Thread: 47-55.1 bump steer
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Old 10-19-2023, 12:43 PM   #5
1project2many
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Join Date: Mar 2012
Location: Lakes Region NH
Posts: 3,158
Re: bump steer

I'd love to see pictures of the 47-55.1 installation.

Generally the steering box is connected to the knuckles through linkage that has minimal length change as the axle moves. One way to do this is to connect the steering box to the RH wheel through a long drag link then use a long tie rod to connect the LH wheel. Jeep used this scheme in multiple vehicles.



This kit provides an aftermarket improvement for vehicles with more suspension travel and lift:



Ford has also used a version of this on F series trucks for years. This image is from an '05 to '13 F series:



The stock TF system appears to have been designed with interesting geometry interaction during front spring compression. When the spring compresses from stock height the axle is moved forward, potentially causing the wheels to turn slightly right. But at the same time the end of the drag link traverses an arc which potentially causes the wheels to turn left. If the box is moved to the front of the axle this interaction can be reproduced but it would take some planning. Do you have any pictures of your truck currently?

I would look at the "at rest" angle of a stock drag link when the vehicle is parked and compare it to the "at rest" angle of the drag link when installed on a front steer conversion on a truck with lowered axle. If the "at rest" angle of the modified truck causes the drag link to be parallel to the frame or even higher at the box end than at the knuckle end, I would expect unwanted steering changes and the need for frequent corrections.

Last edited by 1project2many; 10-19-2023 at 01:10 PM.
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