Re: How far should rear springs arch?
[Re: A727Tflite]
#2583405
11/26/18 09:27 PM
11/26/18 09:27 PM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
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Phila. Pa.
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This is why production springs have very little arch, for toe control.
Drag race springs (without traction aids) generally want stiffer front segments, a higher front eye, and bias for launch control.
Exactly. Stock springs were designed to be flat under average intended use. That's why there were so many different spring packs. reposting from another thread:Increasing the rear arch can improve launch on the drag strip if properly combined with sticky tires. It is also used sometimes by circle track cars in combination with other changes to improve coming off the corners. On a production car, arch can have negative handling effects. Flat is basicly correct. This is how Chrysler designed 'em. Chrysler explains it in the in this booklet about handling. Trying to find the original rear ride height is difficult. The only rear height info I've seen from the factory is at Hamtramck Historical. http://www.hamtramck-historical.com/PassengerCarBumperHeights-01.shtml Note that on page two that these are for fully loaded (5 passengers, full fuel) but does not say what options. Also the bumpers are somewhat adjustable and the body has some slop. So these are visual body related, not so much suspension setup info. If you will be taking it to the track, then the arch may be helpful. Adding helper springs is only good for specific loaded situations. Otherwise its stiffening the rear roll rate and can lead to oversteer when your not going to appreciate it.
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Re: How far should rear springs arch?
[Re: Mattax]
#2583413
11/26/18 09:38 PM
11/26/18 09:38 PM
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Joined: Dec 2003
Posts: 22,788 Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
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Bitopia
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This is why production springs have very little arch, for toe control.
Exactly. Stock springs were designed to be flat under average intended use. Or maybe to be more precise, flat and approaching level.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: How far should rear springs arch?
[Re: DrCharles]
#2583467
11/26/18 11:56 PM
11/26/18 11:56 PM
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Joined: Jan 2003
Posts: 5,791 Hamilton, Ontario Canada
Magnum
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Hamilton, Ontario Canada
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The shocks only have about 1.5 and 2.5" of rod exposed.
The shock absorber has less travel when standing more upright. The original position has a very steep angle to it. You not only lost compression travel but the same shock is now stronger in that position.
Last edited by Magnum; 11/26/18 11:57 PM.
69 Super Bee, 93 Mustang LX, 04 Allure Super
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Re: How far should rear springs arch?
[Re: Mattax]
#2584041
11/28/18 04:12 AM
11/28/18 04:12 AM
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Joined: Jun 2012
Posts: 1,899 MYRTLE BEACH SOUTH CAROLINA
ek3
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MYRTLE BEACH SOUTH CAROLINA
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This is why production springs have very little arch, for toe control.
Drag race springs (without traction aids) generally want stiffer front segments, a higher front eye, and bias for launch control.
Exactly. Stock springs were designed to be flat under average intended use. That's why there were so many different spring packs. reposting from another thread:Increasing the rear arch can improve launch on the drag strip if properly combined with sticky tires. It is also used sometimes by circle track cars in combination with other changes to improve coming off the corners. On a production car, arch can have negative handling effects. Flat is basicly correct. This is how Chrysler designed 'em. Chrysler explains it in the in this booklet about handling. Trying to find the original rear ride height is difficult. The only rear height info I've seen from the factory is at Hamtramck Historical. http://www.hamtramck-historical.com/PassengerCarBumperHeights-01.shtml Note that on page two that these are for fully loaded (5 passengers, full fuel) but does not say what options. Also the bumpers are somewhat adjustable and the body has some slop. So these are visual body related, not so much suspension setup info. If you will be taking it to the track, then the arch may be helpful. Adding helper springs is only good for specific loaded situations. Otherwise its stiffening the rear roll rate and can lead to oversteer when your not going to appreciate it. the toe is fixed in a solid rear axel. you have to bend the tubes to change it . rear steer is what you are talking about . as the leafs compress, they move the rear end back... if the arch is different in the pair of springs, the long side will move further and will steer .....
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Re: How far should rear springs arch?
[Re: A727Tflite]
#2584119
11/28/18 12:13 PM
11/28/18 12:13 PM
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Joined: Dec 2003
Posts: 22,788 Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
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Bitopia
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However that is not true with deep arched springs if both wheels stay both on same side of axle centiliter in a hard turn, There is still a steering factor, but its not because wheels are moving opposite directions. This exception would certainly not be the norm.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: How far should rear springs arch?
[Re: A727Tflite]
#2584470
11/29/18 12:54 AM
11/29/18 12:54 AM
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Joined: Jun 2012
Posts: 1,899 MYRTLE BEACH SOUTH CAROLINA
ek3
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It rear steers because “toe” has changed through suspension travel - toe relative to the centerline of the car.
On a hard turn one rear tire toes in the other out - relative to the centerline of the car. I am NOT picking on anyone.... toe is when the distance between a pair of tires is not the same . toe in, is less, toe out is more... when cornering in a left hand turn , the right rear [ body ] will roll over and this causes the right rear spring to flatten out making the right rear tire to move back. at the same time , the left rear [body ] is coming up, causing the left rear tire to come forward. thus the rear end has turned to the right . just like a pair of wheels on a creeper do when it is turning . the toe has not changed at all or at any time . if you place toe plates on the rear and measure , what you have is what you have .you can turn the rear but , both tires are moving together . the front spring segment travels through an up and down arc as well and as the spring is flattened out , it gets longer so that side goes backwards. the opposite happens to the other side ! just trying to explain- I know you meant the same thing.
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Re: How far should rear springs arch?
[Re: DrCharles]
#2584510
11/29/18 01:58 AM
11/29/18 01:58 AM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
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Thanks, I appreciate the extra detail. But I only have a 12 ton press and anyway I'd need more than 1/2" arch, at least on one of them. I think these 46 year old springs have had their day and it's time to recycle them into coat hangers New ones will be here tomorro.
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Re: How far should rear springs arch?
[Re: DrCharles]
#2584858
11/29/18 09:12 PM
11/29/18 09:12 PM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
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These: https://www.generalspringkc.com/product_p/33-909.htmIt says "2-1/2 inch lift" so I was a bit wary - but they finally came today and I just finished putting them on. The car looks just right. I don't know if the spring relocation has the front eye at the same height as original - it may have been lowered by whoever did the work. The shackles are pointing towards the rear, but at a less acute angle. With the old springs, the rear eye was just about hitting the frame. I may try lowering the front just a hair. It's a little high right now but Milodon oil pans are expensive to replace! Now for alignment, what should I do about the front ride height? I weigh anywhere from 260 to 295 lb depending on the season so should that much weight be in the driver's seat? Will only occasionally have a passenger.
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