Quadralink / 4 link question

[a_kelley]

On my xyzj I was intending to copy the relative link mount locations off an xj. Is there a better way to determine where to put them? My lowers are 19.5" at what should be ride height. I'm thinking I ought to plug numbers into the calculator.. is there a easy way to measure vertical and horizontal separation at the axle and frame or does someone know the numbers for a stock xj ?

 

[Mac5005]

On my xyzj I was intending to copy the relative link mount locations off an xj. Is there a better way to determine where to put them? My lowers are 19.5" at what should be ride height. I'm thinking I ought to plug numbers into the calculator.. is there a easy way to measure vertical and horizontal separation at the axle and frame or does someone know the numbers for a stock xj ?

You can copy them, but you can probably improve upon the stock setup.

Look at the frame and axle and put the numbers in the calculator.

Look at areas that you can improve, and make changes that will fit with the frame and axle and all other components.

 

[a_kelley]

I think I got measurements all correct, was tricky at first to figure out, but it started making sense. Is the roll axis angle being 6* anything to be concerned about?

 

[Mac5005]

That roll axis angle is opposite of what I want. I shoot for flat, or sloped downward. This way you have roll understeer.

Roll over steer means if you are turning left, and the body rolls, the left(inside) wheelbase starts to get shorter, causing oversteer.

Probably can triangulate the lowers some more , and reduce the upper triangulation some.

Is this a front suspension you are working on ?

 

[a_kelley]

Yes it is. I was thinking of raising the lower links at the axle to help anti dive. The uppers kind of have to stay where they're at since it's a d30. Uppers could be made longer and I've got plenty of room to shift them around, except to bring them in. I can change the lower length, but really just want to throw some uppers in with the lowers like they are and get it to roll, so I can move it again. Add there is a distinct possibility that these axles will be replaced in the short term future, so it's really just a 3-6 month time I'll run it with the d30. Stock xj uppers are 15.25" long anyway. I had played with the numbers since I posted that. I'm following along your link tech post as well.

 

[Mac5005]

roll steer isn't that big of a deal in the front, as the wheel will be turned anyway. Generally the flatter the better.

The near 100% antisquat (antidive when braking) catches my attention. However this would only be accurate with 100% front braking.. have to mulptiply that #by the brake bias. If you can get it down some, I think that would help. its definitely a challenge to get things to fit with factory frames and drivetrains.

IF you are planning to redo it all anyway, plot the numbers and save the file. Drive it, and note the behavior. Move links and save file. Note the behavior change. My tip there is change one principle at a time if possible. Change Antisquat, then change roll axis angle. This way you can document individual changes and their effect on behavior.

-8" droop is a ton on stock short arm suspension.