More Tahoe lowering questions...

[tooeasy]

Hey, guys,

I have some lowering questions that I can't seem to find specific answers to.

I apologize in advance if these have been answered before (or seem stupid), but I haven't lowered a truck since about 1975 when the main tool was a torch.


My truck is an 03 2WD Tahoe. It's at 35” and 37” now, and I'd like to stay with 17” factory wheels.

I'm going for better looks and better handling, towing is not a concern.

I'm also planning the NNBS front brakes mod at the same time.


Ideally, I'd like to go with Tony's 3/5-6” Custom kit, but I'd like to keep it around $750.

Still, I'd like to go a bit lower than a 2/4 drop, but not lower than 3/5”.


I'm planning on 2” drop spindles in the front.

Can I get an additional 1/2” or so by cranking the stock keys without the ride suffering, or are 1”

keys (in addition to the spindles) a better way to go?

Does either of these options present alignment problems?

Is anyone running the Spindle Source or other eBay spindles?


In the rear, I'm planning drop coils, end links and shorter shocks.

I see some kits have trailing arm re-locators and others don't. At what point (4”? 5”?) do these become necessary or beneficial?

Ditto with shock extenders – some kits recommend shorter shocks, but it seems the extenders would be desirable even with shorter shocks to keep them more upright?


Right now I'm leaning toward McGaughy's 3/5 kit and adding extenders and shorter shocks.

Does anyone have experience with this particular set-up?


Thanks!

 

[TheAutumnWind]

speak with @NORCAL SS ss he will get you set up right

 

[iamdub]

For a 3" drop on a torsion bar front suspension where I wanted to increase handling, I'd probably use spindles and 2" drop keys. The keys can be cranked up to lessen the drop from 4" to 3" or anywhere in between. Cranking them up would increase the spring rate, which would improve the stability/handling, but it won't ride like a go-kart, either. I've never seen 1" drop keys, but I've never really looked, either. If you get these for your 3" drop, it should ride the same in the front, just be 3" lower. Since the suspension is "seeing" only 1"-2" of drop, aligning it won't be a problem. The only springs I've seen for a 5" rear drop are the TBSS coils. They'll drop it a lot, but they're really soft so you have to use stiff shocks to compensate. From a performance perspective, I don't care much for this. I'd rather the spring do the work of supporting the weight and the shocks do what they're supposed to do- absorb "shock" and dampen the movement. Soft springs and stiff shocks are ok when cruising and hitting cracks/dips/humps in the road because it's a single, momentary strike. When taking corners, the load is present for much longer than just that one hard bump. In a turn, the soft springs on the outside would compress but the shocks would too because they don't support weight. They basically just slow down the effect of the weight. If the weight is present for a length of time, such as the duration of a turn, they'll steadily compress right along with the spring. This will lead to increased body roll. Sure, you can counter this with stiffer sway bars, but then you're spending money to counter the shocks, which are there to counter the soft springs. My recommendation is to see if there is an option for a 5" drop coil that doesn't achieve this drop by being an undersized spring being overloaded. I don't think there's anything so readily available for this but I think there's a 4" coil.

The other thing is wanting to keep the 17" wheels. You're giving up a lot of handling performance running small wheels and balloon tires. For a nice compromise between performance and comfort, I'd recommend 20" wheels and whatever tire suits your needs (high-performance, sport, touring, etc.).

It's kinda debatable, but the general consensus is anything over 4" rear drop should get axle relocators. I have a spare set of used relocators and shock extenders if you decide you want some and are trying to get your parts together on a budget. PM me if interested.

 

[TheAutumnWind]

For a 3" drop on a torsion bar front suspension where I wanted to increase handling, I'd probably use spindles and 2" drop keys. The keys can be cranked up to lessen the drop from 4" to 3" or anywhere in between. Cranking them up would increase the spring rate, which would improve the stability/handling, but it won't ride like a go-kart, either. I've never seen 1" drop keys, but I've never really looked, either. If you get these for your 3" drop, it should ride the same in the front, just be 3" lower. Since the suspension is "seeing" only 1"-2" of drop, aligning it won't be a problem. The only springs I've seen for a 5" rear drop are the TBSS coils. They'll drop it a lot, but they're really soft so you have to use stiff shocks to compensate. From a performance perspective, I don't care much for this. I'd rather the spring do the work of supporting the weight and the shocks do what they're supposed to do- absorb "shock" and dampen the movement. Soft springs and stiff shocks are ok when cruising and hitting cracks/dips/humps in the road because it's a single, momentary strike. When taking corners, the load is present for much longer than just that one hard bump. In a turn, the soft springs on the outside would compress but the shocks would too because they don't support weight. They basically just slow down the effect of the weight. If the weight is present for a length of time, such as the duration of a turn, they'll steadily compress right along with the spring. This will lead to increased body roll. Sure, you can counter this with stiffer sway bars, but then you're spending money to counter the shocks, which are there to counter the soft springs. My recommendation is to see if there is an option for a 5" drop coil that doesn't achieve this drop by being an undersized spring being overloaded. I don't think there's anything so readily available for this but I think there's a 4" coil.

The other thing is wanting to keep the 17" wheels. You're giving up a lot of handling performance running small wheels and balloon tires. For a nice compromise between performance and comfort, I'd recommend 20" wheels and whatever tire suits your needs (high-performance, sport, touring, etc.).

It's kinda debatable, but the general consensus is anything over 4" rear drop should get axle relocators. I have a spare set of used relocators and shock extenders if you decide you want some and are trying to get your parts together on a budget. PM me if interested.

if you are just gonna decrank an inch why bother with aftermarket keys? Waste of money. OEM keys are more then capable of that. No advantage to the aftermarket ones.

Cranking the keys up or down does absolutely nothing for spring rate. Torsion bars are linear. The spring rate doesn't change. This is a common misconception.

 

[iamdub]

if you are just gonna decrank an inch why bother with aftermarket keys? Waste of money. OEM keys are more then capable of that. No advantage to the aftermarket ones.

Which is probably why there aren't any keys for just 1".

Cranking the keys up or down does absolutely nothing for spring rate. Torsion bars are linear. The spring rate doesn't change. This is a common misconception.

Fundamentally, this is correct and makes sense to me. I'm no engineer, but it has something to do with the arc of the control arms altering the leverage against the torsion spring because it's not all on the same plane. The bar is also bent while it's twisted. I'd imagine the effect to be numerically minimal, but it always seems that people feel the difference. Maybe it's all in their heads? I've never had any personal experience with de-cranking to drop so I can't share any further.

With this, I'd have to agree and say that the OP could use 2" spindles and de-crank an inch if he wants 3". Or de-crank further if he wanted more (within reason as limited by the adjusters).

 

[TheAutumnWind]

Which is probably why there aren't any keys for just 1".



Fundamentally, this is correct and makes sense to me. I'm no engineer, but it has something to do with the arc of the control arms altering the leverage against the torsion spring because it's not all on the same plane. The bar is also bent while it's twisted. I'd imagine the effect to be numerically minimal, but it always seems that people feel the difference. Maybe it's all in their heads? I've never had any personal experience with de-cranking to drop so I can't share any further.

With this, I'd have to agree and say that the OP could use 2" spindles and de-crank an inch if he wants 3". Or de-crank further if he wanted more (within reason as limited by the adjusters).

They feel stiffer due to the greater compression on the jounce stop when lowered and reduced downtravel.

The jounce stop is what gives you a progressive spring rate feel. If you want stiffer you need a stiffer jounce stop like the z71 version.

I've had t bar cranked vehicles both up and down.

I'm no engineer, but it has something to do with the arc of the control arms altering the leverage against the torsion spring because it's not all on the same plane.

I'd imagine that this part is true to some degree at extreme angles, but doubt an inch one way or the other would make anything more then a negligible difference.

 

[iamdub]

They feel stiffer due to the greater compression on the jounce stop when lowered and reduced downtravel.

The jounce stop is what gives you a progressive spring rate feel. If you want stiffer you need a stiffer jounce stop like the z71 version.

That's ridiculous that someone would ride on or even that close to the stops. If I was lowering my truck and I saw that the control arm was even touching the stop at ride height, I'd definitely make some adjustments. But, not everyone pays close attention to what's going on under their trucks. They buy whatever kit is pushed their way, bolt it on and go. THEN they report back with "ABC kit made my truck ride like crap while XYZ kit didn't", perpetuating rumors all over the internet.

Anyway, not to get off the OP's topic...

 

[TheAutumnWind]

That's ridiculous that someone would ride on or even that close to the stops. If I was lowering my truck and I saw that the control arm was even touching the stop at ride height, I'd definitely make some adjustments. But, not everyone pays close attention to what's going on under their trucks. They buy whatever kit is pushed their way, bolt it on and go. THEN they report back with "ABC kit made my truck ride like crap while XYZ kit didn't", perpetuating rumors all over the internet.

Anyway, not to get off the OP's topic...

Haha yeah I agree.

The jounce stops in the front are actually supposed to be barely touching on a torsion bar sprung truck at stock height. This is by design

 

[TheAutumnWind]

Hey, guys,

I have some lowering questions that I can't seem to find specific answers to.

I apologize in advance if these have been answered before (or seem stupid), but I haven't lowered a truck since about 1975 when the main tool was a torch.


My truck is an 03 2WD Tahoe. It's at 35” and 37” now, and I'd like to stay with 17” factory wheels.

I'm going for better looks and better handling, towing is not a concern.

I'm also planning the NNBS front brakes mod at the same time.


Ideally, I'd like to go with Tony's 3/5-6” Custom kit, but I'd like to keep it around $750.

Still, I'd like to go a bit lower than a 2/4 drop, but not lower than 3/5”.


I'm planning on 2” drop spindles in the front.

Can I get an additional 1/2” or so by cranking the stock keys without the ride suffering, or are 1”

keys (in addition to the spindles) a better way to go?

Does either of these options present alignment problems?

Is anyone running the Spindle Source or other eBay spindles?


In the rear, I'm planning drop coils, end links and shorter shocks.

I see some kits have trailing arm re-locators and others don't. At what point (4”? 5”?) do these become necessary or beneficial?

Ditto with shock extenders – some kits recommend shorter shocks, but it seems the extenders would be desirable even with shorter shocks to keep them more upright?


Right now I'm leaning toward McGaughy's 3/5 kit and adding extenders and shorter shocks.

Does anyone have experience with this particular set-up?


Thanks!

Shock extenders help with the angle of the shock. If you only drop ~3" then extenders and stock style shocks are fine, but for something like 5" you need shorter shocks too.

 

[iamdub]

Haha yeah I agree.

The jounce stops in the front are actually supposed to be barely touching on a torsion bar sprung truck at stock height. This is by design

Interesting. They must be relatively long and spongy, not like the typical dense rubber ones made to keep a rear axle from hitting the frame. I'm glad you told me 'cuz if my girl gets a GMT800 (like I'm hoping), this would be good to know that it's not just "old, worn out and saggy" torsion bars letting it rest on the stops.