4.5 RE extreme duty leaf springs

I got a set of 4.5 RE extreme duty leaf springs for xmas arty:
My question is what degree shim (if any) should I start with?
I also have the 1.5 lift shackles also.
What pinion angle would work best with 6" of lift?

Can we assume you have a SYE?

crazy4mopar said:

4.5 RE extreme duty leaf springs + 1.5 lift shackles = 6" of lift?

Click to expand...

Do you really think that's all the lift you're going to get?
I've probably got close to that just out of my 1462s. Think bigger!!!!
Oh, I've forgotten what shims I have, just wanted to bring to your attention of what you'll really get out of your set-up.
HTH
Thanks,
Dan.

It will depend on your setup of course. SYE will have the pinion angle in line with the driveshaft minus a degree or two to allow for axle wrap and a standard driveshaft setup (factory) will require the rear pinion to be 1 degree less than the transfer case down angle. Use an angle finder and measure your transfer case down angle. Best way to do this is place the angle finder on the valve cover of the engine. This will give the transfer case down angle. Measure the rear differential pinion angle (up angle) and try to shim the rear pinon such that the two angles you found are equal minus 1 degree to allow for acceleration (pinion rotates up during acceleration). thick end of shim will go towards the transfer case on standard driveshaft (to rotate pinion down) and towards the rear of jeep for SYE jeeps (rotates pinion up).


Check out this site for driveline angles:
http://www.pirate4x4.com/tech/billavista/PR-shaft/index.html

I just installed the 4.5 leaf pack from RE with their 1.25" shackles and I got 6.5" of lift with about 200 lbs of weight in the cargo area. It is not uncommon for these springs to give 5.5 to 7.5 inches of lift.


Maybe this helps. You can also search on this topic and there are several posts related to this issue for more information.

I have the 1462s and the RE shackle, and I get right at 5.5" of lift. That's with a bumper, tire carrier, and around 90# of tools in the back.
BTW, I use a 6* shim, and my angle's just about perfect.

I have the 1.5 shackle and 3.5 leafs and sit over 5+ inches in the back still that was 6+ after the lift but after a ton of weight and some flexing in a ditch and about 12 trips this somer it's down to just a bit over 5" of lift in the back I have a 6* shim with SYE and no tcase drop and have no vibes at all. you might go with an 8* just to play it safe or just hang with the 6* it only takes an hour to swap them out. well thats factoring in if you have air tools sorry. hand tools about another 30 min and some muscle cream for later on those U bolts can be a PITA.