The way I understand it the fork bleeders are used after a day of riding before you are going to park you steed in its corral. While riding your bike, the up/down stroke of the piston causes the oil in the shim stacks to cavitate producing tiny air bubbles in the oil. Also during this process the friction created during the up/down stroke of the piston changes the pressures inside the shock and alters the viscosity of the oil, mostly due to heat. Of course all of these different variables will affect the characteristics of the suspensions handling.
What Taff is saying makes good sense to me if you are riding a competition where you are pushing the bike to the extremes. You would probably not want to bleed the shocks in the middle of a race, changing the suspension characteristics, and then having to relearn you bikes handling under competition??? Probably not a something you would want to do unless its running too stiff and you want to soften it up a bit.
It also makes sense that you are not going to know how good/bad your suspensions tune is while sitting in the garage jumping up and down on your seat now are you??? In order to truly know if you shock is set up to your fancy, you will have to run it through the gauntlet of your local area to get a feel for its characteristics. If this is the case, getting it up to "normal operating conditions" is important to get a true idea of how the shock is going to perform, is this not correct? I have not ever seen or heard a story of anyone bleeding their forks while in the middle of competition... who's got time to bleed off air while concentrating on riding?
Taff is right, while riding your bike leave the bleeders alone. Get the shock to operating temp and conditions and ride with it there. When your packing it up at the end of the day, releve the pressure out of the fork and let the oil relax a little bit, it surely deserves a little stress relief after cushioning your *** all day long :wink:
ps. Relieving the pressure allows the air bubbles to surface and seperate from the oil, It also takes unwanted pressure from the fork seals while parked in the garage. This will help maximize seal life and keep the oil from seeping out as well.
Regards,