, but when the shocks crash through the jounce bumpers, you can definitely notice it happening. On a particular road I always travel to buy car parts, there's a railroad track which everyone slows down on. In the Cruze, I would bottom out the front suspension very noticeably at the posted 35mph speed limit. It was unnerving. Furthermore, when turning over uneven pavement, the vehicle would rock left and right a bit, but overshoot the simple uneven pavement in an attempt to stabilize itself. Braking exhibited more nose dive than usual as well.

This could be written off as worn shocks, and some of it undoubtedly is. I have 66k miles on the vehicle now, with about 50k miles on the actual shocks (they were replaced by GM under warranty due to noise early on), but my shocks at 50k miles did not exhibit any of the typical symptoms that "completely worn" shocks do. It is generally stable on the highway (doesn't "float,"), and rides comfortably.


The Visual Difference
An immediate difference can be seen visually in the shocks. The Bilstein shock is longer, and contains a built-in jounce bumper in the shock itself, so you need to remove yours when installing. This does not affect ride height. The strut shaft is MUCH larger in diameter.



The rears were not as big of a difference, measuring a shaft diameter of 12mm stock and 14mm on the Bilsteins, but it is still an increase nonetheless.



Aside from the obvious visual differences, the vehicle maintained the same front ride height, but gained about 1/2" of ride height in the rear. I've read about this happening with other cars, as this is a pressurized gas shock. Since I have a sound system in the trunk, I don't mind the increase at all and expect it to settle a little over time.


The Driving Difference
The initial driving experience was nothing short of remarkable. I had read other reviews people posted of these shocks on other vehicles where the vehicle was described as "taut," and I think that term defines the change quite accurately. The vehicle simply feels more composed, more controlled, more predictable, and more stable.

I have a couple of places where I bottom out the suspension on a regular basis. The first is the railroad tracks mentioned above, and the second is a transition between two surfaces going over a highway overpass. First thing I did once I installed these is go out for a drive on those same surfaces. The highway transition was such a big difference that I didn't even notice it. When I approached the railroad tracks, I felt a little crazy since everyone was slowing down to 25mph in the 35mph zone, and I was accelerating to 40mph. Went over the railroad tracks and barely felt it. The car didn't have the usual nosedive, slam on the jounce bumpers, bounce back up, and level off again. It just kind of rolled over the uneven pavement as if I was driving on a cloud.

This all came as a surprise because on lighter irregularities in the road, the suspension now feels more sporty. Instead of calling it stiff, I'd refer back to the "taut" reference. While you certainly feel more of the road with these shocks than with OE shocks, you feel less of that road on large anomalies, and even the small road anomalies aren't what I'd call "stiff." On the highway, your bead isn't bouncing back and forth as if the suspension was welded; it simply follows the road more securely as if there was some magnetic force pulling the car to the road. That is, until you hit a big hole or bump in the ground and the car just gracefully absorbs it without making you cringe.

I was very deliberate in not wanting to lower the car. I like how cars feel more planted due to the reduction in body sway, but don't like the harshness you get with the reduction in suspension travel. I feel that with these shocks, I got every bit of sporty handling one would out of lowering springs, but without all the harshness.

On a scientific level, the purpose of the shocks is to control suspension travel; the purpose of the springs is to suspend your vehicle's weight. These shocks more strongly limit suspension travel, so you feel more of the small bumps on the road instead of the suspension absorbing them, but in return, the suspension doesn't bottom out and make you wish you'd have slammed on the brakes earlier when going over much larger bumps in the road. The result is almost an oxymoron; sporty, but comfortable; taut. I felt like I was driving a tuned European car.

On braking, I had 1/3 the amount of nose dive I used to, and it was much more gradual than before. While making quick turning maneuvers, there was less body sway, and the vehicle responded to drive input more quickly and more accurately. Going over uneven pavement while turning, when my Cruze used to rock left and right trying to settle back to a resting position, the shocks kept the vehicle riding level and stable. All in all, the vehicle feels much more confident.

I'll admit, this is the first time I've owned a vehicle that had a truly good set of shocks, so it was a bit of a revelation for me, but I can wholeheardly give this upgrade a solid recommendation for anyone looking to improve the ride comfort of their vehicle without turning it into a land yacht, and improve the handling of their vehicle without clenching their buttocks whenever they see a large bump or pothole in the road.


Conclusion
The Bilstein B6 HD shocks are an all-around solid upgrade for the Gen1 Chevy Cruze and will be my go-to replacement shock for any vehicle I own in the future. For those of you with lowered springs, look into the B8 shocks.

Both the Bilstein B6 HD and the Bilstein B8 shocks are available from order from the BNR Website:

B6 HD: Bilstein B6 HD Shocks
B8 Sport: Bilstein B8 Sport Shocks
 

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Discussion Starter · #3 ·
How much do they cost...?
I can't disclose the price I paid for them, but as soon as they show up on the BNR website, I'll be able to let you know. Expect somewhere in the range of $600 for all 4, give or take.
 

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Discussion Starter · #5 ·
Nicely done Xtreme. Your usual high quality work.

In the early 1990s GM started offering Bilsteins as optional on the already hot 9C1 police pursuit vehicles. As I recall they were a $200 option at the time.

My 1999 Tahoe PPV came with Bilsteins as stock. I remember talking to an engineer at Bilstein at that time, and they made three shocks for GM to place on the GMT400s all with different jounce and rebound numbers.

Did you by any chance obtain similar numbers for the B4, B6 and B8 models?

Would you know of the other applications that Bilstein recommends the B4, B6 and B8 for?

Do you have the Z-link rear suspension?
Thank you.

I don't have the numbers for the B4, but the numbers for the B6 HD (there is no B6 Comfort for the Cruze) and the B8 are:


B6 (HD)
OEM Replacement:
Front Left: 35-171669
Front Right: 35-171676
Rear: 24-171687


B8(Sport)
For Lowering Springs:
Front Left: 35-171690
Front Right: 35-171706
Rear: 24-171717

Courtesy of Cass23VSU4: http://www.cruzetalk.com/forum/12-g...kes-nice-quality-replacement-shock-strut.html

B4 is an OEM replacement shock similar to what you'd get in a KYB Excel-G, for example. B6 HD is a sporty OEM upgrade for stock ride height vehicles. B8 is for vehicles with lowered suspension.

I do not have Z-link rear. I contemplated adding it but it would require a new axle, and there aren't enough of these cars in junkyards for me to run out and pull an axle off of one.
 

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Discussion Starter · #9 ·
How are you finding the Bilsteins after a couple of weeks of commuting?
I work from home full time, but they've been excellent. I have about 200 miles on them since I installed them 2 weeks ago and the ride hasn't changed. I still have a bit more ride height in the rear than before, which is great since I have a sound system that weighed the rear down a little. Either that, or I lost a bit of ride height on the front. No complaints either way.
 

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Discussion Starter · #13 ·
Hello! I'm quite excited that you posted this thread only a few weeks ago, as I've been researching struts/shocks to replace on my 2012 LT 130K miles.

Question: If I get the B4s, do I need to find corresponding Strut Mounts from Billstein? Or I can throw on some from Monroe, etc.. I cannot find Strut Mounts from Billstein, and I imagine if I do, they might be a tad overpriced.

Thoughts?

I'll report back how I feel about the B4s.
The B4 shocks will feel just like stock; there should be no difference aside from the difference between your worn shocks and new OEM-like shocks. I'd recommend moving up to the B6 HD.

You can use any strut mounts with the shocks; OEM, Monroe, KYB.
 

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Discussion Starter · #20 ·
What was the reasoning for the new shock mounts? I have yet to install mine and previous experience with shocks was buy shock and reuse metal mounts as they really did not wear out. Is there something I need to look at to determine whether or not I should buy? Do you have a part # as well.

2nd Question - did you use any Camber bolts? I purchased a set of Eibach bolts with my struts and wanted to know if they are needed or not.
The fronts needed to be done as they were worn. The rears, I replaced just to make sure. They weren't bad, but I didn't want to find out they were bad in 10k miles and have to pull the shocks off again. Not that it's difficult on the rear.

I bought the mounts from rockauto, KYB for the rear ands Monroe for the front

I did not use camber bolts and don't believe they are necessary on stock springs.


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Discussion Starter · #27 ·
The shop used the wrong nut. The nut that goes on top of the first strut plate is much thinner than the one I see under there. I managed to dig up a picture of the nut you're supposed to be using. The nut pointed in the picture is much thinner than the one I'm seeing on your strut.

 

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Discussion Starter · #30 ·
Thanks Extreme,
They used the lock nut that came with Bilsteine's. I still have the flat nuts. I suppose the springs have to be compressed if I remove the lock nut to install the flat one while strut is in the car and can that be done without removing the hole strut?
Thank you for your help.
Yeah, the locknuts go on the top plate. The flat nuts go on the bottom plate. Springs do have to be compressed to replace that nut. Removing the whole strut is just two more bolts, so I'd just remove it.

The tough part is getting that nut tightened and the old one off. I'm not proud of my method, but it seems to have worked. Ideally, you want a special tool for that purpose (a strut nut tool). I ended up being able to sort of wedge a 15/16" wrench in there to get the original one off, and used a 15/16" socket with vice grips tightened around it to put it back on. A proper 24mm strut rod nut socket runs $50...
 

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Discussion Starter · #32 ·
Done.

To add to my review, I was very happy to see how these performed when I was towing my boat. I have a 14' Aluminum boat that weighs about 900 pounds boat + trailer. Since last year, I've added these shocks, a rear sway bar, front and rear upper strut tower bars, and a rear lower chassis bar.

The improvement in towing capability is incredible. The Cruze had no problem towing the boat before, but now, I don't even feel that the trailer is behind me. Even going over railroad tracks or big bumps, there is no "pogo" effect on the rear (due to the weight shift of the trailer), and the chassis remains very stable. I'm still very happy I spent the money on these shocks, and would encourage everyone else to save a little more and get these instead of OE replacements.
 

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Discussion Starter · #35 ·
I wonder if I installed a Ultra Racing front tower brace to take up the gap between the tall self locking nut and the top plate if that would solve my problem or would the plate still bottom out on the nut?[h=1][/h]
I don't know. Others have installed these shocks without the problem you're running into. I don't think the UR front tower brace will fix it.

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Discussion Starter · #40 ·
I found the Repair Manual for the shock and strut install and plan on ordering these this weekend. However, does anyone know the strut top nut torque is? I purchased the tool and would like to do a write up/how to. Not the one on the plate as that's in the repair instructions, but the nut under that on the mounts? Also, do they come with new shock absorber nuts? It calls for new ones.
Torque specs can be found here:

Chevrolet Cruze Repair Manual: Front Suspension - Suspension
 

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Discussion Starter · #43 ·
I have a couple questions. Sorry if the first one is really newbish. lol


1. When it says 66 lb/ft + 60 Degrees does that mean you torque it to to 66 lb/ft and then just eyeball 60 degrees more of a turn? Sorry, never used torque specs.


2. Do new rear bolts come with the shock absorbers? It calls for new ones.
Yep, eyeball 60 degrees and you'll be good. Give or take 5 degrees won't make a difference.

Shocks do not come with bolts. That said, I re-used mine.

Just to confirm, these are the extras you can get to go with everything? I recently got new mounts and links but debating on ordering the covers and bushings.
Don't bother with front sway bar bushings, they're already poly from the factory. No need to replace the accordion boots either. Definitely replace the mounts and the sway bar linkages.
 

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Discussion Starter · #45 ·
Since I recently replaced the front mounts and links I'll leave them. I have the moog ones. But I'll order mounts for the rear.
I replaced my rear mounts, but honestly did not feel that I needed to. The rears looked fine.
 

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Discussion Starter · #51 ·
CG doesn't really have anything to do with dampers though. Curb weight would, but that would only suggest stiffer dampers. I think you're confusing dampers with roll bars.

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Discussion Starter · #53 ·
No, I'm not.

Softer dampers will allow for more body roll (assuming the springs are matched accordingly).

If your CG is at a typical height, you will incur more body roll than if your CG is much closer to the ground, with the same dampers, because your rotational moment will be greater.
The problem is, dampers do more than just control body roll. They also control the rate of suspension travel which, in a vehicle that weighs a few hundred pounds more, would require stiffer shocks, if anything, due to the requirement for stiffer springs to support the additional weight. Shocks still have to be capable of controlling unsprung weight so you don't bottom out over road anomalies like I did in the Cruze when mine had 60k miles on them. The effect on body roll is a secondary benefit changing shock absorber stiffness and will only be noticed in sharp, split-second maneuvers. Exiting a highway on ramp, where body roll increases slowly, shocks will have little to no influence since their purpose is to control the rate of suspension compression and decompression (jounce and rebound), not the position of suspension compression. That task is given to the roll bars. Shocks control the rate of suspension travel in very rapid loads, which is why they are also known as shock absorbers.

Body roll is caused by the weight of the car leaning in a turn. I know you're aware of this, I'm just re-stating it for the benefit of others. Compared to driving over a bump on the highway at 70mph, the onset of body roll is much, much slower. A damper will control how quickly the body rolls, but not how much it does. Body roll occurs slowly enough that dampers don't really have much of an effect on it. At best, you'll feel less body roll for a very short period after you engage the turn, but the shock will give way to more body roll very shortly afterward. If I put my entire weight on a shock absorber off the car, it will fully compress, at a specific rate. If it will compress just under my own weight, why should we expect that it will have a consequential effect in total body roll?
 

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Discussion Starter · #56 ·
the z link is so heavy though, how are the shocks now? seeing as its almost 3/4 of a year since this post?
Still excellent. I very much enjoy them every day. @jblackburn can give you some impressions as well since he drove my car at Lordstown. Everything I've said about them still applies.
 
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