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!

 

[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.

I wonder why nobody ever made an offset T bar for the strut. I bet you could have a 1/2” offset one and then could have it on top of the strut yet lower it 1” (since it’s 2:1). Hmmmm I do have some machinist hookups.

 

[swathdiver]

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.

You will lose torque big time with a camshaft designed for a car.

 

[Ilikemtb999]

You will lose torque big time with a camshaft designed for a car.

Yup

Here’s a great non vvt cam comparison on an early 5.3

https://www.google.com/amp/s/www.hotrod.com/articles/ls-cam-test-comparison/amp/

 

[swathdiver]

Yup

Here’s a great non vvt cam comparison on an early 5.3

https://www.google.com/amp/s/www.hotrod.com/articles/ls-cam-test-comparison/amp/

Funny, I just quoted that same article on another forum a little while ago! Big fan here of the Crane Cam Trio and especially like the first, the smallest cam, for mine someday.

 

[Ilikemtb999]

Funny, I just quoted that same article on another forum a little while ago! Big fan here of the Crane Cam Trio and especially like the first, the smallest cam, for mine someday.

I just got my TSP vvt stage 2 cam in the mail yesterday. Just need to find the time to install it now.

 

[iamdub]

I wonder why nobody ever made an offset T bar for the strut. I bet you could have a 1/2” offset one and then could have it on top of the strut yet lower it 1” (since it’s 2:1). Hmmmm I do have some machinist hookups.

Ingeniously simple idea. I think a forged offset T-bar would be great. The trick wold be getting it into the shock eye. A two-piece bushing would work, but how long would a two-piece bushing last? Or maybe a two-piece T-bar, like male and female halves? Press fit to eliminate wallowing?

 

[Doubeleive]

New drivers inside door handle

 

[Ilikemtb999]

Ingeniously simple idea. I think a forged offset T-bar would be great. The trick wold be getting it into the shock eye. A two-piece bushing would work, but how long would a two-piece bushing last? Or maybe a two-piece T-bar, like male and female halves? Press fit to eliminate wallowing?

I have qa1 coilovers on my Buick and it uses a multi piece bushing with clips to hold everything together. Seems pretty solid. Their T bars aren’t offset though. I need to get my hands on a stock T bar

 

[Blue Rock]

Replaced my driver's side motor mount today (no more take off clunk). FYI for those replacing this themselves, it's not too bad of a job. My truck is a 2007 Chevy Tahoe 5.3. Thanks to this forum I used the Hummer H3 passenger side mount which is the same as the Police PPV mount GM Part number 25847739. I got it on Amazon for $85. This was the second time I replaced my mount since owning the truck, so opted for the more heavy duty this time around. I was able to access the bolts on the block much easier from underneath the truck than trying to fight them from up top.

 

[kbuskill]

Ingeniously simple idea. I think a forged offset T-bar would be great. The trick wold be getting it into the shock eye. A two-piece bushing would work, but how long would a two-piece bushing last? Or maybe a two-piece T-bar, like male and female halves? Press fit to eliminate wallowing?

Or you could buy lower control arms that are drop arms.

I doubt very seriously that there would be enough room for the off set T-bar between the strut and the arm.

Here...

Unless it was a lot more shallow.

I felt the same way at first about bolting these up like this BUT a couple things sway my decision.

1st off... Rough Country is a pretty big company with a well known name and a lot on the line to loose if something should fail. I am certain they did their homework on the shear strength of the bolts in this configuration before allowing them to go to market. My guess is grade 8 was probably sufficient and they said "let's include L9 hardware just as a CYA". I am certain they don't want to be liable for any injuries... or worse.

2nd... @07Burb has been running his like this for a while (20k+ miles) with no ill effects and, I'm not knocking him or his truck, I don't even think that the shop that installed his this way even used the "grade 9" bolts. From the pic I saw it appears that they may have just reused the factory bolts. I base this off of the fact that all of the L9 hardware I have seen has that gold (yellow zinc) color to it and his don't appear to be that way. Although I may be mistaken.

I just don't see it being a problem for normal everyday driving.

Now if you were jumping ramps with your truck I could see the potential for failure but even then I would just about bet on breaking ball joints before breaking two 180,000 psi minimum tensile strength rated bolts.

I believe I will order 3.5" bolts because the factory bolts are 3" long and I would like a little extra length so that I can install a second nut to act as a lock nut on top of my actual lock nut on top of the blue lock tite I intend to use... definitely don't want them backing out.

The guy that mentioned the castle nut and cotter pin has a good idea but I don't know about drilling an L9 bolt... that may prove to be a chore plus it might possibly weaken it some how.

I think the lock tite + lock nut + secondary nut will be just fine.