Hey Denny,When I worked for GM I was taught rear steer spindles the tie rods were under compression and prone to flex. Front steer spindles the steering was less prone to flex. The reason being the tie rods were always under extension. You see, the wheels are always trying to splay outward from the front when moving forward. Which is why I feel tubular tierods would help make your situation better. Just my 21/2 cents worth.
That reasoning makes sense
...& again, thanks for continuing the discussion (helping me & hopefully others understand this stuff better)
...but, do cars have their front wheels toed inwards or are they running "true"?
Here's where my thinkin' is (after thinkin' it thru a few more times)
If the front wheels are "toed in" a little bit (like they are on this & many karts)
...& the kart is going straight forward
...it seems as if rear tie rods would actually be, being "pulled on" or in tension
But, when the kart turns all of that "goes out the window"
...& on turns, the tie rod on one side would be in tension
...while the other side is in compression
The Domino Effect
So, it seems like a (my) component choice (big, plastic wheels) + a design error (short spindle arms) added up to create an effect (an overleveraged steering shaft)
Then, when them big, plastic wheels flexed (on turns)
...& then, flexed back (into shape)
...they sent that energy, thru the tie rods, to the steering shaft (causing it to flex)
Then, when I added the center brace (stiffening the shaft)
...it just resulted in sending that feedback, up to the steering wheel
* The wheels are 20" across
...so, from the axle to the edge of the wheel, would be a ~10" "lever"
...& the spindle arms are ~3 1/2"
So, the wheels currently have a "leverage" advantage of ~3:1 over the spindle arms