What is what?

[Krasi]

I'm starting with all the appologies in the world for the lame question I'll ask - which clicker does what?

Here are pictures of my suspension (09 EC300):

Pic 1 - Front Top

Pic 2 - Front Bottom

Pic 1 - Rear Top

Pic 2 - Rear Bottom

The explanations in the User's Manual get me confused, plus the pictures are for Marzochi (I believe) and mine is Sachs. I know all suspensions are similar, but this is the first time I actually fiddle with one. I read a lot but still am quite confused what is what and how it influences the operation of the suspension. I refer to the clickers. Rear spring preload, for example, is pretty straight forward and "common sense".

 

[MattR]

...which clicker does what?

Here are pictures of my suspension (09 EC300):

Pic 1 - Front Top
This adjusts the rebound damping.

Pic 2 - Front Bottom
This adjusts the compression damping.

Pic 1 - Rear Top
There are 2 adjusters. The inner screw adjusts the low speed compression. The outer knob adjusts the high speed compression.

Pic 2 - Rear Bottom
This adjusts the rebound damping.

I added the clicker references under each title above.

Just remember...
Write down your current settings for a baseline. Count the number of clicks until the screws/adjusters are fully seated (inward). This will establish the "number of clicks" to return to your baseline setting. Most people refer to the settings as "number of clicks out from fully seated". Where fully seated would provide the maximum damping setting (slowest rate of rebound/compression motion).

 

[Dingo]

This is excellent, any chance it can be pinned?

 

[Dingo]

This is excellent, any chance it can be pinned?

PS: Krasi - Wash yer scoot!!

 

[Krasi]

Thank you very much, Matt.

Let me elaborate a little more, if I may, just to confirm to myself I got it right.

So, the front bottom clicker (Pic 2) determines how fast/easy/"softly" the fork compresses, i.e. goes up, right? The "fully seated" position is the hardest setting, i.e. the fork is slower/more difficult/"harder" to compress?

The front top clicker (Pic 1) does the same, but for the extension movement of the fork, correct?
And there is no spring preload for the front springs (at least not on my forks)?

The same applies for the rear shosk too I suppose, but I'll need some help with the slow and fast compression.

P.S.
Dingo, believe it or not she is washed. I just forgot to "go down on her" and take care of the bottom side

 

[Skidad]

Yes you are understanding everything correctly and hopefully someone will explain the rear low/high speed better as well. The GG manual is an absolute joke and uses many outdated pictures and no clear info on suspension clicker setting or explanations of what they really do. They should be ashamed passing that thing off as an owners manual.

.....and I'm not gonna touch that last comment

Why doesn't GG (Marzocchi/Sachs) provide nice rubber covers for the bottom of the forks to protect the damping adjuster from dirt and mud? Seems to be asking for trouble IMO.

 

[MattR]

So, the front bottom clicker (Pic 2) determines how fast/easy/"softly" the fork compresses, i.e. goes up, right? The "fully seated" position is the hardest setting, i.e. the fork is slower/more difficult/"harder" to compress?

You are almost correct, but made a slight typo above (see my red highlighted words). I will try to describe it another way...
Compression is when the distance between fender and wheel axle gets smaller/less. So, when riding the bike, this is when the wheel travels upward towards the fender or your bike is moving towards the ground (depends on your reference point). In any case, it is when you are squeezing the two ends of the suspension fork or shock together (i.e., compressing). If you continue to compress the fork or shock, you will at some point "bottom out" your suspension and the tire will rub the fender. The extension movement (also called rebound) is the opposite behavior.

The front top clicker (Pic 1) does the same, but for the extension movement of the fork, correct?

And there is no spring preload for the front springs (at least not on my forks)?

You are correct on both questions. While there is no "external" spring preload adjuster (like on KTM SX/XC forks), you can manually change the spring preload. If you remove the forks from the bike and remove the top cap (like you were going to change the fork oil), you can change the length of the plastic spacer that compresses or adds preload to the coil spring. You will have to do some slight disassembly, but the spacer length can be modified. A PVC water pipe from your local hardware store can be used as a substitute (just match up a similar diameter). Personally, I have not changed my front spring preload... only the rear spring preload.

The same applies for the rear shosk too I suppose, but I'll need some help with the slow and fast compression.

I didn't want to provide too many details initially (keep it simple) but you want to learn... so here it goes:

The low and high speed compression adjusters are slightly misleading. The high speed (larger adjuster nut) is not really "high" speed... but rather it controls motion in a "higher" low speed range or mid speed level. Actual high speed changes are really done by a suspension tuner who revalves the piston and staging of the shim discs.

These two compression adjusters (low and high) are only changing the oil flow thru a bypass hole. So, when you turn the adjuster screw or nut fully seated, oil is being restricted from flowing thru this bypass hole. It now has to flow through the piston valving. Think of it as water faucet... when you turn the faucet handle closed/off, then the water stops flowing. For suspension, when you make the oil flow more slowly/more restricted... it makes the suspension motion slower and feels more firm.

Conversely, if you back out these adjusters away from fully seated, then you are "opening" the water faucet. Your suspension now has oil flowing more freely/less restricted, so it makes the suspension motion faster and feel more soft.

Well, this reply is getting a bit wordy now... sorry if I'm rambling.

Just a final note... I mentioned the 2 compression adjusters are like low and "higher" low speed adjusters. The best way to remember these are the following: if you want to help control/adjust small suspension motions (like roots and rocks) you will focus on the low speed screw. If you want to help control/adjust larger suspension motions (like whoops and jumps) you will focus on the high speed screw/large knob.

Also, a word of caution... adjusting the Rebound screw will also have some effect on the low speed "compression" motion. This may confuse you but the rebound adjuster controls oil flow thru the center of the shock rod (bypass hole). The center of the shock rod (bypass hole) is also active during compression motion. So, a rebound screw adjustment may also need to be combined with a low speed compression screw adjustment to counteract its effect. Sorry if this just confused everyone... but this is something to consider if you are making a rebound damping change... so only make small changes like 1-2 clicks of the rebound screw. Ride the bike over the same terrain, then make another minor adjustment, etc..

Hope this helps!

 

[MattR]

...hopefully someone will explain the rear low/high speed better as well. The GG manual is an absolute joke and uses many outdated pictures and no clear info on suspension clicker setting or explanations of what they really do. They should be ashamed passing that thing off as an owners manual.

Hopefully, my lengthy post will provide some guidence that the manual lacks. This thread will stay "stickied" to be a quick reference for readers.

Why doesn't GG (Marzocchi/Sachs) provide nice rubber covers for the bottom of the forks to protect the damping adjuster from dirt and mud? Seems to be asking for trouble IMO.

That's a good question. My old KTM had some plugs. My Husky and GasGas with Marzocchis (both of them) do not have plugs. So it is a Marzocchi vs. WP issue. Perhaps some WP plugs would fit our fork bottoms. I have not tried myself.

 

[Krasi]

Once again, thank you very much, Matt.

Can we try a theoretical case study now? For example, a typical "problem" for me is that the front end bounces too much off rocks and roots at low speeds (bike wise). Especially on hill climbs. At least this is what I think, but after many hours of reading and watching instructions may be my body position was wrong...
Anyway, if I want to correct this I think I should reduce the compression damping by turning the Pic 2 clicker counter clock-wise. This is confirmed by this troubleshoot guide - http://www.kantaron.com/motorcycles/Motorcycle-Suspension-A-Troubleshooting-Guide_27855/ (it's for street motorcycles, but it's also applicable for us too I hope)

http://www.brucessuspension.com/kb3.htm on the other hand states I should start with the rebound?

P.S.
I also found these articles on suspension setup:
http://www.off-road.gr/article17.html
http://www.off-road.gr/article11.html
http://www.off-road.gr/article18.html

 

[iancp5]

First remember I am no expert!

When setting suspension I usually back compression off quite a lot. How much depends on your springs. I have harder springs than standard so I would start with compression wound right off to zero on the clickers. I'd then set rebound to stop bouncing - you can get it quite close just pushing down & releasing the suspension yourself and making sure it doesn't oscillate. Fine tune on a track so it neither packs nor kicks - whoops are a good test. Then set compression (high speed in your case) so it doesn't bottom very often on the bigger hits, small jumps etc. Low speed I would just try and get it to feel plush over small stuff.

I think you need to have the springs right first though. You also want to set the oil height and preload on the forks so you use a good bit of travel on the type of terrain you ride. Rear preload you can measure to set correctly (only works with correct springs) but my forks always seem to have too much stiction to be accurate setting sag by measuring. There's no one correct setting, depends on rider and terrain. Without a mobile workshop & test track like you race it's a lot of slow trial and error. I often run a larger air gap than standard (120mm on Marz 45mm) to use a bit more travel on my woodland terrain, I have very few big hits or jumps.

 

[MattR]

Krasi,

Those are decent links. The guidelines from Bruce's Suspension and MX-Tech are similar. Here is the MX-Tech guideline:
http://mx-tech.com/downloads/tuning_guide.pdf

Like iancp5 mentions, it is very important to first get your sag settings correct. If your race and free sag settings are in the ballpark, then you have the correct spring rate and preload. If these are not right, then you will be fighting balancing issues (front to back) along with damping issues, so it is best to eliminate some variables.

Assuming you have the spring tuned properly, then I agree with Bruce's and MX-Tech guidelines to start with rebound damping. It provides the most control and most folks mis-diagnose issues and play with the compression adjusters. If you get the rebound set right, then you won't be changing this later on too much.

The final step would be adjusting the compression adjusters. You can soften this up until you find yourself using too much suspension travel. Then, slowly add more compression damping.

Sequence:

• Ensure all suspension linkage, pivots, etc. are properly greased and smoothly working.
• Springs (preload and rate) adjustment
• Rebound adjustment
• Compression adjustment

For your specific example, I would add more rebound damping control (stiffen it up). Your compression may be fine, but it may help to reduce it slightly.

 

[MattR]

It may also help you to put a plastic zip-tie around the lower fork tube. Put it on lightly and position it against the dirt wiper. This will provide a quick check on how much travel you are using.

 

[Skidad]

Krasi,

How much do you weigh? Most new bikes are set up from the manufacturer for about a 175 lb rider (79.4Kg). If you're considerably outside this range either lighter or heavier you will most likely need different springs and this would need to be addressed first or everything else is out the window.

Search the suspension forum for setting the rear sag especially and don't be afraid to turn away on the clickers to see how changes affect the bike.

One of the best things you can do is find a nice short loop that is typical of the riding you do. Spend the day riding around that same loop and just keep trying different adjustments and rear sag settings to see how the bike reacts and what feels best. Go from one extreme to the other to feel the affects of the clickers.

 

[Krasi]

Thanks for the input. I belive I understand what I should do.

Here is my current situation:
1. Own weight (w/o gear) - ~87kg, i.e. ~191 pounds. I'll try to loose some in the spring. Way too circular shape these days
2. Static sag - 21mm
3. Race sag - 90-100mm depending on where I sit on the seat.
4. Current outside temp - -7 C (~21 F). First test ride is a good month or two away. It's not uncommon to get as low as -25 C (-13 F) in February.

Once again, thanks for the help, and I'll continue with my theoretical preparetion for the season.

 

[Skidad]

You need more sag. Check suspension forum.

I would say you're also very close to if not outside the range of the stock springs.

 

[twowheels]

A Few Minor Revisions

A couple points to add to Matt's description

The low and high speed compression adjusters are slightly misleading. The high speed (larger adjuster nut) is not really "high" speed... but rather it controls motion in a "higher" low speed range or mid speed level. Actual high speed changes are really done by a suspension tuner who revalves the piston and staging of the shim discs. This is largely true. The compression adjusters are working on a valve dealing with fluid displaced by the shock shaft into the reservoir as the shock compresses. The compression stack in the shock body is dealing with fluid moving from one side of the piston to the other. The shaft and the piston obviously move at the same speed, but the fluid velocity is determined by the volume flow divided by the area the fluid travels through. Port sizes, both on the shock piston and between the shock and reservoir determine the actual fluid velocity through each component. The compression stack on the shock piston can have low, medium, and high speed damping elements, but they are not adjustable without disassembling the shock.

These two compression adjusters (low and high) are only changing the oil flow thru a bypass hole. So, when you turn the adjuster screw or nut fully seated, oil is being restricted from flowing thru this bypass hole. It now has to flow through the piston valving. Think of it as water faucet... when you turn the faucet handle closed/off, then the water stops flowing. For suspension, when you make the oil flow more slowly/more restricted... it makes the suspension motion slower and feels more firm. On recent shocks, the low speed compression adjuster is a needle jet, much like a fuel screw or the rebound adjuster. The high speed adjuster actually works on a spring against the compression valve shims, so adding high speed is actually preloading the valve stack making it more resistant to fluid flow into the reservoir.

How do you know if you should tune using the high or low speed compression adjuster? Consider the shock shaft speed, not the motorcycle speed. For a given forward speed, if the wheel has to climb this / the shaft speed is slower than if it has to climb this |. Rolling whoops and G-outs would be considered "low speed" events. Roots, square edged bumps, and jump landings are typically considered "high speed".

A note of caution: The displaced fluid wants to take the path of least resistance. If you crank down on your high speed compression, you're forcing more of the fluid through the low speed port, and you can easily end up with choked flow or orifice damping. The overall damping is a function of the interaction of both flow paths.

 

[nick790]

So how would you set fast/slow speed adjusted?

Is there a correct order to do it in?

What are we looking to get from each adjuster and in what conditions?

 

[twowheels]

So how would you set fast/slow speed adjusted?

Is there a correct order to do it in?

What are we looking to get from each adjuster and in what conditions?

The short course goes like this -

* make sure your bearings are in good shape, your linkage is lubed, your shocks and forks are reasonably fresh, your tires are adjusted to proper inflation, and your axle is in the middle of its adjustment range.
* measure race sag, adjusting if necessary (see separate posts for proper values). Confirm static sag is in range. If not, install a stiffer or softer spring as appropriate and repeat the process.
* start with the clickers (rebound and slow comp) in the middle of the range, as with the high speed comp knob or adjuster
* warm up yourself and the bike
* if at all possible have someone else watch what the bike is doing and take notes. Ride a small loop a couple of times between each adjustment. Ride at the pace you normally ride or race at!
* adjust one clicker at a time, using large adjustments at first, then narrowing down on your final setting. Remember that every adjustment will affect the function of the others, so this is an iterative process
* adjust the rebound damping first, dialing in enough that you don't bounce after dropping off a small curb. Lighter rebound tends to be best, so use just enough to control the "springy-ness" of the bike. Too much will lead to packing and sensations of harshness as if there were too much compression damping
* attempt to ride over the same set of roots or square edged bumps at a consistent speed, dialing out enough high speed compression to eliminate harshness while still controlling pitch. Try a jump to see if you've created a bottoming issue. If so, dial in more damping.
* ride through some rolling whoops at speed and watch behavior of the bike on jump faces. If you're bottoming in these cases you need more low speed compression.
* look at your notes to make sure you've headed in the right direction and toward your optimum ride
* if you think you've got the ride dialed, go on a longer loop to see how it all comes together
* if your bike is still not behaving as you think it should, carefully craft a description of what it's doing under what conditions and what settings you ended up with, and then dig into the internals

Hope that helps.

 

[nick790]

Thanks,

Trying to get my sachs shock to feel like my old ohlins one.

 

[Hrosiiik]

I'm starting with all the appologies in the world for the lame question I'll ask - which clicker does what?

Here are pictures of my suspension (09 EC300):

Pic 1 - Front Top

Pic 2 - Front Bottom

hallo,
i just whant to ask. What fork is in the picture? I have same forks, but no stiickers on it. I dont know what fork do I have.

Sorry for my english.

Filip