just picked up a set of rear shocks for my 2010 ultra now the new shocks came of a 2017 ultra that were too tall for the original owner (lucky me) my question is why is only one shock adjustable? How does the other one know that the other shock has been adjusted

 

That is how the system works Just put them on adjust the one side. It they are truly 2017 ones a few turns makes a difference.
Start at 15 turns and work your way up until you find the best ride for you. Do not go by settings for the older premium shocks.
You will likely adjust them different for 1 and 2 up a few turn effects the ride.

 

I noticed they click at every 1/3 turn and on the shock the max setting is twenty whit h if I'm right would be forty clicks now I'm 250 lb art you talking clicks or numerical setting?

 

2017 shocks go up to 23 . This varies from what owners manual say by a couple turns. Close enough to get you in the ball park.
When wife is with me Adding a couple turns works for us.

 

So that would be 46 clicks right?

 

if they click at every 1/3 turn, then it would be 3 clicks per turn....

don't worry about how many clicks it is, go by full turns.

 

The one with no adjustment controls rebound only the other adjusts for preload,

 

They don't think it be like it is, but it do.

 

LOL!! That was good.

 

Btw I did have a typeo it one click per 1/2 turn my bad