Originally Posted by syzygy9
I am struggling to see how an increase form the stock 0.48 to 0.70 is required. I had my own (2011 990 Adv) forks resprung to 0.56 with a revalve to suit - that's an ~17% increase in spring rate and it seems fine for my 85kg 'naked' + gear + load.
On a recent trip across Australia with lots of fast and slow dirt roads (and some really gnarly sections) I am not aware of ever bottoming the forks but did use all of the suspension travel. Front and rear were set to 'max payload'; with no load this setting feels quite stiff.
I am no suspension guru so happy to defer to the experts, but my understanding was that if you are using all of your travel and not bottoming, you're pretty close to the mark. Of course, if all you are doing is riding on smooth roads than compliance may not be your primary concern, rather things like fork dive under braking, and you can get away with much stiffer and less compliant forks.
I know where you are coming from. The traditional train of thought for pretty much all the 950/990 ADV was to put a set of anything from 0.54 to 0.58 kg/mm springs in with a revalve. However, there has been a bit of a shift and experimentation with putting in stiffer springs with alternative valving (putting in 0.58 kg/mm would also require a revalve of course). Think of it as a bit of a different path. I had mine with 0.56 I think, and while it was light and day better than stock, I still feel that it could have been stiffer, with the valving modified to suit to get it to move through the stroke nicely. They carry so much bloody weight over the front end, you can certainly jack up the spring weight.
If you were in the USA/Canada, I'm sure a call to SPS etc would give you an idea on the current train of thought and methodology in getting the most out of the ADV machines.