I am by no means a master mechanic but I do like to tinker and wrench on my bike when possible and I know a thing or two about bikes. One thing that I am lost on is suspension and shocks. I have an 07 Street Bob with YSS shocks on the rear. I have been tweaking the rebound on them and I think I have them set to where I want it. My questions revolve around pre load.
The bike currently is set pretty stiff, and when I go over medium or large bumps the rear sends jolts through me. It seems like it is just set too stiff. I would like to soften the ride a little to give my old back some relief. So I assume I would need to lessen the pre load. Is that correct?
Also, if I ride two up would I need to give the shocks more pre load to prevent the suspension from bottoming out? Sorry for my ignorance but I am used to the bagger style suspensions where you just add a little air to the shock to adjust things... Thanks.

 

We gotta keep in mind the key word "Suspension" here.
For me the pre-load setting is about how the bike handles and corners.
(maneuvering/control)
Too soft and the bike won't lean well without pulling the weight over,
Too stiff and the rear wants to bounce/push itself away from the movement.
Yes, preload does effect the "shock absorber" aspect of hitting bumps but that's what the shaft and pistons are all about.
It can be kind of confusing.
Unfortunately I'm still running the stock shocks and the pistons are not in good shape because of the idiot previous owner, he liked a soft pre-load and didn't change the setting when he rode 2 up with his 200 pound wife.
I have mine set at 3 (of the 5 settings) for the best handling, and have to move to 5 if I add even a 110# teenager as a passenger.

When I see a large bump coming, I sit up a bit. I don't know how to explain that besides saying I ride the bike, not just sit on it. If I see the vehicles in front of me bouncing,, there's a bump coming,, or the road sign that say's "Bump",, or just plain olde watching the road.

 

So I played with the shocks a little today and I think I have found an acceptable setting by lessening the pre load.
Now if I want to take my wife would I want to increase or decrease the pre load. My common sense is saying I would need to increase pre load to prevent the shock from bottoming out when riding two up, but my common sense has been wrong a time or three.

 

increased preload = stiffer ride carries more weight
decreased preload =softer ride carries less weight
adjust for the weight carried.
next ?

 

Here you go. I suggest you do a search on the site first. There are a lot of info that has already been talked about, Good luck.
https://www.hdforums.com/forum/dyna-...ur-shocks.html