A couple of thoughts if you are going to a linear spring in the front forks of a Speed Twin 900. In my case I weight about 220 lbs with all my gear. Racetech suggests a 90 lb. spring. The ST900 is a fairly light bike and I figured that 90 lb. springs where too strong for me, so I went with the 85 lbs. These springs do make a big difference in how the front end feels when under braking or just going down the highway. You have to be careful when setting up the preload. Too much and the front end is harsh when dealing with small bumps on the highway. Racetech suggests 25 mm or 1" reduced preload. I originally used the 15 mm preload measured from the top of the fork tube. That was way too harsh. The fork cap has about 16 mm of preload. In the end I measured down 25 mm from the bottom of the threads and cut the spacer to length. I tired other lengths, cutting the spacer in smaller increments, putting it all back together, then measured the sag ( I just measured from the handlebar ends to the floor in the garage). I found that the suggested preload gave me approx 1 " of sag on the front end. As a result the forks handled smaller bumps better and it had no affect on the bigger bumps or brake dive.
I'm a big fan of linear springs and have put them in Gold Wings, Vstroms etc and overall they work better in my opinion. Takes a bit of work go to get the preload set right, but then you are good to go. Race tech also gives a fork oil height, which I used.
