Join Date: Sep 2004
Location: Medford, County of Jackson, Oregon, USA
Model: None at present
I'm not recommending anything but I put the same amount of oil in my forks with Progressives springs as I did with the OEM. Seems to work okay, no problems, no hard ride. If that worries a person I'd leave out about 1/2 oz.
If you really want to know, it could be measured by getting a piece of PVC pipe longer than the spring and big enough to fit the spring into, putting a cap on one end and flling up the pipe with water. Measure the height of the wate from the top of the pipe and then put the other spring into the pipe and make the same measurement. The difference in height would tell you the difference in volume of the two springs and the amount of oil to reduce to compensate.
Unfortunately Progressive doesn't say how much that would be, they just give the height of the oil from the top of the tube with the fork completely collapsed.
None at present
Past 'Wings: GL1100, GL1200, GL1500, GL1800
Current BMW C650GT