Minimum castor??How much is too little??

Im doing the alignment on my new lift/long arm set-up.Basically Ive got about a 1/2* of castor and 12* on the pinion.I drives really good and The driveshaft is almost dead on.Im thinking about adding just 2* more?

I have 4* caster, my pinion looks good and no DW. Steering could be better, but I think that has to do with the inverted Y.

I have the LP D30 also.

I used to have some DW that I found out to be caused by worn UCA bushings but in before that I dialed my caster down to about 2* which eliminated it. The jeep would wonder on the road and would change direction if it shifted it's weight. Quite the bear to drive but the DW was gone.

Now with new bushings I've brought it back to about 4* and almost all the wondering is completly gone. I'd say about 4* was the magic number minimum caster for my rig. That's at about 5.5" lift with a HP dana 30.

I think I'll bring it back a bit more in the 5.5* range and see how it does.

RCP Phx said:

Im doing the alignment on my new lift/long arm set-up.Basically Ive got about a 1/2* of castor and 12* on the pinion.I drives really good and The driveshaft is almost dead on.Im thinking about adding just 2* more?

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You might be ok running a 2000 without much castor for a while, but once the suspension and steering joints start getting some wear in them you may be in for a suprise bout of DW when you least expect it. I would also think that you steering would tend to wander with your current setting (and even with the 2° setting).

Before radial tires became popular typical caster settings were in the range from 1/2 to 2 1/2 degrees. Toe-in settings at 1/16" to 1/4" inch.

Radial tires flex and steer easier, allowing more caster without giving the driver (or the power steering pump) a workout. Typical settings are now 4-8 degrees. Toe-in at 0" to 1/16" inch.

Power steering allows more caster, and manual steering less caster. Dialing in caster results in more steering effort to overcome the self centering effect of caster or kingpin rake, and additonal caster places more load on the suspension components due to the forces involved (why it feels harder to steer).

Toe-in also adds self steering effect, similar to caster, and non-radial tire set-ups ran less caster and more toe-in. Radials use more caster and less toe-in.

What is too little caster? When the steering is so light it wanders and fails to self center the steering.

What is too much caster? When the steering is heavy and sluggish to drive with excessive steering effort.

Variable assist (speed sensitive, slow at high speed) power steering cars run around 8-degrees, and variable rate (slow at center position) power steering cars run around 4 degrees.

Zero degrees is too little caster, most power steering vehicles with radials run 4 degrees or more of caster.

Caster is a tuning tool, to trade straight-line stability for steering effort. The stability comes at the price of added force on the steering system and pump, and the same forces transmitted into steering effort (with the power steering boost reducing the impact on the driver directly). Even if you as a driver do not feel the forces of excessive caster, the suspension components and bushings still have to resist the effort.