I just installed an OME 2.5 lift with 2" longer (1" lift) shackles. The caster angles measures out at 6 degrees negative in the front and about 7 degrees out in the rear. Does this seem excessive to anyone else? I figured that they should be about 3 degrees out max. Has anyone else run the same setup and found the same angles? I'm figuring I'll put an 8 degree shim in the front to err on the positive side but it just seems like a lot of shim to me.
Way negative Caster Angle
- Thread starter hamm
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Thats a huge shim !!!! How are you figuring this all out ?
What year cruiser? (Or, how worn out were your old springs?)
Which OME 2.5" springs?
Longer shackles and/or lift springs would give you a positive caster angle (rotates the front axle third member 'up')
Can you post some pics?
Which OME 2.5" springs?
Longer shackles and/or lift springs would give you a positive caster angle (rotates the front axle third member 'up')
Can you post some pics?
BlueCruiser84
SILVER Star
Longer shackles actually give you negative caster if you are still in the stock configuration (if you have a shackle reversal then a longer shackle would give you positive caster). Positive caster is when the top of the knuckle is closer to the rear of the vehicle. I'll let my friend Google set you straight.
http://www.mkiv.com/faq/caster.jpg
How are you measuring your caster? Also, I'm pretty sure there is no such thing as caster on the rear axle. There is pinion angle, but I wouldn't think you'd have to worry about that with a 3 inch lift.
Brian
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How does the truck RUN?
The reason I ask is that I just finished servicing [knuckle overhaul and tie rod change] the front axle on an 85 FJ60 with an OME lift. It had a lot of caster like yours [I meant to take a picture of the 3rd to illustrate] but when I took it on a test drive, it had ZERO issues with wander, diving or vibration at any speed from 0-65, so I told the customer not to worry about it.
Best
Mark A.
The reason I ask is that I just finished servicing [knuckle overhaul and tie rod change] the front axle on an 85 FJ60 with an OME lift. It had a lot of caster like yours [I meant to take a picture of the 3rd to illustrate] but when I took it on a test drive, it had ZERO issues with wander, diving or vibration at any speed from 0-65, so I told the customer not to worry about it.
Best
Mark A.
I did a 2.5 inch suspension and a 2" shackle... I bought the suspension kit from Jtoutfitters and they sent me 3 rears and 1 front! had to get it in the shop to get a new one custom made for me cause jtoutfitters would'nt replace it. ANY WAYS, It was fine with the sime for the front it came with. But ever time I slow down the drive shft viberates...why?
driveshafts
Pirate4x4.Com - Extreme Four Wheel Drive
Check and see if your driveshafts are in phase
http://images.google.com/imgres?img...=driveshaft+phase&um=1&hl=en&safe=active&sa%3
Pirate4x4.Com - Extreme Four Wheel Drive
Check and see if your driveshafts are in phase
http://images.google.com/imgres?img...=driveshaft+phase&um=1&hl=en&safe=active&sa%3
- Thread starter
- #8
I'm measuring the caster angle with a bubble level-angle finder on a level floor. There's just enough of a lip sticking out from the trunnion bearing caps that I can set the edge finder along the knuckle surface. I'm pretty confident in the accuracy.
As for the rear "caster", what I meant to say was the rear companion flange is about 7 degrees tilted upward as compared to the transfer case flange.
I haven't driven the rig yet as I'm still getting it back together after a complete suspension/steering/brake upgrade. Before I did all the work it was completely unsafe at any speed because the steering slop combined with what may have been negative caster with the old springs made it change lanes at random. I'd like to get the angles pretty close before I get it all together and take it to the alignment shop. I was mainly asking the question to see if anyone else had found their angles to be that far off with OME plus 2" shackles--it just seems excessive from what I've researched.
As for the rear "caster", what I meant to say was the rear companion flange is about 7 degrees tilted upward as compared to the transfer case flange.
I haven't driven the rig yet as I'm still getting it back together after a complete suspension/steering/brake upgrade. Before I did all the work it was completely unsafe at any speed because the steering slop combined with what may have been negative caster with the old springs made it change lanes at random. I'd like to get the angles pretty close before I get it all together and take it to the alignment shop. I was mainly asking the question to see if anyone else had found their angles to be that far off with OME plus 2" shackles--it just seems excessive from what I've researched.
Try measuring the angle of the front pinion flange. It is usually 90 degrees on stock cruisers with +1 degree of caster. -6 degrees is pretty far off. The extanded shackles would only change it by 2.8 degrees. Either there is something wrong with the spring shape or the location of the spring and shackle hangers or your measurement is wrong. OME is mighty proud of their spring shape and the location of the spring perch pad to give the proper caster is/was a patented feature.
Thanks for setting me straight Brian. For some reason I thought stock was -1 degree and that shackles a few inches longer than stock almost made the caster 0, so even longer ones started making it in the positive area.
- Thread starter
- #11
Pin head: I measured the pinion flange also and it's within a degree of the trunnion measurement so I figure it's accurate. Your comment on the OME springs accuracy is exactly why I'm posting the question. Maybe when they went to the Dakar springs the accuracy dropped a little. The guys at Man-a-Fre told me they have seen them need 6 degree shims before. I'm just a little surprised at how far off the angles are. I'm going to throw in some 6 degree shims and take it to the alignment shop next week when it's back together.
