A while back I read on here about using lowering ball joints and found a link for them http://www.colemanracing.com/catalog...?cPath=49_1421

Here's my situation:
I have reduced some weight on the front end of my car by eliminating the A/C and smog pump and I also relocated the battery to the rear of the car. I figure this has taken ~70-80 lbs off the front and and between the battery and subwoofer I'll be adding ~ 80 lbs to the back end.

I don't want this change in weight distribution to make my car sit higher in the front than the back. Would counteracting this effect by using an extended stud ball joint be a good move? If it is, I'll also have to figure out how much I need to compensate (the stud lengths can be increased by .1", .2", .3", .4" or .5" over the stock length.

I also plan to get the Eibach Pro-Kit to lower the car 1" in the next year or so. Should I try evening it out now ( I need new ball joints anyway) and going with a 1" lowering all around later, or should I leave it be for now and get lowering springs with unequal drops for the front and rear later? Are there any benefits to one method of lowering over the other?

 

ive never heard of lowering ball joints, but i did click your link....

thats .500, .400,.300, ect... as in, the max is half a inch longer. i donno if thats going to be anywhere near a visual change.... seems too small to worry about...
if needed, id just cut the springs some... but i doubt with your minimal weight mods, its even a problem.


raising the spindle like that would throw off your steering.. you could probly correct it with a bump steer kit...

off the top of my head, i donno what else it would effect...
but ive never heard of lowering a car this way..

 

The extendeed balljoints are used mainly to set the front geometry of the A-arms and roll center height. It is another adjustment tool in dialing chassis balance.

In your case, it sound like the geometry has lifted from less weight and you would be better suited to just slightly trim the coils to set the car back to height. That minor trimming is not going to effect the coil frequency in a way that will cause ill effects on ride, if anything it will slightly increase rate and a mild dampner like a tokico would be plenty adequate to control the rebound.

 

This is an interesting subject, I would really need to look at a set of them, and see exactly which metod they are using. I'm assumeing the it uses a longer stud, with a diffrent taper on it, so the spindle sits highter on the stud. This has a couple of benifits. 1) Roll height. This is a good thing, it moves the roll center in front heigher, when you lower these cars, this drops much more in from than in back, which causes some not so desirable roll charictoristics. 2) this should also give you slightly less bump steer, as the tie-rod angle is closer to where it should be.

There are of course a few other changes from moving a suspension point like this, I won't go into them all. This really is a nice choice if you are lowering the car, as it will get back some of the geomitry changes. Ideally when you lower this, you would want drop spindles, as it will then lower the car, but retain the front-ends geomitry, then when you lower the rear to match, you lower the rear roll height (a good thing on these cars), and if you use relocation brackets, you anti-squat and roll steer should be unaffected.

 

Dewey, I hear what you're saying about drop spindles being the best choice. Unfortunately, they aren't really an option for us 3rd genners. Also your description of the method is the same as I understood it to be. It appears to me (an admitted amateur with steering and suspension stuff) that a ball joint with a lengthened stud would have the same general effect as a drop spindle except for the fact that the same amount of strut travel would be lost as when you shorten the spring.

I also realize that the visual difference of .5" at most is minimal. I just figured since I'm replacing the ball joints anyway it may be a good opportunity to compensate for the small change in ride height from the transferred weight. It's also easier and maybe less risky for me to go with a different ball joint than to cut my springs. Are there any drawbacks to using a ball joint with a lengthened stud instead of shortening the springs more?

 

the most obvious, is that you have taken weight off the front. if you cut the springs, you are raising their rate even more. which will make the steering balance mismatched even more. Its going to give you even more understeer on a car that already has an understeer problem.

The thing about this, is the whole setup is a package, Dean and I could go on all day with you, about spring frequency, roll centers, IC's, weight distrobution etc. There really is no perfect setup, you use all of these diffrent things as tuning tools. myself, I would get the ball joints, instead of cutting the springs up, in most cases. That is likely what you are looking for.

But then again, see Dean recomends triming the spring a hair. I will admit he is better at this than I am. Heck if you have the money, mess around with this stuff, and do the mods for yourself, and feel the diffrence.

 

LOL, this is certainly not the case. To me the extended ball joints make sense but I wanted to ask the more experienced on here if there were any pitfalls to them. I'm knowlegable in the mathematics behind it all being an engineering student and having taken statics and currently taking mechanics of materials, I'm just not experienced in many of the automotive applications.

 

John, the problem I see with him leaving the springs alone and installing the extended balljoints is that the angle of his A-arms right now is steeper than stock. Insalling the extended balljoints into it will retain the droped out angle of the arms while giving him back his original ride height. This will also make his front roll rate increase due to the high roll center on factory springs

Now if he does insall the Prokit at the same time then the addition of the extended ball joints would be more preferable to give him about 1" drop front and 1" drop rear overall while raising the roll axis inclination and keeping the A-arm geometry close to stock but slightly more favorable toward parallel through travel due to the lowered stance yet increase spring rates to compensate.

 

But he has less weight to act on the roll center, so raising it, with less weight *could* (you and I both know at this point, we are both guessing, since neither of us know the exact geomitry) even out his roll. I am pretty sure the rear roll center is heigher than the front, even in stock form. this would even out his roll axis. with less weight to act on it, i don't know that he would actualy notice a change in the ammount of roll. You are also not raising the front spring rate.

(NOTE: to everyone that is reading this, I am asking for RTFC's opinion on this more than I am stating something. This has I beleive, now moved in to a theoretical thead.)

 

I think I added to my statement just above and you posted before I had it edited for clarity.

"This will also make his front roll rate increase due to the high roll center on factory springs"

Its the same basic priciple whether you raise the roll center or you increase the rate, they will both cause understeer.


Yes the rear is higher than the front in stck form but on a car that is not fully build it most likely a better senerio to guess that the lower front rollcenter will help a notoriously understeering car to turn. I would not recommend him lowering the rear roll center, or raising the front roll center unless the rest of the car is altered to turn-in better then he can balance the steady state. He, like many others, just need to stay off the throttle heavy on exit until the rest of the car is built up to par- and that means $$$$ to do correctly.

I goatta go, I can continue this later if needed.

 

JeremyNYR
Nice to see a fellow WNYer on the suspension forum. I agree with what the others have said, this is a good idea if you are also changing springs and ride height front and rear but this alone would not seem like a good idea. (Cheap plug time) check out www.wny-scca.com and look in the solo2 section, autocross season is coming soon. Autocross is a great way to see just how the suspension changes affect the car.

I am planning to lower my car with weight jackers, and I may do this so that I can go a bit lower (ride height) and cause less of an imbalance front to rear. If that drop spindle ever happens I will be buying those.

 

it sure would be nice if the drop spindles were plentiful for our cars. I suppose I'll have to do some reasearch and work through some of the math.

As for my plans with the car, I'm definitely replacing the bushings and ball joints in the next week or two. I've already removed the originals and I'm treating the a-arm itself with POR-15 this week. so if I go with lowering ball joints, it will be now. Then I'm planning on going with the prokit for next summer. Funds don't allow to lower it at this time.

As for my inteded use for the car: mostly cruising in the summer with occasional track visits and I'd like to try the autocross thing also.

 

The ball joints mentioned don't lower the car.

Shorter Springs Do.

Shorter Springs also change the camber curve so that more negative camber needs to be set at ride height.

After the car has been lowered the extended stud lowers the outside arm in relation to the spindle.

This allows the car to have camber gain on suppension compression.

If the car is lowered to the extent that the lower a arm is parallel to the ground at ride height, and the suspension is further compressed camber is lost because the a arm gets shorter.

This is the disadvantage of the strut suspension.

 

Respectfully,
You need to re-study an the lower balljoint position in any conventional coilspring front suspension. An extended balljoint will in fact lower the car exsactly as much as the specified extended length (.1" -.5" based on joint selection) because it in fact positions the spindle height.

Upper balljoints will have no effect on ride height.

The rest of your info is correct and helpful.
You see very sharp thought on what I have seen you post. Good to see some experience around here. Where you from? maybe I know you by chance? I'm in So. Calif.

 

Respectfully,
You need to re-study an the lower balljoint position in any conventional coilspring front suspension. An extended balljoint will in fact lower the car exsactly as much as the specified extended length (.1" -.5" based on joint selection) because it in fact positions the spindle height.

vsixtoy,

Thanks for setting me strait.

I was not thinking clearly and did not consider that the spring load would be the same and the strut would compress to eat the higher spindle position. I appreciate the correction.

What ball joints are you running? What is the coleman part # for our cars?

I was looking to try and find a ball joint that was threaded so I could play around with trying to optimize camber curves. I am not smart enough, YET to determine all the various consequences to playing around with the roll center.

This may not be a good idea, but if we did not try what we did not know we would still be living in caves.

 

Actually the best unit you can use for race settings is an adjustable monoball, rather than a standard balljoint. they don't last as long though and need bearing replacement unless you go to a very highend sperical bearing.

We use the GM midsize lowwer balljoints on our 3rd gens. Right now on my stock arms I have a standard Moog balljoint. I have been waiting on options to materialize in the way of front coilovers and have had discussions with Spohn in the past on development of them. Unfortunately for right now, I this car too low for any coilover setup to function and have been holding off on the frontend until such products I want come availiable (ex: Belltech drop spindles).

After a few years of waiting, I had to finally just temporarly refit my current arms with urethane bushings when I dropped the front to fit the brake setup I built. I am still buying time until I can hopefully get the setup I want with coilovers and drop spindles. At that point I will fit the lower joint on Steve's rodend tubular A-arms with a Coleman GM K-6145 style monoball (part # 835-450) with a better bearings than the ones they come with (I run Aurora highend sperical bearings in my strutmounts, PRN-12T's). It will leave me with the adjustment provisions if I choose to use them to raise the front roll center for further testing.

I build my cars strictly for a hobby because I drive the crap out of them daily. I don't ever car about building a car to rules, I like a car to run as fast as it can regardless of any class regulation- I race the clock, not others. It makes for personal challanges and continual advancement.

 

The ball joints listed on the Coleman site are actually made by Howe. Their web site has more info than Coleman's. http://www.howeracing.com/Suspension...nts-Lower.htm.

Howe does not stock the GM "metric" (F/G body lower) ball joint with the extended length studs - they are special order. However, Savitske Classic and Custom keeps them in stock with the .5" longer stud, and they come with poly boots as well. http://www.scandc.com/

Adding .5" of height to the lower ball joint, either with mono-***** or with the ball joints, will in fact make bump steer WORSE, not better. Matter of fact, it gets downright scary!

The nice thing about the Howe ball joints vs. mono-***** is that they have a much greater range of motion and they will last a hell of a lot longer. I run mono-***** on my car, and at full droop the angle of the stud is severe enough that it binds on housing. But, the car only sees limited use on the street, so the cost of mono-***** out-weighed the other factors.

Some of these same issues were discussed back in this thread: https://www.thirdgen.org/techbb2/sho...hreadid=260379

 

Exactly… To compensate for the change you’d have to space down the tie rod end to spindle joint a comparable amount.

As far as some of the discussion about changing camber gain… a modified macpherson strut setup has very little useable camber change in it anyway, so for the most part you’re best off setting camber about where you want it and keeping roll stiffness high enough that it doesn’t change much (on a lowered 3rd gen there isn’t enough suspension travel to really do anything else anyway).

Assuming that you go and fix the bump steer after you mess with this, taller ball joints might be useful in raising the front roll center as an alternative to lowering the rear and allowing for the use of lighter front springs/sway bars with similar performance (ie, a more streetable setup). If it was me I’d shoot for a lighter sway bar and try to keep the spring rate the same to control brake dive.

Myself, I’m going the other way, lowering the rear roll center and going with stiffer springs out back which will be somewhat harsher on the street but should also work better with revised rear LCA locations at the dragstrip (yea, I build most of my stuff to handle but use it at the dragstrip almost weekly… oh well), hopefully the end result will be the ability to _actually use_ more rear antisquat with a relatively stiff tire on the launch pad.

 

You can replace your outer tie rod end with a rod end bump steer kit to bring the bump steer back to an acceptable amount. Without puting the bump steer guage on the car before and after the longer ball joint install I wouldn't be able to tell you how much the tie rod would need to be lowered. But if the ball joint pivot point was lowered .5" then a good starting point would be to lower the outer tie rod pivot .5". Affco makes a ball joint that would lower the ball joint pivot point even more. I think it is 1". You will proubably have to ream the taper out to 2" per foot instead of the stock taper at 1.5" per foot.