How bad will a 4-bar suspension be with lower bars not parallel to the ground? - Hot Rod Forum : Hotrodders Bulletin Board
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Old 05-02-2012, 08:48 PM
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How bad will a 4-bar suspension be with lower bars not parallel to the ground?

'49 Ford F1 truck.
Triangulated 4 bar rear coilover suspension.

If the lower bar is higher in the front (~~ 12 degrees from parallel with the ground). How unpleasant would the truck be to drive for typical street operation?

I am going to make drop downs for the front lower bar brackets to get them parallel to the ground. I am just wondering how much unpleasantness that extra work is saving me.

Even though it is triangulated, I understand that looking from the side the upper and lower bars should meet around the center of gravity.

p.s. I do not want a lowrider, so C-notch is not a good option.


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Old 05-02-2012, 10:40 PM
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For the bars to meet at the center of gravity, you will need to have the front of the lower bar higher than the rear. Visualize the intercept of the lines to land somewhere around the back of the engine/bellhousing area slightly above the crankshaft. Its always a good idea to add some adjustability though.
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Old 05-02-2012, 11:46 PM
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Quote:
Originally Posted by jamieson
'49 Ford F1 truck.
Triangulated 4 bar rear coilover suspension.

If the lower bar is higher in the front (~~ 12 degrees from parallel with the ground). How unpleasant would the truck be to drive for typical street operation?

I am going to make drop downs for the front lower bar brackets to get them parallel to the ground. I am just wondering how much unpleasantness that extra work is saving me.

Even though it is triangulated, I understand that looking from the side the upper and lower bars should meet around the center of gravity.

p.s. I do not want a lowrider, so C-notch is not a good option.


Thanks!!
A good page on suspensions is by Billy Shope (of Ramchargers fame). The usual link is broken; this is an archived shot of it.
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Old 05-03-2012, 05:33 PM
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Thanks for the replies.

I was under the impression that the lower bar being parallel to the ground and the two bars (if extended) intersecting at the COG were two separate guidelines. However, I suspected what you are saying was correct because in many cases the two guidelines are mutually exclusive.

Thanks for the way-back link, I had seen a link to that page somewhere before, but the link was broken. I forgot the wayback machine even existed.

Even with the lower bar at a 12 degree angle (lower in back), if I install the upper triangulated bars at a 6 degree angle (on the vertical plane -- 40 degrees on the horizontal plane), they will meet very very close to the COG. Is this all I need to do?
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Old 05-03-2012, 05:54 PM
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What is wrong with this diagram?
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