What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[iamdub]

Look up rough country 2/4 lowering kit.

They simply bolt the strut to the bottom of the control arm with a 1/4" spacer.

They do however provide what they call "grade 9" bolts in there kit... which I had never heard of before.

Turns out "grade 9" is also known as F911 or L9 and has a 180,000 LB shear strength which they claim is 20% stronger than grade 8.

I certainly don't plan on doing this without the "grade 9" hardware which I have already been looking into.

Well, I'll be damned.

 

[Ilikemtb999]

Dang, so without the spacer do you think it would be in the 1.5” range? I’ve been wanting to get another inch lower up front but I’ve been putting off buying lowering struts.

ARP bolts are 180,000+ tensile strength and cheap.

 

[kbuskill]

Dang, so without the spacer do you think it would be in the 1.5” range? I’ve been wanting to get another inch lower up front but I’ve been putting off buying lowering struts.

ARP bolts are 180,000+ tensile strength and cheap.

I am guessing that to be about accurate but obviously I have never done it... lol

As far as hardware is concerned, my guess is that grade 8 would probably be fine and that Rough Country simply chose to use "grade 9" as a CYA.... BUT I'm still gonna use the L9 hardware for the same reason... lol



This is from RC installation manual...


You have to grind one corner of the strut bar so it fits flush under the control arm.

 

[GranPrix]

...you gotta fill me in, bro!

Giggity

 

[iamdub]

Giggity

Well played, sir!

 

[the_tool_man]

I don't care what those bolts are made of. As an engineer, that arrangement makes me cringe. There is NO factor of safety beyond the load-bearing ability of those bolts and nuts, to prevent suspension collapse. At the very least, you should use a heavy castle nut with a cotter pin to prevent loosening. Inspect often!

 

[09 L9H]

If I ever have to mechanically delete the AFM, the likelihood of a cam upgrade is pretty high.

LS9 cams are less than $130 on Amazon. I've been eyeing one, but idk how much the install labor would cost, and I don't have the tools, space, or patience to do it myself haha.

 

[Ilikemtb999]

I am guessing that to be about accurate but obviously I have never done it... lol

As far as hardware is concerned, my guess is that grade 8 would probably be fine and that Rough Country simply chose to use "grade 9" as a CYA.... BUT I'm still gonna use the L9 hardware for the same reason... lol

View attachment 212237

This is from RC installation manual...
View attachment 212238

You have to grind one corner of the strut bar so it fits flush under the control arm.

A set of 4 ARP 8740 chromoly bolts is less than $30.

 

[kbuskill]

A set of 4 ARP 8740 chromoly bolts is less than $30.

Guy I found on EBay out of Texas will ship me four 7/16-14 x 3 1/2" L9 bolts and 8 washers for $11 shipped. He is looking to see if he has L9 lock nuts to go with them.

 

[Ilikemtb999]

Guy I found on EBay out of Texas will ship me four 7/16-14 x 3 1/2" L9 bolts and 8 washers for $11 shipped. He is looking to see if he has L9 lock nuts to go with them.

Let me know how low you get with this!