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Lowering Links For Leaf Spring Suspension

Posted By: knyech1

Lowering Links For Leaf Spring Suspension - 12/01/09 05:21 AM

I was on here a long time ago and I seen someone come out with links that gave you the option of raising the rear 1", lowering the rear 1", or lowering the rear 2" on a leaf spring suspension. Are these still available and who makes them?
Posted By: rockerbob

Re: Lowering Links For Leaf Spring Suspension - 12/01/09 11:36 AM

Here's a bump for ya
Posted By: StripeHOG

Re: Lowering Links For Leaf Spring Suspension - 12/01/09 11:46 AM

they sell lowering blocks at auto zone
Posted By: 67HEMI

Re: Lowering Links For Leaf Spring Suspension - 12/01/09 01:36 PM

AFCO sliders in place of the rear shackles is what I use. Depending on shackle length it will lower it at least an inch.
Posted By: 67Charger

Re: Lowering Links For Leaf Spring Suspension - 12/01/09 02:33 PM

I think he is referring to the front hangers with multiple mount holes...


...and I can't remember where I saw them either.
Posted By: megajoltman

Re: Lowering Links For Leaf Spring Suspension - 12/01/09 03:19 PM

http://www.firmfeel.com/leafhang_a.htm
Posted By: knyech1

Re: Lowering Links For Leaf Spring Suspension - 12/02/09 01:54 AM

Quote:

I think he is referring to the front hangers with multiple mount holes...


...and I can't remember where I saw them either.



yes I am

and the link above not sure that is them, I thought there were more holes than that but maybe not...
Posted By: megajoltman

Re: Lowering Links For Leaf Spring Suspension - 12/02/09 03:18 AM

Quote:

Quote:

I think he is referring to the front hangers with multiple mount holes...


...and I can't remember where I saw them either.



yes I am

and the link above not sure that is them, I thought there were more holes than that but maybe not...



I know I have seen one with 3 holes in it somewhere on the web can't seem find it
Posted By: bill_greenwood

Re: Lowering Links For Leaf Spring Suspension - 12/02/09 04:05 AM

When I built my car, I drilled an extra set of holes in the front spring box just for that purpose.
My question is, would lowering the rear (generally speaking) have a tendency to help or hurt my launch? This will have the effect of giving my bottom 4-link bar a slight downward angle. Any thoughts?
Posted By: knyech1

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 05:43 PM



I wanna know too
Posted By: MR_P_BODY

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 06:26 PM

Quote:

When I built my car, I drilled an extra set of holes in the front spring box just for that purpose.
My question is, would lowering the rear (generally speaking) have a tendency to help or hurt my launch? This will have the effect of giving my bottom 4-link bar a slight downward angle. Any thoughts?



In theory it would be lowering the IC which normally
gives you a shofter hit on the tire but increases the
length of time it hits the tire
EDIT
with doing just the lowering holes on the front you
really arent lowering the IC, your just lowering
the body some(the front spring bolt is still in the
same position as before) but you will have lowered
the rear of the body which should have made it easier
for the front to transfer the weight to the rear
(the CG would by rights have been moved up slightly)
Posted By: F1Scamp

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 10:15 PM





In theory it would be lowering the IC which normally
gives you a shofter hit on the tire but increases the
length of time it hits the tire
EDIT
with doing just the lowering holes on the front you
really arent lowering the IC, your just lowering
the body some(the front spring bolt is still in the
same position as before) but you will have lowered
the rear of the body which should have made it easier
for the front to transfer the weight to the rear
(the CG would by rights have been moved up slightly)




Lowering the front spring eye bolt height would be lowering the IC.
Also it will be raising the body of the car. You would have to bring the bolt above the factory bolt height to lower the body.
Posted By: MR_P_BODY

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 10:39 PM

Lowering the front spring eye bolt height would be lowering the IC.
Also it will be raising the body of the car. You would have to bring the bolt above the factory bolt height to lower the body.



Lowering the front bolt would lower the IC if you really
were lowering it BUT in this case you really arent,
its still in the same position in relation to the diff,
the IC is measured from the C/L of the diff and from
the ground, the spring arch didnt change when its
put in a upper or lower hole... it would be true if
this were actually a ladder bar
Posted By: F1Scamp

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:09 PM





Lowering the front bolt would lower the IC if you really
were lowering it BUT in this case you really arent,
its still in the same position in relation to the diff,
the IC is measured from the C/L of the diff and from
the ground, the spring arch didnt change when its
put in a upper or lower hole... it would be true if
this were actually a ladder bar




Have a diagram to show what you are saying? I have a couple of diagrams showing it is measured from the front of contact patch through the front of the spring bolt.?
Posted By: MR_P_BODY

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:14 PM

Have a diagram to show what you are saying? I have a couple of diagrams showing it is measured from the front of contact patch through the front of the spring bolt.?



Have a diagram of what... how the IC is measured?
Posted By: F1Scamp

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:15 PM

I made this horrible paint image to show what I meant. Am I wrong?

Attached picture 5877453-IC.JPG
Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:19 PM

my impression is if you lower the front spring bolt mount.
you are lowering the I/C...
(your raising the rear of the car..)
and your changing slightly the pinion angle.

if you wanted to lower the rear ride height
youd have to raise the front spring bolt mount
or you could put sliders on the rear of the spring..and lower the car..
but moveing either end of the spring will move I/C
the rear sliders effectively move the front spring eye down..when the chassis it self lowers.
the tire stay put..so the angle from tire to front spring mount still moves..
cheaspt.
Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:21 PM

Quote:

I made this horrible paint image to show what I meant. Am I wrong?



the only factor that i see may need to be addressed with this picture is
if you choose the upper hole in the diagram
you would have to adjust (lower) the position of the box/square in that drawing to account for the lower ride height..
cheapst.

Attached picture 5877465-5877453-IC.jpg
Posted By: MR_P_BODY

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:25 PM

Quote:

I made this horrible paint image to show what I meant. Am I wrong?



Well it doesnt have anything to do with the bottom of
the tire when you measure the IC... first in a ladder
bar or a leaf spring you cant change the length of
the IC, a ladder bar you can change the height of the
IC, but in a leaf spring you cant UNLESS you change
the arch of the spring where it would set up higher
or lower, but in the case here the arch didnt change
so the front bolt is still in the same height with
relationship to the diff... all that happened in this
case is the body moved up or down
Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:31 PM

Quote:

Quote:

I made this horrible paint image to show what I meant. Am I wrong?



Well it doesnt have anything to do with the bottom of
the tire when you measure the IC... first in a ladder
bar or a leaf spring you cant change the length of
the IC, a ladder bar you can change the height of the
IC, but in a leaf spring you cant UNLESS you change
the arch of the spring where it would set up higher
or lower, but in the case here the arch didnt change
so the front bolt is still in the same height with
relationship to the diff... all that happened in this
case is the body moved up or down




double check that MrP..

the reason i say this..is ..
if you take that diagram and measure the distance from the center of the axle
to the lower hole
then to the middle hole
then the top hole..
you will find the top holes distance will be the longer/longest distance of the three positions.
unless you drill the three holes along a radius from the center axle..(not as shown...as shown its running in a straigh verticle line..)
so you would either have to move the Box/chassis down...
to reach the spring bolt
or
raise the center line of the axle ..again...so the spring bolt will reach the hole.
this will inevitably change the three points that factor to find I/C
the only point (of the three) that doesnt move is the bottom of the tire..as it is setting on the ground...
and its relation ship to the axle centerline as these two points are determined by tire diameter..but i dirgress
cheapst

Attached picture 5877475-5877453-IC.jpg
Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:44 PM

this would show it with mounting holes along a radius...axis off the center line of the axle.

Attached picture 5877504-radiused.jpg
Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:45 PM

this would represent the effect of the change
from putting the the spring in the top hole.
and the chassis moveing down..to accomidate for the new ride height.

Attached picture 5877506-lower.jpg
Posted By: MR_P_BODY

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:47 PM

double check that MrP..

the reason i say this..is ..
if you take that diagram and measure the distance from the center of the axle
to the lower hole
then to the middle hole
then the top hole..
you will find the top holes distance will be the longer/longest distance of the three positions.
unless you drill the three holes along a radius from the center axle..(not as shown...as shown its running in a straigh verticle line..)
so you would either have to move the Box/chassis down...
to reach the spring bolt
or
raise the center line of the axle ..again...so the spring bolt will reach the hole.
this will inevitably change the three points that factor to find I/C
the only point (of the three) that doesnt move is the bottom of the tire..as it is setting on the ground...
cheapst



I dont see how your changing the arch of the spring
to make it longer... all I see is that the body moves
up or down... I dont see it changing the front bolt
in relation to the diff, unless you add or subtract
weight to change the arch of the spring...... JMO

Posted By: cheapstreetdustr

Re: Lowering Links For Leaf Spring Suspension - 03/20/10 11:58 PM

Quote:

double check that MrP..

the reason i say this..is ..
if you take that diagram and measure the distance from the center of the axle
to the lower hole
then to the middle hole
then the top hole..
you will find the top holes distance will be the longer/longest distance of the three positions.
unless you drill the three holes along a radius from the center axle..(not as shown...as shown its running in a straigh verticle line..)
so you would either have to move the Box/chassis down...
to reach the spring bolt
or
raise the center line of the axle ..again...so the spring bolt will reach the hole.
this will inevitably change the three points that factor to find I/C
the only point (of the three) that doesnt move is the bottom of the tire..as it is setting on the ground...
cheapst



I dont see how your changing the arch of the spring
to make it longer... all I see is that the body moves
up or down... I dont see it changing the front bolt
in relation to the diff, unless you add or subtract
weight to change the arch of the spring...... JMO





ok...ill buy that..
unless the see/saw effect of the rear spring mount moves..with the new chassis angle..behind the axle moves..(up)..
its prolly miniscule ...looking at that.
ill have to chew on this more..
but your point is taken...
cheapst
Posted By: Kiddart

Re: Lowering Links For Leaf Spring Suspension - 03/21/10 01:40 PM

Mancini Racing has them with two holes I think they are 70 bucks a pair in stock. Make sure you check Pinion angle when you move from hole to hole. You may need to add a very small 1 or 2 degree shim to get you where you want or take out depending what you are currently at. But them again I am not the smartest I am just recalling to what I have learned on here from Monte and Mr. P.

Attached picture 5878381-DSC05993.JPG
Posted By: F1Scamp

Re: Lowering Links For Leaf Spring Suspension - 03/21/10 04:14 PM

So.... I just want to make sure I am grasping this correctly.
The only way to effectively change the instant center on a leaf spring car is to change the height between the axle center and the front spring mount bolt? Correct?
So the flatter the front spring segment is, the "softer and longer" the car will "hit" the tire. The more arched the front spring segment, the "harder" it will "hit" the tire, more prone to wheelie's, etc.
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