How to adjust rear suspension on an F800

My (english) manual refers to turning the adjustment screw by "clicks" example: turn fully clockwise then back one and a half clicks. So, if the adjuster screw does not click, how much is a click? is a click one full turn? That was my guess

Like you I am mystified why someone wouldn't simply just turn the frickin screw, regardless of the direction, and then observe the outcome. Turn it counterclockwise and its soft? Then clockwise must make it hard! What is the fear in trying?

I admit that the first time I read that instruction it seemed confusing. Then I put the screwdriver in the slot, and rotated the screwdriver in a random direction. I observed, hey, the tip of the screwdriver is rotating towards the H! This makes so much sense! Voila ... suspension hard. Not only that, after a ride I took about 60 seconds and turned it in the opposite direction, this time when the screwdriver rotated the tip went towards the S and the suspension became soft.

At no time during the procedure, when the screwdriver tip was observed at the top of the rotation to be turning towards the opposite letter, did I become alarmed. But that's just me - and in past experiments I have indeed stripped bolts and rendered some parts useless. So maybe its just comfort level and accepting the fact that if you try something without consulting anyone there is a risk of screwing it up. That, unfortunately sometimes, is how some of us learn!

troll comments unintended

Holy shit dude, you're still WRONG, and you're still going at it! :huh

We've all agreed that the book explains it horribly. Therefore, there is no sense using the book to try and figure it out. Let's let go of the book. IT IS EXTREMELY CONFUSING, as we can plainly see.

I am DEFINITELY not confusing spring preload with rebound!! I don't need a lesson on that thank you. Read post #33 from this thread and if you still still think I'm confusing spring preload with rebound damping then you're obviously VERY confused yourself, and we should not even continue this. I'm starting to understand why itsatdm posts once and moves on.

http://www.advrider.com/forums/showpost.php?p=14972513&postcount=33

#1, I don't believe for one second that you talked to anyone at any BMW dealer. #2, IF you did, did you ACTUALLY talk to a BMW mechanic? #3 IF you actually did talk to a mechanic and he/she certified BMW tech told you that clockwise makes damping softer and counterclockwise makes damping harder, they should be fired. In fact, what dealer did you speak with? I'd like to give them a call.

Alan, you are so WRONG on this one you need to just let it go. CLOCKWISE IS HARDER DAMPING, COUNTERCLOCKWISE IS SOFTER DAMPING. Period. That's just the way it is, regardless of how far you want to look into the horribly worded manual.

You're reaching hard here.

Well, Alan, I just actually spoke with my BMW mechanic and guess what they told me: CLOCKWISE MAKES DAMPING HARDER AND COUNTERCLOCKWISE MAKES DAMPING SOFTER. So basically what you're doing when you follow what the manual says is making damping fully hard by turn the screw in all the way clockwise, and then you're softening it up a bit by turning the screw back out from full hard by 1.5 turns.

I even decided to record the conversation with my iPhone if you'd like to take it that far.

Checkmate.

oserLets start a poll. Every one who believes turning clockwise increases rebound raise their hand. If Griz and I agree on this, what more proof do you need.

Cheers, and I need to start taking your advice itsatdm.

Thank goodness.

Northern or Southern hemisphere?

And I was afraid I wouldn't get responses to a too simple question...

In the end I tightened the preload (it doesn't have an end... it just kept turning so I stopped after a dozen turns) and the damping all the way in.

Hmmm. My preload has an end. You might check into that one.
As for the question/discussion/answer, I'm glad we bantered it about.
Some get heated/wound-up, but overall we're on the same page now so that's cool.
That's what its all about.

Y'all ride safe! (Or you'se guyss, depending on where your from.)

The only thing I am confused about is how people can possibly misinterpret the instructions or the symbols... Absolutely mind boggling.

That being said... I've seen worse during validation of manuals I have written myself so maybe a healthy debate is warranted...

In the interest of ensuring correct information is passed along (not to mention challenging false opinion on the internets), it must be noted that in the context of this discussion, the above statement is wholly false.

The rebound screw on the bottom of a shock controls the low speed damping circut. This is basically a wedged (or parabolic) screw that gets run into and out of a slightly larger hole, together which create a gap (orifice) through which the oil may pass. If the screw is turned in more, the orifice is smaller, and that reduces the amount of oil that can flow. The result is a stiffer feeling (slower) rebound damping. Turning out the screw has the opposite effect. Ergo, righty-tighty, lefty-loosy applies.

For the record, the slow speed compression circuit found on some bikes follows similar logic though sometimes with different components.

The image Griz posted and commented on is the valve and shim stack, which a COMPLETELY different component of the suspension. Not to mention its adjustable only on very few suspensions--and never, that I've seen at least, on the rebound circut. What he rudimentarily described is known as the "preload" of a shim stack, and is sometimes adjusted on "three way" shocks that have a high speed compression adjustment. Absolutely no relation to the current discussion.

Here's the first image the googles found for me sort of showing what a low speed needle looks like.

Kudos guys - there is so much good information in these 4 pages on whether to turn the screw clockwise or counter-clockwise. All I know is that when I rotated the adjustment counter-clockwise my bike became slower, both on and off-road. Once I cranked it all the way in clockwise, my F800 was faster, my seat became more comfortable, my low speed throttle response became smoother (without the need to add a soldered resistor thingy) and my GS-911 miraculously started working with my iphone.

You are correct here bxr, as it pertains the damping design you show in your pictures, yes. However, whether you would like to admit it or not, there are plenty of rear shocks out there that use a piston valve shim stack for HIGH SPEED DAMPING, and a 'wedged parabolic screw' for LOW SPEED DAMPING. Though, yes, I admit that some MODERN rear shocks use your pictured type. Either way, the both adjust the same way and have a similar if not the same effect on oil flow damping.

Yes, the valve stack I posted was a from a front fork. I said so if you remember. However, the principle is the same. And ADJUSTMENT is the same for damping on forks AND rear shocks. CLOCKWISE is HARDER damping and COUNTERCLOCKWISE is SOFTER damping. So, yes, my example using the front fork cartridge valve stack as an example actually does help out in this discussion and DOES pertain.

As an example, my Susuki DRZ400's rear Showa fully adjustable shock uses VALVE STACKS like in front forks for HIGH SPEED DAMPING, just much larger. It then uses the 'needle' in your picture above for LOW SPEED DAMPING. These "needle valves" are what the clicker adjusters connect to.



As an example, my Showa fully adjustable front forks on my DRZ400 have both compression and rebound damping controls. The screws for adjustment for these setting are DIRECTLY connected to the VALVE STACKS.You always try to do this bxr. Swoop in on the coat tails and try to claim something I've said is wrong or that it doesn't pertain when it fact it is right and actually does pertain. I'm not going to let you bend and twist what I said so that you can make me look wrong again. If you actually read what I said you'll notice how well it actually does pertain. You'll notice how I was full aware that I was using front forks as an example. However, the principle of damping and how it works and is adjusted remains the same from front cartridge forks to rear shocks.

What I've stated above is wrong. Clickers on most if not all adjustable forks and rear shocks tend to only adjust low speed compression and rebound damping and are connected to a "needle valve" as bxr140 has stated in this thread. However, some rear shocks (especially MX/off road rear shocks) also have a clicker for high speed compression damping. I can only assume that this clicker connects to a separate needle type valve internally for high speed damping.

I´ll keep going at it for some more turns. How many (clockwise) till you got to an end?

Now that what know what is true regarding cartridge forks that actually have rebound and compression damping adjusters (which is a lot of them), it is equally important to understand that there are many many rear shocks of new and old that use THE SAME type of setup for damping: piston valve stacks. There are also some rear shocks that use a combination of a piston valve stack for high speed damping and a needle for low speed damping.



However, as we are all aware, the semantics regarding which type of internal components reside inside YOUR rear shock or front forks is not important to this thread.

What is important to this thread is WHAT YOU DO TO THE SCREW TO ADJUST IT!

And once again: on every single suspension component my mechanic (and I) have ever seen, CLOCKWISE for HARDER damping, COUNTERCLOCKWISE for SOFTER damping. This goes for rebound damping and compression damping on forks, as well as rebound and compression damping on rear shocks, high or low speed.

Cheers.

If it was cranked out a lot you will be cranking it for a long time till you get to the end. When you have it turned all the in you will feel a definite stop.

Griz, you are still wrong. Seriously, lose the ego, drop the hypocrisy, spin, misdirection, and lies that frequent your backpedaling posts (all of which are present in your last two posts), and for christ's sake fight that inane need to always get the last word.

Instead, just listen. And hopefully learn.

If a fork or shock has a [low speed] external adjustment--EXACTLY like the one on the F800GS shock--it changes an orifice in a circuit that is COMPLETELY SEPARATE from the valve and shim stack. In all cases where there's a rebound adjustment--again, EXACTLY like the GS shock, which is the topic at hand--the adjustment runs a needle in and out of a hole, where the needle is either at the bottom of the shaft running perpendicular to the shaft, or the needle is actually in the shaft, running parallel to the shaft. None of this is debatable. This is simply how low speed external adjustments work and, to be crystal clear, this is EXACTLY how the rebound adjustment on the F800GS shock works. Not to mention your DRZ.

To elaborate, this is exactly why rebound (and sometimes compression) adjusters are in the top center of a fork. They are connected to a long rod which runs [through] the length of the shaft to the actual needle/orifice which is way down by the [typically rebound] valve.

Furthermore many (not all) low speed externally adjustable compression circuits work with similar needle/hole passages. In the case of shocks, the compression adjustments are almost always on a remote or piggyback reservoir, and in rare cases, they're paired with a high speed adjustment which is typically a more complex needle/hole system, but a needle none-the less. For the record, I've seen some compression adjustments come in the form of disk with different size holes in it that sorta gets adjusted view-master style.

Unfortunately, you're getting very confused with respect to the high speed circuit--the circuit with the valves and shims. For one, there is simply no such thing as an external adjustment that "directly connects" to the nut securing the shim stack. Again, that kind of adjustment DOES NOT EXIST. In some cases where there is a high speed external compression adjustment, the external screw compresses a small spring which changes the preload on the shim stack...but that's never the case with shocks--just forks, and there's no direct connection. To try and externally adjust the torque on the preload nut directly would be a futile effort. It would be like racing a bus around a go-kart track. You just won't get the fidelity. Really, I can't be clear enough here--you are 100% wrong when you say "the compression damping and rebound damping screws at the top and bottom of the forks connect DIRECTLY to and DIRECTLY adjust the 'firmness' of the compression and rebound piston valve stacks." That is NEVER the case and is a HORRIBLY incorrect thing to say.

Finally, I'm not sure where you got the idea that some shocks only have piston valves and some shocks only have needles and some shocks have both. Since like 1980 (or even before then), EVERY shock ever made has had a piston valve/shim stack. And every one of those shocks has SOME kind of fixed orifice for low speed damping. In cases where there's no external adjustment, that orifice is simply a hole in the side of the damper shaft. In cases where there is an adjustment, as noted already, that adjustment is a needle. Repeat the paragraph over again for forks except that pistons/shims didn't get widespread use until a decade or so later, and some low tech bikes still don't use valves/shims.

So, I think that about covers it. I'd be happy to clarify anything, but if you're just going to backpedal and manipulate my words AGAIN, unsubscribe now.

For reference, so you can see for yourself how this stuff REALLY works, here's a classic two-way (low speed rebound and low speed compression) shock:
http://www.penskeshocks.com/files/PS-8983BOMWITHCD.pdf

And here's a new style three way shock (adds high speed compression) with a completely separate high speed adjuster. (Their other three way shocks have the high and low speed screws coaxial to each other.)
http://www.penskeshocks.com/files/PS-8770CDBOMDRAWING.pdf

Here's a regular three way shock:
http://www.penskeshocks.com/files/PS-8987WITHCD.pdf