Lowering the rear …
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Lowering the rear …
...the front will be later..
I purchased a lowering kit (long bolt). For my ‘90 auto.
I understand I need to use more thread lowering the nut in order to lower the rear of the car.
I don’t really understand why lowering the nuts (toward the ground) the car will be lower.
This is not clear to my simply mind. I’m searching a technical explanation.
If I have a bike and I need to lower it I just use shorter shocks and the bike will be lower. (this is easy to understand).
Others question: If I drop the bolt 1” the car will drop 1”? and the rear spring will be stiffer or softer?
Maybe someone will answer to my question with a word: “stiffer!”
maybe the real answer culd be: "like before"
But…my poor simply mind is thinking: “softer”
If I raise up the nut I will increase the pre-load on the spring , if I lower the nut I will decrease the preload on the spring. (for hypothesis if I have a more longer bolt (say 20”) and I could drop the nut at the end of the last thread the spring will be totally Unloaded = softer).
The end of the story is that if I lower the rear of the car the rear suspension will be also softer!?!??
Please help me to understand…. I like to do modifications on my car …. I need also technically understand what I’m doing.
Sorry for my bad English too……
Thanks.
-Beppe-
I purchased a lowering kit (long bolt). For my ‘90 auto.
I understand I need to use more thread lowering the nut in order to lower the rear of the car.
I don’t really understand why lowering the nuts (toward the ground) the car will be lower.
This is not clear to my simply mind. I’m searching a technical explanation.
If I have a bike and I need to lower it I just use shorter shocks and the bike will be lower. (this is easy to understand).
Others question: If I drop the bolt 1” the car will drop 1”? and the rear spring will be stiffer or softer?
Maybe someone will answer to my question with a word: “stiffer!”
maybe the real answer culd be: "like before"
But…my poor simply mind is thinking: “softer”
If I raise up the nut I will increase the pre-load on the spring , if I lower the nut I will decrease the preload on the spring. (for hypothesis if I have a more longer bolt (say 20”) and I could drop the nut at the end of the last thread the spring will be totally Unloaded = softer).
The end of the story is that if I lower the rear of the car the rear suspension will be also softer!?!??
Please help me to understand…. I like to do modifications on my car …. I need also technically understand what I’m doing.
Sorry for my bad English too……
Thanks.
-Beppe-
Pro
Joined: Jun 2001
Posts: 648
Likes: 0
Re: Lowering the rear … (conv90)
:lurk:
I'm curious about the same questions you asked. When my mechanic was doing new bearings on the rear he put in new poly bushings and longer bolts for the spring. He didn't get the height right and I've got to lower it down.
I'm curious about the same questions you asked. When my mechanic was doing new bearings on the rear he put in new poly bushings and longer bolts for the spring. He didn't get the height right and I've got to lower it down.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Re: Lowering the rear … (conv90)
waiting for some answer, another question turns around my mind...
If I need to add strenght to the rear spring I need to relocate the spacers from over the spring to the lower side of the spring...or the inverse?
-Beppe- :confused:
[Modified by conv90, 8:41 PM 3/28/2003]
If I need to add strenght to the rear spring I need to relocate the spacers from over the spring to the lower side of the spring...or the inverse?
-Beppe- :confused:
[Modified by conv90, 8:41 PM 3/28/2003]
Racer
Joined: Oct 2002
Posts: 372
Likes: 1
From: Corunna Mi
Re: Lowering the rear … (conv90)
Maybe an easy way to think of it is to picture the spring out of the car and it forms an arc. The weight (car body) is placed in the center of the arc and the ends where the bolts go hold it all up towards your ceiling. Since you are lowering the spring ends closer to the ground the weight (vette) lowers closer to the ground. Spring rate would not be any stiffer or softer other than what the longer travel of the shocks might contribute. . Can you see now what the spacers would do? You only need them relocated to the bottom to make the bolts that hold them on the same length as with the spacers on top.
:steering:
:steering:
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: Lowering the rear … (conv90)
The better method of lowering the rear is to flip the spacers from on top to under the spring. You can still go a bit lower with the long bolts. It changes your rear alignment as well as the spring rate. It reduces the pre-load, so initially, your spring is effectively softer.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Re: Lowering the rear … (h rocks)
bad-zr1 said: " Maybe an easy way to think of it is to picture the spring out of the car and it forms an arc. The weight (car body) is placed in the center of the arc and the ends where the bolts go hold it all up towards your ceiling. Since you are lowering the spring ends closer to the ground the weight (vette) lowers closer to the ground. Spring rate would not be any stiffer or softer other than what the longer travel of the shocks might contribute.
h rocks said:
well, I want to see if I understand.
If I lower the rear lowering the nuts on the bolts, the car will be lower (the spring will be not stiffer and not softer, It will be the same as before.)
If I flip the spacers from on top to under the spring i will lower also the car but I will change the rate of the spring too (softer)
.....So if relocate spacers from BOTTOM the spring to over the spring I must think The car will be Higher and stiffer...
I'm right?
-Beppe-
h rocks said:
The better method of lowering the rear is to flip the spacers from on top to under the spring. You can still go a bit lower with the long bolts. It changes your rear alignment as well as the spring rate. It reduces the pre-load, so initially, your spring is effectively softer.
If I lower the rear lowering the nuts on the bolts, the car will be lower (the spring will be not stiffer and not softer, It will be the same as before.)
If I flip the spacers from on top to under the spring i will lower also the car but I will change the rate of the spring too (softer)
.....So if relocate spacers from BOTTOM the spring to over the spring I must think The car will be Higher and stiffer...
I'm right?
-Beppe-
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Melting Slicks
Joined: Mar 2002
Posts: 2,526
Likes: 104
From: Stafford Va
Re: Lowering the rear … (vstol)
One other thought, I have grawled under several vettes and their rear axles are level or very close where mine are not. Bringing them to level will lower the car some. Any suggestions?
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Re: Lowering the rear … (conv90)
IN THIS WHEEK-END I thought to my questions and maybe I have some answer to myself .
These are my conclusions :
Lowering the nuts on longer bolts, I have a relocation of the point where the end of the spring attaches to the wheel. This ‘relocation’ is under the standard point. The spring is attached to the car body so the body of the car will be lower than before.
I can’t in any way change the rate of the spring using spacers. If I add spacers over the spring I only change the point where the body of the car attaches to the spring. (the car will be higher ).If I add spacers under the spring (again I only change the point where the body of the car attaches to the spring and the car will be lower).
The only way to change the rate of the spring is to….change the spring!
I can slightly change the quality of the suspension using different shock absorbers.
If someone think that I’m completely wrong, please give tech explanations.
-Beppe-
These are my conclusions :
Lowering the nuts on longer bolts, I have a relocation of the point where the end of the spring attaches to the wheel. This ‘relocation’ is under the standard point. The spring is attached to the car body so the body of the car will be lower than before.
I can’t in any way change the rate of the spring using spacers. If I add spacers over the spring I only change the point where the body of the car attaches to the spring. (the car will be higher ).If I add spacers under the spring (again I only change the point where the body of the car attaches to the spring and the car will be lower).
The only way to change the rate of the spring is to….change the spring!
I can slightly change the quality of the suspension using different shock absorbers.
If someone think that I’m completely wrong, please give tech explanations.
-Beppe-
