Castor measurement

[ilmir]

Hi,

I was wondering if somebody could help me regarding the theory behind measurement of the castor angle. What is the theroy behind the Dunlop-Castor Measurement device where you steer the wheel to 20° each side and it shows the castor. Is this device measuring the difference in camber and how is this related with the castor?

Thanks for your help in advance.

 

[GregLocock]

Yes, that's how it works.

It is one of those bits of maths that is very hard to explain in a text environment. Probably easiest is to imagine three points on the wheel, work it out from there. Note that the KPI is somehwat involved.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[NormPeterson]

Some (not so) light reading on the subject.

http://www.hunter.com/pub/undercar/2573T/index.htm

]

The practical approximation linking the 20° and a camber range measurement to caster used by those sort of tools is pretty simple. Actually, there isn't anything all that special about ±20° other than it being a large enough angle such that errors in the camber measurements aren't magnified too badly in the caster "output", and that most vehicles can actually achieve that much steer angle.


Norm

 

[ilmir]

Thanky you very much