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For practical purposes, only the upper control arm frame brackets matter.

Plates like in your drawing wouldn't have a lot of resistance to brake torque. You might consider making some sturdier bolt-on brackets.

I've seen brackets like yours, but they were either old-school stock car stuff made out of steel plate, or thin stuff on drag-car chassis that didn't always use front brakes anyway.

Is the intent of the adjustable geometry to change the driving characteristics of a completed car, or to adapt a single design to achieve similar geometric characteristics across multiple cars using a variety of spindles? The concept should generally work either way, but each would 'ideally' be approached a somewhat differently. This seems to show a bit of both in it, leading to additional compromises.

I have considered similarly having a second set of holes for the IRS mounting points, to have separate 'road and track' and 'drag' geometries.

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

I suppose the adjustment for the lower arms could be used to keep the arms level at various ride heights. Not that you'd want to go adjusting that very often but it could work for the once-a-year trackday or something. If this is the case, the holes should probably be aligned vertically so as not to affect the track width. Probably all semantics though, and in the case I just mentioned, it's probably better to just set the ride higher and live with downward-angled arms while driving on the street.

Actually the idea came to me after spending hours in front of a computer staring at one of those suspension design programs (no criticism, I wrote my one too). I thought if I just built all this adjustability into the suspension that I could just drive the dam thing and fiddle with geometry in real time as I go.

This an adaptation from another chassis design converted to Locost so the Heim jt plates are look like elephant ears.

I think there is definitely some merit in this idea, as most people designing suspensions necessarily rely largely on the second-hand learnings of those who came before them. As drawn, it would allow one to get first hand experience with all manner of 'unconventional' geometries. However, the extremely wide range of geometries available does cantilever the brackets out there quite a ways too. So as an adjustable driving experience platform, it would be a great teacher. However, I think in reality it would be considerably more practical to narrow it down to 2-3 on the UCA and 1-2 on the LCA. Due to the spacing required between holes, beyond that it tends to start getting into some pretty wonky stuff...Unless experiencing those happen to be part of the goal as well.

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Nice idea Bobber, I would like to see someone make it and test it. I used to be perplexed as to why suspension pivots for the UCA don't move dynamically to suit the attitude of the car, on the fly adjusted by the driver. With the arms positioned parallel so that grip during acceleration and deceleration could be maximised by holding wide tires square to the road or moved to the cornering setup by lowering the inner UCA mounts to give aggressive camber gain for cornering. I imagined a switch on the steering wheel for flipping between the 2 (or just leaving it in corner mode!). Bump steer tends to ruin all the fun with on the fly geometry chameleons (then again the porsche 962 had no issues with bump steer as the steering tie rods were in the same plane as the upper control arms, IN THEORY why not set the rack in the plane of the lower arms?). How much rack adjustment is required to control the bump steer figures with the layout you sketched?

I am building this in my garage right now. I got slowed down by a stroke which has left me in a chair. The geometrical extremes of the suspension require almost 3-in of length adjustment in the steering links to eliminate bumpsteer which I provide by sliding end connections. The steering arm to spindle connection also slides for vertical adjustment. I will use a Chev Cavalier rack with its center located link to drive my adjustable center link.

Bobber, that looks nice. Very clean!

Below is my Car9 front suspension mounting tabs per Horizonjob's design. In this implementation changing the plates is used to change the geometry, although multiple mounting holes in the plates could have been used instead. Rectangular tubing has sleeves welded in to support mounting bolts.

Rear suspension does use multiple hole locations for CA's and trailing arm geometry changes.

Steering rack uses shims to change the vertical position.

Seattletom,
Elegant solution to this idea applied to a Locost! And sleeving the tubes as well in a potential stress area. I'm going back to read your build.

Thanks, Bobber. The credit goes to Marcus (aka Horizonjob.) He came up with the design.

I've never built a real car, but my experience in RC led me to design bolt on brackets for my BEC build. RC cars have ridiculous amounts of adjustment; track width, roll center, anti-dive/squat, camber gain, bump steer, dynamic rear toe, ackermann and more, Ack!

So my main bracket option is my best guess, if it's horrid, make some different brackets.

Cool build.

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."
"Sometimes I sits and thinks, sometimes I just sits." - Satchel Paige

That's a pretty slick looking setup there, Bobber.

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Johnsinski
That's sort of what I had in mind as well. My waterjet shop has my bracket design on file. I just send in an update for different holes and pick up the brackets next day. The set up I have now just has the three most extreme geometry positions.
Do all these adjustments help you or hinder you. Thx.