Math: Axle shift per inch of lift
07-21-2016, 05:32 AM
#31
JK Junkie
Yes this drawing is better IMHO. I would change the red triangle to A', B', and C' (or change both triangles to A1 vs A2 and B1 vs B2, etc). If you change the red triangle to primes (A' for example), my forumula becomes:
A' = sq rt (B^2+A^2-(B+Delta B)^2)
and Delta A = A-A' which gives you the shift.
If you use A = 60", B = 10" and Delta B = 2", for a 60" axle 10" stock height and 2" lift for easy math, you get A' = 59.6" and Delta A = .4"
A' = sq rt (B^2+A^2-(B+Delta B)^2)
and Delta A = A-A' which gives you the shift.
If you use A = 60", B = 10" and Delta B = 2", for a 60" axle 10" stock height and 2" lift for easy math, you get A' = 59.6" and Delta A = .4"
Last edited by 14Sport; 07-21-2016 at 05:40 AM.
07-21-2016, 07:18 AM
#32
JK Newbie
07-21-2016, 08:07 AM
#33
JK Junkie
07-21-2016, 08:16 AM
#34
Super Moderator
07-21-2016, 08:20 AM
#35
Super Moderator
Yes this drawing is better IMHO. I would change the red triangle to A', B', and C' (or change both triangles to A1 vs A2 and B1 vs B2, etc). If you change the red triangle to primes (A' for example), my forumula becomes:
A' = sq rt (B^2+A^2-(B+Delta B)^2)
and Delta A = A-A' which gives you the shift.
If you use A = 60", B = 10" and Delta B = 2", for a 60" axle 10" stock height and 2" lift for easy math, you get A' = 59.6" and Delta A = .4"
A' = sq rt (B^2+A^2-(B+Delta B)^2)
and Delta A = A-A' which gives you the shift.
If you use A = 60", B = 10" and Delta B = 2", for a 60" axle 10" stock height and 2" lift for easy math, you get A' = 59.6" and Delta A = .4"
So the diagram needs to be updated so that the variable C in the bottom triangle is labeled as such and not C' if the preference is to use variable labels such as A' and delta A. At the end of the day, it's the same thing that I originally showed using the same equations I already defined.
Last edited by Rednroll; 07-21-2016 at 08:39 AM.
07-21-2016, 08:27 AM
#36
JK Newbie
Yes I followed your logic. I'm just partial to A and A' because as an Enginerd, I am partial to the way I do my math. Because they were both labeled A, instead of differentiating them with an A and an A', it made sense that you changed the variable names. In the long run, the variable names don't make or break the results of the equations so they all work. It's just a matter of which is more clear.
07-21-2016, 08:50 AM
#37
Super Moderator
Yes I followed your logic. I'm just partial to A and A' because as an Enginerd, I am partial to the way I do my math. Because they were both labeled A, instead of differentiating them with an A and an A', it made sense that you changed the variable names. In the long run, the variable names don't make or break the results of the equations so they all work. It's just a matter of which is more clear.
I tend to stay away from labeling variables with the prime accent and delta that you prefer, because you get in that habit and it will cause you much grief if you ever write any code in programming languages. Especially with those accent marks.
In code writing
F= (A-X) is a valid expression using valid variable labels.
A'=(A-Delta A) is not and you would never make it past the compile stage.
Last edited by Rednroll; 07-21-2016 at 08:55 AM.
07-21-2016, 08:58 AM
#38
JK Newbie
I tend to stay away from labeling variables with the prime accent and delta that you prefer, because you get in that habit and it will cause you much grief if you ever write any code in programming languages. Especially with those accent marks.
In code writing
F= (A-X) is a valid expression using valid variable labels.
A'=(A-Delta A) is not and you would never make it past the compile stage.
In code writing
F= (A-X) is a valid expression using valid variable labels.
A'=(A-Delta A) is not and you would never make it past the compile stage.
07-21-2016, 08:59 AM
#39
JK Junkie
However C=C' because the length of the track bar does not change and it is for that reason of C not changing and becoming a constant length variable that the axle shift occurs and since that value does not change, that is the reason we're actually able to solve this problem using Algebra variable substitution for the value of C into the bottom triangle's pythagorean theorem equation.
So the diagram needs to be updated so that the variable C in the bottom triangle is labeled as such and not C' if the preference is to use variable labels such as A' and delta A. At the end of the day, it's the same thing that I originally showed using the same equations I already defined.
So the diagram needs to be updated so that the variable C in the bottom triangle is labeled as such and not C' if the preference is to use variable labels such as A' and delta A. At the end of the day, it's the same thing that I originally showed using the same equations I already defined.
You guys are way beyond me. 
Here you go, red. Trying to keep everyone happy.
07-21-2016, 09:30 AM
#40
Super Moderator
Since defining and using variables in all programming languages are essential, I've just learned to get away from how things are typically written in math books and establish habits that work both in math and programming since math and programming are directly related in most cases. It makes my brain hurt less.
Last edited by Rednroll; 07-21-2016 at 09:54 AM.