Author Topic: Steering Gear Ratio Vs Overall Steering Ratio  (Read 2422 times)

Offline Toploader

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Steering Gear Ratio Vs Overall Steering Ratio
« on: October 21, 2013, 05:25:42 PM »
OK  I see that if the pitman arm on a box moves through 90 degrees  - lock to lock and it takes 4 turns on a GT box to do this then to move the pitman arm 360 degrees  ( 1 turn ) it would take 16 turns = 16 :1, the gear ratio.

I have only seen the spec of 16:1 given.
Do you know how the overall steering ratio of 21.7 :1 is calculated ?

I am curious thats all   :)

Would it be how many turns on the steering wheel to move a road wheel 360 degrees ( if it could ?)

To eloborate on a discussion from another thread, my findings regarding this subject are:

1. Steering gear ratio: Ratio of revolutions between input shaft and output shaft.

2. Overall steering ratio: Ratio of the turn angle on the steering wheel to the turn angle on the spindles = steering gear ratio + gearing effect (leverage) from the steering linkage, e.g. a 22-degree turn on the steering wheel (ex slack!) results in a one degree movement of the spindles.

One source of relevant Mustang specs can be found here, including the 21.7 : 1 number:
http://mustangtek.com/Library2/MustangaCompleteGuide.html
Go to page 22.
76A-Y-D2-13H-72-6-6
1965 Californian Built Silver Blue Convertible

Offline cobraboy

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Re: Steering Gear Ratio Vs Overall Steering Ratio
« Reply #1 on: October 22, 2013, 06:06:17 PM »
I will have a read thank you.
13th April 1965 Dearborn K GT on the other side of the pond.