What should caster be on front axle?

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LukeZero

LukeZero

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I'm doing a spring over and shackle reversal on my 66 FJ45 SWB P/U and need to know what the factory caster setting was and should I go back to factory or is there a better setting. Most of the driving will be on the road with 35s or 36s ( I haven't decided which yet.) Thanks in advance, Luke
 
If yours is stock and drives okay use one of those magnetic angle finders (a Harbor Freight one will do) and measure yours at the pinion flange and duplicate that when you put yours back together. Hammerhead probably knows what it's supposed to be, or he can measure one of ours and let you know if someone else doesn't tell you first
 
The factory setting is 1 degree. IMO a caster of 2-3 degrees gives a better on-center feel. Though without a knuckle cut and turn it's hard to set it independently of the pinion angle.

Dave
 
I agree with the 2-3 deg setting. 80's are set this way and I think it makes for much nicer on road feel. My 4" lift 35" tire FJ40 has 1 deg caster on one side and 1.5 deg on the other (that's just the way it is, heard a lot are like that ::) )
it drives ok, not scary, but I'd like another degree or so.

I'd say if your cutting and turning go for a 3 deg. The only negative is more steering wheel effort in turns. Not a biggie if you have power steering.

if not cutting and turning, you do have to watch your pinion angle. I'll defer to others more qualified in that dept ;)
 
Pete and Dave are both right. You can just match the stock angle at the pinion if doing SOA without cut-n-turn. If doing cut-n-turn add a few degrees more for the improved handling characteristics. I have mine at a total of 4° rolled back with my 35s and it works great. Give it toe-in of about .200 and enjoy. 8)
 
We're talking positive caster or negative caster? Say you're looking at the drivers side of the truck. The line though the kingpin would be somewhat closer to the door at the bottom than at the top, or laid back like the rake of the windshield. My gut tells me that to be like a caster (on a shopping cart) it should be the former not the later. But, if you don't ask stupid questions, you do stupid stuff. Thanks, Luke
 
+1 caster is stock...the upper trunion is set back slightly from the lower

mine is in the +4-5 range....not exactlee sure. Regardless, larger diameter tires like more caster.
 
The rake should be back. Windshield like.

I had 38" tires on my cruiser and 8* of caster. Handled beautifully.

The bigger the tires the more caster the rig will like.
 
i guess that makes sense, I wouldn't want to have the shopping cart shimmy on the front wheels while driving.
 
BTW, do a cut and turn ;)

You only had 4 or 5* woody? I thought you had more.

Woody's works well. 8 might have been excessive then ;)
 
Yeah, I forgot to mention that I have the front axle stripped of stuff, and am using Woodys tech article as a manual to do a cut and turn-but that I forgot to measure the stock caster before starting, so when I got the advice to "just add a couple of degrees to the stock angle, and you'll be fine"- that didn't answer my problem. Thanks a bunch, everyday I learn something new. Luke
 
Well, when I did it I bolted up the axle into the truck in the SO position that I wanted. (making sure to get hte cruiser as level as possible.

While it was in there I adjusted the pinion to point at the Tcase, and then adjusted the caster from there. Tac weld the knuckles for grins, pull it back out and burn them bak into place.

That way you will know that they are about what you want and you will be happy ;)
 
Think of caster as riding your bicycle, the front forks kick out away from the pedals, then think of how it was to ride with forks backwards. Thanks to Butch Lewis for this tip. Also, what are the side effects of too much positive caster?
 
mine was in-out of the truck 5 times to set caster and pinion angle....

Honestly, I don't know the exact numbers on mine, but will likely get those measurements when I finish reassembly next week. I KNOW it's not 8...lol

TOO much caster means the rig moves left/right as you steer....picture a road grader...lol
 
oh, and for ideal caster....

With the rig on the tires and with the tires at your "street" pressure, caster should end up like the graphic attached:

The red line is caster...note how it runs thru the middle of the hub...also note that the leading edge of the caster line meets the pavement at the exact same point as the leading edge of the tire footprint. This is exaggerated, but techically it's what you want.
 
Excellent graphic Woody, now it all makes sense to me... why the larger the tire, the more caster you want. Man, the stuff I don't know could fill a book, I just wish I knew which book so I could read it. Thanks a bunch, Luke

PS. I learned a new motto today...

If you don't have time to do it right, you don't have time to do it twice.
 
I set mine to 5 degrees and i'm running 37in swampers. I love the way it drives and handles. :flipoff2:
 
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