Now that I have the frame pretty much done(I have yet to put in the FU-1, and FU-2 tubes as well as the LR diagonal tubes, and a few other minor things), it's time to start on the front suspension. This is one part i've been looking forward to(since it will allow the wheels to be attached), but also dreading(since this might well be the most important part of the whole build).To do the front suspension, I need to start somewhere,but where? It's one of those chicken or egg things. What do you start with? I finally decided to start with the track. Since I was using the Miata rear subframe, the rear track was already determined. Most cars have a front track pretty close to the rear,(Miata is 56.2 rear and 55.5 front). So I decided to go with the stock Miata track. How to actually transfer that information to the front suspension got me to thinking. Since I already had my frame with rear subframe mounted and rear wheels attached, I didn't want to put the frame back on the build table at this time. Here is what I did. I attached a small dolly to the front frame to give me the correct ride height. Then, I took a front wheel, with tire and hub attached, and positioned it against one of my basement posts, which I new to be vertical. I drew a line on the floor from the center of the tire to a point which will be under the rear tire. I moved the car to the position on this line, allowing for the slight difference of front and rear track. Now, I could measure accurately from the front ball joint over to the lower frame to determine the length of the lower control arm. I knew that most people used a lower control arm parallel to the ground, so that part was not very hard. I realize that one could use a cad program or other means to do this, but I didn't know exactly how far the ball joint was from the center of the tire. Also, this gave me a "real world" feel for what was going on. After reading about other people's builds, my lower arm looked a little long, like 2-21/2 inches longer than most. So I went back and double checked. Yep, my numbers were correct, but why was my arm longer than one using the same upright. My arm is longer than some who are using a book frame and I'm using a +4 frame, so my arm should be shorter with the same track. I did a little checking and found that the front bulkhead lower frame tube on a book frame is actually wider than my lower tube, but my upper frame rails are wider, which will give a more pronounced angle to my front bulkhead. What will this do to my upper arm lengths? Will find out later. My lower arm length worked out to about 20 inches long when the front to back mounting point is 12 inches apart.(19.925in). This gives me a perpendicular length of 19 inches. Pretty long, but the numbers don't lie. I played around with different arrangements with the lower arm. I tried making i asymetrical, with the front leg perpendicular and the rear leg longer. I liked this look pretty well, but it lengthens the wheelbase some and I wasn't sure what that would do to the strength, so I went back to the symetrical design. This will also allow both left and right arms to be identical(with my building skills, they probably won't be identical twins, more like fraternal twins).
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