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hello, i currently have a black 04 dodge ram 4x2 rc sb hemi. ive done some stuff to it such as a cam and headers but im looking for something different at a reasonable price and ive always liked how the trailblazers looked. ive been looking around and have been seeing how you guys have been lifting your trailblazers. most seem to have z71 springs in the rear and spacers and/or bilsteins hd shocks up front. but i have some questions for you guys.

i want some lift but nothing extreme. i want a little lift and have it sit level.

thinking z71 springs in the rear. are you guys still using trailblazer shocks after switching springs?

are there any other mods i would have to do to get this much lift?

what is the best way to lift the front? spacers or shocks?

how does ride change from lifting it this little bit?

after getting this much lift what is the best or one the best off road tire sizes to run without any spacers or having any rubbing issues?

thank you in advance Paul
 

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[spoonfeed]
i want a little lift and have it sit level.
Why is level important to so many people?

thinking z71 springs in the rear. are you guys still using trailblazer shocks after switching springs?
You can, but it will limit your articulation. Most people switch to z71 bilstein shocks or bds shocks.

are there any other mods i would have to do to get this much lift?
How much lift is 'this much'? BDS gives 2", MarkMC and SMaxx give 2.5".

what is the best way to lift the front? spacers or shocks?
Shocks do not add lift.

how does ride change from lifting it this little bit?
It rides a little more like a truck. When you add spacers to the front, it also limits your down articulation of the IFS, so you are more likely to feel the bump when hitting the down stop. Z71 springs are stiffer, and provide a harsher ride.

after getting this much lift what is the best or one the best off road tire sizes to run without any spacers or having any rubbing issues?
If you would have done a little reading here or on my site, you would find that the maximum tire diameter without spacers is 30.5". If you go over that size, you will be hitting your upper ball joint.
[/spoonfeed]
:tiphat
 

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with spacers upfront. does it hit the bump stops alot?
a preload spacer does not increase suspension travel so it would not hit the bump stops any more than stock. Technically, it could impact less because the preloaded spring resists compression more aggressively than without hte spacer. This is why the ride is more firm/harsh.
 

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It would mean the compression bumpstop may not be reached as often, but there is another side to the equation. The extension bumpstop (internal to the shock) will be reached more often because the down travel of the wheel is less than stock. So, if you are going up an off camber hill, you can expect to lift your front tires off the ground pretty often.

Spring spacers do not change the spring constant, so the ride does not get any harsher or firmer as a result of adding only a spacer.
 

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Spring spacers do not change the spring constant, so the ride does not get any harsher or firmer as a result of adding only a spacer.
I completely disagree. I've added spacers to my tacoma and tundra, and both vehicles had noticeably more harsh rides. It was harsh enough that I spent $950 on a set of DR coilovers for my tundra (and lost 0.5" of lift) just to get a better ride.

When you pre-load a spacer, you are giving the effect of "more weight" without actually increasing the weight. This creates lift because the spring is "pushing back" harder, but with stock weight, the vehicle sits higher.

So absolutely it affects ride!
 

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I don't want to go back and forth here, but this has been discussed at length. I've even made the following diagram for past discussions of this sort:

It's simple physics. The spring constant (rate) of a spring has units of "force"/"distance" (example: 700 N/mm or 700 lbs/in). So the force that the spring pushes back is of the equation: force = displacement X spring constant. The force acting on the spring does not change (which is approx 1/4 of the vehicle's weight) when you add a spacer. Neither does the spring constant (because it directly is related to the dimensions of the spring, which have not changed). Thus the displacement must remain the same in order to keep the equality. The spring does NOT compress any further with or without a spacer.

The misconception that you are 'preloading' the spring comes from the assembly of the strut. When the strut is assembled, yes, the spacer compresses the spring more, but that is only because of the extension limit of the shock.

The harsher ride that you are perceiving may come from upgrading your shocks. An aftermarket shock like the Bilstein HDs that most of us run has a higher dampening rate that is meant to decrease the 'mushy' and 'bouncy' effects of the stock shock. The harsher ride is a slight side effect of a higher dampening rate.

I hope this clears things up a bit. Cheers.
 

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blah blah blah

The spring does NOT compress any further with or without a spacer.
CORRECT. But given the same "pothole" the overall length of the strut will reduce less, and thus you have less "suspension" travel actually working to absorb the bumps == harsher ride.

Think about it.

The misconception that you are 'preloading' the spring comes from the assembly of the strut. When the strut is assembled, yes, the spacer compresses the spring more, but that is only because of the extension limit of the shock.
And "LOAD" (either from the spacer limiting the space for the spring to extend, or from vehicle weight) is still LOAD. The spacer provides the effect of a heavier load without actually increasing weight. It "preloads" the suspension.

The harsher ride that you are perceiving may come from upgrading your shocks. An aftermarket shock like the Bilstein HDs that most of us run has a higher dampening rate that is meant to decrease the 'mushy' and 'bouncy' effects of the stock shock. The harsher ride is a slight side effect of a higher dampening rate.
On my Tundra, I retained the factory shocks. EVERYTHING about the vehicle remained the same, except for the spacer. Even ran with stock tires until after the DR coilovers.

I hope this clears things up a bit. Cheers.
I've been crystal-clear on this issue. Honestly, I think it is you that needs to brush up on it. Cheers.
 

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CORRECT. But given the same "pothole" the overall length of the strut will reduce less, and thus you have less "suspension" travel actually working to absorb the bumps == harsher ride.
The suspension has less extension travel with a spacer installed. This is why you should not install too big of an inner strut spring spacer. If the weight of the vehicle barely overcomes the preload of the spring, you will experience an extremely harsh ride because you will be riding off the internal bumpstop of the shock (but that would be the cause of the harsh ride, not the spring).

However, when the spring operates between extension or compression stops, the spring will function exactly the same with or without a spacer. Think about this:

Two struts, A and B. Strut A has a 2" internal spring spacer. Strut B has a 2" external strut spacer. Will one give a harsher ride? Strut B is the same thing as just lowering the vehicle frame's strut mounting tower by 2"... you should agree that should do nothing to affect ride stiffness (although it will give you 2" of lift). Strut A is the same exact thing, but it reaches the end of the shock before strut B does. The only effective difference in the dynamics of strut A and B is that B can extend 2" further than A due to the mounting position of the shock piston rod.

For an interesting and detailed read about springs and how 'preload' affects (or doesn't affect ride stiffness) go here:
http://www.sportrider.com/tech/146_9510_tech/index.html
You won't find any technical articles that support the claim that spring spacers affect the spring constant, or that they change the ride firmness.

The spacer provides the effect of a heavier load without actually increasing weight. It "preloads" the suspension.
If it provided the effect of a heavier load, wouldn't the truck sag more? If you add in a 2" spacer, which somehow increases the load on the spring... you wouldn't get 2" of lift because the spring would be compressed further, right? Luckily physics keeps this from happening.

On my Tundra, I retained the factory shocks. EVERYTHING about the vehicle remained the same, except for the spacer. Even ran with stock tires until after the DR coilovers.
There are three possibilities here. A, you experienced the placebo effect. B, it's possible that your shocks may have been designed to have more dampening when in an extended state. C, your shocks did not provide enough downward movement and you were riding off the extension bumpstop whenever your suspension was extending.

I've been crystal-clear on this issue. Honestly, I think it is you that needs to brush up on it. Cheers.
I didn't mean to stir the pot here, but I like for people to have the facts straight. When it comes to items of physics, they can't be fought with perception.

If the above article and post doesn't convince you, we may just have to agree to disagree. No harsh feelings? :)
 

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If it provided the effect of a heavier load, wouldn't the truck sag more? If you add in a 2" spacer, which somehow increases the load on the spring... you wouldn't get 2" of lift because the spring would be compressed further, right? Luckily physics keeps this from happening.
Stand next to a wall and push on it. Do we agree that the wall "pushes back" with force equal to the force you exert on it?

This force that you exert, is effectively what "weight" is, thanks to gravity. Now apply the same "force" without the "weight". What happens? The wall actually moves you.

Maybe I'm not making myself clear.... But this is a well-known fact in other communities. You can believe whatever you want. We will have to agree to disagree.

This was explained to me years ago, in great detail, made perfect sense, and I observed it, in practice. The tacoma rode more stiffly with the spacers, but it was still a good ride. The Tundra was unbearable. That is why I went to the DR coilovers. When I spoke to Wheeler's Offroad while buying the coilovers they even confirmed that problem.

How could that be toyota-specific. Do they put voodoo on their springs? No.
 

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Stand next to a wall and push on it. Do we agree that the wall "pushes back" with force equal to the force you exert on it?
Sure, this is Newton's 3rd law of motion.

This force that you exert, is effectively what "weight" is, thanks to gravity. Now apply the same "force" without the "weight". What happens? The wall actually moves you.
Force = mass x accelleration

Weight is just a certain type of force that is due to the gravitational acceleration constant.

I'm assuming you are referring to pushing harder on a wall than is required to hold your body at a constant position. What you are describing is explained by the formula:

[Force(of your push) - Force(required to hold you up)] / (your mass) = the acceleration your body will experience

I'm not sure how that pertains to the application at hand?

Maybe I'm not making myself clear....

How could that be toyota-specific. Do they put voodoo on their springs? No.
I guess that's another option. You never know with those crazy Japanese engineers.
 
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