air or no air w/ progressive front springs

[81xsproject]

I got some progressive rear shocks off ebay. They are ablolutely amazing!!! I also got some progressive front springs. Should I still use air in the tubes? Would the air pressure balancing kits help?

[Jerry]

I don't use air in my XJ's forks since having the Progressive front springs installed in 2001. You still can, of course, but the pressure would be very low, a couple psi at best. Remember, air does not change the spring rate, it just determines the threshold force required to make the forks compress. If you use air, a balancing kit is the way to go, and use a low-pressure pump (bicycle pump) or, as I use on my rear air shocks, one of those CO2 inflation kits sold in bicycle shops and other accessory outlets to change fork pressure.

[motoman]

Hey Jerry..........ridin' weather is great out there...(hint,hint).

[mason79]

air does not change the spring rate, it just determines the threshold force required to make the forks compress.

does the air play a role in how fast the fork overcome rebound damping? oh air does not compress...

or is it more like preload?

[Jerry]

Air pressure is Preload. Rebound damping is a function of the fork oil being forced though drilled passeges in a valve in the fork leg. Some folks try different weights of oil to get the "feel" they want, 10 wt is standard but you can get lighter (7.5 wt) and heavier (15 wt) oils.

Suggest you try the Progressive springs first, get the correct pre-load (about 1/4 to 1/3 of the total suspension travel with you on the bike, may need a helper for that) and see how the springs work for you.

There is a tech tip about improving the XS / XJ handling. It is getting a bit out of date now, but still some good pointers:

Improving your XS/XJ handling