My rocky mountain has a Fox Float R rear shock and I have never adjusted the pressure, although I do have the pump. Now, what pressure should I have it at? I am 165 and ride XC. I think the manual is floating is around so I can read that, but does anyone know? Also it has the little dial on it to adjust how fast/slow the rebound is. what actual difference does the rebound speed make? How does it translate into ride performance. Thanks guys.
Here's the deal: You may as well throw the shock manual in the trash, as far as recommended pressure settings are concerned.
Even for the same shock, frame leverage ratios are different, as are rider preferences, as are specific frame sag criteria.
Wrap a zip-tie or twist tie around the shock shaft. Fill it with a reasonable amount of air. Sit on the bike and (with the aid of a wall or a friend) determine how far your shock is sagging with just your weight on it.
You'll need to measure sag as a percentage of your shock's stroke. For instance, 1/2" of sag over a 2" stroke = 25% sag (.50 / 2.0 = .25 = 25%). Different bikes call for different sag. 'fer instance, a lot of XC rigs might like 20% to 25%, whereas some FR & DH bikes are better off at 30-40%. But there are always going to be exceptions, and the terrain you ride might dictate more or less, so find out from your bike's Owners Manual (or company website) what they call for.
To dial in your rebound, do this: First, get your shock air pressure worked out. Then, do a high speed run with rebound dialed all the way out. Then do a high speed run with it dialed all the way in. If your rebound adjustment is worth a crap (some aren't), you find that dialed out tries to buck you off the bike, while too much causes the suspension to "pack down" after repeated hits, recovering too slowly. Like Goldilocks, you want something inbeteeen -- something "just right". Knowing what "too hot" and "too cold" feels like helps you find that sweet spot.