Anyone have a real answer? I'm using the stock front mount and build a new rear, I will buy I spring to level once omplete. Should the rear of the leaf be higher, lower, or level with the front at rest?
Your leaf springs need to run at stock angles---Level! This means your pinion is at the same degree as stock. If you have modified your suspension via the schackles or spring mounts, move both ends of the spring the same amount!
You can't do a rear shackle flip and maintain factory angle without builing a hanger in the bed. I thought 1/2 the reason for a shackle flip was the increase in lift to get rid of the block. The rears are much more sloped than the front factory.
Huh? Rear axles dont have the issues that fronts do with stearing??? What are you trying to do? If you are talking about a rear axle....set the perches at the desired pinion height for the drive shaft? Are you sure you are on the right web site?
I'm going to do a shackle flip on the rear, and go to a normal style shackle. I realize the rear is not as critical as the front however the springs will not work the same at any angle. Once I figure out the the angle, front to back, I will build the perch to accept a 6" long shackle. Then I will get a spring that gives me the desired height, then set the pinion angle. I want to build it correctly, not just slap something on there and say done, that's why I'm asking.
Where to put the rear spring mounting point in relation to the front in regards to how the spring functions best.
The pering will work the same no mater where the mounts are. Shackle angle will make the only difference. I think this is alot of work for little benifit if any. moost of the time people change shackles to get lift or correct pinion angle. My best advise is to put the shackle on a 45 deg. angle towards the rear.
fact...leaf spring do not work the same no matter where the mounts are.....
now, the amount of variation in how differently they work is debatable....
1/2 ton rear ford springs.....
in factory configuration, the rear pivot (where shackle is) is considerably higher (~6"+) than the front.....which transfers some of the weight of the chassis into tension in the spring as well as bending. It also has an exagerated effect because the spring center pin is offset toward the front, locating the axle closer to the fixed, lower end of the spring.
now, when I did my shackle flip, I put the spring mounting points about level to the chassis/ground.
this netted not only lift, but also increased travel out of the spring. You can argue this all day, but by having the spring points "more level" you get more travel out of them. this is because this increases the leverage on the rear portion of the spring (which is longer) and makes it "work harder". Of course, the side effect of this is that the springs actually get overworked, and begin to sag, and will certainly eventually fail. up side is that you do get increased travel, and stock replacements are dime-a-dozen...
I would also prefer mounting a spring as level as possible. When the rear of a spring is jacked up (from an extended shackle or whatever) It puts the axle center that much further below the fixed point of the leaf spring. This gives the axle more of a tendency to wrap or "walk" under the spring on steep climbs. Obviously the more the angle, the more the effect. It is really bad on thin flexy springs (cruiser springs) .
but then again, it still has to be better than lift blocks
I'm positive the angle matters, just not in what way. when a leaf is angled the axles wants to move up and down, because the axle travel in the hypotinuse of the triangle it increases the spring rate and decreases the anount the spring moves relative the axle.
But what's best? I think you are correct about antisquat also, but not positive.
On a typical leaf spring rig: raising the front mount does increase anti-squat. It also causes the axle to move more front to back as the suspension cycles (read this as: drive shaft and tire to fender issues).
Having the front end lower reduces anti-squat and calms the suspension down. It also has front to back movement issues.
Having the springs flat is about as close to neutral as you can have with leaf springs. Front to back is minimised.
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