Ball joint extensions instead of drop spindles?

[avendlerdp]

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...

[Tyson Schmidt]

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

[avendlerdp]

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?

[DG624]

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?

[avendlerdp]

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

[avendlerdp]

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.

[dave231]

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

David

[burgermeister]

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.

[TRE Cup]

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

[avendlerdp]

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?

[TimT]

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

third

[Jeff Alton]

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

[911st]

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.

[DG624]

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?

[911st]

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.

[DG624]

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?

[Kevin Stewart]

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

[daleflesburg]

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.

[Eagledriver]

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

[DG624]

I have been doing some searching and found this solution at SCCH.


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.