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Discussion Starter · #1 ·
I just bought an Id and built it up and was wanting to see what kind of air pressure, sag, rebound,and volume. I was wanting a good starting point. I do alot of climbing and I would say moderately technical trail riding with 2-3 foot drops max. I weigh around 145#. I am running a fox talus up front. Just to give me an idea include your riding style and weight.
Thanks for any info

Brass Nipples!
2,006 Posts
I'm working on my wife's Truth settings now.

Start with sag. Release all the pressure out of the shock. Don't sit on the bike with the shock depressurized. With the air released, twist the AVA chamber out to the maximum volume setting. Gently compress the rear end, sliding the o-ring up to the bottom of the shock body.

Then pressurize the shock with 150 pounds or so. The shock will extend. Measure the space betwen the o-ring and the bottom of the shock body when it is pressurized. My wife's Truth has a 50 mm stroke.

Divide this shock travel value by 4. This is the amount of recommended sag (the amount of compression you want with you just sitting on the bike). Either by yourself or with an assistant, sit on your bike in a normal riding position. Slide the o-ring up again, then gently step off the bike without compressing the shock further. Stepping onto a small stool can help this. Measure the sag. Add or subtract air until your sag reaches the recommended 25% value. Write this pressure down, you'll want to remember it.

Next go find an area with some good bumps that you can ride again and again. You will want to set the rebound (red knob) as fast as you can without it being too fast. By this I mean you gradually turn the knob counterclockwise until you feel the rear end springing you up off the bump. Once you feel that you've found a too fast rebound setting, increase the rebound damping (clockwise) one click at a time until that too fast feeling goes away. You'lll know your rebound is too slow if you feel the rear end gradually packing down in a series of quick bumps: the too slow rebound will interfere with the ability of the shock to extend for the next bump.

Now go ride. If your bike works well with the AVA chamber volume at maximum, great. If you bottom out harshly, depressurize the shock and decrease the AVA setting one level at a time, then repeat the other tuning steps. Once the AVA chamber is set properly, the spring rate will increase at the end of the shock stroke to make bottoming out harder. You don't want to decrease the AVA volume unless you're bottoming out. The maximum volume gives the best ride: it mimics a coil spring best at that setting.

Once you get things set up, write everything down. As the shock breaks in, sometimes settings change slightly so be aware you may need to repeat this process once in a while. Check your shock pressure frequently at first. You will notice that even if you immediately take your shock pump off and recheck the pressure, it will read lower than your last setting. This is because pressure from the shock is used to pressure the pump's hose. If in a week or two, the pressure isn't any lower than the reading you get when you immediately reconnect the pump, you know you don't have a slow leak.

If you notice the ride changes or you're bottoming out more, you need to check the shock pressure right away. If the shock develops a leak and you continue to ride, you can hurt your frame.

Hope this helps.
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