1946 chevy truck build.

[Kermitt47]

Hi, I am going down a similar route so this thread is interesting. If you wanted to make the side view equal length then the top bar would have to be longer than the bottom bar? Is there an acceptable ratio to aim for or is it just to keep the pinion change to a minimum over the suspension travel?

[joedoh]

Originally Posted by Kermitt47

Is there an acceptable ratio to aim for or is it just to keep the pinion change to a minimum over the suspension travel?

its the latter, unequal lengths will keep the pinion angle and rear steer to a minimum. Just like upper and lower control arms are unequal length, equal length control arms will have MORE camber change, and it will be wacky camber too.

a good way to check this stuff out before even ordering bars is to scale model it with paper first. figure out how far apart (y axis) the bars will be at the front attachment and at the rear axle. then cut some paper strips and use round head fasteners (office supplies) and a hole punch to make an "axle" and "bars" and a "frame"

then you can use a pencil to trace the pinion angle at different heights.

[dillonv2008]

Originally Posted by joedoh

its the latter, unequal lengths will keep the pinion angle and rear steer to a minimum. Just like upper and lower control arms are unequal length, equal length control arms will have MORE camber change, and it will be wacky camber too.

a good way to check this stuff out before even ordering bars is to scale model it with paper first. figure out how far apart (y axis) the bars will be at the front attachment and at the rear axle. then cut some paper strips and use round head fasteners (office supplies) and a hole punch to make an "axle" and "bars" and a "frame"

then you can use a pencil to trace the pinion angle at different heights.

So why does this set up work if from side view bars are equal length. Id Like to redo mine a little so I can run bags on bars.

[joedoh]

Originally Posted by dillonv2008

So why does this set up work if from side view bars are equal length. Id Like to redo mine a little so I can run bags on bars.

since I cant see that going up and down and know that it actually DOES work. but if it does:

bar length. look how long the bars are, longer bars = larger arc of operation = more stable in travel

look very closely. the lower bars are shorter than the upper. this is the same ratio I talked about, upside down.

[dillonv2008]

Originally Posted by joedoh

since I cant see that going up and down and know that it actually DOES work. but if it does:

bar length. look how long the bars are, longer bars = larger arc of operation = more stable in travel

look very closely. the lower bars are shorter than the upper. this is the same ratio I talked about, upside down.

So since my lower tabs would go further forward. If I was to attach them to the driveline support I built then from too view I'd want my lower Bars to be shorter in length? The side view center axle to link tab doesn't matter anymore?

[dillonv2008]

Originally Posted by Kermitt47

Hi, I am going down a similar route so this thread is interesting. If you wanted to make the side view equal length then the top bar would have to be longer than the bottom bar? Is there an acceptable ratio to aim for or is it just to keep the pinion change to a minimum over the suspension travel?

from what ive read about the lower and upper bar lengths is you want the upper bar to be about 70-80% of the lower bar length from a side view. dont just cut the bars and make it shorter. its all from a side view. so in my drawing I did the lower bars are parallel to ground and example 30" long center of axle to end of bar link. so my upper bars need to be in the 70-80% range. but the upper links are going to be at an angle so cutting them to early before measuring like I did will make them possibly under that 70-80 range. you have to consider the angle they will be at in your measurments forgetting them in that 70-80 range. so in the example if lowers where 30" center axle to end link. 30-25%= 22.5 but they will be at an angle so you have to add for that angle in your measurments.so the bars them self might really be 25" but with 30* angle or whatever it will from a side view be 22.5 which is 75% of the length of lower bars .. ?? get it kinda I might of made it more confusing haha