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for the upper, why not just screw the hiem into the rearmost tube and weld a tab on the side of the tube for the fork end to attach?

how will you attach the suspension to the lower arm?

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Good point. Was originally going to oriate the heim vertically, but looking at race vehicles, looked better in this orientation. Mine as well decrease number of tubes and welds.

What do you think of the steering tie rod attachment?

Here are a couple ways to do it.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Looks good. Thanks for drawling that out for me.

What is the reason for moving the steering attachment lower on the spindle? Is it to avoid hitting the rim? The rationale I was using for putting it even with the upper heim was to "eliminate" bump steer (make it easier to at least).

Does the top heim go in single shear, as drawn above?

With the updated UCA, would I be able to adjust camber w/o disconnecting anything?

Also, would I bother cutting off the original steering attachment on the knuckle? Or is that asking for trouble?

Thanks again! (sorry for baazzzillioon questions)

I lowered the arm to straddle and clear the upper clamp bolt and uca range of motion, but it could be higher and still clear with a little adjustment. I don't follow what you mean about bumpsteer, since it is a result of many variables. The drawing is just a rough idea, plus you need to decide on the right kpi for the tire size and rim offset, then move the ubj accordingly. Another option is to offset the ubj outboard of the spindle arm and ream to accept the standard balljoint you have already, with no modification to the uca.

Yep, single shear. That is why the bolt and joints are larger than they would need to be for double shear.

The rear link is still adjustable but it changes camber and caster at the same time.

I'd cut off the original arm then grind the cut smooth and chamfer the corners, but it isn't hurting anything right now and you may change your mind later about using it.

I like the use of the production roof and windscreen frame. Saves a lot of work.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Vsusp file:

lolita

What do you think?

This is an updated version that adheres to Olley's Rule a it better.

Does that camber curve look OK? The roll center stays put for the most part.

Front frame construction.





I'm going to make a little gusset to support that bottom mount better

Did some work with steering placement. Got toe change to 0.01. Ackerman looks decent too.

So, been gone for a while. Might get some time to work on the car in a month though.

Switched to a mustang sn95 front spindles and brakes. The scrub radius was just too hard to correct on the previous setup. The mustang stuff also has plenty of aftermarket support. Using a K772 for the upper ball joint and K727 for the bottom. Should be pretty stout.

Going to post this here for future reference.

lolita

Hi Nick, glad you are still at it. I missed some of this stuff, end of last winter was kind of crappy for me.

So I am curious why you are going for a "buried" roll center on the front, below the ground.? I'll have to think about what that means, it's at least a little unusual.

I think you did have an acceptable scrub with your old setup ( about 1" ), was that Subie spindles? Now you have a negative scrub radius. That isn't wrong and you see it on some production cars, especially front wheel drive, but also I think the Porsche 928.

I see looking a little more carefully that that is happening because there is 16+ degrees of KPI. That's a lot. Is that coming from an adapter? I see when looking at the ever popular Pinto/Mustanf II units that they have about 10-11 degrees, and the oval track folks went to the trouble of getting a forging made with only 7 degrees.

I didn't look carefully at the rest yet, like camber curves. Is that why you have the front lower arm going uphill to the wheel? I do just a little of that in my car's rear suspension, because the lower arm is very high off the ground with T'bird uprights. It's only something like a 0.5" tilt though.

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So the Roll Center has been a bit tricky. I was reading through some old sports car team notes and found that they had the RC start just below ground and then migrate above ground with roll. All the force transfers to the contact patch, with some significant body roll, but also with good mechanical traction. As the car rolls, the RC comes above ground and then the force travels more though the spring/pivot. Also, the RC hardly changes with wheel height or ride height. I also have adjustable UCA inner pivot mounts....so maybe I can mess with it!!

The scrub should hopefully be about 0 to 0.1 with the brake rotor attached. The KPI is high from the adapter, but the adapter is sturdy and I trust it.

That all being said, open to any suggestions!

Augie was helping me make the jig for the lower control arms. Except he just wanted to see what parts fit together. Doesn't get that whole LH and RH thread thing.



Temporary fitting. Need to get a longer swedge tube. Waiting for LH 1/2 -20 heims to arrive in the mail.

Arms tacked together:







Does anyone see any issues? Still have time to make changes...I think