The computer ate my post!!
Dammit jim!!
Here's a much shortened version:
I'd send 'em back because I'd expect a 'set' of springs to be selected out of the parts bin to be at least close to the same length. If you can pick two that are NOT the same length, you can just as easily pick two that ARE the same.
The big deal is that they not CHANGE. Check 'em after a few rides. If the measurement changes (there might be some 'settle'), they're no good.
OEM preload is over 30mm. That's bogus (sez me). FRP seems to like lesser rated springs with more preload. That's fine. I've tried that and don't like it. A higher rated spring with less preload is superior. My imo and all that, but .40 springs and 30mm preload will give you a harsh response.
Oh.....that's what you've got!! Isn't that amazing!!??
In any case, do indeed set preload separately (measure spacer independent of the other) for each spring.
Re: sag (thus preload)
From a racetech article on their
website :
It's important to stress that there is no magic number. If you like the feel of the bike with less or more sag than these guidelines, great. Your personal sag and front-to-rear sag bias will depend on chassis geometry, track or road conditions, tire selection and rider weight and riding preference.
Thus, set your suspension accordingly. The rear: 90-100mm. The front: 35-50mm.
You'll likely find things much better with a 'reasonable' (sez me) preload of 10mm or so.
Have a good time!!