Fox DHX 4.0 question


May 23, 2009
Port Orchard, WA
so i was riding today and was jumping down this:

and off the first bit i kept maxing out or i guess you could bottoming out the shock.
i need to know how i might be able to help stop by changing the rebound or maybe preload?
any ideas?

sorry on crappy quality, taken with my camera phone


Aug 21, 2009
Washington State
I'm pretty sure the DHX 4 does not have bottom-out adjustment (only the DHX 5 has that). If you find your riding style and weight are causing bottom out on this shock, you may need a different spring.


Nov 19, 2008
you should probably get a heavier spring. but im guessing its due to the fact that your not smooth since your just started riding. or its your deraileur hitting your chainstay when you land. put air in you rear shock to. rebound controls how fast the shock goes back after taking a hit and compression controls how fast it compresses when taking a hit


Sep 2, 2009
Fresno, CA
You'll feel it if the bike bottomed. There will be a harsh stop in the travel, and it may hurt your legs if you bottom hard enough. To get the same affect as bottom out dampening, put a small amount of oil, 5cc or so, in the Boost Valve (the schrader valve on the end of the piggy back). This will add more compression to the last part of the stroke of the shock, and make it more difficult to bottom.

Go to the bike shop where you got the bike, and have them set it up for you. You should be sitting in about 33% sag. Sag is how much the travel compresses by jut sitting on the bike, in normal riding position. If you are going to just be hucking stairs, then tell your shop to set it up around 20%-25%. This should make it a little harder to bottom, yet you still still get small bump compliance for downhilling.

If you are not able to go to a bike shop, to change the amount of preload, there should be a "collar" on the end of the spring. it will black, metal, and have big ridges. Tighten this to add more preload, and loosen to reduce the preload. Preload is how much tension is on the spring, when the bike is just sitting there with no pressure on it. At minimum, you should have about 3 complete 360 degree turns on the spring. This is just to keep the spring in place, so it doesn't come out of place when riding.

*Edit*: For clarification, rebound controls how fast the shock returns to full travel. Rebound can seem confusing to set up, but it's really simple. Adding rebound will slow down the time it takes for the shock to return to full travel. Taking away rebound will speed it up. If you are going to mainly be doing stair hucks, then it isn't a bad idea to set the rebound up fairly slow, or by adding rebound. for downhill, you want the tires to comform to the ground, so set up the rebound faster, or less rebound, so the wheels can regain from a hit faster, and go back to getting traction. Don't go too fast on the rebound though, or else the bike will start to "skip" around turns, and become unstable.
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