Forkin' around

[Guest ratchethack]

You could vary the 22mm setting to set the correct sag only (do not ride it!) to determine the correct final spacer length at the 22mm setting. This could save the time and material of making several sets.

A good thought, FuelCool. This could save time. I've always used the technique of extrapolating a "target measurement" of how much more or less preload I believe I need to achieve optimum sags based on current sag measurements, then cut new spacers to suit. Sometimes it takes 2 tries to get it right, because it's not a direct 1-to-1 extrapolation, and I wind up with something a few mm different than expected on the first try. Using a cutoff saw and PVC, the biggest "cost" of doing this in terms of time and effort is only sweeping up the PVC sawdust afterward. It'd be easier and more accurate to simply dial in more or less preload on purpose-built adjusters, though -- no doubt about it. I'm not likely to cut new spacers for a desired 1 mm change in preload, but I'd certainly spin an adjuster to achieve the same thing.

[Dan M]

From what I can tell damping and dampening can both be used to refer to the supression of oscillations, but damping is more common.

Damping seems to be much more popular for refering to shock absorber, but not exclusive.

But to damp or to dampen seem more interchangeable when discussing suppression of oscillation.

Damping does not seem to be used to describe moistening, unlike dampening.

Definitions of dampening on the Web:

 

* The resistance caused by fluid in a shock body when the piston moves through it.

www.geocities.com/h3ath3ry/dictionary.htm

 

* moistening: the act of making something slightly wet

wordnet.princeton.edu/perl/webwn

 

*Dampening refers to the musical technique of muting an instrument while playing it, or soon after, before it has lost its sustain (stopped ringing). It can be used on a wide variety of string and percussion instruments. This may be done with a mute.

en.wikipedia.org/wiki/Dampening

 

Definitions of damping on the Web:

 

* The process of minimizing the noise emitted from a coaster.

www.geocities.com/RollerCoasterTalk/definitions.html

* Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce oscillations.

en.wikipedia.org/wiki/Damping

 

* The progressive reduction or suppression of oscillation in a device or system. Viscous damping uses the viscosity of liquids or gases to effect damping.

www.geomechanics.com/dspapp.cfm

FROM WORDNET

http://wordnet.princeton.edu/perl/webwn

Verb

* S: (v) stifle, dampen (smother or suppress) "Stifle your curiosity"

* S: (v) moisten, wash, dampen (make moist) "The dew moistened the meadows"

* S: (v) muffle, mute, dull, damp, dampen, tone down (deaden (a sound or noise), especially by wrapping)

* S: (v) dampen (reduce the amplitude (of oscillations or waves))

* S: (v) dampen, deaden, damp (make vague or obscure or make (an image) less visible) "muffle the message"

* S: (v) damp (restrain or discourage) "the sudden bad news damped the joyous atmosphere"

* S: (v) dampen (check; keep in check (a fire))

* S: (v) dampen, damp, soften, weaken, break (lessen in force or effect) "soften a shock"; "break a fall"

 

Noun

* S: (n) moistening, dampening (the act of making something slightly wet)

The same happens to me, so it is better say damping when talking shocks and besides, if I say, "I need to adjust the rebound dampenininiinging" the technojargon nazis attack me even if they are not correct.

 

 

Thanks Dave, For awhile there I was transported back to catholic grade school, knuckles sore from the nun's ruler. I guess I really wasn't paying attention in Sister Ratchet's class. (she was anal retentive too)

[Guest ratchethack]

There is the possibly apochryphal story about Mike Hailwood's work on the handling of one of the early Honda multis.

 

Mike having had an exciting few laps trying to restrain the rear end at a UK race track, the Honda engineers took the rear shockers off and were discussing what to do.

 

Legend has it that MH picked them up off the bench, walked across the track and hurled them into the lake that was on the infield.

 

A perfect case of dampening the dampers. Permanently.

Heh, heh. Outstanding, Mike.

 

If it's humor that earns attention to this, I nominate this story for the definitive explanation of damping vs. dampening.

 

I've read a lot of stuff on suspension over the years. Some of the most valuable material was written by knowledgeable engineers and deeply experienced technicians who couldn't spell worth a squared-off tire with no tread in the center left behind the shed as a future rain basin f'er mosquito breeding back in 1951. I wouldn't trust their use of "dampening" to be correct any more than I'd trust their spelling of "sockit rentch" -- but that's just me .

 

But I can tell you that the professional publications I've read and the suspension manufacturers that seem to make a halfway professional effort to be correct with wot they put in front of their target market (many don't!) seem to make a distinction between damping and dampening, even if most of their target market doesn't pay any attention wotsoever. Call me anal retentive , but it's one o' the things I happen to've noticed over the years.

 

Now the Web is full o' lots o' unqualified as well as very well qualified stuff. How's a simple guy supposed to be able to separate the wheat from the chaff?

 

Sources, my friend. Sources and a little effort! We discussed this for a year on a since deleted thread. Some learned a few things about sources in that thread. Many did not, and some probably never will.

 

Example: Wikipedia is often directly quoted here and elsewhere as if it's the ultimate fountain of truth. Have the folks who quote Wikipedia ever noticed that it's an "open source" Web site? When looking up something on Wikipedia, take a look at the tabs at the top of the page where you find a lookup topic. The 3rd tab is, "Edit this page". Yes, this drops ANYONE into the source material, and YOU can add, delete, or change anything you want. Your changes become the new content! It's more or less an open blog. The only credentials an editor needs is an ability to use a keyboard.

 

Does this mean that Wikipedia has no value wotsoever? Certainly not! Used properly, it can be a great resource as a guide! But as always, consider the source, and if y'er research has any importance at all, and discovering the truth is any part o' y'er interest -- f'er God's sake, verify wot you've found and cross it with multiple sources that ARE credibly backed up as appropriate with regard to the key info y'er after!! As a general guide, authors and publications with achievements and backgrounds in the area under question and the publishers who make their business distributing their work often have hard-earned reputations to uphold, and will go to some expense to protect themselves from a legal standpoint as may be -- and often is -- worth substantial effort from time to time! Anonymous sources have nothing -- ZIP -- to either protect or to lose by putting out false information, intentional or otherwise.

 

Generally, the reliability of information available is directly proportional to the quality of its source. Seems pretty obvious, doesn't it??

 

It would follow that the closer to anonymous the source, the less credible. A guy named Fred on a blog, f'er example, may agree perfectly with y'er point of view. Fred may in fact have expressed himself very well in the blog, but if all that can be known about Fred is that he agrees with you -- well, Fred ain't a very good source to depend on f'er y'er idea of wot the truth is, IS HE??!

 

Now here's a link to a site that IMHO -- this is just me, f'er cryin' out loud! -- probably has a pretty credible handle on the use of damping vs. dampening when it comes to suspension:

 

http://www.racetech.com/articles/SuspensionAndSprings.htm

 

The President of Race Tech, Paul Thede, who wrote the piece at the link, may or may not be a Rhoades Scholar. Chances are pretty good he isn't. He may not even know how to use spell checker. But his stuff has been published (as indicated at the link) by Sport Rider magazine, which more'n likely has a higher probability of knowing how to use spell checker than many, and I think this, among other things, might elevate Thede's credibility somewhat over "ambient" -- at least when it comes to trying to figure out what is "more correct" in terms of proper usage when discussing suspension.

 

Yep, this is just one example, but there are many others and I gotta go.

 

Now this is just me -- and again, by all means, consider the source! -- but I happen to agree with others here. Suspension components don't have anything to do with dampening unless it's raining or they're leaking, or they've been dropped in the lake, whether it was Hailwood threw 'em there, or just y'er average Joe.

 

Rant mode OFF.

 

Cdr. Hatchracket, Proponent of Dry (but properly lubricated!) Suspension Components Whenever Possible

[badmotogoozer]

I could have a field day here! You're all lucky I'm trying to be a bettermotogoozer.

 

Sheesh! TomAto Tomato.

 

Rj

[Dan M]

I could have a field day here! You're all lucky I'm trying to be a bettermotogoozer.

 

Sheesh! TomAto Tomato.

 

Rj

I'm with you, I thought this was a tech forum, not an English language clinic.

[Lamedog]

Ouiji - How about an update on your project? Are you done, did it help, what would you do differently? Any tips for those (like myself) who are about to install our own Wilbers springs? It was interesting watching this potentially productive thread degenerate into semantics and hypothetical, but perhaps it's not too late to salvage a learning or two...

 

What happened? I just received my own fork springs from Todd but was scared off by this piece. Which seemed to have spawned another more recent fork thread (son of rebuilding the 6 speed) but that also wandered off to nowhere in particular. What have you to say about the process?

 

Also: I haven't found this in the "How To" threads, am I just not finding it? I'll search again, but it seems a fork rebuild/sag set piece would be most useful. My V11 manual and Guzziology are helpful, but a photo piece would be

[Ouiji Veck]

Hey dog...

My forks won't be here till tomorrow.

Sorry I /we got ya all confused.

It's pretty straight forward as far as I can see...dexpite my efforts to make it otherwise.

Basically it looks like pull your front wheel ...then up in the center of the bottom of each fork

bottom is an allen bolt ....crank that out. ..unscrew the big aluminum nut up top and the whole mechanism slides up and out. (be sure your supported well )

 

It turns out the position of the blue nut is very important. If you haven't spun it on the thread

...well fine...but it should be 22mm down from the top of the rod. The conclusion was that nut is intristic to the compression and rebound adjusters on top of the cap.

Hold against the blue nut to screw the top cap off.

 

Up top... under the blue nut...on top of the spring.. is a retaining ring with a slot in it.

( looks like a washer with the center detented and a slot )

If you depress the spring you can fenagle the retainer out...

 

Other than that it's a matter of putting it back together...(after you clean them out...don't know

how I'm going to do that exactly but I imagine there's evil crud down there)

Assemble them ...leave the caps off...collapse the forks all the way...fill with your favorite weight suspension fluid...5 wt and 7.5 seem popular..book says 10wt

I belive it was .4 liter (13.5 U.S. ounce) per leg but it's best to set your oil by measuring down

the tube to the level of the oil..(after you burp all the air out by pumping them (stay dry )

...100mm is the accepted air space between top of fork tube and top of oil.

ratchethack says 125/150 synth. CARTRIDGE FORK FLUID.

 

Set up per "FuelCooler" (probably from Guzzi Tech or somewhere...looks like what I've seen before)

 

185 lbs geared-up rider and 1/2 tank of fuel.

Rear sag - 6mm bike only

-34mm laden

Front sag -25mm bike only

-35mm laden

Rear Rebound -13 clicks out

Rear Compression -23 clicks out

 

Front Rebound - 9 clicks out

Front Compression - 12 clicks out

 

Forks through upper clamp 10mm.

Bitubo damper set minimum.

 

It's a starting point.

 

Good luck..

I'll post when I'm finished with mine.

 

Oh yea...every one here is

ya can't expect an intelligent discussion to go on too long.

I wouldn't have it any other way.

[Lamedog]

Ouiji: Thanks for the update! Pulled my own forks last night. Shop manual and a paste up of various threads from the "How To" section, including a fine brief summary by Carl Allison. As usual, once I'm into the job the anxiety-part is displaced by "wrenchisfaction" - the combination of interest and the satisfaction often found at the end of a spanner....

 

Thanks again...

[Tom M]

It would be quite nice, and thoughtful of the engineers if the threaded rod was threaded further down by maybe 30mm and there were two nuts; one to lock the cap and one below it to adjust preload.

Now that may be is a modification worth considering.

 

FWIW I tried to add a couple jam nuts to my damper rod so I could adjust preload without cutting new spacers and without changing the location of the blue nut. The damper rod is 12mm with a fine thread so I bought four M12 x 1.5 "fine thread" jam nuts. They didn't fit, the rod thread is finer than 1.5. It must be M12 x 1.25 or 1.0, which are both available from specialty hardware vendors but not at my local hardware stores. If I have to go back into the forks to adjust preload I'll verify the thread size and report back.

[Lamedog]

Here are results of my effort installing Wilbers springs. I have an '02 LeMans with Marzocchi forksthat I bought used. Can't say for sure whether the previous owner had changed springs from stock, presumeably not.

 

Before: (stock?)

unladen/static sag: 14 mm

laden/dynamic sag: 44 mm

stock spacers: 120 mm

 

After: (Wilbers, don't know rate(s), but gave Todd my riding/kit weight at 200 lbs)

unladen/static sag: 10 mm

laden/dynamic sag: 45 mm

new spacers: 130 mm

 

So things didn't change much, but progressive springs are a different concept and I can handle a softer ride if on hard braking the overall dive is not worse than before. (I take this to be the concept).

Unfortunately, my test ride was cut short when it became evident I had damaged a seal during the process so can't speak to performance. I am going back in tonight to repair the seal and would appreciate help on the basics of setting air gap...

 

Directions are for air gap of 100 mm with fully compressed fork, springs and spacers out. OK. What about the inner cartridge adjusting rod - in or out? No mention in the manual or Wilbers direction. I presume this is only a few mls and symmetric for both forks, so not to worry?

 

Also: Neither the manual nor Wilbers instructions, nor my search on the topic is clear on whether the annular space between the slider and outside of fork tube should be filled with fluid. Wilbers says to degassify the outer fork tube by pumping, but I take this to mean degassify fluid in the inner fork tube, using the outer slider as a vacuum pump. (Pumping the cartridges is covered separately). I presume since this is where the seals are that fluid is intended to be there, but seem to recall when setting the gap that the fluid was still within the fork tube and had not overfilled into the outer "slider". So I purposefully added fluid to the outer annulus in one leg and the other not figuring that after pumping it should end up the same so long as I check and adjust final gap. (I apologize for having been a scientist as well as engineer). And yes, the seal leg that failed was the one receiving fluid in the annulus.

 

OK guys. Fix me.

[dlaing]

So things didn't change much, but progressive springs are a different concept and I can handle a softer ride if on hard braking the overall dive is not worse than before. (I take this to be the concept).

That is kind of surprising results.

But probably better than before.

Some benefits of the new over the old are that your front ride height can be lower.

The progressives should balance the forks better and give more control when breaking, and should be less prone to bottoming out.

And you are obviously not over-sprung, you should get a softer, more comfortable ride

[Guest ratchethack]

Here are results of my effort installing Wilbers springs. I have an '02 LeMans with Marzocchi forksthat I bought used. Can't say for sure whether the previous owner had changed springs from stock, presumeably not.

 

Before: (stock?)

unladen/static sag: 14 mm

laden/dynamic sag: 44 mm

stock spacers: 120 mm

 

After: (Wilbers, don't know rate(s), but gave Todd my riding/kit weight at 200 lbs)

unladen/static sag: 10 mm

laden/dynamic sag: 45 mm

new spacers: 130 mm

 

So things didn't change much, but progressive springs are a different concept and I can handle a softer ride if on hard braking the overall dive is not worse than before. (I take this to be the concept).

Unfortunately, my test ride was cut short when it became evident I had damaged a seal during the process so can't speak to performance. I am going back in tonight to repair the seal and would appreciate help on the basics of setting air gap...

 

Directions are for air gap of 100 mm with fully compressed fork, springs and spacers out. OK. What about the inner cartridge adjusting rod - in or out? No mention in the manual or Wilbers direction. I presume this is only a few mls and symmetric for both forks, so not to worry?

 

Also: Neither the manual nor Wilbers instructions, nor my search on the topic is clear on whether the annular space between the slider and outside of fork tube should be filled with fluid. Wilbers says to degassify the outer fork tube by pumping, but I take this to mean degassify fluid in the inner fork tube, using the outer slider as a vacuum pump. (Pumping the cartridges is covered separately). I presume since this is where the seals are that fluid is intended to be there, but seem to recall when setting the gap that the fluid was still within the fork tube and had not overfilled into the outer "slider". So I purposefully added fluid to the outer annulus in one leg and the other not figuring that after pumping it should end up the same so long as I check and adjust final gap. (I apologize for having been a scientist as well as engineer). And yes, the seal leg that failed was the one receiving fluid in the annulus.

 

OK guys. Fix me.

Lamedog, since I suffered the same injury to meself (nipped a seal -- easy to do, innit?) and had to re-do a complete disassembly one time, and since I've got a similar (but not the same) Marz fork and installed Wilbers progressives from Todd (not at the same time), I may be able to help a little.

 

If I may recommend a seal installation technique that may save another excursion, it would be to install the seals on the fork tubes first (with liberal fork fluid on both the tubes and seals, twisting them on carefully) and then install the tubes into the stanchions, (install retainer clips on the tubes with the seals!), this may help.

 

I don't know (and don't want to speculate) wot your objectives were with the new springs to begin with. Your sags with previous set of springs look too low rate for my general purpose "rule o' thumb" for the road (regardless of rider/cargo weight), but everyone has different objectives, kind of riding, terrain, etc..

 

NOTE: The difference between progressively wound springs and straight rate is NOT as significant as most seem to think. The chief difference, IMHO, is that progressives allow a slightly wider range of compliance and maintain more correct chassis geometry over a wider range of loads and different kinds of terrain. IMHO (Part II), this is why they have been increasingly found as OEM components in recent years. Interestingly enough, I've noticed that Pro's seem to be increasingly using them on the track.

 

You've gone down-rate with the change, as indicated by the difference between laden and unladen sags before and after. (difference before = 30 mm, difference after = 35 mm). This is not a particularly significant change, but you've increased preload by 10 mm, which would be at least as significant as the rate change, IMHO. I'd anticipate the potential to be riding around on the air spring, which would leave you missing significant fork travel and compliance, and I would expect a relatively harsh ride on the air spring, with only a few usable inches of travel at the end of the fork stroke. My "rule o' thumb" target is 18 +/- 5 mm sag differential. My objectives were exactly the opposite of the way you went, having started with sags nearly identical to wot you have now with the Wilbers, and going stiffer, winding up with a 12 mm sag differential. "Just missed" my target range, so it's a mite stiff for general purpose road work, but it's very well matched to my 95 N/mm rate rear spring and a more "sporting" ride. For me it seems to be a good tradeoff between mountain work (which I weight more heavily) and general purpose riding. Unlike with the stock springs, now I get full use of the entire range of fork travel, and it's a softer and more compliant ride than the stock springs provided.

 

If you could ID your springs by part number (Bestellnr) this might help facilitate things. We don't have the same Marz forks, but at least we'd know if we're talking about the same springs. Mine are 600-062-01. These are rated .7 - 1.1 kg/mm, and are the equivalent of a .9 kg/mm straight rate spring.

 

I would urge you not to be concerned about oil being in the "outer annulus" vs. inner when filling. If you pump the cartridges properly free of air, it all ends up in the same place anyway, with both sides being equal. This means that "the annulus" will dump its contents into the fork tubes when the fork is extended, and they will equalize right-to-left. With the forks fully compressed and springs and spacers out (all else installed, the inner adjustment rod will make little appreciable difference, as you noted, but I measured mine with them installed), believing this to be correct per Guzzi service manual instructions. As you fill them, they will behave differently with regard to how rapidly they take fluid and release air (de-gassing). This is as it should be on my fork, which has rebound damping on the right, and compression damping on the left. If your fork has both damping functions on each leg, it will not matter -- the procedure is the same.

 

At one time I had the email address of Klaus Huenecke at Wilbers USA, (can't seem to find it now). If you can reach Klaus thru the Wilbers USA Web site, I can recommend him as a customer service contact. He was fairly quick with responses to a few Q's I had at the time I did my rear shock.

 

Don't know if this is of much help, but always pleased to contribute to the cause if I'm able.

 

NOTE: I did several edits to the above to correct first pass errors on my numbers.

[Lamedog]

That is kind of surprising results.

But probably better than before.

 

Dave: You're too kind - I expected a "gloves off" response from my SoCal brothers (but we can only wait for Hatchetwhack to weigh-in). Perhaps something like "you can't measure your butt", or "we're not gonna risk potentially getting crosswise with Todd without your establishing more credibility than you have to date, Lamedog. And what with this Lamedog name anyway?". For folks focussed on numbers (I was), the result is dissappointing. If I hadn't increased spacer length, I'd have ended up with more sag than I'd started with. Ran this past Todd, who knows way more, and rides far better than I. Believe I correctly interpret his guidance as "Go ride your bike, its not just about the numbers". I will definitley ride the bike for a while before making another change - I'm no racer type, and really only made the change cause I wanted to wrench. The other spring alternatives I saw for my weight range were shorter so I opted for Wilbers over adding what looked like a whopping amount to preload spacers, or buying additional springs.

 

BTW: Can you tell the new kid (me) - Is fork travel (bottom out) dependent upon internals (spacer, spring coil stack and cartridge), the fork tube contacting the adjusteer cap, or the slider dust cap contacting the end of the fork tube at the wheel end? I'd presumed it is the internal stack. In this case increasing preload spacer length would reduce fork travel, but I have read elsewhere this is not the case. Anyone know the real answer for this bike with stock springs/spacers?

[Guest ratchethack]

...(but we can only wait for Hatchetwhack to weigh-in). Perhaps something like "you can't measure your butt", or "we're not gonna risk potentially getting crosswise with Todd without your establishing more credibility than you have to date, Lamedog. And what with this Lamedog name anyway?".

Hmmm. I find this a somewhat curious, negatively-loaded comment, Lamedog. In fact, I find it more than slightly bizarre. Have I offended you in some way -- personally? I certainly don't recall, but yes, I can well imagine how it could happen if you happen to be a particularly "sensitive type". Perhaps you've taken offense to one or more of the positions I've taken in other posts not involving yourself?

 

If my input here isn't of interest to you, Lamedog, just say the word (any explanation purely optional) and I'll delete my post above along with this one.

 

On second thought, I don't think I'll bother. But without some kind of an explanation -- you needn't bother either -- I b'lieve I'll leave any further exchange here to others.

[Lamedog]

Ratchet: Our posts passed in the ether, so I had not read your thoughtful response when I responded to Dave with my joking/inappropriate reference. I did not mean to offend yourself, Dave, Todd or Klaus, though the sequence of posts would make it seem I was more than rude. My apologies and I again, I appreciate your help. I read the forum to such an extent I feel pretty calibrated with major players, but it is more than fair they don't know me from Adam. I believe it is not the first time I have made this mistake and appreciate your continued patience.

 

Once again, I appreciate your help.