I'm having a bit of trouble picking out some fork springs. I'm rebuilding my 02' forks with 04' internals and new stuff. Wasn't going to worry about springs as was ok with stock, I never track and only push it sometimes. The roads are bad. Real bad. Gravel, corrugated, potholes, pothills and dead things. I've got a little money to spare so thought I'll chuck in some new springs to suit weight. This is where I have a little problem. I use two spring weight calculator's, sonic springs and race tech. I don't have scales at home but the ladies at the airport let me hop on their scales with my gear on. I weigh 95kg or 210lb with my kit on. Sonic springs calculator gives me two rates depending on the type of bike I select, .85 and .90. Racetech gives me a rate of .95.
I'm thinking with my riding style, bad roads and a preference for a "plusher" ride I should go with a .90? Also the rear shock is a Wilbers progressive spring 180-130. Thanks.
Keeping in mind your rear spring is a 130/180 N/mm (742/1028 #/inch)I'd be trying 0.85 to 0.875 absolute max.
0.95 is simply whacko wrong for your particulars.
Ohlins has a spring that's around 0.88
Racetech needs a .90 and a .85 paired to get a 0.875, so you need a supplier who will break into 2 springs sets to make you up a blended pair.
15 mm of installed preload (that measurement determined with the ride height adjusters all the way out so all rings showing)
And use a higher oil level to give you some more spring effect for heavy braking on good pavement, said oil effect not impacting your described normal riding. Say 140 mm of oil, not 125.
Lightish on the rebound adjustment.
Stick with 10W oil, but use decent stuff.