Mountain Biking - Tuning Super T

Whats the difference between the screw in the middle of the adjuster on top of the fork leg and the adjuster itself?

Also, what does adjusting each leg do, I think the left is preload, and right is rebound, but im not sure

what exactly these refer to:
Preload
Rebound
Compression

Thanks

Whats the difference between the screw in the middle of the adjuster on top of the fork leg and the adjuster itself?

Also, what does adjusting each leg do, I think the left is preload, and right is rebound, but im not sure

what exactly these refer to:
Preload
Rebound
Compression

Thanks

I believe the screw is for compression adjustment, and the adjuster is for preload. Both adjuster knobs should be for preload, and if there are 2 screws then they both are compression. But I dont really know, you should go to the marzocchi site and download a tech manual, which I am going to do in the next minute to answer your question. Since you didnt list the year of the fork, go here and download a manual for the right year http://www.marzocchi.com/template/listSPAManuals.asp?IDFolder=126&LN=UK&Sito=mtb --- A simple test of the adjustments would yield results you can feel also. Preload is the load that is put on the springs before is it compressed at all. Rebound is the rate that the fork rebounds at after compression. Compression is the rate of compression (like when your pushing down on it).

The fork is a 2002 Marzocchi Super T

Thanks, Ive figured the some things out.
The big knob on each leg is preload, and the little screw in the center of the knob is rebound.
Correct me if im wrong.
Ive set he preload all the way down and the rebound all the way down, and the fork is too stiff. How can I make it softer- with a lioghter spring, with less viscous oil?

To make it softer you want to have less preload, so turn the knobs counter clockwise. Rebound dosent really have anything to do with stiffness. If you have the rebound cranked down the fork will probably return to full travel too slowly.

OK, thanks for the tip on rebound, but If the preload is all the way down, how can I make the fork easier to compress still. I have to adjust the compression I assume, but how does that get adjusted if there is no adjuster for it.
Do I need a lighter spring, or perhaps less viscous oil?

but If the preload is all the way down, how can I make the fork easier to compress still.

Preload down as in no preload?? I dont think your fork has compression adjustment, so if you have no preload and it still feels too stiff then you will need softer springs or a lower weight oil. There is probably 7.5 wt in it right now unless you or somebody who owned it before you changed it.

yo adam, ill rebuild the fork with some 5wt for you, but wait till you ride to see if you really need it changed, it might be better then you think, but to make it softer, you will probably need softer springs, or there may be preload spacers, i dunno

peace

When you say
Ive set he preload all the way down and the rebound all the way down,

do you mean you've turned the adjusters all the way in (clockwise rotation)?

If so, you have set the preload to the maximum, which may be why
and the fork is too stiff. How can I make it softer- with a lioghter spring, with less viscous oil?

Just turn the pre-load adjuster knobs all the way out (counter-clockwise), that should soften up the fork. You want to set the pre-load to where you compress the sping about 20% when just sitting on the bike! It takes some playing around and making some small adjustments and a lot of test riding.

Also, if the fork is new, realize that there is a break-in period where there is a lot of stiction. May take some riding, then readjusting.

L8R

I turned the preload to its farthest counter clockwise (least pressure) setting, but, today, I got my neighbors picnic table and purposely nosed a couple drops off of it, and I measured the travel and it came to a hearty 5-9/16," with the preload all the way down, which is good, because for something like a 6 or 8 foot drop that would make good use of all the travel. If i want it softer I'd have to get a lighter spring/less viscous oil though right?

no, not less viscous oil, only a lighter spring will make it softer, ive told you so many times, les viscous oil will only make it compress and rebound faster, it will not make it "softer", unless your running like 20wt oil in it and theres not enough sustained pressure on it to actually force the oil through the dampers, but im guessing its 7.5wt oil and thats probably what should stay in it if you dont understand what it does

peace

Adjust your preload to set your sag, don't use it to adjust your final travel. Once your sag is right if you still aren't using as much travel as you'd like lower your oil level, if you start bottoming out too easily raise the level back up a little. Oil level adjusts the progressiveness of your fork. Unless you are very light (less than 130lbs or so I'd guess) you won't need lighter springs, just less oil. If lowering the oil level doesn't do the trick then using a lower viscosity oil will help.

The difference is that lower viscosity oil will speed the fork up, making a bigger difference on high speed hits (drops are low speed hits). Changing the oil level affects the fork at all speeds, but the affect is only felt near the end of your travel.

I learned this from reading a MX mag and it finally clicked. You can stiffen up/or soften your final stage of compression by increasing or decreasing the oil level in the fork. You see, as you move the fork through it's travel, you are compressing the oil chamber, AND the air chamber. So, by reducing the volume of air, you reduce how much the air chamber can compress (Duh, Right.)

If you are bottoming out the fork, you want to decrease the air volume by adding oil to each leg. This will make the travel in it's last 1" or so, more linear and the suspension will firm up towards the limit of its' travel. Marzocchi sets this level from the factory and most heavier riders need to add some oil. I think they recommend no more than a 10% change.

Likewise, if you do not use all your travel due to being lighter weight, you can decrease the oil level and you'll be able to utilize more of the available travel.

This doesn't affect the initial stages of travel, but will affect the end stage.

L8R

I learned this from reading a MX mag and it finally clicked. You can stiffen up/or soften your final stage of compression by increasing or decreasing the oil level in the fork. You see, as you move the fork through it's travel, you are compressing the oil chamber, AND the air chamber. So, by reducing the volume of air, you reduce how much the air chamber can compress (Duh, Right.)

If you are bottoming out the fork, you want to decrease the air volume by adding oil to each leg. This will make the travel in it's last 1" or so, more linear and the suspension will firm up towards the limit of its' travel. Marzocchi sets this level from the factory and most heavier riders need to add some oil. I think they recommend no more than a 10% change.

Likewise, if you do not use all your travel due to being lighter weight, you can decrease the oil level and you'll be able to utilize more of the available travel.

This doesn't affect the initial stages of travel, but will affect the end stage.

L8R

You're close but just missed the mark. Adding oil to a fork does reduce your air volume, but it has no effect on your compression damping, it causes your spring rate to ramp up. Most people think that all of their spring is the coil, they don't realize that Marzocchi runs what in effect is an air assisted coil. As most people know, air can be a very progressive spring, like if you have an air only shock on the back of your bike. At the top of your travel your bike is being help up completely by your coil spring, but as you compress your fork you are compressing the air inside the fork causing it's pressure to rise, now you're getting an air spring effect as well. Adding oil causes that air spring to become more progressive.

This has no effect on compression damping, and as oil does not compress (which is why if you add too much oil you can get hydraulic lock).

Check out the manual for the allowed levels of adding or removing oil before you start playing with things as well. There is normally around a 10% variance allowed, adding or removing more than that can destroy your internals, cause hydraulic lock, or cause you to blow your seals.

That's pretty much how I understood it, but you did a heck of a lot better at explaining it!

Thanks
L8R