Short pitman arm

Tom Cavallaro

Tom Cavallaro

Senior Member
I'm thinking of replacing my pitman arm with the short one. What is your experience and how much will it lengthen my turning radius? Will I always have to make only K turns after making the change? Tom
 
I am not sure about your actual turning radius, but I had a flathead powered 32 roadster with F1 steering box and a shortened pitman arm. This thing steered like power steering. People couldnt believe, as I could palm the wheel while parking. It took much more effort to steer before I shortened the arm! Rich
 
I've heard stories about the turning radius being reduced,but have never seen it in real life.I've installed maybe ten or a dozen for others,but all were on two tooth boxes,maybe it is different on the seven tooth.Every one hit the spindle stops both before and after.I did have one fellow tell me his turning radius had changed after,so I took a good look to see why.His spindles were still hitting the stops,and at that point I didn't know what to say.His mind was made up,facts pointed out to him meant nothing.I've discovered that I never bring the wheels around to full warp anyway.I was showing somebody the stop nuts on a chassis I put together back in the 70's,The paint is old rustoleum,if the spindles ever touch that it would leave a mark.
 
I put a shortened pitman arm on prior to a long road trip we took this summer. I did not notice the reduction in steering wheel pressure much but I really noticed the reduction in the turning radius. In situations where I could just do a simple U-turn, I had to back up and re-direct. The change caught me off guard a few times. I am going to change back to the original.
Update: Interesting comments on some posts that follow noting no change in turning radius. On my '29 the turning radius was increased enough to notice. My limit in turning full right to full left is in the steering box...not in the other components so the shorter pitman arm is causing the change...
Good Day!
 
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I shortened the pitman arm on one of my "A's" a couple years ago an inch and a half. Didn't change the turning radius because it came against the stops on both sides. It made a big difference in the steering ease and I've had thoughts of shortening it some more.
 
I've put the shortened pitman arm on both my "A's" ('29, '31) and have not noticed any increase in the turned radius. I like them and will always use them.:)

Bob-A:D
 
It appears to me that any play in the steering would be exagerated with the shortened pitman arm. Would this be true?

Regards,
Dave
 
daves30tudor said:
It appears to me that any play in the steering would be exagerated with the shortened pitman arm. Would this be true?

Regards,
Dave
Click to expand...

Yes and no. The play in the box itself will remain at the same number of degrees to take up the play from left to right, as you are NOT changing the box ratio itself. The free-play in the linkage from the pitman arm forward WILL be exaggerated by the reduced arm leverage.

Example: Say you have 1 1/2" wheel free-play left to right. If 1" is from the box itself and 1/2" is from slop in the front-end, decreasing the pitman lever arm from 7 1/2" to 6" increases only the front end component. The "new" wheel play will be 1"+(1/2"x 1.25)= 1 5/8"

If you have a tight steering box and a tight front end the increase will not be noticeable, however it will take 25% more wheel rotation for your normal driving maneuvers. This I find objectionable and is why I use the stock arm. I've driven A's with short arms and it feels like I'm driving a bus. That wears me out on long drives.
 
I put one on my 29 tudor, like it a lot, wheels turned stop to stop before and after, so it made no change in turning radius on my car.
 
I have read somewhere that Henry found that by shortening the pitman arm it was easier to steer, which was done in 1932. This can be verified by som of our pros here.
 
Tom Cavallaro said:
I have read somewhere that Henry found that by shortening the pitman arm it was easier to steer, which was done in 1932. This can be verified by som of our pros here.
Click to expand...

The '32 pitman arms were indeed shorter, but they were also linked to a front end with different geometry on the spindles and different tires. Drawing a conclusion that the steering was 'easier' because of a single component change out of a system that also had other changes cannot be logically supported without further investigation of the complete system.
 
I prefer the short pitman arms and will always use them. Steering is easier when the wheels are turning, like power steering. It slows down the steering geometry a bit so it doesn't seem as direct. Our roadster and sedan steer as well as a modern car when they are moving. The shortened arm does add a small fraction of free movement at the center but hardly enough to notice. The cars with two tooth steering turn the wheels lock to lock so I don't think that the turning radius is increased My sept 29 has seven tooth steering and doesn't turn the wheels all the way from lock to lock and probably increases the turning radius a bit but no real problem. Some other mods also make steering easier. I use the teflon buttons in the tie rod and drag link ends. I use needle bearings and NORS Buldog sector and new worm gear plus all the other good parts to rebuild the steering and front end. Wiley Higgins rebuilt the steering and pitman arms with new balls.
 
I had similar concern about the effect of a shortened Pitman arm, and having heard different points of view about the Pros & Cons. As I had a spare used Pitman Arm I decided to do a cut and shut on it as a trial and decide for myself. One short drive at low speed convinced me of the benefits. Returned back home and ordered a new one from the parts suppliers and replaced the original until the short one arrived.
Cutting and re-welding your own is definately not recommended.
 
I have shortened a bunch of these and to my knowledge, they are still in use. If you want to do the job yourself, you need to cut your V's really deep and use a good 220V welder to get full penetration.
 
I like mine and so did the guy i got the car from. Did not know this till i bought a new shortened one to put on and took off my old one,only to find it was the same thing when comparing the two ha. Starting to amass a box of unused new model a parts from mistakes.
 
Thank you gentlemen. After I rebuild the sector housing...I think I'm going to try the shortened arm...the thought of feel of power steering in the A is giving me goosebumps...LOL
Tom
 
I changed to the shortened pitman arm just because the physics of the thing made sense. I haven't noticed any difference in turning radius, but it does contribute to easier steering.
 
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