I've been reading all of the posts about shackle angles and such, and i'm still not sure what to do about mine. My FJ62 currently rides on 2.5" OME springs, and I am running man-a-fre 2" extended shackles. These shackles currently sit damn near a 90 degree angle...why is this bad, and how in the hell do i fix it? While i'm at it anybody have any thoughs about a shackle reversal kit from man-a-fre?

IMHO, when the spring is flat, your shackle should be around 45* (or so). With lifted springs, the spring needs to flatten out as it is compressed so the shackle can't start out at 45* or it can pin itself against the frame. This is why most arched springs have a near 90* shackle which sucks.

With a 90* shackle at ride height, you are basically riding on the full spring rate of the spring. This is why most lift kits seem to ride way too harsh compared to flatter springs. The 90* shackle doesn't allow much down travel and also tends to invert way too easy. As the shackle angle becomes less than 90*, the shackle is effectively softening the spirng rate of the spring and the ride seems smoother.

I agree with Eric that when the spring is layed out flat you should end up with roughly a 45 degree angle and that with a lift spring your ride angle could be non optimal while the flex angle is "IDEAL".

What you could do to check this is out on your cruiser is place a tape measure or down the spring following the curvature and get a reading from eye to eye, lets say the spring comes in at 47".

Support the vehicle and remove the weight from one spring and remove the bolt from the shackle end of the spring.

Measure in a straight line from the eye at the fix end of the spring to the intersection of the free end of the shackle 47" down straight line. Now take the angle reading of the shackle and this should be about 40 - 45. If it is close to this then question have to ask youself is how much greater than 45 can you go with out inverting the spring. Perhaps others have tried various angles and can give a more definitive answer as to what angle will definitely invert and what is a gray area.

I personally decided not to gamble and hence my ride height angle was roughy 90 and the truck was harsh on road and such. In the rear I got lucky and the ride height angle was in the 15 degree range, I also can not flatten my rear springs out due to clearence issue with the inner fender well.

I've run 4" lift springs with the shackles at a 45 degree angle. It CAN be done, you just need to make some careful measurements.

first off, you need the distance eye to eye of your springs, not at resting height but at their flattened height. let your tape measure follow the curvature of the spring and note this.

Now, with the weight of the truck on the springs, determine how far forward you need to move your shackle to come close to a 45 degree angle. Generally, moving it 2-3" forward is not a big deal.

Finally, determine the shackle length required to keep the springs from compressing onto the frame on compression. The distance between the solid mount and the shackle mount PLUS the shackle eye length should be about 1" more than the flattened eye to eye spring length.

There is some experimenting with mount location and shackle lengths involved. It can be done however.

a friend of mine has an fj40 with monster SUA 7" with shackles at 45 degrees

the only problem is they are pointing toward the diff at 45 degrees, so the shackle is backwards

so its more like 135 degrees

:rolleyes:
he bends springs and stuff as well as gets AWESOME shackle inversion whenever he takes it offroad, but he is higher than some springovers, cause he also has 2" body lift and 3" longer shackles:rolleyes:

what a weapon:rasta:
ghetto BUILT