Ball joint extensions instead of drop spindles?
 

Hello all-

I am actually asking this about a different car I am racing but since it's a strut car too and since all the smart people hang on this board I am asking here.

The idea It seems like a ball joint extension could be made that would lower the end of the control arm to preserve camber gain while allowing the car to be lowered. It would do the same thing at dropped spindles but be a lot cheaper and easier.

I have access to a lathe and experienced operator but don't know what material (steel for sure) would be strong enough to be safe. I know there are some steering link extenders used to regain geometry on lowered cars and these would be similar just a lot thicker.

Thoughts? Perhaps this is a bad idea but a guy's gotta put it out there...

it doesn't address the lost suspension travel, because you haven't shortened the strut above the spindle.

Good point Tyson. The question is how much travel is there before the rest of the car hits the ground anyway? How high off the ground is the car just on the bump stops? I've never done this test but perhaps someone else here knows.

I think the value would be to add camber gain at any ride height but I can see why some would feel it to be a kind of hokey solution.

Does anyone have a suggestion as to what material would be best to make such an item?

What car are do you have? The 944-24 have an A-arm type front suspension (similar to rabbit) that can benefit from a longer ball joint pin. I was thinking of doing this to mt rabbit using 944 parts. Paragon Parts has this part for $250. Also Jason@SCCH.com has a part for MK1 and MK2 VWs that has a bigger in to allow lowering without geometry changes but I have not tried this approach. Is this what you are interested in?

http://forums.pelicanparts.com/uploa...1232153239.jpg

Found this on the interweb. Looks like others are thinking about this idea too.

I guess we'll go a bit off the p car topic...

The car I am running is a Geo Metro, same as Suzuki Swift. It's a total frankenstein with a Honda suberbike engine. Here is a little press about the last event it entered, and won.

http://jalopnik.com/5119427/and-the-arse-freeze+a+palooza-lemons-winner-is-the-metro-gnome-motorcycle+engined-geo

Here's the thing, the "24 Hours of Lemons" series is for cars that cost $500 net, and so I am not really allowed to spend much money on this. I think I will try and make some of these myself and see how they do. The car needs to get a lot lower and the control arms are already past horizontal. Hence the extended balljoint pin idea.

I was just thinking this would be a cool thing for 911's as well.

Not to stay off topic but some friends and I are building a Lemons car to compete this year. See ya out there!

David

I think it's a pretty bad idea from a safety point of view. A ball joint is usually mostly buried in a healthy steel casting - the load is very much shear. Making the stem longer would add significant bending moment, which the attachment diameters are not designed to carry.

As Tyson pointed out, you don't gain any suspension travel, which is probably an issue if you're lowering the car enough to think about raising spindles.

And you still have to address the lower ball joint to steering rack relationship, or risk a pretty funky handling car.

second what burgermeister and tyson said- 2 good reasons NOT to do it

Bending and breaking awaits
saw this on a local club Rabbit racer, he had very poor results with it and using chrome moly to boot

I take it this guy with the Rabbit had a rig like this break? I would love to know more. I am not sure what would get changed in the rack relationship other then the rack needing to get moved up to keep the tie rods parallel to the control arms. Toe out on bump=bad.

Our car weighs under 1500 lbs so I am not too worried about it failing, but there may be other reasons to not do this. Cost being a biggy. I'll probably just live with the bad geometry and do the Chapman thing. Keep it from moving much.

Hey Dave231, where are you located? What Lemons event are you looking to do?

third

how does this theory hold up in the 944 world. I have seen two different aftermarket A-arms out there with different "pin lengths". I agree it looks suspect but are the 944 ones failing?

Cheers

I like it.

One of the advantages of raising the spindle is it restores the shock travel. However, if the car is lowered to the height you like, has suffer springs, and is not having any problems the extension should do work.

Another opportunity could be to add more offset so we can gain more neg camber. Increasing the a arm angle will increase neg camber gain with compression but one will likely loose static neg camber.

Bad idea on a 944 with known issues. Though if the bottom hole is made at an angle it could correct for the loads that are put on the ball joint with a lowered car.

Should work well on a 911 in may causes as it dose not have the issues a 944 dose. Might be worth getting this idea to ER for review, could be a low cost low impact way to improve the front suspension geometry for sport use.

This will increase bump steer and that would have to be addressed.

How will lowering the car with coilovers change the geometry...less travel or change the steering or both? It seems that Macpherason Strut suspension should be adjustable. Are certain cars stuck with their existing ride height?

The same as lowering it with the stock torsion bar suspension.

Only the spring type changes, none of the attachment points change.

You do get access to higher spring rates and you may loose some front tire clearance depending on the spring diameter used up front around the strut.

If I use a revised A-Arm ball joint pin (longer bigger pin diameter) and different tie rod length then that should compensate for the height changes but do you still need a tie rod change if you have restored the parallel A-arm relationship with a longer ball joint pin? I am thinking (correct me if I am worng) that a lower car will have an A-Arm that is higher at the wheel than the frame...a longer pin will adjust this to more flat (parallel). Then will there still be a need for other changes to steering linkage?

there are many manufacturers that make extended ball joints but usualy are maxed at 500thousands, qa1 howe,, monoball guys that use carrots etc, i have been usuing extended ball joints for a while on a race car with strut lowers and a frame uppers it actually helps getting the roll center right. if you were only lowering a car a half inch,, half inch longer ball joints would put the roll back to the specs before it was lowered at least at the ball joint , the pin angle would change causing a diiferent roll. in other words the roll with longer ball joints would change because of the different pin height,, and the bump would be destroyed, iI have never done a 911 roll center but having done 100 cars,, with raised pin and extended ball joints the camber gain would actual slow down

i just ran the specs on another strut car i worked on and camber gain went from -.62 to -.57, Kevin

Fellas,

to lower a car you need to shorten the overall length of the strut. This can be done by shortening the strut and the shock. The easiest way is to adjust the torsion bar so that the ball joint end is Raised in relationship to the body, not lowered.

You would have the spindle raised to keep proper alignment and avoid bump steer.

At some point you will lower the car too much and the shocks will bottom out and damage things, so at that point you should use modified (shortened) shocks so they do not bottom out.

Lengthen the ball joint would raise the car.

Daleflesburg,

The problem he is trying to solve is improving the angle of the A-arm when lowering the car. Extending the ball joint will lower the A-arm back to it's normal angle when the car is lowered by using shorter springs or adjusting the torsion bars.

This plan will work fine if the joint doesn't break and the shock doesn't bottom out. It accomplishes the same thing for the geometry as raising the spindle.

-Andy

I have been doing some searching and found this solution at SCCH.
http://forums.pelicanparts.com/uploa...1232668933.jpg

This is for a VW front suspension but as you can see the A-Arm is level and the tie rod seems aligned. The A-arm pin has allowed the lowering of the suspension.

Hey! For some reason my subscription to this thread got broken and I did not know that there where all these replies.

Anyhow, I see now that some people have gotten what I was trying to say here and why long stem balljoints could be a great mod for moderately lowered cars. The steering tie rods would have to be re-positioned but there are kits for that already.

Here is what is available for 944's. I contacted the seller but they would not give me the ball diameter so I could check if they could be adapted to 911's or my race car.

I have half a mind to buy a set and then head to the junkyards to find ball joint sockets that would work then weld them into the a-arms on the race car.


http://forums.pelicanparts.com/uploa...1233113091.jpg

Kevin-

Could you clarify? If the a-arm is tilted down more wouldn't there be greater negative camber gain? I thought that was what the longer ball pins where supposed to do.

I am trying to get more neg. camber on bump and run less static neg camber.

Sorry for the double post...

your right i worded it backwards just rechecked, by lowering the ball joint it went to -.62, i am not sure i understand you, if the bump is off it just creates + or - toe. lets see if can remember this, if you want less static camber on the front end ride hieght and more when the front is compressed you are going to have to do something to get high camber gains, on an A frame upper car you would need shorter upper control arms. you can improve camber gains on a strut car by moving the strut towers in. this would create camber gain but you will have to rework the spindle to get the static camber out. and one inch may yield as little a -.10 degrees more, remember there are racing strut towers where you cut your tower out and replace it with one that gives more strut angle. if it were one inch higher with a half inch longer ball joint you would regain your travel, but bump would still be out. its possible if you took exact measurements i could check your camber gains etc, but sometime exact measurements may mean you have to cut a ball joint in half to find the center, Kevin

also keep in mind caster can cause a car to feel darty and should be checked to make sure your requirements are met before welding if you should replace the tower

While the GEO may be light, it's suspension was similarly designed to support that lightweight. I understand you have lightened the car further, you are also racing it, pushing it harder than the design intent. Compound this with a ball joint extension that is weaker than the factory design, and you have potentially a serious failure.

If you know how to calculate the loads and strength of materials, do so. If you don't know, then guessing is trolling for trouble.

Even if you can make it safe, this is a jiggy workaround solution. Instead why not focus your efforts on figuring out how to properly raise the spindles.

As an aside, Chapman wasn't condoning suspensions that don't move. He was deriding poorly designed suspensions that had to resort to super stiffness to work reasonably well.

The only thing that gave me heeby jeebies was that ball joint extension you posted....

I favor as few connections as possible...in suspension links...

And I'm aware of what those qm etc guy do with their suspensions..

Heck I have a bunch of qm parts set aside to make my 935 susp..

the best bet would be to move the spindle pin, but i have been using extended ball joints up to a half inch for a long time, any more then that i wouldnt do it, actualy most of the mono ball stuff is built so you can put washers inbetween to extend them, and i like mono ball carrots less then ball joints, mono balls have less rotation then a ball joint,(when i say ball joint I mean a racing ball joint), Kevin

Reestablishing the A arm angle on a lowered car reduces the static neg camber (brings the bottom of tire in) but again allows for neg camber gain with compression ( bottom of tire moves out). Thus, no real improvement unless you do something at the top of the strut to gain neg camber.

It makes much more sense to do it the right way and send your struts out and have them raise the spindles and decamber them at the same time. It as about $250 to raise them and another $200 to decamber them.

You still have to get a bump steer kit.

Now you have enough static neg camber, you get neg camber gain under compression, and you restore travel the the front so there is less risk of bottoming out.

I get that. While I would like to get the geometry right, it may be that I'll have to live with a sub optimal setup and just make it not move much.

Here's the thing, the Geo is a front drive car so raised spindles are not an option unless they are custom forged etc.. Long stem ball joints might help and that's why i am looking them up. I am going to contact QA1 and see what they have available. They do make one with the right stem diameter so I'll see if they make an extended one in that size.

My idea here is to allow one to use LESS static neg camber by building it into the geometry under compression. That way the tire is flat when the car is going straight and gains neg camber only when turning. For a front wheel drive car contact patch on corner exit is a big issue with an open differential and since my Geo has twice the stock Hp this is issue #1.

Thanks for all the input. If anyone knows who makes a long balljoint with a 15mm diameter stem let me know.

Datsun guys have been doing similar for a long time with 240z's. They use a balljoint mount that bolts to the rest of the strut though, so they just fit a machined spacer between the balljoint fitting and strut. Improves camber curve on lowered cars. And yes, typically they also run a shortened strut insert ( I think one designed for VW's from memory ).

GEO! :rolleyes:

OK. After a bunch of time doing other things I got this project done. I welded a threaded chromolly bung into the spindle and run a bolt through a spherical bearing pressed into the control arm where the oem balljoint used to sit.

Just did a track day and I gotta say this was a MASSIVE improvement. The car now only needs .5 degrees of static neg camber because it gains a lot of neg camber when the suspension is compressed. Much better handling is the result.

The reason this applies to 911's is that I think most people lower these cars with the torsion bars and not drop spindles. I now would venture to say that even the casual user should consider drop spindles BEFORE anything else. It allows you to lower the car and not have to have over stiff torsion bars. You also don't have to kill your tires with a ton of static neg. camber since there will be good neg. camber gain under bump.

Here is a phone cam pic of my home made setup. It hasn't broken yet and I doubt it will give any trouble. Pic. it sideways. Sorry.

http://forums.pelicanparts.com/uploa...1238948702.jpg

Welded?

You may want to put that on an extremely frequent inspection list. Welding reduces high cycle fatigue performance by a huge amount in any steel, and unless you did some annealing afterwards you won't get the durability of the chromoly part in the heat affected zone of the weld either. You will get the strength, but not the durability.

Thanks for the info about the welding. This car gets gone over a lot since it's a race only app.. I will check these every time it hits the track. By the way, the threaded bung protrudes into the ball joint hole in the spindle 1". It's not just a butt weld.

I pre-heated the parts to 550 degrees, tig welded, then wrapped in fiberglass to slow cooling. Many before me have welded spindles with similar techniques. Let's hope I got it right.

Anyhow, point of all this is that maintaining geometry in a lowered car is worth the trouble big time. Just turning the torsion adjusters to lower the front is not going to do anything but make the car look better in pictures.