Interesting.
Good to know....Yeller wrote: ↑Thu Aug 24, 2023 6:04 pm There really is no such thing as too much caster. the "ideal model" says 6.5 degrees, where that is from I have no idea but GM used that number on their leaf sprung 4x4's. My J truck is at 3.5 (stock spec) and I feel it could use more. My bronco is at 11.5 and it drives like its on rails but steering is very heavy, but that is what ram assist is for LOL. I actually have ram assist on both trucks.
Stuka wrote: ↑Thu Aug 24, 2023 10:10 pm Not sure you will be able to get those shackles as short (or close to) as stock. There is room for a closer hole sure, but the spring eye will likely hit the shackle where it narrows. But its certainly worth a try.
But as noted above, those shackles will not only ruin your caster angle, but they will also allow the axle to move side to side.
What Yeller said. With lifteted and bigger tires I shoot for 3-6 Degrees caster. The bigger and wider the tire [supposedly] the less caster you need. The idea being the distance from center [pivot/spindle] increasing the weight and drag of a wider tire increases the effect of caster on the road.Yeller wrote: ↑Thu Aug 24, 2023 6:04 pm There really is no such thing as too much caster. the "ideal model" says 6.5 degrees, where that is from I have no idea but GM used that number on their leaf sprung 4x4's. My J truck is at 3.5 (stock spec) and I feel it could use more. My bronco is at 11.5 and it drives like its on rails but steering is very heavy, but that is what ram assist is for LOL. I actually have ram assist on both trucks.
rocklaurence wrote: ↑Fri Aug 25, 2023 8:50 am What Yeller said. With lifteted and bigger tires I shoot for 3-6 Degrees caster. The bigger and wider the tire [supposedly] the less caster you need. The idea being the distance from center [pivot/spindle] increasing the weight and drag of a wider tire increases the effect of caster on the road.
tgreese wrote: ↑Fri Aug 25, 2023 11:57 am Probably more accurate to measure the circumference and divide by pi. I get the same diameter as you for a 235/75R15 using arithmetic. Supposedly the tire manufacturers routinely overstate the height of a given tire. TireRack will list the actual diameter if you find your tire on their site.
3/8" of extra lift would certainly be a visible change, especially if the rear stays unchanged.. but I figure shortening the front shackle will pull out some lift so they should cancel each other out pretty effectively.devildog80 wrote: ↑Fri Aug 25, 2023 12:13 pm Found the same on my '84 GW tires as I was only a smidge over 1/2 inch smaller diameter to go back to the stock tire 235/75R/15 for road use. vs the 31/10.5/15's the PO had on it, but were literally cooked from sitting for 18 years.
And the shims you will add to correct caster will not add any height to your rig persay as they are tapered with maybe 3/8 inch width at the actual spring pak bolt. Not enough to worry about height when you get the benefit of driveability.
Not to mention the new tires will be your biggest improvement there.
I would change tires first, adjust your shackles as planned, then see if you still need caster adjustment.
You are right again!!!Yeller wrote: ↑Fri Aug 25, 2023 5:33 pm Sure you are getting lift with the shim? It goes in top if the spring and the axle sits on top of that so it would lower it by the thickness of the shim, not lift it. That is unless you have a spring over but that is a long way from stock. Now if you used a shim on the rear to correct pinion angle, that would lift it by the thickness of the shim, it is spring over.
HA... no doubt!rocklaurence wrote: ↑Sun Aug 27, 2023 3:30 pm Be careful with all that cleaning of parts. A FSJ may reject clean and painted parts. It will only accept parts covered in its own oil.