Here is another
valuable post from Jesse Ybarra regarding the use of off-set wheels on a
narrow-track FC-150. Many FC owners ponder this question and Jesse once
again covers all the issues that come up regarding these trucks. Thanks
for your insight Jesse!
The following is a copy of what I previously wrote to Jim, he is also new with a
Most new FC-150 Narrow track Owners, people that have a first edition 57-58
narrow track, have never driven their vehicle, or any FC, the narrow tracks are
the best they can be, as they are. Additionally a lot of new people don't know
the difference, they think they own or have a narrow track, because they compare
the later 58-65 FC-150 wide track that they own, to an even more wider track
FC-170. To avoid arguments, I usually avoid talking about narrow tracks on the
forum, I personally like them as they are, and because one person with wide
wheels driving on dirt roads at 35 mph in rural Kansas, is not likely to over
correct the steering, like another person on an interstate in Los Angeles or
Phoenix and hit a banked curb.
Because of the changes of our roads in our country, most cities in 1957-58, did
not have highways or interstate as we know them today, as we improved the roads,
in the late 50s early 60s, the instability off pavement and problematic
maneuverability on paved roads, inclined higher crown at the centerline and low
gutters near the curb, required the narrow track to have a lot of the necessary
geometry and engineering improvements that were needed to be done, a whole new
chassis, was created, with the larger wider Dana 44 axles, allowing for spring
over and spring hangers, that were able to be mounted outboard the frame on the
later wide track FC-150, The wider stronger front axle allowed the springs over
the axles, allowing more clearance so that the wheels can turn without hitting
the springs and frame at full turn, the steering boxes are different because the
frame mounting location and angle of the bell crank changed also, even when the
later wide track 63-65, were made they had cross steering like the FC-170, all
these necessary improvements made them safer, including the rear counterweight.
Because the wide/narrow tracks are so different, any acceptable change on a wide
track, will be an opposite negative change on the narrow track.
The narrow track having the springs under the axle, has the spring hangers
mounted under the bottom of the frame, stock c type shackle bolts are at a
disadvantage, changing them to double shackles makes roll over easier on them.
When you change to wider offset wheels, assuming the inside spacing stays the
same, the centerline of the tire is moved outward, 5" to 7" for example, as you
turn the wheel, more strain and effort is required to rotate the bell crank,
also the width of a tire has increased causing the sidewall plies to have more
area to grip, this is multiplied with low ply sidewalls on radial tires verses
bias belted with higher ply sidewalls, twisting harder against the wheel
mounting flange. In some cases hitting a road hazards that crack the wheels,
because of the offset.
The front will be even dangerous with a wider width because of the already over
cantilever effect on the spring under the frame and axle, because of the heavy
cab and engine weight concentration over the front axle, any increase in width
will also be very hard on the bearings of the small Dana 27 front axle.