VB&P smart struts and camber change
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Drifting
Joined: Sep 1999
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From: Wylie TX
VB&P smart struts and camber change
I was looking into getting some smart struts for my car. Actaully, I was going to just get the bracket since I already have their HD rods.
I understand that the stock system will increase the negative camber when the suspension is loaded and that the smart struts put the strut rods parallel with the half-shafts to prevent camber change with wheel travel. Isn't increasing the negative camber a good thing? I'm not talking about for straight line performance. I've seen some auto-x camber settings in the 1 - 2 degrees of negative camber. Wouldn't it be more ideal to have say 1/2 degree normally and have it increase to 1 1/2 degree when you go into a turn?
I think I'm just going to put in a spacer on my current bracket to reduce the amount of camber change, but I'm not convinced I should set it up so that they are parallel with the halfshafts. What are your opinions on this?
I understand that the stock system will increase the negative camber when the suspension is loaded and that the smart struts put the strut rods parallel with the half-shafts to prevent camber change with wheel travel. Isn't increasing the negative camber a good thing? I'm not talking about for straight line performance. I've seen some auto-x camber settings in the 1 - 2 degrees of negative camber. Wouldn't it be more ideal to have say 1/2 degree normally and have it increase to 1 1/2 degree when you go into a turn?
I think I'm just going to put in a spacer on my current bracket to reduce the amount of camber change, but I'm not convinced I should set it up so that they are parallel with the halfshafts. What are your opinions on this?
Race Director
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From: San Jose CA
Re: VB&P smart struts and camber change (Chris A)
The problem isn't with negative camber, but I believe that the unladen wheel goes quite positive through the suspension travel, which is definitely not a good thing. Also, the inside wheel goes excessively negative. The purpose of the Smart Struts is to maximize contact patch through the corner by minimizing camber change.
-Steve
-Steve
Thread Starter
Drifting
Joined: Sep 1999
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From: Wylie TX
Re: VB&P smart struts and camber change (Pacin'California)
I haven't run the numbers yet, but I plan on calculating the amount of camber increase per 1" of wheel travel. I still believe some camber change during wheel travel is better than none.
I also think having a little of positive camber on the inside (unladen) wheel is a good thing as well. Just as the outside wheel tends to ride on the outside portion of the tread (hence the neg camber) in a turn, the inside tire will tend to ride on the outside portion of the tread, so a little pos camber would help keep more tread in contact with the ground.
Anybody else have any opinions/facts on this?
[Modified by Chris A, 1:32 PM 11/26/2002]
I also think having a little of positive camber on the inside (unladen) wheel is a good thing as well. Just as the outside wheel tends to ride on the outside portion of the tread (hence the neg camber) in a turn, the inside tire will tend to ride on the outside portion of the tread, so a little pos camber would help keep more tread in contact with the ground.
Anybody else have any opinions/facts on this?
[Modified by Chris A, 1:32 PM 11/26/2002]
Race Director
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From: San Jose CA
Re: VB&P smart struts and camber change (Chris A)
Taken from VB&P Product catalog:
"At 2-1/2 inches of wheel travel, the 1963 Corvette rear camber setting changes over 2°. The same car equipped with Smart Struts® has a measured camber change of less than one tenth of a degree at over 5-1/2 inches of wheel travel!"
http://www.corvettefaq.com/c3/6link/index.html
A review of a six link setup, which promotes the same ideas as the struts.
I'll try to think of a way to measure camber change using trig. Been a while since I've taken a geometry class.
-Steve
*edit* I would guess you could simulate suspension travel by jacking or lowering the suspension, and remeasuring travel. Get a measurement for the car at "neutral loaded' suspension travel, then jack it up one inch, and let it down an inch from the neutral position, to find how much a loaded wheel changes camber in one inch, and how much it changes when being unloaded an inch.
[Modified by Pacin'California, 3:03 PM 11/25/2002]
"At 2-1/2 inches of wheel travel, the 1963 Corvette rear camber setting changes over 2°. The same car equipped with Smart Struts® has a measured camber change of less than one tenth of a degree at over 5-1/2 inches of wheel travel!"
http://www.corvettefaq.com/c3/6link/index.html
A review of a six link setup, which promotes the same ideas as the struts.
I'll try to think of a way to measure camber change using trig. Been a while since I've taken a geometry class.
-Steve
*edit* I would guess you could simulate suspension travel by jacking or lowering the suspension, and remeasuring travel. Get a measurement for the car at "neutral loaded' suspension travel, then jack it up one inch, and let it down an inch from the neutral position, to find how much a loaded wheel changes camber in one inch, and how much it changes when being unloaded an inch.
[Modified by Pacin'California, 3:03 PM 11/25/2002]
Thread Starter
Drifting
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From: Wylie TX
Re: VB&P smart struts and camber change (Pacin'California)
Steve, I think your missing my point. I'm not talking about stock vs. smart struts. I'm trying to figure out if a little camber change during wheel travel is good. To me, I think it is. I'll be putting a spacer between my strut rod bracket and the diff to put my strut rods closer to parallel with the halfshafts than the stock system.
Le Mans Master
Joined: Aug 2000
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From: Austin TX
Re: VB&P smart struts and camber change (Chris A)
See the archived article on suspensions from the Vette Improvement Program written by John Greenwood. He describes what you are talking about and includes a couple of graphs.
It's an excellent article.
It's an excellent article.
Melting Slicks
Joined: Jun 2001
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From: Moro IL
Re: VB&P smart struts and camber change (Chris A)
I think you have your negative and positive backwards unless I'm reading something wrong. I'll attempt to make a crude sketch here. /car\ this is negative and you'll notice both tires are loaded on the inside edge. \car/ this is positive and both tires will be initially loaded on the outside edge. Your outside tires of a turn will always have the greatest loading, this is why you'll often see the inside front tire on many race cars be a little off the ground on a turn on that side of the car. I've never seen a road race or autocross car run positive camber anywhere. It simply gives you too little contact patch on the outside tires as the outside tire tries to roll positive. Now circle track where they just turn one way all the time may be another story where they may want to run positive camber on the inside tires but they would still need to be negative on the outside.
:cheers:
Pat Kunz
:cheers:
Pat Kunz
Race Director
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From: San Jose CA
Re: VB&P smart struts and camber change (Chris A)
I'll try this again...
Taken from "How to Make Your Car Handle", by Fred Puhn
"For best cornering power, the camber should be zero on the outside tire in a corner. Let's assume that your car has a camber change of 2 degrees positive at body roll of 3 degrees. If you select 3 degrees as the maximum body roll, the static camber would have to be set at 2 degrees negative to make it zero in a corner." p 87
Camber change is expected, but it seems moreso to be related to body roll than suspension travel. I suppose this is up to interpretation...
"Suspensions are designed and adjusted mainly to keep those wide tires flat on the surface even during suspension movements." p 20
I'm supposing that the problem with the stock strut design is that there is far too much camber change- the same problem inherent to the suspension in the swing-axled Corvair, although that was to a far greater degree. When the body rolls, the wheel is naturally going to pivot. Camber change is expected, but undesired. Alignment is intended to correct camber change. Static negative camber is undesired, but a fact of life for proper cornering. The "perfect handling car" would have 0 body roll and 0 camber the entire time. (Not a very comfortable ride... )
-Steve
Taken from "How to Make Your Car Handle", by Fred Puhn
"For best cornering power, the camber should be zero on the outside tire in a corner. Let's assume that your car has a camber change of 2 degrees positive at body roll of 3 degrees. If you select 3 degrees as the maximum body roll, the static camber would have to be set at 2 degrees negative to make it zero in a corner." p 87
Camber change is expected, but it seems moreso to be related to body roll than suspension travel. I suppose this is up to interpretation...
"Suspensions are designed and adjusted mainly to keep those wide tires flat on the surface even during suspension movements." p 20
I'm supposing that the problem with the stock strut design is that there is far too much camber change- the same problem inherent to the suspension in the swing-axled Corvair, although that was to a far greater degree. When the body rolls, the wheel is naturally going to pivot. Camber change is expected, but undesired. Alignment is intended to correct camber change. Static negative camber is undesired, but a fact of life for proper cornering. The "perfect handling car" would have 0 body roll and 0 camber the entire time. (Not a very comfortable ride... )
-Steve
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Melting Slicks
Joined: May 2002
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From: Wisconsin
Re: VB&P smart struts and camber change (Chris A)
You know what I say? Someone with a G-Tech go test your car a few times for a skidpad rating, install the smart struts only, and do a few more skidpad runs. Stock vs. stock w/smart struts. Should pretty much tell us if they improve a lot or a little.
Thread Starter
Drifting
Joined: Sep 1999
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From: Wylie TX
Re: VB&P smart struts and camber change (Schmucker)
73 LS-4, yes I did screw up. I got my inside and outside backwards. I have now edited that post to correct it.
flynhi, thanks for reminding me about that I'll go back and read up on it.
[Modified by Chris A, 1:33 PM 11/26/2002]
flynhi, thanks for reminding me about that I'll go back and read up on it.
[Modified by Chris A, 1:33 PM 11/26/2002]
Team Owner
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: VB&P smart struts and camber change (Chris A)
I have smart struts with poly ends. In my setup it only requires @ .63 degrees of neg. camber to get equal heat across the face of rear tires. On both autocross and the 100 ft skid pan.
Racer
Joined: Oct 2002
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From: Marlborough MA
Re: VB&P smart struts and camber change (Chris A)
OK, so what is the physical difference between the stock system and the "Smart Struts". Are the inboard pivot points lowered/farther outboard than the stock? That is the only area where I can think they could've changed the suspension geometry to improve the amount of camber change.
I boought them as part of the Performanc Plus System purchase, but my 75 is still out in the pasture awaiting the finishing of the garage... :rolleyes:
I boought them as part of the Performanc Plus System purchase, but my 75 is still out in the pasture awaiting the finishing of the garage... :rolleyes:
Thread Starter
Drifting
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From: Wylie TX
Re: VB&P smart struts and camber change (75 BBC Stingray)
Yes, they lower the strut rod mounting location on the diff making the strut rods (at least close) parallel to the halfshafts. I'm going to save the $120 for the bracket and just put a spacer on my existing bracket. The smart struts also have a cam to adjust the height of the diff side of the rods.
Race Director
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From: HONOLULU HAWAII
Re: VB&P smart struts and camber change (Chris A)
Chris A,
I'm watching this post....since camber is very important in both drag racing and circle track....I was told 1 degree of positive camber was good in drag racing since the weight of the car during launch sets the tires to zero for a good flat to the ground patch.....I'm not sure if this is true or false...however I'm always open to suggestion to find the best set up....I have the V/B system on my car and the struts are horizontal to the half shafts......I will be watching this post with great interest.... :seeya Cappy
I'm watching this post....since camber is very important in both drag racing and circle track....I was told 1 degree of positive camber was good in drag racing since the weight of the car during launch sets the tires to zero for a good flat to the ground patch.....I'm not sure if this is true or false...however I'm always open to suggestion to find the best set up....I have the V/B system on my car and the struts are horizontal to the half shafts......I will be watching this post with great interest.... :seeya Cappy
Team Owner
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: VB&P smart struts and camber change (8T1-7T9 BIONIC VETTE)
If this statement is true: I don't know why VB&P used 63 as an example other than it might have the worst case senario for Vette IRS.
-------------------------------------------------------------------------------------
"At 2-1/2 inches of wheel travel, the 1963 Corvette rear camber setting changes over 2°. The same car equipped with Smart Struts® has a measured camber change of less than one tenth of a degree at over 5-1/2 inches of wheel travel!"
--------------------------------------------------------------------------------------
Cappy, You would want your drag vette rear tires placed at or near "Zero" camber to get the max contact patch. Then of course testing
-------------------------------------------------------------------------------------
"At 2-1/2 inches of wheel travel, the 1963 Corvette rear camber setting changes over 2°. The same car equipped with Smart Struts® has a measured camber change of less than one tenth of a degree at over 5-1/2 inches of wheel travel!"
--------------------------------------------------------------------------------------
Cappy, You would want your drag vette rear tires placed at or near "Zero" camber to get the max contact patch. Then of course testing
Safety Car
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From: Fountain Hills AZ
Re: VB&P smart struts and camber change (8T1-7T9 BIONIC VETTE)
Chris A,
I'm watching this post....since camber is very important in both drag racing and circle track....I was told 1 degree of positive camber was good in drag racing since the weight of the car during launch sets the tires to zero for a good flat to the ground patch.....I'm not sure if this is true or false...however I'm always open to suggestion to find the best set up....I have the V/B system on my car and the struts are horizontal to the half shafts......I will be watching this post with great interest.... :seeya Cappy
I'm watching this post....since camber is very important in both drag racing and circle track....I was told 1 degree of positive camber was good in drag racing since the weight of the car during launch sets the tires to zero for a good flat to the ground patch.....I'm not sure if this is true or false...however I'm always open to suggestion to find the best set up....I have the V/B system on my car and the struts are horizontal to the half shafts......I will be watching this post with great interest.... :seeya Cappy
Race Director
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From: HONOLULU HAWAII
Re: VB&P smart struts and camber change (Vetterodder)
Vetterodder,
Yep....Took the front sway bar off and it really improved the lift up front...I love watching the nose jump up during launch....I also removed the rear sway bar and handling continues to be excellent in turns....must be the V/B Front Mono spring set up....and the G-Force 17" tires.....I don't know.....but it handles well without both sway bars. :seeya Cappy
Yep....Took the front sway bar off and it really improved the lift up front...I love watching the nose jump up during launch....I also removed the rear sway bar and handling continues to be excellent in turns....must be the V/B Front Mono spring set up....and the G-Force 17" tires.....I don't know.....but it handles well without both sway bars. :seeya Cappy
