Bilstein shocks thread

Silverado-Hareek · April 25, 2019

40 minutes ago, MBSierra17 said:

Let's assume that the relaxed length of the spring is 13", and when on a stock truck, it compresses to 11" in the strut assembly down to 7" with vehicle weight.

With bilstein 5100, the strut assembly may only be at 9.15" (11-1.85 raised from the bottom), but the vehicle weight will still only further compress the spring to the exact same 7" with weight. Hence, modified ride height, exact same spring rate.

Please note these numbers are arbitrarily chosen.

Exactly! The spring is compressed from 9.15" down to 7" which is only a change of 2.15" as opposed to 4" of compression (11" down to 7") in the stock setup because the spring is pre-loaded by the 5100's. Same vehicle weight, less spring compression because of pre-load.

Silverado-Hareek · April 25, 2019

6 minutes ago, Sierra Dan said:

Many with the KO2's report a firmer harsher ride.

Especially with the E load ranges.

I'm certain that's where most of my rough ride comes from. The 5100's are valved almost identical to the 4600's which I had on my old truck with P rated tires and that truck road a little better. Regardless, I still like the rugged feel of my 2014 setup.

Snowcamo · April 25, 2019

22 minutes ago, Sierra Dan said:

Many with the KO2's report a firmer harsher ride.

Especially with the E load ranges.

Still the same with p rated tires.

Sierra Dan · April 25, 2019

14 minutes ago, Silverado-Hareek said:

I'm certain that's where most of my rough ride comes from. The 5100's are valved almost identical to the 4600's which I had on my old truck with P rated tires and that truck road a little better. Regardless, I still like the rugged feel of my 2014 setup.

4600 and 5100 are built identically on the internal side other than a longer shaft for the 2" of lift.

4weight · April 25, 2019

I got my 5100's in this week and can't wait to get them on. Putting that rears on myself next day or so and to my mechanic for the fronts. They are cool looking right out of the box. And again, always install the rears with the Bilstein logo right side up, regardless of boot down or up. Called them myself this week to confirm that.

4W

Edited April 25, 2019 by 4weight

MBSierra17 · April 25, 2019

1 hour ago, Silverado-Hareek said:

Exactly! The spring is compressed from 9.15" down to 7" which is only a change of 2.15" as opposed to 4" of compression (11" down to 7") in the stock setup because the spring is pre-loaded by the 5100's. Same vehicle weight, less spring compression because of pre-load.

You're thinking about it wrong. In both scenarios, the starting length should be the full 13" of the non compressed spring. Then both scenarios end with the 7" compressed spring. The difference is the perch height of the bottom of the spring, and where you're temporarily holding the top of the spring (ie, assembled strut). The spring has a linear coefficient, and in both cases is supporting the exact same force. When it reaches the compressed length.

The spring does not get stiffer simply because you're starting from a more compressed state...

I feel I should clarify... As the two struts are assembled, the 5100s strut assembly is more load on the spring. Once vehicle weight is added, however, they both reach the same compression and are at equal levels of compressive force. The lift height is directly from the modified perch height, not the preload.

Edited April 25, 2019 by MBSierra17

CH15GMC · April 26, 2019

4 hours ago, Sierra Dan said:

Have you installed these yet?

I haven't had time to get them installed and most likely it won't be until next weekend. The anticipation is killing me!

CH15GMC · April 26, 2019

On 4/18/2019 at 11:01 PM, Randys Denali said:

I received my Bilstein 6112 47-273702 shocks today and you were right, these shocks are huge. I placed my order on 3/28/19. The part number on the box has me questioning if I received the correct product. It looks like the right product, but the part number on the box is 24-242509. Is that what you received as well?

I'm getting rid of the factory magnetic shocks because they're way too stiff and replacing it with the 6112's and 5160's in the rear. I'll be removing the rough country 2.5" lower spacer and installing the 6112's at the top setting. If my truck isn't level after, I may install a half inch lower spacer to even it out. I'm using the x-ineering delete kit to get rid of any alarms. I'm looking forward to a smoother ride. Those magnetic shocks are way too jarring driving on rough roads. I'm hoping to have mine installed by Saturday morning.

Thanks for sharing that you received your shocks.

After I saw you're post I check my part number and I have the same number as you, 24-242509. Did you confirm this is the correct part number?

Randys Denali · April 26, 2019

1 hour ago, CH15GMC said:

After I saw you're post I check my part number and I have the same number as you, 24-242509. Did you confirm this is the correct part number?

Thanks for getting back to me with that. Yes, per Bilstein that part is the correct shock number.

I tried to put the shocks on this last Saturday, but the shaft was too big to fit through the top mount assembly on the magnaride shocks. I spoke to the guys at Battle Born Off-road and they helped me figure out a solution to replace the top mounts with some KYB mounts for the SLT model. I should hopefully have them by next week and installed by next Saturday.

The anticipation is killing me too waiting to install my shocks...

Edited April 26, 2019 by Randys Denali

CH15GMC · April 26, 2019

30 minutes ago, Randys Denali said:

Thanks for getting back to me with that. Yes, per Bilstein that part is the correct shock number.

I tried to put the shocks on this last Saturday, but the shaft was too big to fit through the top mount assembly on the magnaride shocks. I spoke to the guys at Battle Born Off-road and they helped me figure out a solution to replace the top mounts with some KYB mounts for the SLT model. I should hopefully have them by next week and installed by next Saturday.

The anticipation is killing me too waiting to install my shocks...

I got the same response when I asked about the part number. I was concerned there for a little bit. I haven't installed them. I got new mounts, covers, bump stops etc. for them so I can get them assembled and switch them out myself. Most likely it will be next Friday so I can get an alignment Saturday.

Sierra Dan · April 26, 2019

16 hours ago, 4weight said:

I got my 5100's in this week and can't wait to get them on. Putting that rears on myself next day or so and to my mechanic for the fronts. They are cool looking right out of the box. And again, always install the rears with the Bilstein logo right side up, regardless of boot down or up. Called them myself this week to confirm that.

4W

They are monotube design. Makes no difference which way you mount. Boot up or Down. I tried both ways for about 1,000 miles and no difference at all in ride or handling.

My end preference was boot up. You can either flip the decal or remove it all together.

Silverado-Hareek · April 26, 2019

19 hours ago, MBSierra17 said:

You're thinking about it wrong. In both scenarios, the starting length should be the full 13" of the non compressed spring. Then both scenarios end with the 7" compressed spring. The difference is the perch height of the bottom of the spring, and where you're temporarily holding the top of the spring (ie, assembled strut). The spring has a linear coefficient, and in both cases is supporting the exact same force. When it reaches the compressed length.

The spring does not get stiffer simply because you're starting from a more compressed state...

I feel I should clarify... As the two struts are assembled, the 5100s strut assembly is more load on the spring. Once vehicle weight is added, however, they both reach the same compression and are at equal levels of compressive force. The lift height is directly from the modified perch height, not the preload.

This makes sense. I understand what you are saying now. Thanks for the clarification and bearing with me as I worked through the logic.

Silverado-Hareek · April 26, 2019

3 hours ago, Sierra Dan said:

They are monotube design. Makes no difference which way you mount. Boot up or Down. I tried both ways for about 1,000 miles and no difference at all in ride or handling.

My end preference was boot up. You can either flip the decal or remove it all together.

Correct the orientation shouldn't matter from a performance standpoint. But the reason they suggest boot down is to protect the main shock body from damage as it houses the guts of the shock. Also, if any dirt or moisture were to get on the piston, it would flow away from the seal where the piston enters the main shock body rather than settle around the seal. I'm not sure if it makes a major difference as Bilstein sells shocks that go in either direction, but technically the 5100's are intended to be installed boot down and for these reasons which is to protect the shock and make it last longer. Do with that info what you will.

Yondu · April 28, 2019

On 4/26/2019 at 12:07 PM, Silverado-Hareek said:

Correct the orientation shouldn't matter from a performance standpoint. But the reason they suggest boot down is to protect the main shock body from damage as it houses the guts of the shock. Also, if any dirt or moisture were to get on the piston, it would flow away from the seal where the piston enters the main shock body rather than settle around the seal. I'm not sure if it makes a major difference as Bilstein sells shocks that go in either direction, but technically the 5100's are intended to be installed boot down and for these reasons which is to protect the shock and make it last longer. Do with that info what you will.

I believe the reason they recommend boot down is to remove unsprung weight from the suspension side of things. It makes no real difference, but technically a small amount less weight will slightly improve their performance.

A damaged shaft is a bigger concern then a dent in the shock body.

z71skywalker · April 28, 2019

Gentlemen,

Sorry for the late reply as I've had these installed for well over 2 weeks. I've attached some pictures. The truck was completely leveled with the Bilstein 5100s at the highest setting. Front and rear it was spot on.

Some notes:

As others have said, take your old strut assembly somewhere to get them swapped. We had a hell of a time. We tried a floor mounted spring compressor to no avail, and the rentable threaded rod tool also. I ended up giving up and taking them to a local shop. Much easier, cost around 45 dollars.
The rear installation took about 15 minutes on a lift. Super easy as expected.
The ride has improved so much from the stock Ranchos. Those things are garbage. With the wider stance the truck feels much more stable as well.
This setup rubbed at about 3/4 to full turn, and reverse was almost un-useable. I went and bought the Rough Country Fender Trim pieces and broke out the angle grinder. This was much easier than I thought it would be, and now i have ZERO rub. Full lock turn, full lock reverse. Can't even tell I did it. I saw people doing the NorCal mod but for 17 dollars, the trim plates seemed like the way to go.
This setup is great. Rides great, looks great. I might go with a 4" Fabtech sometime next year. I'm not quite sure. I'm so happy with the ride quality i'm not sure I need to do anything different. I would only consider it to lift the truck up a bit more.
The next day I took my truck to get aligned as it was off pretty bad. I highly suggest getting this checked after doing the install.

2018 Chevrolet Silverado Z71 Midnight Edition

Tires: Nitto Ridge Grappler 305/55r/20

Wheels: Black Rhino Barstow Matte Black 20x9.5 -18 offset.