Ok this is probably obvious, the front forks on my ST4S had the pre load set to approximately 22mm, (5 rings showing) I have adjusted it back to standard 16 mm (3 rings showing). That means I have increased the preload made it stiffer, Right? (no sarcy comments please!) Only when I took it out for a short ride it didn't seem to have made a lot of difference!
You probably need stiffer springs, there's a lot of stuff out there on setting the sag etc (probably on Ducati.ms?) But my simple view is tie wrap on fork leg to see where/ how much sag sitting on the bike and what travel is used (likely all) on a normal ride. To me it seems Ducati softened off it's stock springs after the carb ss / 916 era as my 888/900sl don't bottom out easily but the 1000ss/paulsmart /999 I used to own all needed at or near max preload and still blew through all the fork travel to easily.
You are correct, you have increased your preload. However, not being to feel much difference probably points toward the fact that the sag is not set correctly for your weight. You need to get your full riding kit on and stick a cable tie on a fork stanchion. Get a friend to balance the bike and sit on it. Measure the travel and then set the sag accordingly. For the 4s 15-20mm front sag with rider is good, with 30-35mm at the back. One thing though, the front of an ST4s is not Ohlins, it is Showa, unless someone has done some customisation to the bike before you got it. In which case, you are a jammy git! A
I have been on a longer ride today and it feels ok, agreed I need to set the sag, but the question was really about am I making it stiffer or softer! Logic told me I had made it stiffer, but the previous owner said he had stiffend it up because he likes it that way! I was just surprised that I had to wind it in to get it to standard settings! BTW Ascalon, your right they are Showa I knew the rear was ohlins and just assumed the front were too...never good to assume!
Adjusting the preload makes no difference to the 'stiffness' of the springs. All adjusting the preload will do is set the working range of the suspension somewhere between topping out and bottoming out. After that the next important thing is setting the rebound on a roadbike. Find a local suspension wizard and ask them to set the suspension for you. It is an art.
