Spindles and Ackerman Angle

[bubba57-chevy]

I've been lurking for a while, and slowly designing a bsr. Nothing fancy, just a good running, good handling ride. My question is, since most spindles come "pre-fab'd" with no ackerman built in, is it worth the effort to weld your own spindles from a "u-weld-it", or do the regular 90 degree spindles work ok? I don't have a problem welding them up, but was just wondering.

[Randy on a Stool]

You can get the ackerman effect on your steering shaft pitman arm also by building a wide plate w/ two holes side by side. Play around with the geometry, but it does help.

[bubba57-chevy]

Thanks for the idea, is there some sort of formula or process for the spacing of the tie rod attachment point to the pitman arm? Or is it trial and error?

[Randy on a Stool]

First is the relationship of pitman lengths. Steering post and spindle pitman length the same will steer like a bike, as in the front wheels will turn same as handlebars. shorter pitman on steering shaft will make easier,slower steering. Trial and error is how I figured it. The ackerman is also trial and error, but with a pitman length of 2.5" at spindle, 2.75" at steering, and a separation of 2.25" at the steering post, it works SOOO much better than my first build w/ no ackerman ! This based on 31" long wheelbase. You'd probably have to play around with the numbers, but its the past center effect of ackerman that is key, making inside tire turn tighter than outside.
I am now on my third build and each one gets better. The first is a 6.5 clone that will probably do 45 or more, but is too twitchy for me to go more than 25-30mph. I have not torn it down for paint yet, as I may re-do the steering geometry.
Good luck, be careful, and have a blast ! Let me know if I can help further.

[bubba57-chevy]

Thanks Randy, will do.