for everybody that is using offset shackles
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pntastar69
Well-Known Member
Its a 1/2" offset so its 1/2" inward from the stock location.
It depends on which shackles you use. The MP offset shackles are .8" offset. Others are .5 (1/2"). That's why I always stuck with the MP.
67dartgtgo
Well-Known Member
Rusty's right. I moved my perches 3/4" with the MP set.
my68barracuda
Well-Known Member
question
I understand the offset rear shackels and moving the spring perch,, but with that set up do you just leave the front spring mount in its stock location?
thanks
I understand the offset rear shackels and moving the spring perch,, but with that set up do you just leave the front spring mount in its stock location?
thanks
It actually doesn't depend on what kit you use. While the MP kit claims to move the springs 3/4", if you actually measure the front hanger the difference is only 1/2" from stock.
I have a MP set on my Duster, and I measured it and compared it to the stock hanger when I read Dr. Diff's comment that the MP kit only had a 1/2" offset, just like his. There's only a 1/2" to the frame to move the front hanger. And because of the recessed bolts Dr. Diff uses, you don't have to cut a hole in the frame like you do to clear the front eye bolt like you do for the MP kit. I wish I'd known THAT before I installed the MP kit in my car.
You can put the perches in 3/4", and it will get you a little extra space, but it also puts a side load on the springs. I installed my MP kit with the perches at 42" C-C, so the springs are in line with no side loading.
No, the front hanger is offset as well, 1/2" inboard so the hanger is against the frame.
What's your opine on shimming the front hangars,as per the Mopar chassis book(per drag strip specs,not road racing) Just curious,on your thoughts,72 (002/003 springs...)
You mean shimming between the frame and the hanger to correct the thrust angle right? Those are used in all kinds of applications, not just drag racing. Hotchkis sells shims with its springs to correct thrust angle,
But I'm not a drag racer, and I know that the SS springs have different arches and spring rates. The only thing about that is the thrust angle might tend to change a bit when you're under load, like launching the car, so the static thrust angle and the dynamic thrust angle might not be the same thing. In that particular case, I don't know that you'd always want to correct the static thrust angle, since you might care more about what it's doing at launch. Maybe someone that knows their SS springs or drag racing better than I do can comment. But typically, yes, you'd want to use the shims to correct the thrust angle of the rear.
You mean shimming between the frame and the hanger to correct the thrust angle right? Those are used in all kinds of applications, not just drag racing. Hotchkis sells shims with its springs to correct thrust angle,
But I'm not a drag racer, and I know that the SS springs have different arches and spring rates. The only thing about that is the thrust angle might tend to change a bit when you're under load, like launching the car, so the static thrust angle and the dynamic thrust angle might not be the same thing. In that particular case, I don't know that you'd always want to correct the static thrust angle, since you might care more about what it's doing at launch. Maybe someone that knows their SS springs or drag racing better than I do can comment. But typically, yes, you'd want to use the shims to correct the thrust angle of the rear.
Thanks. Saw the front to back ,parallel measurements. You answered my question.
my68barracuda
Well-Known Member
, I had seen the off set rear shackels,, but not the fronts,, I'll look for those.
another question.
when the perches are moved,, are the existing ones typically scraped when they are cut off?
asking as the 8.75 housing that I have now has new perches on it, can they be cut off and moved, or it best to just pick up another set?
thanks
Yes. The old perches are generally canned. The accepted and easiest method to remove them destroys them. You cut them down the center length wise and break each individual piece off. But be forewarned. If you get the MP replacements, the damn locating hole for the leaf spring pin IS THE WRONG SIZE! It's too big. I always used Competition Engineering, but I am sure Mancini has some too. They are not expensive.
All of them I have ever installed from MP were right on top of 3/4" Here's the proof. The others that only move them in 1/2 do not require a hole in the frame rail for the nut on the back side of the front hanger, the MP hangers do. I have installed a lot of these kits. I don't know where you're measuring from, but either one of two things has occurred. Either Mopar has changed the kit to only move them in 1/2", OR you are measuring incorrectly.
Look at these links. Anyone who can read a tape measure can see clearly that there is more than 1/2" offset in those shackles.
http://www.summitracing.com/parts/DCC-4120075/
Look at how the brackets are made. Yes, the studs ARE 1/2" offset compared to stock, however, the brackets are made so that they offset the rest. Look at how the bracket walls are offset as well. You cannot measure just the offset of the studs that hold the bracket on. You have to measure the entire amount, including the offset of the bracket itself. They move the spring inboard exactly what MP says they do. I have measured it enough that I can do it in my sleep.
http://www.summitracing.com/parts/dcc-4120077/applications/
http://www.summitracing.com/parts/DCC-4120075/
Look at how the brackets are made. Yes, the studs ARE 1/2" offset compared to stock, however, the brackets are made so that they offset the rest. Look at how the bracket walls are offset as well. You cannot measure just the offset of the studs that hold the bracket on. You have to measure the entire amount, including the offset of the bracket itself. They move the spring inboard exactly what MP says they do. I have measured it enough that I can do it in my sleep.
http://www.summitracing.com/parts/dcc-4120077/applications/
famous bob
mopar misfit
rrr nailed it. 3/4" offset front, center, and rear. can be done w/o cutting the original spring perches off . I did it------bob
moparlover
Well-Known Member
something else to be aware of... i was told that 275/60R15's fit with the offset shackle kit.
however, it depends on the wheels. i have a set of american racing torq thrust ii's. the BFG radial t/a 275/60R15's on those rims with the offset shackle kit were about 1/4" from the spring. on an 8" rim they have an 11 inch section width. apparently there are different offset torq thrust ii's available. the set i got from a guy on here have had enough of an offset backspace that i would be rubbing the springs every time i went around a corner. so the wheels play a part in this equation as well.
so for now i will be running MT 26X10's which have a 10.2" section width running on 8 in rims...
however, it depends on the wheels. i have a set of american racing torq thrust ii's. the BFG radial t/a 275/60R15's on those rims with the offset shackle kit were about 1/4" from the spring. on an 8" rim they have an 11 inch section width. apparently there are different offset torq thrust ii's available. the set i got from a guy on here have had enough of an offset backspace that i would be rubbing the springs every time i went around a corner. so the wheels play a part in this equation as well.
so for now i will be running MT 26X10's which have a 10.2" section width running on 8 in rims...
Fisher
Old Guy with a Cool car.
Two things!! 1 on my 71 duster completey stock I can fit a 15x8 wheel with a 4.5 bs with a Mcreary L-60x15 tire. You can get your little finger between the leaf and the tire!
2- I have Mancini Polly bushings with Dr diff shackle kit. The chrome Molly sleeve is just a bit longer than the bushings when installed so the shackle come in contact with the sleeve and not the bushing! I have been told to trim the sleeve flush as well as leave it stick out! It only sticks out 1/16 per side ! Was going to just snug it up and see what this does? I am thinking it would keep everything free with no binding or friction!
2- I have Mancini Polly bushings with Dr diff shackle kit. The chrome Molly sleeve is just a bit longer than the bushings when installed so the shackle come in contact with the sleeve and not the bushing! I have been told to trim the sleeve flush as well as leave it stick out! It only sticks out 1/16 per side ! Was going to just snug it up and see what this does? I am thinking it would keep everything free with no binding or friction!
You may have moved the perches 3/4", but the hangers and brackets are only a 1/2" offset. There's only 1/2" available to the frame, so unless you sectioned your frame rails the hangers only moved a 1/2". I have the same exact kit, its not a 3/4" offset.
Exactly. The MP advertising is a little deceiving. I guess if you move the perches 3/4" you get a little more room right at the perch, but not over the entire spring.
On a Duster you can fit more than that with the right backspacing. I have 295/35/18's on mine with the MP 1/2" offset, I did trim a 1/2" off the inner quarter lip though.
grimreaper
Cross Member
There is approx 9/16 space from factory front spring hanger to frame. No way to get the 3/4 MP claims.
I already explained this. Dr. Diff's kit uses a bolt with a recessed head and flips the nut to the other side of the hanger. It puts the spring hanger directly against the frame, just like the MP kit, but doesn't require the hole because the bolt sits flush with the outside of the bracket.
As far as measuring the bracket, yes, you can measure from the studs. Why? Because the studs don't move. They stay in the stock location. So, you can measure from the center of the studs to the outside of the bracket and compare. No, you can't use just that measurement, but if you measure from the edge of the hanger to one of the studs on the MP kit, and then measure from the same stud on the stock hanger to the edge and subtract the stock number from the MP kit, you will get the amount of offset.
There is approx 9/16 space from factory front spring hanger to frame. No way to get the 3/4 MP claims.
Exactly. And, you lose some of that 9/16" too, because if you look back at where the hanger mounts you can see there's an overlapped section of metal that keeps you from sitting perfectly flush against the rail.
Maybe when it stops raining I'll crawl under my car and take a picture of my MP kit. You can move the perches 3/4" if you like, but the hanger is only offset a 1/2".
The measurement is not taken at the bracket. You must measure the inside of the spring in relation to the frame rail. You can clearly see in your own photo there is MORE than 3/4" between the inside of the spring edge and the frame rail. Yall keep on arguing all you want. I know what has worked for me in the past and I will continue to do it.
mopowers
Well-Known Member
A picture says a thousand words...
Yup, there's about 1-1/16" from the frame to the inside of the spring, no arguing that. 9/16" of that is space, the other 1/2" is bracket and bushing. Pretty obvious in the picture.
Since the bracket and bushing can't go inside of the frame rail, the bracket can only move over 9/16". Since the bracket doesn't even sit flush with the frame, you only get about a 1/2". So how far can the spring move at the bracket? About a 1/2". No more, unless you somehow move the bracket inside the frame rail.
So, can you move the perch 3/4"? Sure. Does that move the spring 3/4"? Only at the perch. At the bracket, the spring is still only offset a 1/2". So, how much tire space does that get you? Well, let's see- something less than 3/4" and maybe a little more than 1/2". Since the spot that the tires rub on the spring is closer to the bracket than the perch, you get a smidge more than a 1/2", and you put a bind on the spring for your trouble. A 1/4" isn't much to squeeze the springs, but it won't even get you an extra 1/8" of actual tire clearance, so why do it?
Even with the springs offset a 1/2", the springs aren't the tire clearance issue. If you don't move the inside of the wheel tub, the 1/2" offset is all you can actually use anyway, because that puts the outside of the spring even with, or slightly inside, the wheel tub opening. So, even if you only move the perches a 1/2" to keep them inline with the brackets, you end up rubbing on the wheel tub before the springs anyway. The 295's on my Duster have never touched the springs, but they do occasionally kiss the inside of the wheel tub if I hit a driveway drainage or dip too fast.
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