Strange steering part on McLaren front hub

[hardingfv32]

From the McLaren thread....

What is the gold part on the top of the hub for?

This looks like a way to change the height of vertical location of the steering arm. As the hub rotates/steers the pin is guided up & down changing the height of the steering arm.

They are are modifying the bump or roll steer for some reason.

Brian

My guess would be the pins on the end of the track rod make the arm pivot rather than go up and down. Thus the slot in the far side of the clevis goes the opposite direction.

So the gold part (TiN coated) is possibly moving in and out using a thread system. Possibly changing the toe adjustment as the car steers?

Brian

[Tim.Wright]

Id agree with scarbs. I think its changing the angle of attack of the steering link as the front wheels are steered.

Tim

[manchild]

It could be actually changing toe depending on suspension load even when car is not steered, in a way that toe would be different for example during braking, than on straights at full speed etc. That would result in lowered rolling resistance and tyre-wear.

[Jersey Tom]

I can't tell from just the one picture.

Bump-steer is a good tuning parameter for handling, but that little clevis looks too thin to take any sort of load. Wouldn't say its for Ackermann either.

If I had to speculate I'd go with Tim and Scarbs lines of thought.

[xpensive]

I also agree with scarbs, but to what purpose, to have the steering arm acting like a wing on the inner wheel at turning?

[hardingfv32]

Id agree with scarbs. I think its changing the angle of attack of the steering link as the front wheels are steered.

The angle of attach of the aero shaped steering link. I did not appreciate that point. Good thought. As stated is makes sense considering the structures apparent strength.

They would move in opposite directions on each side as the wheels are steered. One side would generate lift and the other downforce. Is that something that would beneficial? Shouldn't the track in the gold part be V shaped to always get a downward movement of the leading edge?

Of coarse none of this seems to sit well with the rules: no adjustments while moving or the control arms being aero neutral.

Brian

[Jersey Tom]

Of coarse none of this seems to sit well with the rules: no adjustments while moving or the control arms being aero neutral.

Brian

Well it's all pure speculation. Would need a couple other views of the thing to get an idea of what it does.

[hardingfv32]

I am assuming it is a legal system. Hoping for a straight forward rules interpretation to help rule out some of the possible purposes of the part. If we have to add rules interpretation to the variables, then the puzzle gets a little harder.

Brian

[Caito]

Could it be that it is just fixed? Maybe adjustments made need to be made in that curve, so they just have that piece as a "guide". If they need to make an adjustment they just move it up or down, but using that as a guideline.

[Jersey Tom]

Also very possible.

[Pup]

That little piece seems far too delicate to be an adjustment for any suspension piece. Is there something else on the wheel that would benefit from being adjusted with steering? Brake bias side to side perhaps?

[marcush.]

if you happen to have ball type joints on both sides of the steering/toe rods the rod can rotate around its longitudinal axis.normally this is restricted by the clevis clamping the outboard balljoint.
This could lead to incertain or even illegal angles of attack for a non round steering/toe rod -maybe it´s just to keep the rod from assuming illegal positions ?

[xpensive]

if you happen to have ball type joints on both sides of the steering/toe rods the rod can rotate around its longitudinal axis.normally this is restricted by the clevis clamping the outboard balljoint.
This could lead to incertain or even illegal angles of attack for a non round steering/toe rod -maybe it´s just to keep the rod from assuming illegal positions ?

That's it marcush, with the slot in the opposite direction on the other side, the steering arm will of course keep itself horizontal when turning.

[hardingfv32]

imaybe it´s just to keep the rod from assuming illegal positions ?

I could see where an aero shaped steering control link might want to drop its trailing edge, lift angle of attach, do to its weight but you would thing that the slot would be closer to horizontal than it is just to maintain a legal aero neutral attitude.

Brian

[marcush.]

imaybe it´s just to keep the rod from assuming illegal positions ?

I could see where an aero shaped steering control link might want to drop its trailing edge, lift angle of attach, do to its weight but you would thing that the slot would be closer to horizontal than it is just to maintain a legal aero neutral attitude.

Brian

not sure ,brian as the steering axis is inclined so the steering arm will move through a vertical arc as well ...the slot should not be straight ,I agree.