Hauling VERY heavy with an '02 Tahoe Z71, NEED stiffer springs

[AuroraGirl]

Here’s my Silverado rpo list for HD 2500 wt with good load options , I think it may be diff for suburban but it shows what each value means to gm

 

[Marky Dissod]

Do you have air ride on Tahoe? The trailblazer has same rear setup right?

Thankfully, no - if it did, my focus would still be as it is now,
treating the air ride as a secondary supplementary system that I'd not want to need. Does that make sense?
Or I might delete it ...

Don't know much of anything about TrailBlazers.
Very much doubt any EnTrail has rear coil springs that'd be both stiff enough AND tall enough -
but if I'm wrong, I'll be grateful all the same.

Here’s my Silverado rpo list for HD 2500 wt with good load options, I think it may be diff for suburban but it shows what each value means to gm ...

GK torsion bars, FT keys. That definitely helps.

Y'know what does NOT help? RPO YD6 is far too common across the entire GMT800 family; it says nothing if EVERY GMT800 has YD6!

GMT821s/Tahoes & GMT831s/Suburbans 1500 use the same rear coils, right?
What about the GMT805/Chevy Avalanche 1500? Do they also use rear coils?

 

[CPB]

Doesn't make sense to me, since an air spring is designed for this very purpose.

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[Marky Dissod]

Doesn't make sense to me, since an air spring is designed for this very purpose.

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So are stiffer (thicker) coils. Since my Z71 did not come with any air shocks or springs,
adding an air spring system (at least to me) seems more complicated than choosing better suited coils, which will also improve handling when unloaded;
the vast majority of the time, I am UNloaded.

 

[CPB]

So are stiffer (thicker) coils. Since my Z71 did not come with any air shocks or springs,
adding an air spring system (at least to me) seems more complicated than choosing better suited coils, which will also improve handling when unloaded;
the vast majority of the time, I am UNloaded.

Either way you are adding something it didn't have originally. The benefit to adding the air spring is you just drop it to 5psi and your stock coil is behaving as normal.

 

[stutaeng]

Yeah, I agree with @CPB . Timken, Sumo or air helpers, and "send it."

And regardless, you can't compare a lighter vehicle with the same torsion bars as a heavier vehicle because they don't weigh the same: damping factors are unequal.

And the rear suspension stiffness won't be the same either (coil spring vs leaf springs, even with stiffer coil springs,) so there's that. I think even different wheelbase lengths may have an effect on ride quality...So it's not an apples-to-oranges comparison.

 

[Marky Dissod]

Either way you are adding something it didn't have originally.
The benefit to adding the air spring is you just drop it to 5psi and your stock coil is behaving as normal.

Adding air springs and an air spring system still leaves me with easily schmushed coils (AND bars).
Replacing easily schmushed coils and bars with less-easily schmushed coils and bars cures me of the normal behavior.
I don't like 'stock coil behaving as normal'. It's MY Tahoe; as much as I care for them, it does not belong to my freeloading riders.

Yeah, I agree with @CPB. Timken, Sumo or air helpers, and 'send it'.

Think I prefer the Timbren rubber bumps over the Sumo airy foam bumps, but those will come AFTER the stiffer bars / coils.

... regardless, you can't compare a lighter vehicle with the same torsion bars as a heavier vehicle because they don't weigh the same: damping factors are unequal.

And the rear suspension stiffness won't be the same either (coil spring vs leaf springs, even with stiffer coil springs,) so there's that.
I think even different wheelbase lengths may have an effect on ride quality ... So it's not an apples-to-oranges comparison.

Not trying to make a Tahoe 2500 (or use it like one!), there's likely a reason why GM avoided doing that.
Let's say I'm trying to make a more stiffly sprung PPV/SSV, except without knowing ANYthing about ANY of the spring rates of ANY of the springs, damnt.

(With luck I'll find a 6.0L, then I'll be working on a PPV-PV ...)

 

[Marky Dissod]

Look what I just found:

https://www.moog-suspension-parts.com/universal_coil_springs.asp

This will - eventually, after I do considerable perusal and research -
show me all the OTHER springs that could be usefully compatible with Tahoes / Suburbans / H2s, in addition to Moog's recommendations.

Now I just need to find such a listing for torsion bars ...

For now, I see Moog 81069 or 81071
81069 ... 2 pigtails ... 17.177" Free Height ... 5.266" Installed Height ... ??? Inner Diameter ... 0.64" Bar Diameter ... ??? Spring Rate ... ??? Load ... constant
81071 ... 2 pigtails ... 16.042" Free Height ... 5.266" Installed Height ... ??? Inner Diameter ... 0.64" Bar Diameter ... ??? Spring Rate ... ??? Load ... constant

Kinda suspicious that the inner diameter, spring rate, and load are missing ...

 

[Marky Dissod]

Can I make use of this:

Part Details

www.drivparts.com

Looks like a jounce bumper for an H2 or for 2500s & 3500s ... ?

 

[AuroraGirl]

Can I make use of this:

Part Details

www.drivparts.com

Looks like a jounce bumper for an H2 or for 2500s & 3500s ... ?

This is a black version of that one (kryptonite) on a 2500HD

The squish is probabyl because I did not yet replace shock absorbers, since doing so the shape has 80% returned to proper
if your front suspension matches this yes you can use it, but to my knowledge you cant because i assume yours is like the 1500 which is im pretty sure different

 

[Marky Dissod]

View attachment 3814
This is a black version of that one (kryptonite) on a 2500HD

The squish is probably because I did not yet replace shock absorbers, since doing so the shape has 80% returned to proper
if your front suspension matches this yes you can use it, but to my knowledge you cant because i assume yours is like the 1500 which is im pretty sure different

Kryptonite sells these? One of the few companies that seems to have a reputation superior to GM OE. If so I'll get it from them.

 

[AuroraGirl]

Kryptonite sells these? One of the few companies that seems to have a reputation superior to GM OE. If so I'll get it from them.

i dont see any listed under 1500 or suv section

they are not the same im 99% sure so you probably cant use them without making a bracket of some kind
these are designed to always contact the suspension when at rest

 

[99Sierra2500]

Hopefully I won't need to start another thread to ask 2500 owners how stiff they think their rides are ...

Stiff. I have AT tires on my rig, ok when dry, terrible when wet. Part of that is how heavily sprung the vehicle is. My experience from racing cars is that the first mods for performance handling are tires, shocks, and sway bars. Poly bushings sacrifice ride for stiffer handling too. SUV's have extra wallow as their center of gravity is higher.

 

[Marky Dissod]

i dont see any listed under 1500 or suv section
they are not the same im 99% sure so you probably cant use them without making a bracket of some kind
these are designed to always contact the suspension when at rest

If I have to choose between them, vs Timbren rubber bumps ... gotta think on that one ...

Stiff. I have AT tires on my rig, ok when dry, terrible when wet. Part of that is how heavily sprung the vehicle is.

Ok, so, if I go too stiff, I can expect wet braking to get worse? Is that what you're getting at?
Luckily I drive like a normal person when it rains or snows, but please feel free to expand on this.

My experience from racing cars is that the first mods for performance handling are tires, shocks, and sway bars.

Pretty much, except also springs.

Poly bushings sacrifice ride for stiffer handling too. SUV's have extra wallow as their center of gravity is higher.

Since I'm not racing for profit or glory, I'll use GM OE S10 bushings instead of polyurethane - unless I can find S10 polyGRAPHITE bushings.

 

[99Sierra2500]

There is a vid that went through the groups of a gmt800 spinning out, high center of gravity, too heavily sprung, it'll lift a wheel, lose contact patch. You can also still do poly end link bushings on your sway bars if going OE. Edit, the weakest link towing and hauling is probably the 4l60.

 

[Marky Dissod]

There is a vid that went through the groups of a gmt800 spinning out, high center of gravity, too heavily sprung, it'll lift a wheel, lose contact patch.

Was it a Tahoe/Yukon or a Suburban/XL? Or was it a pickup truck?
Most important, WHICH WHEEL(S) LIFTED?

Any other 'data' about the spring 'rates' involved - as in, which bars and/or coils? - would be greatly appreciated.

 

[99Sierra2500]

It was a pickup, the vid isn't important. You will always lift a rear tire first as it's a live axle.

 

[Marky Dissod]

Looks like Moog omitted several numbers from their master spring chart,
which absolutely flummoxes any hope I have of comparison;
forced to simply trust either General Spring or Dorman ...

For now, only question left is: where do I source torsion bars?
(Am I stuck with used torsion bars from junkyards?)

 

[Marky Dissod]

For now, only question left is: where do I source torsion bars?
(Am I stuck with used torsion bars from junkyards?)

At risk of redundancy, I was actually asking if anyone knows anywhere else, besides junkyards, to source stiffer torsion bars?

 

[Eidobon]

If mods think this post belongs in a different subforum, please move where best.

Tried asking over @ TYF, zero responses as of now ...

GMT800 Stiffer front torsion AND rear coil springs?

Yday I did a friend a HUGE favor: folded down the seats & loaded about 450SqFt of rolled-up Kentucky BlueGrass into the back of my Tahoe Z71. (Any idea how much that weighs?) Wish I'd had the presence of mind to take measurements, damnt, but I know these things: 1. Unloaded, my Z71 is too tall...

www.tahoeyukonforum.com

Hauled 46 5ft by 2ft rolls of Kentucky BlueGrass in my '02 Tahoe Z71's cargo area on Friday,
which shoved the trailer hitch down to about 12" off the ground at rest.
Since I'm very likely to do some very heavy hauling like this again in the near future,
the idea of turning my Tahoe into a '2500' in hauling terms (NOT TOWING!) is about to become a necessity.

I really think I need stiffer SPRINGS front and back. Now I'm trying to figure out how much stiffer a Tahoe can safely go.
1. Any '2500' vehicle owners in the NYC area, whether pickup or Suburban? I'd like an idea of what I'm getting into.
2. Anyone know which front torsion bars and coil springs were used by a Suburban 2500?

Hummer H2 non-air spring
Or
Complete Z85 set
Then
Add or improve airbags and bump stops