Posted by Torvald [172.68.174.233] on Thursday, October 26, 2023 at 20:07:24 :
Back in June of �22 I posted a couple of questions pertaining to front axle wheel castor. One had to do with measuring castor angle, and the other was what to set the castor angle at for easy tracking at highway speeds.
No one had a good answer for how to measure castor angle, but there was good advice on what angle to aim for; 3 � 5 degrees. More castor gives better tracking at high speeds but less castor is easier to turn at low speeds.
I eventually found that in TM 9-1808B (one of the WC technical manuals) pgs. 101 � 104 and the diagram on pg. 90 have a good discussion on castor and the relationship between the various parts of the axle housing and castor angle. It turns out that the angle as supplied by the factory was supposed to be 1 � degrees positive. Furthermore, at this1 � degrees positive the front differential is tilted up to the rear by 8 degrees. So the castor angle can be measured by checking the differential angle. :)
It turned out that after re-arching my springs, my castor angle was at the prescribed 1 � degrees when the beast was fully assembled, so I put in a 2 degree angle shim to get 3 � degrees castor. A 5 degree castor would have been even better at high speeds but I wanted to retain relatively easy steering at very low speeds too. Now the Beast runs down the road at 60mph without trying to wander into the ditch and is still steerable at very low speeds.
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