|   Clueless about fork tuning - HELP!!!!! | Big Ring King
Jun 18, 2003 6:25 AM | | OK here's my disclaimer. I'm stupid.
I've been riding a rigid (yes, rigid) front fork for years, now I'm on a Marzocchi Z2 Atom race, and I'm sure it's not tuned right. I'm 150 lb and I ride real aggresive XC on technical trails. Can y'all help me tune my fork? The manual does not help very much in describing the effect of +/- on the knobs...
First off, it's a coil/oil fork - what does the spring preload knob do? For my weight, where should it be set?
Second, what does the rebound control do? What happens if I crank it up or down? |
| Some pointers... | JoelW
Jun 18, 2003 7:10 AM | | Preload sets the amount of sag the shock has when you are just sitting on the bike. For instance, if the fork has 100mm of travel, and when you sit on it and have someone measure the travel left, the difference in the total travel (100mm) and the travel let when sitting on it would be the amount of sag. Your fork probably has a recommended amount of sag listed somewhere. If not, I'd guess a value somewhere around 20% (or 20mm of sag on a 100mm fork).
Rebound is how fast the fork uncompresses. Fast rebound means that when you hit a bump the fork quickly readjusts to full operating height, where a slow rebound will have the fork expand back more slowly. Rebound is a matter of preference, but I've always found that setting the rebound to be as fast without a pogo effect is where I want it. Start in the middle and go a little each direction and see which one feels more natural. |
| more pointers....simple physics | FM or MF
Jun 18, 2003 9:17 AM | | An efficient spring returns %100 of the force it absorbs. So without rebound damping, your fork is only delaying impacts... think of it like this:
you hit a bump
forks' spring (either air or coil) absorbs the hit temporarily
as the sring rebounds, it has to pull a plunger through oil. As it does this, the energy is converted to heat due to the friction. The heat disapates as the oil cools back down. Impact absorbed.
If you set yoru rebound damping too slow, then the fork doesn't have time to set-up for the next hit- it "packs down"
I usually set the rebound as fast as it can go, but where you can still see that the fork rebounds slower than it compresses. |
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