Planning ahead for 3/4T 4WD Suburban suspension

[77 K20]

I've heard the difference between the Tuff Country EZ ride springs and the HD springs is they put an extra leaf on the bottom of the HD pack. If it rides too stiff you can remove that bottom leaf. I don't know what the difference in cost between the springs is.

I was running 285/75R16s with what was actually a 3" lift.

Here is some of the articulation with the longer front shocks on the HD springs:

 

[Hunter79764]

And that's a 3/4T, right? That looks about perfect for what I have in mind. I did a little looking through your build thread but mostly the later stuff. Does it cover your setup in this configuration too?

 

[77 K20]

Yeah- 3/4 ton (K20). My older posts in my build thread lost the pictures somehow, but I covered pretty much everything I did to it. On the second page I did try reposting what pictures were lost.

I've went from 235/85R16s to 265/75R16s, to 285/75R16s, to 315/75R16s and now 37x13.50R17s.

The 285s and the 315s were probably the "best" for still using the truck on the highway and for a useful daily vehicle. Definitely cheaper. And lighter when changing a tire.

 

[Bextreme04]

I’ve got 4” Tuff country EZ rides on the front and stock GMT-400 K2500 suburban 63” rear springs with a 2” shackle flip. Using Tuff country 4-6” lift shocks and front sway bar disconnect bracket. I have the HD lower spring removed, but it sits noticeably too low in the front and I’m also going to be swapping in a 454, so I’ll be putting the HD spring back in and an ORD add-a-leaf to move the axle forward about 1/2-1”.

It rides pretty darn nice and smooth. Just got new rims and tires on today. 315/70R17 Falken wild peaks on 17x9 procomp 69 series rims.

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[Hunter79764]

I appreciate it guys. That definitely gives me some ideas in line with what I'm picturing with mine...

 

[Mr Clean]

I've already got 56" springs rear, so that helps. I forgot about a shackle flip in the rear, that might be the better option vs blocks for not much difference in price (assuming the $225 brackets have what I need, a set of blocks and new U bolts looks like about $100).

On the front, I don't have a winch but I do have a BEEFY grill guard, made out of some 5" or 6" angle iron and a bunch of 2" square tube, all of it heavy wall. Between that and the LS swap I plan, I really won't know where the front end weight is going to end up but I'm with you, I'm guessing the non-HD springs would be better suited for me. When it gets here, I'll get a front end weight and compare that with the spring dimensions and load charts to see what kind of lift I'll get on mine. I want it up a little, but not so much that the current tires make it look like a linebacker on ice skates (tires were nearly new when I bought it, 265/75-16's, ~31.5", and can't really justify replacing them right away). I love the look of the Humvee wheel/tire combo, but realistically I'd probably just go to 315's at most, maybe 305/75's. Unless I can find a couple more 16.5 rims, which makes the Humvee tires more attractive since I'm so cheap... The Super Duty shock mounts seems doable as well, I need shocks so I'll probably try to get some mounts installed and upgrade shocks at that time, which may or may not be the same time I do the rest on the front end.

Again, it's more the looks as the current worn out stock setup has done everything I "need" it to do, and there's not much rock crawling where I'm at (Dallas/Ft. Worth). Only once so far have I dragged anything, and once got stuck in sand at the beach until I had the kids jump out and lock the hubs... it's good having minions for stuff like that

I have some rear blocks you can have. I'd have to measure them, IIR they are 3 inch, maybe 4. As far as that goes I'm about to pull the 4 inch lift springs out of my Blazer....

 

[Mr Clean]

I’ve got 4” Tuff country EZ rides on the front and stock GMT-400 K2500 suburban 63” rear springs with a 2” shackle flip. Using Tuff country 4-6” lift shocks and front sway bar disconnect bracket. I have the HD lower spring removed, but it sits noticeably too low in the front and I’m also going to be swapping in a 454, so I’ll be putting the HD spring back in and an ORD add-a-leaf to move the axle forward about 1/2-1”.

It rides pretty darn nice and smooth. Just got new rims and tires on today. 315/70R17 Falken wild peaks on 17x9 procomp 69 series rims.

You must be registered for see images attach

Eric new wheels and tires look good...

 

[Hunter79764]

I have some rear blocks you can have. I'd have to measure them, IIR they are 3 inch, maybe 4. As far as that goes I'm about to pull the 4 inch lift springs out of my Blazer....

Man, I appreciate that. On those lift springs, is that front or rear? If fronts, I might would buy them off of you. Rear, I'd have to see how they would go since I've got 56" 7+1 or 8+1 right now (can't remember offhand) and I'm not sure what my load capacity needs to be yet.

I like your name, by the way, and you even spell it right

 

[Mr Clean]

Man, I appreciate that. On those lift springs, is that front or rear? If fronts, I might would buy them off of you. Rear, I'd have to see how they would go since I've got 56" 7+1 or 8+1 right now (can't remember offhand) and I'm not sure what my load capacity needs to be yet.

I like your name, by the way, and you even spell it right

They are front springs, blocks in the rear. You can go look at my build thread and see how the truck is sitting with no motor. It will be a bit lower on your Suburban. If you are interested, I'll make you a serious deal on the lift.

LOL...I didn't even catch that...Yes...The real way to spell it...I never could understand how you get a SHA sound out of Sean. I did date a girl many...many moons ago that spelled it Shaun...

 

[shiftpro]

A little flexy is honestly enough, I mostly just need hunting duty and beach cruiser for vacation etc. I've yet to really need more capability than it has stock, but more is always more better, right?
33's is fine, cutting fenders is fine (everything is bedlined and most stuff is dented up, this will never be a "nice truck" again), and with 4.10s I feel pretty comfortable for a while, but who knows?

What's the small tire flex combo?

Ok so you have realistic expectations, that makes things easier! Are you certain you have 4.10 gears? That's very low for a Sub.. I actually never thought that was an option. If they are 4.10s, you can easily run a larger tire... but again the 12 bolt can be compromised. Your driving habits will make it or break it.

To make room for bigger tires, let's say you go with the 2" ORD or Tough Country (do not confuse with Rough Country) you could use an ORD 1" easy-inch whatever they call it, and move that front axle forward a bit. Then you can trim off the lower 'fange' from the front of the fender.
On the rear yes a shakle flip, but a few thing to watch out for... you will want a CV joint coming out of the transfer case and a slip joint in the drive shaft. Or... shim the rear end back to stick after you raise it up with the shackle lift.

A raised steering arm will be fine with 2-3" lift.

One last tip my friend, use the 'quote' feature on the bottom right so we see your responding or asking questions. That way we won't miss you.

 

[Hunter79764]

They are front springs, blocks in the rear. You can go look at my build thread and see how the truck is sitting with no motor. It will be a bit lower on your Suburban. If you are interested, I'll make you a serious deal on the lift.

LOL...I didn't even catch that...Yes...The real way to spell it...I never could understand how you get a SHA sound out of Sean. I did date a girl many...many moons ago that spelled it Shaun...

I was looking for your location ("Just pay shipping" on something from Hawaii turns into "just go ahead and buy new" pretty quick, haha) and the name caught my eye. Yeah, I continue to be amazed at how many ways people can screw up my name sometimes. If you have a price in mind, PM me and I'll see if I can scrounge some money together. I'm not in a real hurry either, I think I've got my projects booked up through next spring right now. Old houses, old cars, a small zoo (dogs, cats, chickens, etc.), and young kids seems to keep me busy...

 

[Hunter79764]

Ok so you have realistic expectations, that makes things easier! Are you certain you have 4.10 gears? That's very low for a Sub.. I actually never thought that was an option. If they are 4.10s, you can easily run a larger tire... but again the 12 bolt can be compromised. Your driving habits will make it or break it.

To make room for bigger tires, let's say you go with the 2" ORD or Tough Country (do not confuse with Rough Country) you could use an ORD 1" easy-inch whatever they call it, and move that front axle forward a bit. Then you can trim off the lower 'fange' from the front of the fender.
On the rear yes a shakle flip, but a few thing to watch out for... you will want a CV joint coming out of the transfer case and a slip joint in the drive shaft. Or... shim the rear end back to stick after you raise it up with the shackle lift.

A raised steering arm will be fine with 2-3" lift.

One last tip my friend, use the 'quote' feature on the bottom right so we see your responding or asking questions. That way we won't miss you.

Mine is a 3/4T, so its a 10 bolt front and a 14 SF rear, and I'm fairly certain its 4.10's but I can't find my photo of the RPO tag again to make sure. It's possible they are 3.73's, but I've had 4.10's in my mind. And I drive fairly easy in general, which helps. My wife, on the other hand, will be the one to break stuff if I give her the chance. It will probably get a torque cam into the otherwise stock 6.0, but even down the road I'm not planning to beat it with big block torque and crazy rocks. On the bright side, if she does break it she is then much more understanding when repairs need to be made, so that's good.

I'll take a look at the rear driveshaft setup and keep that in mind.


One other lingering question, on my rear axle I've got what I believe is a brake pressure adjusted that changes brake bias (I think?) based on suspension compression. Do I leave that intact and adjust for the new ride height, or ditch it and run a longer flex line, or...? I plan to dig in to it at some point, I know I have a rear brake fluid leak that I need to find, it's just low on the totem pole right now. If I do need some brake system work, I don't know if I should go out of my way to keep it vs ditch it vs leave it along unless I need to do something.

Thanks.

 

[Bextreme04]

4.10 is usually the standard gear ratio for a 350 in a 3/4 ton. 3.73 is the default for 454 3/4 ton power team in most years.

 

[Bextreme04]

Eric new wheels and tires look good...

Thanks! I'm really happy with them. Much better than the original 80's turbine type alloy 16's that were on it before and the new rubber made a huge difference over the ancient bald 35's that were on it before.

 

[shiftpro]

Mine is a 3/4T, so its a 10 bolt front and a 14 SF rear, and I'm fairly certain its 4.10's but I can't find my photo of the RPO tag again to make sure. It's possible they are 3.73's, but I've had 4.10's in my mind. And I drive fairly easy in general, which helps. My wife, on the other hand, will be the one to break stuff if I give her the chance. It will probably get a torque cam into the otherwise stock 6.0, but even down the road I'm not planning to beat it with big block torque and crazy rocks. On the bright side, if she does break it she is then much more understanding when repairs need to be made, so that's good.

I'll take a look at the rear driveshaft setup and keep that in mind.


One other lingering question, on my rear axle I've got what I believe is a brake pressure adjusted that changes brake bias (I think?) based on suspension compression. Do I leave that intact and adjust for the new ride height, or ditch it and run a longer flex line, or...? I plan to dig in to it at some point, I know I have a rear brake fluid leak that I need to find, it's just low on the totem pole right now. If I do need some brake system work, I don't know if I should go out of my way to keep it vs ditch it vs leave it along unless I need to do something.

Thanks.

I think most will agree... I've always deleted them. I find they get rusted and don't work, yet the brakes still stop the truck so off with it.
Does your rig have a tach?
4.10s with stock 31" tires would be so revy on the highway. I don't think Eric is correct about 4.10s being standard on 3/4 tons. I have an 85 K20 Camper Special with 3.73s. I've had a few and they all had 3.73... even the Camper Specials. Now moving up to one ton camper special or CAC dually and they all came with 4.10.
But... as we see over and over, it seems any and every option may end up where we're not expecting it.