4 Link angle question.

I have a question about a triangulated 4 link. I understand that the optimum angle is 45 degrees. Now if I am talking about the upper bars, is that 45 degrees to the diff like this \|____|/. Or can it be a combined 45 degrees to the lower bars like this \/____\/? I guess what my real question is can both upper and lower bars be at angles or do you need one set to be parallel? Will there be some binding if both bars are at an angle?

I would steer you away from both being on an angle. I do not have any real geometric reason, though I did set my s-10 up like that for a few months and i had trouble with it wanting to wobble. I adjusted it a few different times trying to get it straight, then decided to just go traditional straight on bottom. When it comes to the top being a 45 I do not believe you are going to see any difference if they were to be more or less. A large number of kits sold would make it impossible to have a 45 with the length of the top bars sold. Think of it like this, if you had both top and bottom bars straight, that would control your front to back so you would need a pan hard bar for your side to side movement. If you add just a slight angle to your upper bars you will still prevent side so side movement, but create more strain on your link ends. You should never see binding unless one of the 4 bars were mounted unsymmetrical to the other. Keep in mind your differential angle as well. You can look it up to get more info and understanding on it but your output shaft on your transmission should be parallel with your input on the differential. I would say the main reason is to keep oil evenly in the case.

one more good thing to do which i forgot to mention is take a few nails and cardboard and make a scaled down model of the for link. For ever 1" make the scale like a 1/4" move it back and forth until you find what you are looking for in terms of even movement.

You want one set of bars to be parallel to the frame and one set to be angle. You can do it the traditional way with the lowers parallel to the frame and uppers angled or lowers angled and uppers parallel to the frame(satchell link) They don't have to be exactly 45* but the closer the better technically to keep the rear end straight and moving through the motions properly.

Ok. Now would this all apply to a front axle? Say on a traditional style hot rod with a Ford I beam axle?

45* is optimum but rarely obtainable. Anything over 30 will hold the rearend in place. You can do a double triangulated 4 link or a satchell link and it will work for you, just be careful about triangulating the lowers too much and causing torque steer.