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Shock & differential spacers

Icutmetl

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Icutmetl Enthusiast

Icutmetl

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Posted

At what point do differential drop spacers & shock extenders become a must when adding front end height? 
 

I want to add an inch to both ends of my truck; the max I want to add to the front would be 1-1/2”. I like the rake, and have garage door clearance issues. 
 

 

 

 

Waaazooo Senior Enthusiast

Waaazooo

Posted
Posted
At what point do differential drop spacers & shock extenders become a must when adding front end height? 

 

I want to add an inch to both ends of my truck; the max I want to add to the front would be 1-1/2”. I like the rake, and have garage door clearance issues. 

 

 

 

 

This is a pretty complex question, shock spacers depends upon the shock that you’re using and it’s total travel.

 

Differential drops are really only needed when your CV axle is at too great of an angle to operate without binding. I found that when lifting my truck front end more than a couple of inches the cv angles were to the point of the ribs on the boot were rubbing 5907490da26a520246c3ff0e5e39dc81.jpg

 

They were never binding but was at the limit that people told me it was borderline bad. I sit at about 12-15* from horizon, now. I used a 3/4 spacer and it improved enough I was happy. I don’t have an after picture.

 

 

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Icutmetl Enthusiast

Icutmetl

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28 minutes ago, Waaazooo said:


This is a pretty complex question, shock spacers depends upon the shock that you’re using and it’s total travel.

Differential drops are really only needed when your CV axle is at two grade of an angle to operate without binding. I found that when lifting my truck front end more than a couple of inches the cv angles were to the point of the ribs on the boot were rubbing 5907490da26a520246c3ff0e5e39dc81.jpg

They were never binding but was at the limit that people told me it was borderline bad. I sit at about 12-15* from horizon, now. I used a 3/4 spacer and it improved enough I was happy. I don’t have an after picture.


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What’s a “two grade?“

 

Assume that stock or stock length shocks are used. 
 

I understand excessive CV joint angles. My question was at what point spacers became necessary. To put it differently & more directly; would differential drop spacers be needed after 1”-1.5”?

dplarson Enthusiast

dplarson

Posted
Posted
What’s a “two grade?“
I read it as ...too great...

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corn18 Enthusiast

corn18

Posted
Posted

Hard to give a definitive answer, but when I was looking to level the front, I jacked up the front and took pics at different heights.  Thread linked below.  I ultimately decided to drop the rear with shackles.  But I did end up cranking in 3/4" of lift on the front.  

 

If I were going to raise the front, I would go 1.5" max without further mods.  Anything higher than that and I would drop the diff, buy new UCAs and get shock extenders.  Basically the full rough country front leveling kit.

 

 

https://www.gm-trucks.com/forums/topic/236884-level-or-lift-2015-2500hd/

Icutmetl Enthusiast

Icutmetl

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Posted
1 minute ago, Tom Hole said:

Hard to give a definitive answer, but when I was looking to level the front, I jacked up the front and took pics at different heights.  Thread linked below.  I ultimately decided to drop the rear with shackles.  But I did end up cranking in 3/4" of lift on the front.  

 

If I were going to raise the front, I would go 1.5" max without further mods.  Anything higher than that and I would drop the diff, buy new UCAs and get shock extenders.  Basically the full rough country front leveling kit.

 

 

https://www.gm-trucks.com/forums/topic/236884-level-or-lift-2015-2500hd/

 

Thank you. I’m not going to drop my rear end, though. If I’m understanding you correctly, a +1” change in front doesn’t necessitate spacers- that’s the kind of info I’m after.

corn18 Enthusiast

corn18

Posted
Posted
1 minute ago, Icutmetl said:

If I’m understanding you correctly, a +1” change in front doesn’t necessitate spacers- that’s the kind of info I’m after.

IMHO, a +1" change in front height using the torsion keys doesn't necessitate spacers.

gearheadesw Senior Enthusiast

gearheadesw

Posted
Posted

Ha, I feel compelled to reply, that's my truck's suspension pictured in that link to the other thread.

 

Everyone is saying the right things here. If your shock has longer travel then a stock shock, it may not need a spacer at all. A stock shock, you may want to start adding length in the 1.5 to 1.75 inch territory.

A diff drop is dependent on the rubber fins touching each other as mentioned above, they'll wear out where they touch.

Waaazooo Senior Enthusiast

Waaazooo

Posted
Posted
What’s a “two grade?“
 
Assume that stock or stock length shocks are used. 
 
I understand excessive CV joint angles. My question was at what point spacers became necessary. To put it differently & more directly; would differential drop spacers be needed after 1”-1.5”?

Yeah it was voice to text. Ooops. It’s kind of a judgement call. What do you deem as acceptable.


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Big Whiskey Senior Enthusiast

Big Whiskey

Posted
Posted

Good advice here. On the stock shocks, you can raise the front around 1" without needing to add any hardware. I had a slight bumping/thumping over big bumps and speed bumps with a 1.5" lift in the front (7-8 turns on the factory keys). I added shock extensions, and the noise went away, so that tells me 1.5" is about the limit for factory shocks. If I had a do-over, I would have went with something like the Rough Country 3" kit. I would have installed all the parts, but kept the front around 2.5", which would be just enough to run 35" tires.

Icutmetl Enthusiast

Icutmetl

Posted
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Posted
8 hours ago, Big Whiskey said:

Good advice here. On the stock shocks, you can raise the front around 1" without needing to add any hardware. I had a slight bumping/thumping over big bumps and speed bumps with a 1.5" lift in the front (7-8 turns on the factory keys). I added shock extensions, and the noise went away, so that tells me 1.5" is about the limit for factory shocks. If I had a do-over, I would have went with something like the Rough Country 3" kit. I would have installed all the parts, but kept the front around 2.5", which would be just enough to run 35" tires.

Thank you; that’s good feedback ?

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