Thought I'd put this out there and see what others experiences have been and what others have done...
I've just recently thrown a set of 2007/2008 GSX-R1000 forks on my Monster 620 (the Kayaba's, I understand the earlier GSXR1K forks are essentially the same outside of thicker/stiffer outers and adjustable spring preload on the compression shim stack, might be wrong but I think they all apply here...).
The forks are sprung 0.85 (should be about right for my 200lbs), with bone stock valving, sag is 34mm (rear sag is 33mm, feel at speed and neutral throttle is nicely balanced).
All in all, it's way way better than ever before, but if I didn't have any complaints I wouldn't have anything to tinker with, and I'd have to go find another hobby...
My issues are as follows:
Rebound - the highest setting that doesn't completely hammer me around town or on bumpy roads leaves the bike feeling very unstable, eerily unstable, on sweepers and smooth higher speed turns. About 4-5 clicks back in towards the hard side and the bike begins to stabilize on the high speed stuff, but then the ride is very harsh and I fell like I'm going to hit my head on the headstock after every bump...
Compression - haven't figured this one out completely yet. I've got LS and HS turned all the way out, and it get's over big bumps OK without getting too upset, small bumps are smooth, and feels like the forks aren't moving at all over rolling lumps. This is the lesser of my concerns since it's so far not bad, but I'd rather be running in a more reasonable working range of adjustment.
Also, on the compression,
- was extremely harsh on larger bumps with the stock (125mm) oil height, I dropped to 175mm as a bare minimum starting point (think 200mm is the rock bottom working height, but I threw in some margin to be safe) and it's helped over the big bumps. Still have 25mm of unused travel though..
- I have in mind to bore out the base valves' compression paths to see what happens - currently the base compression valve uses three 1.5mm restriction holes, seems a bit small to me so I'm going to try 2.5mm to see if I can't get more tuning range out of the HS (and hopefully the LS as well). The mid-valves also have what seems to me pretty small holes on the compression side (three 1.5mm holes), but I'm not at the point of pulling out the cartridges yet.
I have new fork seals (all balls), and movement in the compression direction was stiff (even after a couple hundred miles) until I slathered silicon grease in there (did the normal wipe with fork oil on the first assembly). Otherwise I've gone through great pains to assure fork alignment and minimize stiction (turning forks 45 deg at a time in the triples and checking at top and bottom of stroke with fork caps popped), it's <3mm right now so I'm pretty sure it's not a factor.
I have absolutely zero background in suspension valving, this is my first endeavor into the realm, so I'm learning as I go (and hopefully not ruining too many parts along the way).
I'd appreciate hearing any of your experiences with the GSXR 1K forks, and in general anyone's experiences with valve and shim stack modification, and especially any help I can get in making my forks behave.
Thanks in advance!
~Doug
OK, no response, so I'm going to just go ahead and post my own findings.
I've spent a bunch of time researching and experimenting, what I found about the stock Kayaba '07-'08 GSXR1K setup is interesting.
I was focused on rebound, but the rebound valving is really not bad, as I've learned. The problem is in the compression valving...
What was putting me on the focus of rebound was my efforts to keep the tire on the ground. What was really happening was moderate to large bumps throwing the chassis in the air, with the forks trying to extend to keep the tire on the ground - the forks in stock configuration do a pretty good, actually pretty amazing, job of this, extending to keep the front tire on the ground, but it's nevertheless up to the compression valving to make sure to not pass too much of the bump to the chassis, to not throw the chassis up in the air too far, and to give the rebound path at least half a chance of keeping the tire on the ground. And the stock configuration of the KYB fork is very progressive on the compression, turning moderate bumps into mountains, giving the rebound no chance whatsoever to keep the tire on the ground...
I picked up a software tool called "ShimRestackor" that has helped immensely. I can't speak highly enough about it... It has taken me a little bit to learn how to use, but it's very much worth it.
It turns out, the primary compression valves, the base vales (down on the fork lowers), are set up slightly digressive (with the clicker closed). But, the mid valves (on the damper rod), though they have a shim stack on the compression side that is held only by a light spring, have only 3x 1.5mm throats, leading to a highly progressive compression damping force. The mid-valve compression actually overwhelms the base valve at >20in/s suspension velocities (at velocities greater than standard moderate braking chassis upset), and at large pothole velocities forces reach >20,000lb...(as shown by the bends in my stock Brembo aluminum front rim)... at moderate bump sizes, cavitation occurs (I kept wondering why, despite the fork oil being at a pretty constant temperature ~ 70-100F, the fork's dampening faded during rides)...
So, basically, the stock compression is both digressive (harsh on small bumps at low speed), and progressive (extremely harsh on any bumps at higher speeds requiring higher suspension velocities), and to top it off, prone to taking on air and fading...
knowing my forks only have ~34mm to extend (sag with my lard on it), and some 110+mm to compress, I decided I should probably soften the compression, particularly at higher velocities.
What I decided to do was to leave the base (compression) valve alone, and to take the mid-valve and bore out it's compression path. The ports on the compression side of the mid-valves are actually quite large despite the restrictor paths being very small, so I bored with a 1/8" ball-end bore through the three ports - below is one of the three ports bored out:
https://docs.google.com/open?id=0B1DE0ZygiWDycFk5eTZseXZXVFE
(https://lh5.googleusercontent.com/ZqpfYYVl3SilZdEUsDdFhCauwA-4VWDlbAjSeilfMEpQ-DoTESD4Iob39_rO3pwuzNaQUjrmNBQ)
(don't mind the burrs, good thing I'm not a machinist for a living :) )
In conjunction with increasing the flow on the mid-valve compression, I decided to keep a bit of the compression response in the mid-valve, and to build a very light shim stack in place of the spring loaded blow-off valve. I'm using a 0.15mm thick 17mm, 14mm, and 11mm diameter on the shim stack (don't know if they'll hold up, might need to go to 0.1mm and 17/16/15/14/13/12/11mm on the diameter to get a reliable stack).
The benefit here is to have a valve that responds more quickly than the base compression valve, since the base valve is responding to oil displaced by the damper rod, where the midvalve is responding directly to suspension travel... To give at least a little compression damping response at high frequencies of rod movement, regardless of velocity. Also, the vastly increased flow in the midvalve (reduced pressure differential) reduces cavitation. This configuration actually shouldn't take on any air, shouldn't fade at all..
While I had the mid-valves out, I lightened up the rebound shim stack just a bit (~30%) - with the focus being to allow running the clicker near it's closed position, giving a more digressive curve, with less high speed damping - to achieve higher rebound velocity under fully unloaded conditions (ex. recovering from a buckle in the road), with higher damping at low velocities and/or at low forces, so after hitting a buckle in the road the tire quickly reaches for road, and when the tire hits the ground after bouncing over the buckle in the road, and the forces equalize, damping force increases to hold the tire on the road...
results? Well, as far as I'm concerned, completely amazing!!!
bumps, juts, ruts, buckles, etc., don't upset the chassis nearly as much, and the rebound - I was very concerned increasing fully unloaded rebound velocity by ~30% - is actually much kinder and gentler... the bike feels overall still very firm. Dive under extreme braking is just as large, but much more controlled, it happens slower. Rebound is exactly as I wanted, the tire shoots out as if to hammer the ground, but seems to stop short of actually hammering, and consequently stops short of hammering my wrists...
Most importantly, it's easier, at any speed, for me to control the beast!
Will scour through my notes once more an post anything I've forgotten.
Cheers [beer]
~Doug
Great work, it seems you have learned a lot in a very short time [thumbsup]
If you feel you have excessive brake dive, maybe some more oil or some more low-speed compression would help, but I suppose you have ideas about what to do if you feel it is necessary, right?
I've never heard about the ShimRestackor SW before, and on first look it seems great, thank you very much for the tip, I'll sure look into it thoroughly. Which version do you use, the free version or the pro?
It's gotten my head spinning, and yet I feel I'm still only scraping the surface of the subject!!!
I went ahead and sprung for the pro version - it's much less expensive than a typical engineering textbook, and, though it's taken me maybe a few [...uh...hundred...] runs to start getting the hang of how the shimstacks and valves work, it's more direct to the point and visual than a typical engineering textbook - much friendlier to my patience (or lack thereof :) )
For what it's worth, if you know what you're looking for, how the shims work (and you're apt at scaling), I think the free version would do the job. But for me, I think knowing what I'm looking for has been actually my biggest struggle. Having the a tool to simulate at will (along with a lot of test riding over the same bumps, sweeps, etc., at various speeds and so forth) has helped me a lot in building a picture of what [I at least think] I want.
Funny you should mention oil level, I'm very glad for the reminder - That's where I started with all of this (I'd since forgotten, but at first I was hoping I could just suck a bit of oil out and solve everything for free). Dive is not at all terrible, I can now almost bottom it out by braking hard enough to hold the rear off the ground for a little stretch, but that's not far south of 600lb's force on the front (not including the braking force vector itself), which is a bit more than the springs' force at somewhere near full compression. Stock I'd pulled a massive amount of oil out and dared not to move preload in just to get a little bit of extra desperately needed softness, but I do feel I'd like a few mm of spare travel (roads are kinda rough out here), and given the current setup I think higher oil level will probably work best for tuning that in (could use preload instead, but then I'd be giving up extension on the forks, and since I like riding on the rather irregular surfaces that pass as roads out here, that's probably not the best choice...).
[coffee] time!
~Doug
Keep going - I know you're not getting many response. But I'm following along. I'd respond if I had anything more useful than encouragement - but for now I'm just reading along.
Well, your experiences mirror mine while working out the "Showa Blues" issue some years ago .... complete dis/re-assy cycle, test ride, repeat .... I also did not know more than bare basics when I started out. After a while it gets pretty annoying that the midvalve is absolutely as far into the fork as you can get.... no shortcuts :-X
Having finally worked out what was wrong with the stock Showas, I've just used the shimming I got with the Öhlins or K-Tech shimstacks as that works great compared to stock.
However, beeing pretty light and not liking the rattle you get from sharp-ish road irregularities (sort of same roads here, apparently ...) I've slightly modified the compression shimming on my Öhlins forks to soften the high-speed compression damping, enabling me to dial in some more low-speed damping with the adjuster screw to counter brake dive.
I run about 120 mm air cushion in the Öhlins (and my Showas, for that matter); I've never been able to use the last 10 to 15 mm of travel no matter how I've tried even though I can not run lighter springs as that would ruin sag settings. However, more oil will add pregressivity; if you log in to Ohlins and search out a manual for their RT forks, there are some curves there that basically applies to all forks of roughly similiar dimensions.
The shimming changes I've made have been pure, slightly educated guesswork, but the Shimrestackor would obviously take much of the guesswork out.
Friday night, time for [beer]
Looked over the ReStackor website, and read just about all of the info.
Got such a huge brain boner I bought the ReStackor Pro.
Well,
I've tried to get the demo vesion to work on my Win7 computer, no luck so far :(
Anyone else got it to work on a Win7 machine?
Quote from: MonsterHPD on November 14, 2012, 12:01:28 PM
Well,
I've tried to get the demo vesion to work on my Win7 computer, no luck so far :(
Anyone else got it to work on a Win7 machine?
Yes, works fine on my Win7 laptop.
What is it doing?
Are you running with Excel or OpenOffice?
Quote from: Speeddog on November 14, 2012, 12:16:50 PM
Yes, works fine on my Win7 laptop.
What is it doing?
Are you running with Excel or OpenOffice?
I run Excel, and now it works. I thought I had the decimal sign configured to "dot" since that is what my excels show, but apparently the configuration was "comma" anyway; when I changed that, it ran OK.
Will take a while to understand what is going on, though ... and it seems most results are shown in "new world units", like lbf, F, in .... or is it just nother setting to discover?
Anyway, seems to be pretty useful, so I'll probably give in and order the pro version.
All of the measurements of physical parts are Metric, Output is Imperial.
So a mixed bag, just like real life. [laugh]
Yeah, I've tripped myself up a few times putting in a "comma" instead of a "dot", I can only imagine how hard I'd scratch my head over a dot/comma config swap!
I do love the metric/imperial mix [laugh] the ReStackor-metric.xls has outputs in metric (and inputs too!), but the metric/imperial mix works since all of the valve pieces are simple metric values, and the scale I'm using to weigh the bike and everything shows pounds [laugh]
I've heard the US is going metric, inch by inch .... ;D
MonsterHPD, [laugh] [clap] ... I've gone to great measures to find shortcuts in getting to the midvalves, now I just yank the cartridges out with the forks still on the bike ;D
https://docs.google.com/open?id=0B1DE0ZygiWDyaGllcGlVemNtVWM (https://docs.google.com/open?id=0B1DE0ZygiWDyaGllcGlVemNtVWM)
I'd read up on your Monster "Showa Blues", really amazing work!!! (was going to point you to it until I realized it was your work in to begin with [thumbsup])
For anyone else with Monster/ST Showas:
http://www.ducatimonsterforum.org/index.php?topic=55303.0 (http://www.ducatimonsterforum.org/index.php?topic=55303.0)
If I had these forks I'd immediately chuck this in the "mandatory mod" bucket!
Slide Panda, Thanks! Suspension is a tough subject, a very personal one too.
Through this, I even worry a little that the settings/changes I share might be taken by someone as the right way to go for them (all while I'm still figuring things out myself!!!).
On that note, and going back over my notes, I thinking it might be helpful for anyone struggling with the same problems if I share how I got to making the decisions I made.
I started off thinking maybe I could do some quick static force analysis and figure out the damping from there... Then I started thinking about what type of bump to optimize for, where in the bump, what speed, chassis upset, tire deformation, dv/dt, da/dt, steam started coming out of my ears, and... Then I must have hit my head or something and realized if I just could find a point where the suspension was working well as is and I could shape the damping curve around that point (KISS theory).
Compression:
For me this was the difficult one.
I'm blessed to live on a street made of concrete slabs that seem to keep shifting relative to one another (thanks I think to the Loma Prieta fault line that passes nearby). There are many square steps of various sizes on this street, some pretty exact at 1 inch, that allow me to test my bike's suspension and compare it directly to stock data available online. Worst case, there are curbs of pretty precisely 4 inches in some spots if I need them.
My cursory mathematical studies showed me that I would have to live with some chassis movement - if I damped low enough to prevent the chassis movement to any sized square step at any reasonable speed, the ~40lbs static unsprung mass on the front end of my Monster would not decelerate in time to keep the tire roughly in contact with the pavement.
Bearing this in mind, I took a 1inch step at various speed, trying to find the speed where chassis movement was noticeable but tolerable. This would be the best case scenario - the highest damping force to keep the tire on the ground along with a tolerable amount of chassis movement. The speed I found was ~25mph, which I believe equates to somewhere close to 100in/s suspension movement.
Then, I had to characterize the suspension outside of that point:
1) below this speed, the suspension was softer, and put me at risk of losing contact with the ground
2) above this speed, the suspension was too stiff, and bucked the chassis
Neat trick, don't know this is really valid, but I set up the rebound to overdamp to the point of "packing", then ran the bumps.
- If the front felt like it falling immediately after the bump, I figured compression was not enough and allowed the wheel to go airborn and lose contact with the ground - the excessive rebound then let the chassis fall to force the wheel on the ground.
- If the front felt steady at the bump, the front compressed just enough...
- If the front kicked up then fell at the bump, too much compression - the compression damping forced the chassis up. Think the whole assembly goes airborn, then the whole assembly falls to the ground.
At any rate, I had my goals - soften it above 100in/s, and stiffen it below 100in/s. Next, how much?
Thinking through this, I think linear damping above 100in/s would be just right - suspension velocity increases roughly linearly with bump size, and (I think) roughly linearly with forward velocity, and my thought is therefore the deceleration required to keep the tire on the ground, and thus the force required, also increases linearly... Don't really know, but just my guess.
Below 100in/s - well, think I got a case of "more is better". At slow suspension velocities, my though is that gravity will take care of things, but higher damping will help with brake diving and mid-corner brake/acceleration adjustments (I never make mistakes on corner entry speed... ;D ). Really, I'd have pushed the low speed damping curve higher if I though I could do so without impacting the rest of the curve. The tradeoff here is that city streets get more harsh at low sped and some road features (i.e. slow lumps) become more noticeable (I think that's all, but...).
Here's how I shaped the compression damping curve to fit my needs (yellow is OEM, thick light blue is the new curve):
https://docs.google.com/open?id=0B1DE0ZygiWDyYkw5RDZyYVdXWmc
(https://lh5.googleusercontent.com/R02x1I5vAPYQhobpnr8jYt7qg9Y1py5ua8t97GqwtPkEY_DoZuNUkgcnP_P9G9ZOE8YdIKTH16A)
(note, flat coefficient curve = linear force-velocity relationship, so my hope is the damping force-velocity relationship that works well at 100in/s also works well at 1000in/s)
Rebound:
For me, this was much easier - rebound force is bounded by the sum of the sprung force plus weight (force) of the unsprung mass, regardless the size of the dropoff, and the resulting damped velocity corresponds to this force.
So, what I wanted to do was find a rebound setting on the original setup where a total unloading of the suspension (square dropoff in the road) didn't result in the tire hammering the road (hammering the handlebars), and set this as my new full stiff position. As an additional step, I did want to make sure the rebound was not underdamped at this setting (since I was planning to make it my heaviest damped setting), so I ran some sweepers to make sure the front was not unstable/fidgity, and if anything pushed/tucked a little.
With me on the bike the front weighs in at just about 250lbs, so 250lbf became my fulcrum for the original valving and setting vs new valving at full closed clicker, and my goals became:
- above 250lbf, I want the wheel to extend faster, this will help recover from upsets more quickly (I think...)
- below 250lbf, I want to dampen more
Original valving and clicker setting in solid blue, new valving at full closed in yellow:
https://docs.google.com/open?id=0B1DE0ZygiWDyRnAzN0g2Q0dpRGs
(https://lh4.googleusercontent.com/M_qj4kooyYR3d735WZb_PsNktTWuOsPRy7MBlhDGQJeMs2Bc1yee02IFrZYalvd9s5xq5Rqfsv8)
Beyond this, my thought here is that as the tire hits the ground and forces from the road begins to counter forces from the spring, chassis, unsprung mass, having higher damping (lower resulting velocity) below 250lbf will slow the unsprung mass more quickly and result in less bounce, fidgitiness, etc., overall allowing me to run the clickers out a little to get both higher unloaded rebound velocity and more stability. For this, my though was that targeting a ~210lbf crossover would work (250lb full - 40lb unsprung).
Basically, my thought is I can run less damping even at the static 250lbf level, and get more of both grip and stability, if I can run more low speed damping. I don't know if this is true or not, or if it even makes sense, but that was my guess. So, at 4 clicks out:
https://docs.google.com/open?id=0B1DE0ZygiWDyXzY3ZHlhZWgweWs
(https://lh5.googleusercontent.com/RZUQPnrOz4plMsxL150XOqWqcbeIsXitUrZ2YqL_QZxLryDP13V8H09F7J7n1h5QvGvTI0zmqJA)
Compression isn't killing me anymore, grip is great at 4clicks on rebound, which also feels very comfortable and stable to me, so I'm very happy. But, I've got to put some good miles on this setup - I might be entirely wrong on my assumptions and/or goals...
[coffee] !!!
Well, FrankenDuc, this got steam coming out of my ears, I'll re-read when my head cools down again [clap]
I suppose the next "necessary" purchase will be some proper suspension data-logging equipment. With the guesswork taken out of the shimstack layout, and from the suspension movement caracteristics, surely suspension heaven will result ... :)
[laugh] been keeping an eye out for years for an excuse to pick up some nifty little MEMS inertial units:
https://www.sparkfun.com/categories/160 (https://www.sparkfun.com/categories/160)
I think this might be the perfect application! I just have yet to pick out the appropriate acquisition/storage device - the Arduino's I think not quite fast enough for suspension characterization...
I've still got a few more miles of "human" testing to go through though - End of day, as long as the suspension gives me more confidence, let's me push harder and wears me out less, even if it slides a bit more, it's better!
Very impressive guys.
Learning a great deal from this. Will have to read and reread though. [laugh]
Thanks heaps.
Digging around the web over the past week or so, I stumbled across a set of whitepapers from Optimum G Vehicle Dynamics Solutions that might be useful to anyone venturing down this path:
http://www.optimumg.com/technical/technical-papers/ (http://www.optimumg.com/technical/technical-papers/)
Look for the set of 5 whitepapers under the "Springs and Dampers" section of the page. It's aimed at the four wheeled race variants, but I'd venture to guess most of it applies to our two wheeled steeds. 100% applicable or not, this is a great set of papers to read through, a lot of really good information in them!
As I'd mentioned in an earlier post, the single greatest struggle I've had has been determining a starting point for setting my damping curves - "what the heck sort of damping do I want out of my suspension and how the heck do I put what I want into mathematical terms???"...
If I look at the work I've done on my forks and compare it to what Optimum G recommends, mine actually pretty closely matches their recommended curve for a damping factor of ~0.7 (a little rough on city streets, but I have to admit the setup seems to be working very well, nice and smooth, as I push hard and fast).
Based off of Optimum G's papers, if I've done the math right, my 210lbs of sprung mass on the front end with two 0.85kg/mm springs gives:
- natural frequency ~2.0Hz
- base damping of ~14.8lbf-s/in at a factor of 1, multiply by damping factor to get target base damping coefficient.
At 0.715 damping factor, damping base is 10 lbf-s/in:
- recommended 2/3 low speed slope on compression is 6.67 lbf-s/in
- recommended 1/3 high speed slope on compression is 3.33 lbf-s/in
My low speed compression is ~6.67 lbf-s/in, and though my mid-high speed compression is a bit lower than 3.33 lbf-s/in (in the 100-500 in/s range), but at the "bump at highway speed" range >500in/s I'm ballpark ~3.33 lbf-s/in (it's a bit progressive in this region, so give or take...).
Here's the curve again for reference:
https://docs.google.com/open?id=0B1DE0ZygiWDyYkw5RDZyYVdXWmc (https://docs.google.com/open?id=0B1DE0ZygiWDyYkw5RDZyYVdXWmc)
On the rebound side, it's probably useful if I provide the damping coefficient graph (as opposed to the damping force graphs I posted earlier):
https://docs.google.com/open?id=0B1DE0ZygiWDybnptUDF0RHVFVFE (https://docs.google.com/open?id=0B1DE0ZygiWDybnptUDF0RHVFVFE)
Note, this is at 0clks. I started test riding with rebound at 4clks out, and I've been turning it in one clk at a time, and I'm currently road testing at 1clk out on rebound. It seems like I'm gaining stability as I close off the valve, and I can't notice any loss of traction (although perhaps I'm not pushing it hard enough...). I'm testing on the road, not the track, so maybe my results would be different if I had a wide open space with no cages, safety runoffs, and everyone going the same direction as me to really push it on :) Maybe next season ;D
- recommended 3/2 low speed slope on rebound is 15 lbf-s/in, which I roughly match (14.3 at ~5in/s)
- recommended 3/4 high speed slope on rebound is 7.5 lbf-s/in, which I roughly match at ~50in/s suspension velocity
Note, as I've mentioned, rebound velocities are bounded and much lower than compression velocities. Compression can exceed 1000in/s on large highway speed bumps, but rebound from fully compressed, depending on clicker setting, is somewhere around 100in/s, I consider low speed to be 0-10in/s on rebound, and anything over 20in/s squarely in the high speed realm.
So oddly enough, I think I've stumbled my own way on exactly what these papers outline as the recommended damping starting point of a 0.7 damping coefficient, 2/3 low speed and 1/3 high speed on compression, 3/2 low speed and 3/4 high speed on rebound. Pretty cool!!!
If you do go down this path though, don't trust my math or results, do your own math and find what's comfortable for you ;)
Anyways,
[coffee] [bacon]
Hello, all.
Lifting this thread again, cause I'm a bit ??? .... and maybe you can help me
Since I have a couple of different shim stack and piston versions I'd like to try, I've now purchased the pro Shim restackor to help evaluate various layouts.
The restackor in itself is maybe not complicated other than thru all the options where you have to determine what to fill in.
I've also read thru most of FrankenDuc's info, but that will take some time to sink in; unfortunately I can't see the graphs on my PC. Or if it'just me and google not beeing on the same wavelength.....
Anyway, I have one problem and 2 questions with the Restackor:
Problem: When I try to open the facility to define the damper needle geometry, it does'nt open, and does nt seem to be present on the "edit output" screen. Looking up the location "C:\ReStackor\Work_Dir\clkdat.in" on the PC, there is something there, but the file seems to be empty. Any ideas how I could get that to work?
Q1: What sensible value should one pick for Fmax (I'm using the base valve as a training item)?
Q2: What sensible u.wheel should I use?
Any hints would be greatly appreciated.
Kind regards,
Torbjörn.
It's been a while since I messed around with my restackor.....
IIRC, you should first copy the existing clickdat file out into a new folder.
Then open the clikdat file with a text editor.
Modify it and save it with a new name.
Move the original clikdat file out to the folder, then move the new one in.
Then rename the new one.
Something like that....it's quite obnoxious.
As far as the wheel speed and force, I've got some notes at the shop, more later...
Thanks, Speeddog, I'll try that when I feel bright enough ;D
However, this causes me to ask a follow-up question: Where do I find the clickdat file? It seems the file on the location given in the manual is empty, and when I check the .txt-file via the "Edit output"button, there is no data indicating any needle geometry at all. The way I understood the manual, there should always be this data, wether default or custom values are used.
Any reference numbers on the speed and force are most welcome, the restackor thing surely takes some effort before it can be useful.
You should find it stored here:
Drive (C or whatever you use) / Restackor / Work_Dir / clickdat.in
The ".in" file extension is crucial when you make your own clickdat file.
This is what I use for the OEM Showa compression valve:
Showa compression valve needle
3.0
Nclk Dclk[mm]
0 3.0
24 2.52
I've got a seperate folder that I created for putting those files in.
I've got that one saved as a .txt file.
If you open it in NotePad, then do 'save as', enter the name as clickdat.in, *and* Change 'Save as type' to 'All Files' not 'Text Documents', it'll save it as clickdat.in, and the program will use it.
Of course, you have to replace the clickdat file in the above directory with your new one.
And IIRC, you have to have Restackor shut down, then restart after you change the file.
--------------------------------------------------------------
Speed and force, well, I haven't found a great answer.
I was introduced a while back to a Suspension Guru, who had a car background, so I was taking his commentary with a grain of salt.
I asked him about what shock dyno speeds he used.
He said maximum of 5 in/sec usually, but he would sometimes go up to 10 in/sec.
I thought that was *really* slow.
If I'm charitable and use a rear suspension leverage ratio of 3:1, that turns into a wheel speed of 30 in/sec.
Which sounds plausible.
But.
Let's say you're cruising on the freeway.
60 mph is 88 ft/sec, which is 1056 in/sec.
That 30 in/sec wheel speed would be a ramp 1" high and 35.2" long, which is a pretty gentle slope.
Similar to the transitions from the plain freeway to a bridge over a road below grade.
But that's a *way* 'slower' bump than, say, a 1" step between slabs of concrete, or a pothole.`
That's the kind of bump that's the most obnoxious from a comfort and chassis stability standpoint.
That's the wheel speed number I want to know.
I've seen shock dyno curves with 200-400 lbs of force at 10 in/sec.
Taking the 3:1 leverage ratio, and then cutting that in half for one fork leg, you get ~67 lbs at ~30 in/sec.
That's assuming front damping forces approximately the same as rear, which may be a bit off base.
But it gives you a ballpark.
MonsterHPD,
have you been through their user guide online? They have a compilation of some suspension velocity data for forks in the user guide:
http://www.shimrestackor.com/Code/User_Manual/Sections/Suspension_Velocity/suspension-velocity.htm (http://www.shimrestackor.com/Code/User_Manual/Sections/Suspension_Velocity/suspension-velocity.htm)
On wheel velocity, tire diameter and deformation play a big role in sharp bumps (potholes, etc). It's been a while, but IIRC on compression, I assumed 10's of in/s up to 600in/s range for bumps (high speed damping), and the 10in/s ballpark as chassis disturbances (low speed damping - braking/acceleration/centripetal) and road surface variation. The chassis disturbance and road surface variation range would be of critical interest to somebody tuning for a smooth racetrack. For rebound, velocities are bounded by the spring force (minus the gravity force from the sprung mass), so I focused on the 0-100in/s range, again with low speed from chassis disturbances and road variation in the ~10in/s range.
(let me check back through my notes though, I frequently get confused...)
the distinction between low speed and high speed was important for me, as I was trying to tune for a high damping coefficient at low suspension velocities and a lower damping coefficient over potholes.
F.max number gets used to determine up to what shim stack force value to run the shim lift calculations - playing around with it will help you see at what point the shims no longer limit oil flow (and damping becomes progressive). I have to admit, the number is a little IZ_ to me, I'm not sure exactly how to relate it to, say, the wheel velocity at which the damping will start to become progressive, but I would reckon the stack force relates to how much oil must flow through the valve at any given wheel velocity. You can also look at the damping curves and see where damping becomes progressive (...so, I didn't really pay much attention to the F.max number...)
Speeddog, Frankenduc, thanks for your input. Any experience you already have is of great value to me; I won't have to find out myself ;D
The compression needle on the 50/54 forks is not a needle at all, more like a pole, but since only about 15 to 17 of the possible 25 or so clicks, I've been thinking of modifying the needle to make it longer and more tapered. The Restackor might give an indication if I get the needle part to work.
Before I attended the suspension seminar at Reactive Suspension I have not given piston design, or even shimming, much thought, assuming the people at Öhlins, K-tech etc. knows what they are doing. I'm sure they do, but I don't know what their goals are, and I now realize there could be great differences in function depending on design.
I have a set of pistons from italian manufacturer Mupo; they have a total compression port area of some 8.5 mm². The K-tech's have about 9.6 mm², a Gold Valve has about 29 mm², and the stock piston in a DS1000 Showa has about 36 mm². This would probably create big differences at high damping velocities and here also I hope Restackor can give an indication. It's also the reason I'm interested in what damping velocities would be realistic.
I suppose Restackor can save a lot of shop time, but I'm not sure it will save a lot of total time ;)