Originally Posted by Aprilia
Race Sag should be set the same for both bikes i.e. 30% of total travel. If your Terra is only compressing 12mm then spring rates are far far too stiff for you.
It might be that engineers tend to use a stiffer spring for two-rider bikes nowadays. I noticed my WR250R dual sport was much stiffer than my WR250F dirt bike - I bought a softer spring for my 170 lb weight to get the right amount of spring compression - works much better now. If a second rider isn't going to happen, yep, then get a spring that does the job right (if necessary). When I rode the Terra demo, I noticed the suspension seemed too stiff for my weight - hardly any compression when I sat on it - but I also had no idea how it was setup from the factory.