Tadpole/Quad kingpin question ?

[stormbird]

Hi all

So I though I had some understanding of kingpins used on front wheels for tadpoles/quads , although never having built one.

I need to build a mock up to see what the turning circle might be.
However I have just realised I don't know whether the centre line of wheel axle needs to be on the centre line of the kingpin pivot.

Paul

 

[DannyC]

Hi all

So I though I had some understanding of kingpins used on front wheels for tadpoles/quads , although never having built one.

I need to build a mock up to see what the turning circle might be.
However I have just realised I don't know whether the centre line of wheel axle needs to be on the centre line of the kingpin pivot.

Paul

Isn't it the contact patch that needs to be pointed at by the kingpin, and not the centre of the axle?

 

[Popshot]

However I have just realised I don't know whether the centre line of wheel axle needs to be on the centre line of the kingpin pivot.

Paul

Where is the viewers eye? Above? side on? Front? Looking down the kingpin? Assuming the latter, then ideally yes but it's not an essential for most folk*. The kingpiin should also point at the contact patch but again if you have a good reason not to point it there then it can be moved. Karts have it pointing nowhere near. The further from it intersecting the patch though then the further the wheel moves fore and aft during turning and the more room the wheel will want. To keep the vehicle as narrow as possible you need the kingpin pointing directly at the contact patch.
*This will also involve the axle being central to the kingpin centre when looked at as though the kingpin was a telescope so for your purposes it is essential.

 

[stormbird]

Isn't it the contact patch that needs to be pointed at by the kingpin, and not the centre of the axle?

Not quite what I asked ?

See below...

Paul

 

[stormbird]

Where is the viewers eye? Above? side on? Front? Looking down the kingpin? Assuming the latter, then ideally yes but it's not an essential for most folk*.

Correct as it is only a mock up to see what the turning radius is I am not fussed about contact patch stuff [ IIRC brake steer ] nor castor angle [ is that self centering ?] and certainly not paying any heed to Ackerman [/QUOTE]

It is easier to build them out of line [ from above ] however I will try for inline.

Paul