Fast Ratio Pitman and Idler Arm

[racerdude5]

Since these arms are longer than your average arms, the additional length should mean that the arc of the arms has a longer radius. So do these fast ratio arms increase steering angle?

 

[AJ/FormS]

Your terminology is ambiguous but I think I get what you mean.
There are steering stops on the LBJs and LCAS to prevent that.Also, in the steering box, its been said.If there is one in the box, I didnt recognize it in the few that I have rebuilt.

 

[TrailBeast]

Since these arms are longer than your average arms, the additional length should mean that the arc of the arms has a longer radius. So do these fast ratio arms increase steering angle?

It only changes (decreases) how many turns of the steering wheel it takes to get the wheels to the existing stops.
Makes no difference in how much the wheel turns.

 

[AJ/FormS]

And the steering effort to get there, most noticeable at slow speeds and/or fat tires

 

[TrailBeast]

And the steering effort to get there, most noticeable at slow speeds and/or fat tires

And if you ever loose a belt good luck turning it in parking lots

 

[pishta]

fast ratio boxes had stops in the boxes modified to match the pitman arm length.

 

[racerdude5]

Therefore non fast ratio boxes will turn the wheels further when using fast ratio arms, correct?

 

[TrailBeast]

Therefore non fast ratio boxes will turn the wheels further when using fast ratio arms, correct?

The wheel hubs have stops on them, so no matter how fast or slow it gets to them they still stop in the same place, and do not affect turning radius.

 

[jcuda]

I think what's being asked is, "will the steering 'Ackerman angle' be changed?" I have not measured one myself, but I believe that there's no way it cannot be changed. Your bump steer will probably change as well. Noticable on the street? Probably not much if at all.

Anytime that you move your drag link (longer pittman arm & idler arm) and the tie rods hook to the same spindle location... the geometry is going to change. You can still set the toe-in, and with no bumps in the road, the toe will stay consistent. As you move the drag link forward though, anytime the car hits a bump or dip in the road, the amount the toe changes will be different now that the drag link is an inch farther away from the end of the spindle. Same for the Ackerman. As you turn the steering wheel and the drag link moves left or right, the left and right spindle/tire turn at different rates. The farther away the drag link is due to the longer pittman/idler arm, the more exaggerate the difference.

Just for grins, imagine drag link up by the front bumper instead of being under the oil pan. You'd have some crazy compensation to make up with super long tie rods and anytime you turn the steering wheel or hit a bump in the road, all sorts of wierd things will happen at the tire.

Said all that to say this... Not much noticible difference in a street car with just an extra inch on the pittman/idler arms. You'll absolutely notice the quicker steering... the small changes in bump steer & ackerman... not so much if at all.

 

[racerdude5]

I'm referring to a, what I'm asking is will a1 and aA increase with a longer pitman and idler?

 

[Bad Sport]

No, there are stops as mentioned a couple of times, it just gets there quicker.

 

[racerdude5]

Oh okay, thanks. I wasn't sure if what I had asked before made sense, so I just wanted to clarify.