Marzocchi's used to be known for specifying very light spring weights as stock in their forks. Marzocchi finally came to their senses over the past couple of years and realized that the typical rider does not weigh 150 pounds (maybe in Italy). The springs that come with the 2003 Marathon S are considered to be the "heavy" spring weight. These were designed around a "rider weight" (you PLUS all of your riding gear on) of 180-220 pounds. According to Marzocchi tech support, the spring weight for the stock springs is 6.5 kg/cm (which, should be around 36.4 lb/in if I've converted correctly). If you are comparing this to a Fox Vanilla 100, the standard spring for that fork in that travel setting is the green spring which is 35 lb/in.
I weigh 160 pounds without riding gear, so the stock springs are too heavy for my weight. My first few rides, I was only achieving around 78-82mm of travel. (I had messed with oil heights of 45-62mm, without any luck) A call to Marzocchi's tech support revealed that I was riding the wrong springs for my rider weight. The next softest spring set is the "Medium" set.
Below is a chart that blends Marzocchi's spring recommendations with my own (Marzocchi seems to have a huge weight range for each spring set; their techs recommend mixing the sets when you're near the edges of the weight ranges):
Here are my recommendations to get you close:
|
Rider Weight (with gear): |
Correct Springs: |
Comments: |
| 140 and below | Soft | |
| 140-160 | Medium (Orange and Green) | Through your local shop. Quality Bicycle Products Part # FK9851 (Marzocchi Part # 850346/c) |
| 160-180 | (1) Medium & (1) Stock "Heavy" (Red) | |
| 180-200 | Stock "Heavy" Red Springs | |
| 200-220 | (1) Stock "Heavy" (Red) & (1) Extra-Firm (Green) | |
| 220+ | Extra-Firm Springs (Green?) |
For more in-depth tuning information on Spring Weight, see the Advanced Tuning page.
Bottom Line: Proper spring choice is very important on any fork/shock. If you are not getting full travel out of your Marathon S (or you are bottoming-out too easily), be sure you are on the correct springs for your riding weight before you start messing with oil heights, oil weights, etc. You will save yourself a lot of time and headaches if you do this first! If your riding weight (with gear) is near the extremes of the recommended weight for your spring setup, then it would be a wise investment to purchase the next heavier or lighter spring set (keep in mind that you don't have to change the springs in both sides; you can customize the ride by swapping only one spring too).
After you've determined that you are on the correct springs, you need to set the preload. Go throw on all of your riding gear (especially the Camelback and water bottles, which can = 15+ pounds). If you are trail riding, I would suggest 20-25% sag, or 20-25mm of sag. If you don't already have a zip-tie mounted around one of the stanchions, then you need to put one on (see photo) in order to measure your sag and check how much travel you are using during your rides).
Push the zip-tie down the stanchion to the dust seal, then slowly get onto your bike and sit in your normal riding position (you'll want to use a wall for balance). Without bobbing or hopping, carefully tip to the side and get off of the bike. Measure from the dust seal to the bottom of the zip-tie. This is your sag. Adjust the black preload knobs tighter to decrease the sag, and turn them CCW to increase sag amount.
For more in-depth tuning information on Spring Preload, see the Advanced Tuning page.
Damping is always a matter of personal preference. Damping requirements can vary based on your riding style, spring weights, preload, oil weight, and even terrain. For example, with the stock oil weight I was using 4 turns counter-clockwise (from fully closed=slow), but with the 5w oil over the same terrain I needed a slower setting of 2.5 turns CCW.
For more in-depth tuning information on Rebound Damping, see the Advanced Tuning page.
The terrain that you ride most often will also influence your damping choice. I prefer faster rebound damping when the terrain is rougher and slower rebound damping when the terrain is smoother. If you are riding a full-suspension bike, it is essential that the fork's damping characteristics match the rear shock's damping. To test this, I like to ride along on a the pavement and "weight and un-weight" the pedals/handlebars evenly. While you are doing this pay close attention to how quickly the fork and rear shock compress and rebound. Adjust the fork and rear shock rebound so the bike rebounds at the same rate.
The fork manual doesn't seem to have any real information on this subject. Marzocchi used to use oil height as their standard for measuring, and recently they started using volume (cc's). The Marzocchi tech support here in the U.S., gave me oil height recommendations- NOT volume. Go figure.
Here's their email reply:
"The oil level for the fork is minimum 55mm and maximum 45mm from top of oil to top of stanchion with fork compressed and springs out."
Oil height settings will vary with your spring choice too. Choose the proper spring first. When you are experimenting with spring weights, I would recommend setting the oil height around the middle of the recommendations (50mm) and then adding a little or remove a little until you are using all of your travel about 1x per very rough ride (as a general guideline).
Bottom Line: I've tried as low as 62mm, but the tech told me by phone that I'd be better served getting the appropriate spring weight first, and raising the oil level back up to the 55-45mm levels. This will keep the fork supple on the little hits, yet still ramp up enough to avoid nasty bottoming of the fork.
Oil weight changes the damping of both the compression and the rebound. The stock oil weight is 7.5 weight. I've experimented with 5w, but I recently changed back to the stock 7.5w and I was much happier. Despite trying various oil heights, the lighter weight oil caused the fork to blow through it's travel too easily causing an imbalanced feeling in my front and rear suspension. With the 5w oil, the rebound damping was set around 1.5 turns slower than with the 7.5w oil.. At this point, I'm staying with 7.5w.
I understand that many riders in the 200+ range have had success using 10w oil to add greater damping control, especially if you are using Extra-Heavy spring kits (which will require more rebound damping to control the additional spring force).
Standard Disclaimer: This site describes my experiences tuning and maintaining my suspension fork and this information is not an instruction manual. As always, use this information at your own risk. I am not in any way responsible for typos, misinformation, or any of your actions or results. Results may vary.