So I'll ask here

[blacksheep]

I tried asking this question on my build thread with no response , so here goes. First off, I have built custom bikes and know fabrication when it comes to them. But, this is my first ground up build on a ratty. That being said, I have a couple of questions. I set my frame yesterday at the ride height that I want (or close). I am using a buggy spring suspension, with weld on pivots on the rear axle. I'm trying to make sure I have my figures correct here. My pivots will be right at 11" from the floor or ground. My spring height from the center of the eye to the top of the spring is right at 17". The top of my frame is setting right at 9 1/2" off the floor. I'm thinking I want 18.5 -19 " zee in the rear. Is this correct thinking here? Also, how much wider do my spring pivots need to be than my spring eyes? I know I need to make sure that the spring can flex. But, is there a standard measurement for this, becuase I need to know where to weld on my pivots for the rear spring. Thanks in advance, and sorry for what may seem like elementry questions here. I just want to make sure before I start welding.

 

[donsrods]

You kinda have to figure that a frame will settle down 2-3 inches when the body, engine, etc are put on. So build that amount of settle into your height. As far as how far to put your perches out, generally you add about 4.5 inches to the width of the spring, so if your spring is a 31 incher, put the perches so the centers of the shackle holes are about 35.5 inches out.

I find it easiest to remove the center bolt from the spring and just install the main leaf first, then once it is attached to the shackles I start adding leaves, using two big C clamps and some threaded rod through the center of the leaves. Once the leaves are all compressed and I am safely holding the spring packet together with the C clamps, I remove the threaded rod and put the proper center bolt back in and tighten it up.

As for kickup, you want to allow about 4-5 inches from the top of the rear axle housing to the bottom of the frame rail, when all the weight is on it. So if you mock it up with 7-8 inches of clearance with no weight on it, you should be in the ball park.

Don