10 replies to this topic

[MarkH]

A while ago I was looking at someones chassis they were building and they mentioned it was being designed with rear steer. I under stand the chassis will flex at some point towards the middle of the chassis and allow the rear to point off center line. In my minds eye I am having trouble with the direction the rear will point. Does it rotate towards the outside or inside of the turns radius? It seems like the drag from the traction of the tires would cause it to point outward. I guess the other question would be what kind of track would this show any benefit (tight, flat, banked or fast wide turns)? Or, does help to some degree on most tracks?

[Gator Bob]

Good question, Mark.

[Dominator]

Rear steer is mainly used in scale type cars such as euro sports and open 12.  What happens is the rear motor box and axle twist front and back to the front end.  This is effective in these cars as the motors have a lot of torque and are able to keep the chassis flexing. 

[MarkH]

OK, when you say "...twist front and back to the front end" are you saying the twist is about the longitudinal centerline of the chassis or about some "Z" axis in front of the motor box? Do know which way the rear tires are pointing when the flex is occurring? 

[Hworth08]

The frame twist causing the outside rear tire to move forward.

 

It can only work in one direction unless a designer builds a frame so the motor can reverse direction and flop to the other side.

 

We used to tap the wall with ill-handling 1:1 cars just hoping it would slid the rear end back and maybe help something. Usually just resulted in a bent wheel with the bead packed full of paint and concrete.

 

The process works well on dirt cars with 3 and 4 link rear suspensions and a lot of travel. Slot cars not so much.

[MarkH]

So the outside rear wheel will point toward the slot when the steering effect is working. Makes sense. I wish I could remember which thread I was looking at and the build that was being shown and would like to hear how it worked out. I thought it was in Scratch Building but .........

 

I guess the chassis would need to have the pivot/rotational center somewhere near the axle no matter how the geometry works out.

[Gator Bob]

Rear steer car.

 

.

 

[MarkH]

With a Tri-Pod setup it seems like the fore-aft angled wires would need to float at one end to gain some twist. 

 

edit:

Pretty sure the one I was looking at was not A tri-pod but, if memory serves, it was a wishbone style.

[George Blaha]

hey gator,

Is the upper triangulated bar soldered directly or left unsoldered in tubing to allow softer (torsion) rotational motion and with higher down force in higher g force areas (banked turns).

 

Shakey George

[Gator Bob]

George of the _concrete Jungle,

 

Un-soldered  of course... LOL

 

I took the Tubes from Jersey

[George Blaha]

bob,

thanks! I like it!

george