Measurements of some typical crossover steering items...

[Greg72]

I'm going to be doing a "scratch-built" steering solution for the front axle on my build, but wanted to gather some basic measurements of a typical crossover steering setup as a starting point if anyone knows them (or can measure them easily).

• Length of 2WD pitman arm (center of sector shaft splined holes, to center of draglink hole)
• Length of crossover steering arm (center of dust cap, to center of draglink hole)

My plan is to use the Scout II box that I found locally. It appears to be a Saginaw box (has an "S" logo embossed in the casting)... I'm not sure if that means it will have the same amount of travel as the traditional Chevy boxes or not.

Ultimately, I think the amount of "throw" is going to be somewhat dictated by the steering stops that are built into my knuckles, but obviously I can make small changes to the steering arm lengths to increase (or decrease) throw to insure that I get 100% of the available steering from the knuckles...


Thanks.

-G

 

[454Sub]

Well, correct me if I am wrong. But this would need to be measured with the box mounted. As that would directly affect the arm length and placement. Also Im not sure if our style would even be similar to what you use because of your radically different design. I could see the basic measurements would possibly help. I wish I was near my truck to measure for you. But I do know that both arms have to be near the same length, like maybe 85% or closer to get the correct steering. But that can only be determined with the axle mounted, and the box mounted I would imagine. As the farther the box is forward or backward, it would change the length of the arms to longer or shorter.

That being said, I have read your build from front to back, and its a technical marvel. Keep up the good work.

 

[Greg72]

Well, correct me if I am wrong. But this would need to be measured with the box mounted. As that would directly affect the arm length and placement. Also Im not sure if our style would even be similar to what you use because of your radically different design. I could see the basic measurements would possibly help. I wish I was near my truck to measure for you. But I do know that both arms have to be near the same length, like maybe 85% or closer to get the correct steering. But that can only be determined with the axle mounted, and the box mounted I would imagine. As the farther the box is forward or backward, it would change the length of the arms to longer or shorter.

That being said, I have read your build from front to back, and its a technical marvel. Keep up the good work.

Thanks!

Well yeah, I figure all bets are off as far as copying a 'stock' crossover steering setup. But Heath mentioned something important to me recently:

"With the pitman arm length, it is a simple tradeoff, a longer arm will give you more travel, but stiffer steering and less precision. A shorter arm will give you easier steering with more precision, but less travel"

I'm sure he won't mind me quoting him since it's helpful to the discussion here.

His point was that it probably makes sense to study a factory-type setup to get in the ballpark for dimensions and then make small adjustments as needed for this particular application.



EDIT: With regard to the steering box, I'm pretty flexible about where I mount it.... as you've probably seen recently, I'm not afraid to move framerails around to get the packaging to work correctly.



-G

 

[454Sub]

Ok, well mine is a 10bt. But from the balljoint center to the center of the draglink hole is 7in exactly. Now my pitman arm is harder to measure. Its an S googly shape obviously, and its bolted on. So I measured in a straight line across its plane and it comes out to 6 3/8in. Now these cant be exact as they are bolted on and such, but its fairly close to accurate.

 

[B.N.Z.MTNS]

On my 88' k5 (8" lift) w/ PSC 2wd steering box & D60 axle, I just measured center of splined shaft to center of threads on the upper crossover ball joint = 6 3/8" (mine has a 3" drop in the pitman arm). The best measurement I can get from grease fitting to grease fitting on the crossover arm is 41 1/2" (again with the standard drop in the arm and raised steering block on passenger side).

I'm no engineer, but hope it helps.

This is a pic of mine just after I installed it, before I added the hydro assist.

 

[Greg72]

Thanks.

I'm actually looking for the length of the passenger side steering arm, not the draglink (though that is an interesting data point as well)

Basically the center of the upper bearing cap out to the hole (center) where the draglink attaches. I'm guessing it's somewhere in the 6" - 7" range???


-G

 

[pblaze725]

Trying to help



This is a GM 2wd gear box with an XJ pitman arm. From the center of the selector shaft to the center of the drag link is 5 1/2".

I didn't do the traditional cross over, I did the "NorCal_Chris cross over" so I can't give you the other measurement.

 

[454Sub]

Its going to be 7in IIRC, I have seen this data somewhere on here before, cant be sure what thread it was.

 

[B.N.Z.MTNS]

Thanks.

I'm actually looking for the length of the passenger side steering arm, not the draglink (though that is an interesting data point as well)

Basically the center of the upper bearing cap out to the hole (center) where the draglink attaches. I'm guessing it's somewhere in the 6" - 7" range???


-G

Thanks for the clarification. Mine is 7" exactly (from ORD if I remember right).

Be sure to post up some pics when you are done, I'm interested to see what you end up with.

 

[frankin5]

View attachment 140798

This is a GM 2wd gear box with an XJ pitman arm. From the center of the selector shaft to the center of the drag link is 5 1/2".

I didn't do the traditional cross over, I did the "NorCal_Chris cross over" so I can't give you the other measurement.

What is NorCal Chris cross over

 

[pblaze725]

It's a home brew cross over on the cheap designed by NorCal_Chris.


http://coloradok5.com/forums/showthread.php?t=269737&highlight=Cross+steering&page=17


It starts at post 163.

 

[mrk5]

Thanks.

I'm actually looking for the length of the passenger side steering arm, not the draglink (though that is an interesting data point as well)

Basically the center of the upper bearing cap out to the hole (center) where the draglink attaches. I'm guessing it's somewhere in the 6" - 7" range???


-G

I'm going to be playing with steering myself. I'm really looking to get the ideal Ackermann steering for my truck. With the crew cab I'm building I feel like this is important to get turning ability on the pavement.

I had a set of WFO arms that measured 6.25" from center of king pin to center of drag link hole. I'm replacing those with some OTT arms that measure 7".

I'm thinking about machining out the axle shaft yokes to gain more steering angle. There's even a shop that will machine them out for 50 degrees of steering angle. From what I understand the factory box will limit the steering to about 40 degrees in a standard setup. In order to offset this I'll have to move the draglink end on the steering arm closer to the king pin. This will sacrifice some steering power due to loss of leverage but I figure it will be offset by the hydo-assist.

My plan is get as much steering angle out of the knuckles/axle shafts I can. Measure how much throw I can get out of the factory steering box and the pitman arm I have now. Then figure out where the draglink needs to be attached on the arm to allow the full steering angle. It will be interesting to see where it ends up and I suspect there may be need for compromises.

 

[B.N.Z.MTNS]

I'm thinking about machining out the axle shaft yokes to gain more steering angle. There's even a shop that will machine them out for 50 degrees of steering angle. From what I understand the factory box will limit the steering to about 40 degrees in a standard setup. In order to offset this I'll have to move the draglink end on the steering arm closer to the king pin. This will sacrifice some steering power due to loss of leverage but I figure it will be offset by the hydo-assist.

mrk5, would you be moving it closer than the rear hole on a high steer arm? I thought about doing the same type of thing a while back when I had a long bed, but a local offroad shop talked me out of it. They explained that I would go through ball joints or heims very regularly due to the poor leverage. Mine was as daily driver so I opted out of it, but I'm still curious how well it would have worked.

 

[mrk5]

It'll be interesting to see. When I end up with a final location I'll post up about it in my build thread. I can check it again my buddy's high steer arms. Not sure how it would wear ball joints or heims any faster, but maybe I just need to be educated.

 

[kellyjohn]

I have slightly longer high steer arms to locate the tie rod outside the drag link

1st setup the hydraulic ram was mounted to the P side spring plate.
Ultimately it tore the threads out of the axle housing from some serious crawling.

The new setup was an experiment and it works GREAT.

I found that with the high steer arms long enough to allow the tie rod to be further out, it eliminated DW from any slightly worn parts due to their distance from the hub axis, and does not cross the drag link at any degree of turn, or flex.

Just figured I share what I have learned in my travels.

Hope it gives you some ideas.

As I have said before "love your build"!!!

 

[Stomis]

If you use a Toyota box it will oversteer and should allow you to pick up that extra turning without sacrificing your geometry.