Camber after NBS 8lug and 9.25 swap

Supercharged111 · Jan 7, 2020

Hipster said:
What the fun in spending 14 hours or less swapping a frame when you can spend days on end doing it this way. LOL

I want to frame swap myself, and admittedly I haven't scoured online for frames, but if the amount of ECSB 8 lug 2500s on the road are any indication of what lies in the junkyard them's slim pickins.

GMC Burbalade · Jan 7, 2020

You guys are thinking of the IFS as a simple static adjustment for your alignment at ride height, it is not.
The individual IFS systems were designed to behave a certain way and the geometry is specific to that system. Anything that changes the geometry will change how the truck handles, and needs to be carefully calculated to ensure that it will not only get the wheel aligned at ride height, but also behaving correctly as the suspension cycles. You don't want your wheel flapping all over the place any time you hit a bump or a dip. There's tons of factors like KPI and camber gain that you guys are not even thinking about while trying to reengineer the entire system. Each "fix" presented here is only a band aid and does not solve the root issue that it's trying to cover.

I've said it before and I'll say it again. The swap is not impossible, it's just not logical. There's no bolt on combination of parts to do it correctly. It would require quite a bit of fabrication that is far more difficult and time consuming than simply swapping the frame.

Remember, long bed to short bed frame conversion is easy.

Supercharged111 · Jan 7, 2020

If it makes ya feel any better, I'm not.

In plain English, Burbalade is saying that the pickup points, both upper an lower, inboard and outboard, are likely not the same. They're pretty much undoubtedly not the same, and it screws with EVERYTHING. That really is only a fraction of what could be, and likely is, different.

454cid · Jan 8, 2020

Why not just go with awd astro parts to get the better brakes? I wouldn't think the diff would need any suspension changes at all.

b454rat · Jan 8, 2020

There are a bunch of reasons I'm *thinking* of doing it.

1-no 3/4 ton Yukons/Tahoes.
2-can't swap frames. Refer to #1. Thought bout a burb frame, shortening it, but that's a rather large task. I don't even have a garage.
3-want 4.10s. I can get 3/4 ton GMT-400 and 800 parts cheap. There is a metric **** ton of them in one yard, I have access to prolly 5-6 with almost as many. Yeah I can buy 4.10s for the stock 8.25, but would have to pay someone to install them, prolly $500 all together.
4. I want 8 lug. I have a set H2s that look pretty good on the Yukon. 8 lug wheels are all over. I have a 14 full float axle with 4.10s just about ready to go in the Yukon. Not that I'm gonna go crazy, but don't have to worry bout breaking a 14 bolt. Govlock or not, they are tough.
5- bigger brakes. its what got me here, reading the post on the GMT-800 brake upgrade, someone said it would work with 8 lug too. So, here I am.

Like I said, I'm thinking of doing this. I have 90% of the parts to SAS it. DIY4X SAS kit and crossover steering kit, 2 sets of springs, 4" 48s and stock 52s, complete outer rebuild for the HP44, carrier rebuilt kit, new 4.56s if I decide to run those, a Powerlock, DIY4X shackle flip, sure there is more but get the point. Bout only thing I need is calipers/pads/brakelines, and u-joints for the front axle. The H2s already have 35s on them, so would be good for the overall lift.

Yukon is in pretty good shape for being a 96 and in the north east. Don't see too many like it, lifted or not. Having a whipple is a bonus. Having it SAS'd would be even better. Right now just want to get it going and on the road. Get the feeling gonna need brakes all around, and with my luck new calipers. So if I need to do brakes, why not do em once, with 8 lug stuff. Least how I see it.

I might go to the yard and grab an upper off off a 3/4 ton as see if it will go on or not. Think that will answer a lot of questions!!

BNielsen · Jan 8, 2020

Supercharged111 said:
I want to frame swap myself, and admittedly I haven't scoured online for frames, but if the amount of ECSB 8 lug 2500s on the road are any indication of what lies in the junkyard them's slim pickins.

I've see 4 ECSB 3/4 tons in junkyards, they're out there, far and few, but out there.

And I don't know how rare they are in your parts, but counting mine and my brother's trucks there's at least 9 running around,

GMC Burbalade · Jan 8, 2020

3/4 ton UCAs do not swap over to 1/2 tons. In order to do this swap correctly, the UCA mounts need to be spread out for the 3/4 ton UCAs, LCA mounts need to be dropped 1", and some of the diff mounts need to be dropped.

You can split the frame behind the firewall where it goes from boxed to C channel. Combine the 8 lug front with your rear for a custom 8 lug frame. Square the frame once rather than squaring 10+ mount points.

Supercharged111 · Jan 8, 2020

b454rat said:
There are a bunch of reasons I'm *thinking* of doing it.

1-no 3/4 ton Yukons/Tahoes.
2-can't swap frames. Refer to #1. Thought bout a burb frame, shortening it, but that's a rather large task. I don't even have a garage.
3-want 4.10s. I can get 3/4 ton GMT-400 and 800 parts cheap. There is a metric **** ton of them in one yard, I have access to prolly 5-6 with almost as many. Yeah I can buy 4.10s for the stock 8.25, but would have to pay someone to install them, prolly $500 all together.
4. I want 8 lug. I have a set H2s that look pretty good on the Yukon. 8 lug wheels are all over. I have a 14 full float axle with 4.10s just about ready to go in the Yukon. Not that I'm gonna go crazy, but don't have to worry bout breaking a 14 bolt. Govlock or not, they are tough.
5- bigger brakes. its what got me here, reading the post on the GMT-800 brake upgrade, someone said it would work with 8 lug too. So, here I am.

Like I said, I'm thinking of doing this. I have 90% of the parts to SAS it. DIY4X SAS kit and crossover steering kit, 2 sets of springs, 4" 48s and stock 52s, complete outer rebuild for the HP44, carrier rebuilt kit, new 4.56s if I decide to run those, a Powerlock, DIY4X shackle flip, sure there is more but get the point. Bout only thing I need is calipers/pads/brakelines, and u-joints for the front axle. The H2s already have 35s on them, so would be good for the overall lift.

Yukon is in pretty good shape for being a 96 and in the north east. Don't see too many like it, lifted or not. Having a whipple is a bonus. Having it SAS'd would be even better. Right now just want to get it going and on the road. Get the feeling gonna need brakes all around, and with my luck new calipers. So if I need to do brakes, why not do em once, with 8 lug stuff. Least how I see it.

I might go to the yard and grab an upper off off a 3/4 ton as see if it will go on or not. Think that will answer a lot of questions!!

As previously stated, the Astro knuckles will get you better twin piston brakes. From there, you can bolt on the larger, later brakes from trucks with 17" wheels. This gets you bigger, more powerful brakes. Add hydroboost and you'd be hard pressed to need any more.

The bigger front diff is fairly simple to get into a half ton, 2500SS did it and said only the left rear mount needed extended. Years ago I read where someone else had done this swap too. I want to say he used the 2500 axles and that the dust shields for the wheel bearings needed to be trimmed or tapped farther back onto the axle. I believe there is a difference in length between the 1500 and 2500 axles, but don't quote me. That guy stayed 6 lug.

If you can find a 1500HD or 2500LD, you can find a 9.5" 6 lug rear and, if you're lucky like me, it'll have 4.10s and a locker that still works and hasn't exploded. This also gets you bigger brakes than the 8.5.

I concede these options do no get you 8 lugs, but they do get you everything else on the cheap.

b454rat · Jan 8, 2020

Im not calling anyone out or saying there wrong, but its confusing when many have done it and without major hiccups, and then there are some says it just plane won't work. Even if you kept everything the same, say rebuilding the entire front end, everything is gonna be off when it goes back together, where an alignment comes in. Maybe Im just having a hard time understanding all this, cause I haven't tried it, or compared the pieces in front of me. I've never installed a lift on an IFS, but I've done an SAS on one. But going by what folks say here, it just be easier to SAS to get 8 lug and better gearing. Maybe I can pick up a cheap Tahoe/Yukon in the future and try the swap then. I've also heard of the options mentioned as well. But that goes back to not having a garage to work in, or even all the tools to do something like clipping the frame. I wish I took pics, but friend took a 92 Blazer and grafted a 90 frame clip on it. Sat close to stock, and used it as a plow truck. If I were to swap to axles to keep 6 lug, same guy builds Dana 60s, so Id have him build me one of those. Even have a powerlock for a 60. I'll look into the Astro brakes, cause I get the feeling Im gonna need to replace it all....

Hipster · Jan 8, 2020

GMC Burbalade said:
You guys are thinking of the IFS as a simple static adjustment for your alignment at ride height, it is not.
The individual IFS systems were designed to behave a certain way and the geometry is specific to that system. Anything that changes the geometry will change how the truck handles, and needs to be carefully calculated to ensure that it will not only get the wheel aligned at ride height, but also behaving correctly as the suspension cycles. You don't want your wheel flapping all over the place any time you hit a bump or a dip. There's tons of factors like KPI and camber gain that you guys are not even thinking about while trying to reengineer the entire system. Each "fix" presented here is only a band aid and does not solve the root issue that it's trying to cover.

I've said it before and I'll say it again. The swap is not impossible, it's just not logical. There's no bolt on combination of parts to do it correctly. It would require quite a bit of fabrication that is far more difficult and time consuming than simply swapping the frame.

Remember, long bed to short bed frame conversion is easy.

Yes, they don't get it and I have explained several times on this site that just because you can get the static settings correct doesn't mean much. Camber gain, bumpsteer, turn radius etc are all important to the suspension functioning properly. Control arms swing in an arc, if you move the upper or lower mounting points you change this arc and the movement the knuckle goes through.

Camber after NBS 8lug and 9.25 swap

Supercharged111

Truly Awesome

GMC Burbalade

Busy slacking

Supercharged111

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454cid

Sooper Pooper

b454rat

I'm Awesome

BNielsen

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GMC Burbalade

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Supercharged111

Truly Awesome

b454rat

I'm Awesome

Hipster

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