Author Topic: King pin inclination angle  (Read 702 times)

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winr1

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King pin inclination angle
« on: July 06, 2021, 05:43:25 AM »
Cant remember if I posted this before .....


Have a set of 1974 F100 disk brake spindles on my 1965 F100

Would like to use them on an F1 axle instead of buying a disk brake kit for the F1 spindles

I have read the F1 axle has .8125 king pins on an 8 degree inclination
.. and that the F100 axle has .859 king pins on 4 degree inclination

Wanted to bore the F1 axle out to fit the 1974 disk brake spindle

Is there enough material there to do this or will a bushing or such need to be made

Perhaps bore f1 axle to .859 and bend to proper inclination ??

Also, why the difference in king pin inclination ??
Is one more suited to modern roads or such ??


Ricky.

My427stang

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Re: King pin inclination angle
« Reply #1 on: July 06, 2021, 06:50:27 AM »
Man, that seems like a lot of caster/king pin inclination for a vehicle that didn't have power steering, maybe the source is wrong? 8 degrees layback would sort of flop over and fight you in parking lots I would think, but would help at high speeds, something the F1 isn't known for LOL

4 seems pretty standard, although even more than common for the era.

As far as what is there, .023 radius is a pretty good cut, but you'd need to look and see what is left of the F1 axle. Hopefully there is enough material in the stock setup, because opening it to a larger bushing would weaken it more (although back then things were build with a bit of overkill). 

Does the grease travel in grooves in the king pin or the axle?  If the meat is there, look close at how you can get grease to it too
---------------------------------
Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

frnkeore

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Re: King pin inclination angle
« Reply #2 on: July 06, 2021, 12:11:55 PM »
Quote
Also, why the difference in king pin inclination ??
Is one more suited to modern roads or such ??


Ricky.
I don't know the king pin inclination of the two axles but, I can tell you why it is used.

king pin inclination does two things, first it keeps the car or truck wheels pointed forward and does that because when the spindle turns forward , it pushes the tire, into the ground, creating a pressure on it, it does the same if, it is turned to the rear. There is no added weight, when centered, so, it whats to go straight. You can also make a gate, self closing and self centering by using the same type of inclination but, in the opposite direction.

The other thing it does, is center the steering axis on the contact patch of the tire (actually a little to the outside). That reduces the steering effort, as much as possible. If you've ever put after market wheels on a car, that have a positive offset and with no PS, you will notice a increased effort to turn the wheel, when setting still. That is because the tire is now moving in a arc, rather than turning on center. The Mustang in my avatar, had 8.5 wide front wheels with a 1.25 positive offset. If I hit a bump or rut, on one side or the other, it would pull to that side.

That said, if the angle is increased that much, maybe Ford found that the Twin I Beam was harder to stabilize. I do know, that when I bought my new '64 Ford van, it tended to wander. The fix was replacing the radius rod bushings with ones that had less give but, still with more inclination, it shouldn't have need that.

That arc, also creates leverage on the tire and will also cause the car to want to dart, in the direction of bumps and ruts.
Frank

gdaddy01

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Re: King pin inclination angle
« Reply #3 on: July 06, 2021, 03:36:27 PM »
what are you going to put the f 1 axle under ? I used 1949 f 1 axle and springs under a 1962 ranchero , with speedway motors disc kit . i drive the ranch a lot several trips to pigeon forge tenn. on the interstate and drag raced it some also . never any problem . rides as good if not better than anything i own .

winr1

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Re: King pin inclination angle
« Reply #4 on: July 06, 2021, 08:42:43 PM »
Thanks guys

Both have 2-3/8" tall King Pin Boss

Going under  A 65 F100 with coilovers, radius rods and a long panhard bar

Kind of like Bone shaker https://www.google.com/search?q=bone+shaker+ford+drag+car&tbm=isch&source=iu&ictx=1&fir=BxEfl6r2qGgbGM%252CpE7VIuMpPtytmM%252C_&vet=1&usg=AI4_-kQILhJt3oHRd1oP0vsiMoXBI4ASgw&sa=X&ved=2ahUKEwjNz8vR5M_xAhXkl2oFHeskBIUQ9QF6BAgUEAE#imgrc=BxEfl6r2qGgbGM

Or the 2 Lane Black Top Chevy

I saw the Speedway kit, thanks ..... wanted to keep the 5.5 bolt circle and the 74 disk parts are fairly new and paid for


Just looked up 1957-60 FORD F-100 PICKUP AXLE has .859 king pins on 4 degree inclination and same width as a 61 to 64 F100

May be easiest way for me



Ricky.