Shortened pitman

Werner

Werner

Well-known member
Hello at all.

My neck and shoulders have reached an age where steering has become very difficult. I'm considering fitting a shortened Pitman steering arm.

Are there any disadvantages with this? Does anyone have any special considerations for assembly?


I thank you in advance!
 
I don't have personal experience with one but I understand that it will increase your turning radius.
 
I had one I sold because I didn't like increased turns of the steering wheel, didn't seem "normal".
 
I installed one in my 28 roadster because the drag link was rubbing on the tie rod sometimes. The shortened pitman arm solved that problem and it is easier to steer. I have not noticed a difference in turning radius, but it makes sense that that would be the case.
 
I have installed lots of these things,half a dozen for myself and probably a dozen more for other people.On every one the spindles hit the stops with the long arm,and still hit the spindle stops with the short arm.The turning radius can't be different as long as the spindles hit the stops.The wheel winds up with 1/4 to 3/8 more travel.I don't notice it.If you have slop in your steering box you will find the slop much more noticeable,because you have to react to the short arm a little quicker.
 
Keith True said:
I have installed lots of these things,half a dozen for myself and probably a dozen more for other people.On every one the spindles hit the stops with the long arm,and still hit the spindle stops with the short arm.The turning radius can't be different as long as the spindles hit the stops.The wheel winds up with 1/4 to 3/8 more travel.I don't notice it.If you have slop in your steering box you will find the slop much more noticeable,because you have to react to the short arm a little quicker.
Click to expand...

When my Brother in Law bought his Model A, I drove it home for him. He had never driven an A before. The previous owner had fitted a shortened pitman arm. I found the car almost undrivable because of the slack in the steering. We took off the shortened one and put on a standard one. The car was now very drivable and still is with no other work tot he steering.
I wouldn't have one but it's your car, your life.
 
Werner, I don't have the shortened pitman arm but do have a F-150 box which has a lower gear ratio, making the steering easier. The whole front end has to be tight with no slack at the steering wheel. I suspect that is the same with the shortened pitman arm. I understand the F-150 box may be hard to get in Germany. If you can find one it is worth getting because the sector gear that follows the worm gear is actually a roller and this reduces the friction considerably. There is some modification needed to fit the Model A controls (throttle and ignition advance) and light switch. Mine came with the car so I cannot comment on how much work is needed. I did rebuild my box and that is very technical.
 
If you have a junk sloppy steering box a shortened arm will amplify it tremendously.I've seen a lot of that with people that buy one thinking they are getting a magic bullet that will cover up all their sloppy parts.I had a Tudor that I bought with a short arm on it,it was a handful to drive.I put a long arm on,it drove OK.Not great,but you could aim the car without working at it.In reality the car had a junk steering box.
 
When I rebuilt the steering box on my roadster 2 years ago, I installed a shortened pitman arm and have been very happy with it. The steering is tight and requires noticeably less effort.
 
The front steering needs to be in good tight condition it will increase the turning radius as has been said but it will stir easier I personally like it but it must be done right or not much change
 
Hello Werner
My car is restored including the suspension, so everything is tight. I installed the shorter arm and it does help. The car is easier to drive and I don't notice any negative effects. I don't know what the effect would be on a car with a worn suspension.
 
One of my cars ('30) has a shortened pitman arm and teflon inserts on the steering mechanism. All steering components rebuilt. It steers almost as easy as my other car ('30) with a F100 steering box installed. Neither of these cars have reduced steering arc.
 
Shortened arm does not affect turn radius... It only takes slightly more revolutions of the steering wheel to reach the end stops.
 
I installed a shortened pitman arm and Teflon pitman and tie rod ends on my ’28 roadster around ten years ago. The car seemed a little hard to keep in its lane after doing this. With help of this forum, I discovered that the car had a poorly made aftermarket radius rod socket. I replaced this with a new better quality one and that fixed the problem. It still handles nicely today.
 
Guten Abend!


I'm a little confused because I can't find the length measures of the pitman original and shortened.

Who knows?


Vielen Dank,
Werner
 
mhsprecher, if your tie rod is dragging across the drag link, I think you might have a worn out front spring??? If you front spring is worn that much, I think the the front in castor is off too. Does your steering wheel return to center when releasing it after making a turn?
 
I'm no expert on Model A steering, but I replaced the spindle bushings and bearings, the drag link and tie rod parts last winter. Little Bug's steering is now pretty good. She has the short pitman arm.

I too wondered about the wider radius as I had seen comments and found that the backing plates were hitting the extended spindle lock pins as Keith states above. The lock pins are the stops for the steering, right??? My thoughts were that this meant that the worm gear had some extra thread left at each end of the travel with the longer original pitman installed. I believe that the turning radius is unchanged as Keith stated in post #6.

As far as the slack in the steering being magnified at the steering wheel, this makes sense to me. I am familiar with the functioning of bell cranks used in aircraft ailerons control systems. The shorter pitman arm is approximately 1 1/2 inches shorter as I recall. This would mean that the shorter pitman will need to move a greater number of degrees rotation to move the drag link fore and aft the same distance that the longer pitman would move the link with fewer degrees rotation. The short pitman will magnify the slack that is out in front of it, but not slack in the steering box???

Well, I've stuck my neck out this far, I might as well finish lynchin' muhself. LOL

The shorter pitman has the effect of lowering the gear ratio of the steering for the
driver's ease of turning. Kinda like putting a bicycle into a lower gear going up hill.

As for a car that wanders over the road, or even shimmies, I'd check the toe in first.
 
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