How’s your Shortened pitman arm working?

Re: How’s your Shortened pitman arm working?

We have had made the RIGHT HAND DRIVE version made by the same folk who produce the LHD one , So if you need a RHD one we can supply , antiqueford@xtra.co.nz also available from Arizona Model A, I smell salt ?
 
Re: How’s your Shortened pitman arm working?

I’m using one with my newly rebuilt 2 tooth box and I wouldn’t go back.
Three turns from center to lock either way and I can steer with one hand now. I haven’t noticed any difference in turning radius.


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Re: How’s your Shortened pitman arm working?

I have the short pitman arm, am using it with an F100 steering box. No difference in the turning radius, much easier steering while under way.
 
Re: How’s your Shortened pitman arm working?

Installed one on my 29 station wagon it makes a difference have 5 other A's will upgrade those eventually
 
Re: How’s your Shortened pitman arm working?

Mac's says:

Steering Gear Ratio 1928-29, 11-1/4:1
Steering Wheel Diameter 1928-29, 17-1/2"
Pitman Arm Length 6-7/8" hole center to ball center

Steering Gear Ratio 1930-31, 13:1
Steering Wheel Diameter 1930-31, 17"

I gather 1932 is 13:1 and 33/34 is 15:1 .

"Factory production Ford F-100 pickups were equipped with “Armstrong” power steering in the form of a 17.5-inch steering wheel and 16 to 1 steering gear ratio."
http://www.classicperform.com/tech_articles/F-100-steering/Ford-F100-Power-Steering.htm

So if you add a shortened pitman arm it must be about 17:1
 
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Re: How’s your Shortened pitman arm working?

I put one on my 29 roadster, and it definitely steers easier. There is a wider turning radius with the seven tooth box, but it's worth it. Between that and the Mitchell transmission, now my wife can drive it.
 
Re: How’s your Shortened pitman arm working?

The shortened arm depending on length pulls the drag link up and can allow more clearance to the tie rod depending on front spring condition and travel.
 
Re: How’s your Shortened pitman arm working?

Clearly your roads must be a lot straighter than ours, with lots of tight bends, sometimes consecutive, the effective lower ratio caused by the shortened arm results in one having to turn the steering wheel more than originally to go around a corner.
The steering may be lighter but the extra twirling of the wheel can be wearying?
Also, I found that one needed to fit an adjustable drag link to get full lock on both sides.
Fitting the 5.00 radial tyres has made the steering on our car beautifully light with the original length pitman arm.
 
Re: How’s your Shortened pitman arm working?

wensum said:
Clearly your roads must be a lot straighter than ours, with lots of tight bends, sometimes consecutive, the effective lower ratio caused by the shortened arm results in one having to turn the steering wheel more than originally to go around a corner.
The steering may be lighter but the extra twirling of the wheel can be wearying?
Also, I found that one needed to fit an adjustable drag link to get full lock on both sides.
Fitting the 5.00 radial tyres has made the steering on our car beautifully light with the original length pitman arm.
Click to expand...


Uh-huh, I knew there must be a down side.
 
Re: How’s your Shortened pitman arm working?

I get full lock on both sides on my 1930 RHD Roadster. This is both with the original 7 tooth box and the 2 tooth I fitted to replace it. I have 550 X 19 Excelsior Stahl radials. Full lock means contact with the steering stops both ways. This depends on how long the stops are and whether a spring washer is fitted to them. I have read that the 550 radials can contact a brake rod one one side or the or the other too,limiting the lock. This does not happen on my Roadster.
I like the lighter steering and do not particularly notice more wheel turning in bends.
I also have a 1931Tudor with standard Pitman arm to compare it with. I may try a shortened arm on that too, because 2500 miles on a rally last week was quite an arm work-out with the higher ratio steering.
Wensum has a speedster which must be lighter and need less turning effort I think. We both travel the same roads here in NZ and he has Stahl radials too, though he says 500 X 19.
I did not have to fit an adjustable drag link and my wheel is centralised.
SAJ in NZ
 
Re: How’s your Shortened pitman arm working?

I run one on my delivery LHD & liked it so much decided to have new RHD ones made , I also love my LHD F100 box , Mitchell gear splitter, & the wife ,
 
Re: How’s your Shortened pitman arm working?

Are there different length shortened new pitman arms sold by the suppliers?


I plan to fit bias ply 5.50x19 tyres to the front; sounds like I may have contact problems.
 
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