Installing progressive fork springs- more than just remove and replace! Any experienced tips?

Well I got my progressive fork springs (they are the ones listed for my bike, as well as a host of others).

The spings are approx. 1" shorter than my stock springs, and my stock springs are installed with approx. 5" of spacer.

The gist of the instructions that came with the springs is that there needs to be 3/4"-1" of preload when the forks are fully extended. Generally, this is stock for every bike, they say. If I remeber correctly, when my forks are fully extended with the springs and spacer installed, the top of the spacer is even with the top of the fork tube. Therefore, when the cap (approx. 1") is installed, there is 1" of preload on the springs.

So, in theory, because the progressive springs are 1" shorter, I need 1" longer spacers? That would be my logical conclusion.


Also, the progressive suspension instructions say that because their springs will displace more oil than stock springs, there is a maximum oil level cautionary note. The note says that the fork oil should not be higher than 5.5" in the tubes, even if the maintenance manual says otherwise.

They also say that fork oil level is measured with the forks fully compressed. Clymer gives specifications with the forks fully extended.

However, I painstakingly set the fork oil levels 2~ years ago so theoretically by compressing the fork legs and measuring, I get the stock specifications for oil when the forks are fully compressed.

I had one spring removed, with the forks partially collapsed, and I measured the fork oil level at 5" from the top. Obviosuly fully collapsed it would be more like say 4" from the top. This would mean I need to removed approx 1.5" of oil from the forks.

I realize this was a long technical post, but does anyone else have any experience?