Originally Posted by Zerodog
I totally disagree the stock springs need to be replaced in this application. It makes the bike a lot safer to ride and more comfortable. It is the most basic suspension adjustment. You can click your clickers all day long and it still will not be close to right. A big guy + a heavy load will not work with the stock setup. Winding down the preload only gets you so far. It does not alter the final rate of the spring. Springs are not super expensive. I would choose that over any other farkel you could imagine.
Compared to any other travelling bike I've ridden, the stock 640 suspension is excellent (ok, maybe my standards are low). New springs are the first place I'd put money, but proper ride height goes a long way.