Upper control arm length to castor degrees

[Martindfletcher]

Anyone know what delta length translates into a degree of castor shift with the upper control arms? Trying to short cut the trial and a little.

meaning 1/16 or 1/8 inch = x degree more in castor.

Thanks in advance.

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[2Wheel-Lee]

On my EVO adjustable upper arms, if I recall correctly, it was about 3 turns equaled about 1 degree in castor change. I don't recall the thread pitch, but I'm guessing close to 1/16". I made a few changes, so I could be a little off in my memory, but somewhere around there.
If you have adjustable upper control arms, it's real easy to make a change, then check the castor.

 

[AnnDee4444]

Anyone know what delta length translates into a degree of castor shift with the upper control arms? Trying to short cut the trial and a little.

meaning 1/16 or 1/8 inch = x degree more in castor.

Thanks in advance.

FWIW: shortening the UCA 0.25" should roughly equal the same caster change as lengthening the LCA 0.25". Your ride height influences caster as well, and a 0.25" change will not result in a consistent X degree of caster change.

Here are some 24" vs 24.25" LCA comparisons I have collected on this forum. The important difference is that the 0.25" length change is roughly equal to 1.25 degrees of caster change at Rubicon height.

 

[Martindfletcher]

FWIW: shortening the UCA 0.25" should roughly equal the same caster change as lengthening the LCA 0.25". Your ride height influences caster as well, and a 0.25" change will not result in a consistent X degree of caster change.

Here are some 24" vs 24.25" LCA comparisons I have collected on this forum. The important difference is that the 0.25" length change is roughly equal to 1.25 degrees of caster change at Rubicon height.

Thanks
I want .75-1 deg. So I will subtract an 1/8th or 3/16th and I should be good.

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