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Misfit
 
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Adjusting sag on the front end (1100) - PITA!

Oh my aching ballbag.

So in my fine-tuning, I finally got into a careful adjustment of the sag on my Wilbers. After reading several threads I settled on target numbers of 35mm front, 34mm rear. For reference, my bike is a 2001 'Light', has the longer length (Wilbers) rear shock, and now has the 365mm GS torque arm, plus (edit) I have the 10mm Motoyoyo A-arm mod. The rear of course took about 3 minutes, 2 of which were spent taping and marking reference points and then getting my neighbor to measure. Sure enough it needed about 5mm of preload, a pretty significant amount. Grabbed the spanners, loosened the lock ring, cranked down the adjustment ring A LITTLE (edited), tightened the lock ring. Done.

The front on the other hand is a pain in the a$$. I had purchased a MotionPro tool specifically for the purpose, as it was clear that the Wilbers spanner was useless in the tight confines of the shock recess.



But even so, there was no way I was going to get this done with the fairings on, so off they came. And then it was clear that I was going to need to have access from the front, so off came the headlight, mirrors and windshield. Even with my fancy tool, which was a godsend, I can't see how to do this without removing that stuff.



Once if was off, the tool made short work of it. I wised up and measured the amount of threads showing, and then adjusted the rings till there was 6mm additional threads showing. Put it all back together, reset my ziptie on the fork tube, remeasured, and it was perfect at 35mm. Hooray.

Took it out for a spin and it seems better than ever. I also took a couple of clicks of damping out of everything, and while it definitely feels plusher, I may have gone too far. Will work on the damping next in the few sessions, that's much easier, and I took notes as to where I was and what changes I made, so I'll learn something too.

With all my suspension and geometry changes, I also discovered (in this my first night ride on it) that my headlight was now aimed WAY too low, and so did a little adjustment of that too.

Who has a better way of (tool for) adjusting the front preload without stripping the bike? There's got to be a better way...

N.

Last edited by Noblehops; 03-20-2012 at 03:32 PM..
Old 03-19-2012, 06:56 PM
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if the bikes falling into the turn then make a small spacer for the front shock,
it will go on the underside of the frame just in front of the fuel tank,
( this will effectively push the front end sliders down some, and restore the front to rear balance)
you can use fender washers try say 5mm to start with.
Fitting the rear para link if it raises the rear will make the bike turn easier and then it may go past easier and keep falling into the turn,
thats when you need to raise the front some,

NOTE this should not be confused with setting your sag
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Old 03-19-2012, 07:09 PM
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Misfit
 
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Cool Merlin, thanks. I will take note of how it's steering more closely once I nail down a few more variables. I'm getting a lot closer than I was a month ago.

N.
Old 03-19-2012, 07:17 PM
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Would it be easier/quicker to pull the shock to make adjustments then reinstall?
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Old 03-20-2012, 08:33 AM
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Hi,

There may not be a better way, but worst-case, just removing the shock is easier.
The RaceTech equiv of that motionpro tool is a little easier to use too, but doesn't materially change the job. WOW, having to add 5-6mm of preload is RIDICULOUS.
Another wonderful Wilbers out of box experience eh? What kind of static sag did you end up with. Dollars to donuts, you had to do that because they sprung it very softly. I could be wrong though, as they sometimes nail it, and it's always good to learn more, so let us know the corresponding front static sag number too. Do you know your front spring rate?

Good luck with it. You'll learn a lot this way.
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Old 03-20-2012, 08:56 AM
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Quote:
Originally Posted by roger albert View Post
Hi,

There may not be a better way, but worst-case, just removing the shock is easier.
The RaceTech equiv of that motionpro tool is a little easier to use too, but doesn't materially change the job.
Yeah, in all honesty I must admit that never occurred to me. Would you still have to remove one side of the fairing though? That's no biggie, 5-10 minutes to do even if.

Quote:
WOW, having to add 5-6mm of preload is RIDICULOUS.
Another wonderful Wilbers out of box experience eh? What kind of static sag did you end up with. Dollars to donuts, you had to do that because they sprung it very softly. I could be wrong though, as they sometimes nail it, and it's always good to learn more, so let us know the corresponding front static sag number too. Do you know your front spring rate?

Good luck with it. You'll learn a lot this way.
Really? That's a lot to adjust in your (considerable) experience? I guess I'm surprised to hear that. I can tell you what the static sag was before I adjusted the preload - front was 29mm and rear was only 5mm. I will remeasure both tonight if you're interested. The spring rate is just cropped out on that photo, I'll pass that along too.

N.
Old 03-20-2012, 09:47 AM
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How I dealt with it was to cut the standard spanner wrench so there was no handle,, then I took an old cheap 3/8 drive socket and cut it so I just had the square section and welded it to the spanner end.

Then you just insert a ratchet and spin away, I can easily get over 1/2 turn per reposition, and to loosen, just flip it and put the ratchet in the other side if needed. It also worked well on a buddies track bike, as I just put a 2' extension on it and adjusted his from under the seat, even though the adjusters were on the bottom.
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Old 03-20-2012, 10:22 AM
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Thanks for the info.

Well, let me clarifiy. 5mm at the WHEEL is no biggie - kinda common even.
But 6mm at a SHOCK, which generally means 10-20 at the wheel, is QUITE a bit.
Normally only happens with OEM shocks with large riders on Japanese bikes, or some lower spec triumphs or ducs.

But for it to happen on an aftermarket, allegedly properly sprung and setup ´custom shock´ is ridiculous. It means they totally blew the preload or springrate, or both.

Mind you, you´ll always have more static sag on the front than the rear, typically 15mm or so, with considerable latitude. But, 29 vs 5 is just ridiculous. Even as a lay person, knowing that motorcycles are vaguely 50-50 weight distribution creatures, and just using common sense, 5 and 29 should ring alarm bells, no?

I´d be ashamed if that left my shop, and would be very upset with myself or one of my guys. This is why I may sometimes appear a bit disdainful about Wilbers and their ´custom´ setups on the board here, even though I like their products OK. It´s just that they´re for the most part, as far off as any product short of one size fits all ones, but people that don´t know much trumpet their customized stuff. For custom tailored to be of value, the tailor must be competent.

No worries though. It´s probably just a matter of preload, and in any event, if YOU like it, then that´s ultimately all that matters, regardless of the opinion of a suspension geek.
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Old 03-20-2012, 10:23 AM
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Misfit
 
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Quote:
Originally Posted by roger albert View Post
Thanks for the info.

Well, let me clarifiy. 5mm at the WHEEL is no biggie - kinda common even.
But 6mm at a SHOCK, which generally means 10-20 at the wheel, is QUITE a bit.
Normally only happens with OEM shocks with large riders on Japanese bikes, or some lower spec triumphs or ducs.
OK, I'm going to head back and measure the front again. I'm thinking I did something wrong. I appreciate your guidance even though I did not buy these from you Roger. But to clarify, I moved the FRONT adjuster 6mm. I'm not sure how much I moved the rear adjuster, although I did SAY I moved it 5mm. I didn't get the (not so) bright idea to use the calipers till I was working on the front. So don't put too much stock in that "I moved the rear 5mm" comment. I was really referring to adding 5 mm of preload at the axle point where I measured. Sorry that was misleading the way I wrote it.

Here's what I did at the front end though:

I jacked up the front end, so the fork was fully extended, and put a ziptie at the fork wiper. I measured from the edge of the ziptie to the bottom of the top clamp and recorded it. That was 151 mm

Then I jacked the bike back down and remeasured the ziptie. That distance was 122 mm, or 29mm of static sag.

Then I mounted the bike and held onto a nearby shelf. Dismounted and measured the position of the zip tie. That distance was 110 mm, or 41mm of rider sag.

Targeting 35mm of rider sag and contemplating how far I ought to crank down the adjuster ring to get there, I got the bright idea to measure the threads and crank it down 6mm, totally neglecting to think about the fact that I was acting on a point roughly 2/3 of the way down the 'lever' (the A-arm and it's shock mount) and not the end where I wanted 6mm of movement. I snuck my calipers in there, measured what I had showing, and cranked till I had 6 more mm of thread showing, put it back together and it was dead nuts. 35mm rider sag. But it should not have been, I should have overshot, by about half the amount that I cranked it down, or 3mm, as it should have moved the END of the arm about 1.5x what I moved the shock, 2/3 of the way down the arm, I now understand.

SO...

I must have measured something wrong and depending on which time I measured it wrong, it's either off 3mm, or I got lucky. I will remeasure tonight and see.

NOTE! I just realized I did not turn the damping down all the way as you suggested in one of the threads I read. I'm going to do that and then repeat all my measurements again and see what's what.

Quote:
Mind you, you´ll always have more static sag on the front than the rear, typically 15mm or so, with considerable latitude. But, 29 vs 5 is just ridiculous. Even as a lay person, knowing that motorcycles are vaguely 50-50 weight distribution creatures, and just using common sense, 5 and 29 should ring alarm bells, no?
Yeah, I'm following you, and I did notice the disparity, but I chalked that up to the fact that there is more travel in the fork, and so the numbers themselves weren't as important in my mind. I expected more static sag in the rear than I found though. But in this case, assuming I measured correctly, which end is sprung wrong? Is 5mm static sag too little? I can't see how it would matter if the rider sag is correct. Does that suggest too much spring in the rear? Or not enough in the front?

To your point about care in your work and pride in your results, I did have a shock resprung years ago by a really good local guy at the racetrack (Peter Kates, some may know him), and sure enough he got the preload pretty much perfect in his vice. Wilbers has preload and spring rate numbers on the slip they sent, I will scan and post them for your thoughts if you're not out of patience with it.

Do you think it's possible that the torque arm and the barbacks changed the weight distribution meaningfully? I'm tempted to get a couple of scales and see what the weight distribution is front to rear. But it doesn't negate what you said. I'm learning.

Quote:
No worries though. It's probably just a matter of preload, and in any event, if YOU like it, then that's ultimately all that matters, regardless of the opinion of a suspension geek.
Being a suspension geek is one of your finest qualities Roger :-). I've tweaked the suspension at least a little on every one of my bikes, springs and preload at a minimum, shocks replaced or serviced on most. I had to set sag on my GS too after I got my shocks, never gave it much thought. Just thought that's what you had to do, and I'm just getting around to it. My GS is magic on New England roads as a result of the careful adjustment if it. I like it when they are set up right. I really appreciate your thoughts and my education in this. There's always so much to learn.

N.
Old 03-20-2012, 12:34 PM
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Quote:
Originally Posted by PFFOG View Post
How I dealt with it was to cut the standard spanner wrench so there was no handle,, then I took an old cheap 3/8 drive socket and cut it so I just had the square section and welded it to the spanner end.

Then you just insert a ratchet and spin away, I can easily get over 1/2 turn per reposition, and to loosen, just flip it and put the ratchet in the other side if needed. It also worked well on a buddies track bike, as I just put a 2' extension on it and adjusted his from under the seat, even though the adjusters were on the bottom.
A photo would be priceless if you don't mind Richard. I want to make one.

N.
Old 03-20-2012, 12:35 PM
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No, not out of patience. And glad to help even on stuff not bought from me. I call it advertising, and hope that someone eventually does. Just make it easy on me and post up the 4 numbers summarized below (both sags, both ends). Yes, you neglected the leverage ratio, and thus it should have been off instead of right on, at the end. This just illustrates how hard it is to get accurate measurements. There are a ton of places where 1 or 2mm can creep in, and add up. I see it all the time, and still do it once in a while myself. I did about 20 setups yesterday, and needed to remeasure twice. My experience happens to let me pretty easily see/feel/detect when I may have slipped up (thank god) but I sure don't bat 1000 out of the box either.
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Old 03-20-2012, 12:48 PM
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Quote:
Originally Posted by roger albert View Post
No, not out of patience. And glad to help even on stuff not bought from me. I call it advertising, and hope that someone eventually does. Just make it easy on me and post up the 4 numbers summarized below (both sags, both ends). Yes, you neglected the leverage ratio, and thus it should have been off instead of right on, at the end. This just illustrates how hard it is to get accurate measurements. There are a ton of places where 1 or 2mm can creep in, and add up. I see it all the time, and still do it once in a while myself. I did about 20 setups yesterday, and needed to remeasure twice. My experience happens to let me pretty easily see/feel/detect when I may have slipped up (thank god) but I sure don't bat 1000 out of the box either.
You are very gracious Roger. Thank you very much.

Was my front measuring technique OK as described? Headed home shortly, will remeasure and report back in a few hours.

N.
Old 03-20-2012, 01:47 PM
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Be sure all the parts are back on the bike when taking these measurements. I see a picture of a stripped down bike.
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Old 03-20-2012, 01:57 PM
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Quote:
Originally Posted by Mrmerlin View Post
if the bikes falling into the turn then make a small spacer for the front shock,
it will go on the underside of the frame just in front of the fuel tank,
( this will effectively push the front end sliders down some, and restore the front to rear balance)
you can use fender washers try say 5mm to start with.
Fitting the rear para link if it raises the rear will make the bike turn easier and then it may go past easier and keep falling into the turn,
thats when you need to raise the front some,

NOTE this should not be confused with setting your sag
I probably have this wrong, but I believe that raising the rear ride height reduces trail on the front wheel - normally a desireable outcome on a bike made for stable cruising. I thought I saw somewhere on this forum that making this mod to the front shock will also act to reduce trail, - the fork pivot point is repositioned in the arc movement of the A-arm. Lengthening the front shock would be a double whammy if the rear has already been raised.
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Old 03-20-2012, 03:06 PM
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Good catch twodear.
You are right.
Mr Merlin is incorrect.
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Old 03-20-2012, 03:08 PM
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I probably have this wrong, but I believe that raising the rear ride height reduces trail on the front wheel - normally a desireable outcome on a bike made for stable cruising. I thought I saw somewhere on this forum that making this mod to the front shock will also act to reduce trail, - the fork pivot point is repositioned in the arc movement of the A-arm. Lengthening the front shock would be a double whammy if the rear has already been raised.


FWIW

the info i provided comes first hand in regards to replacing the front 19 inch dual sport wheel with a 17 in S wheel this effectively lowers the front end, or looked at another way raises the rear .
This mod was done to my 2001 R1150 GS
Anyway the rear wheel was also replaced with a 17 5.5 in S wheel and a 180/45 17 tire

End result was the front end was dropped from the wheel swap and the front end would fall into a turn it would keep on falling if it wasnt stopped in other words you had to pull the other end of the bar to keep the turn from tightening.
The solution was fitting a spacer of approximately 3/4 inch to the bottom side of the front upper shock mount.
This lifted the front end back to a more level stance and the front end would stop where you put it so the bike became very stable in the turns. after the spacer was inserted.
Since the OP is lifting the rear with a Para arm change, this could be an issue once things are back together.

Simply if the bike falls into the turn and wants to keep falling then the front end is too low compared to the rear wheel,

If on the other hand you have to fight the front end for it to turn then try lowering the front end or raising the rear.

Since your changing the rear height with the para arm this isnt the same thing as changing the suspension sag,
so I was pointing out that if you notice different handling issues this may something to consider and or experiment with.


Modifications came from here http://www.boxer-design.de/en/products.asp?motTyp=12

pictures here http://www.boxer-design.de/en/content.asp?ID=96
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Old 03-20-2012, 03:32 PM
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Quote:
Originally Posted by wswartzwel View Post
Be sure all the parts are back on the bike when taking these measurements. I see a picture of a stripped down bike.
They were back on when I checked it last, but thank you Bill. On my way out there to check them again.

N.
Old 03-20-2012, 03:42 PM
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Quote:
Originally Posted by roger albert View Post
No, not out of patience. And glad to help even on stuff not bought from me. I call it advertising, and hope that someone eventually does. Just make it easy on me and post up the 4 numbers summarized below (both sags, both ends). Yes, you neglected the leverage ratio, and thus it should have been off instead of right on, at the end. This just illustrates how hard it is to get accurate measurements. There are a ton of places where 1 or 2mm can creep in, and add up. I see it all the time, and still do it once in a while myself. I did about 20 setups yesterday, and needed to remeasure twice. My experience happens to let me pretty easily see/feel/detect when I may have slipped up (thank god) but I sure don't bat 1000 out of the box either.
OK, I have two sets of measurements, and a very interesting observation. For starters, I redid my marks, used very thin lines, made sure they were dead vertical, and we measured everything twice to see where we were. So I feel like these are as accurate as I can get, but unfortunately I introduced a big variable - I dialed out all of the damping in the shocks on both ends, and bounced them fairly vigorously to get them to settle as best I could on the springs. I think I just made this all uninteresting to discuss by doing that, but I think I have it set right now.

First-off, remeasuring sag where we were after last night's adjustments, with all the damping out:

Rear Front

Static 11mm (was 5mm) 27mm (was 29mm)

Laden 37mm (was 34mm) 43mm (was 35mm)

Yeah, these numbers are a lot different. Then just for fun, and to make sense out of this disparity between last night's number's and tonight's, before I adjusted the springs, I dialed in about 15 clicks of rebound in the rear and measured it again. It added 7mm to the laden sag numbers.


Then I took out the rebound again so the shock was totally slack, bounced everything, readjusted both ends, measured everything twice, etc.

Rear Front

Static 11mm 27mm

Laden 32mm 35mm


So, what did I learn?

Measure everything twice, as carefully and repeatably as you can.

Wear gloves and unload the rear of the bike before you go reefing on the adjusters. Your knuckles will thank you.

You can cheat and adjust the preload in the front by grabbing onto the spring itself and twisting it in the shock body. If you're lucky, as I was, the lockrings will twist with the shock, at least in the direction of adding preload.

Unload the shock of all damping and bounce it several times to get it to settle on the correct static and laden point of the SPRING, without the input of the fluid or pressure in the damping circuits. Roger pointed this out in an older post, it bears repeating.

But wait, there's more, for reference...

N.
Old 03-20-2012, 05:32 PM
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Shock datum

So these are the build sheets from Wilbers, just for fun.

Front


Rear


I measured the amount of preload on the springs currently as best I could, from the thin shim on top of the spring, to the top of the threaded area, just at the bottom edge of the cap at the shock top, and in both cases, I measured 10mm additional preload then what appears on the build sheets. Again, not CERTAIN that I'm measuring exactly what they measured, but it makes sense to me.

The spring rates are here too. I'm #230 soaking wet, probably #240 or more in my gear, ready to ride. What do you think Roger?

N.
Old 03-20-2012, 05:55 PM
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Ha,

I occasionally let this catch me out too. IF the damping is ballpark of correct, or a little light, it wont affect measurements much. If it's heavy, they it will be really hard to get good sag numbers, and they'll be artificially high (bike artificially low) just as you observed. When I set up, I bounce to see that damping is not going to skew my sag numbers, and loosen up preliminarily, if needed, and then grab sag numbers, and then adjust sag, and then come back and do damping.

>>>>>>> Rear Front

>>>Static 11mm 27mm

>>>Laden 32mm 35mm

That actually makes more sense, as Wilbers, though not always spot on, is usually much closer than you initially reported. I'd kick the tail up another mm or two, but what you have isn't bad, especially with the A-arm and para-lever mods you have.


Now, as for preload, I don't know quite what you mean about 10 more, but I'm pretty sure it's not what you think it is. Basically, you can't measure it from some point on the shock. Preload is simply free length of spring minus installed length of spring. Have nothing to do with any point on shock body really. Unless you have the preload backed off so spring could rattle around unloaded, and then measured again with whatever setting you ended up at, you dont' know the preload it has or had. I'm guessing you don't want to know badly enough to take them back off and do all of that. Wilbers is very probably right on what they put on their sheet.

But, you may know, as one of those spring numbers on each is is quite probably the _nominal_ free length. I'm not dead sure I've seen perfect repeatability in Wilbers' number system (more to do with their spring supplier than them) but that probably means your front is a ~5.5kg/mm (or ~55N) front with free length of 185mm. Similarly, the rear is likely a ~19.0kg/mm (or ~190N) rear with free length of 165mm. Note the shorter spring heavier rate and length and travel on the rear, with the long swingarm, and the converse on the front. Tells you a bit about suspension design AND weight distribution.

Assuming my decoding hypothesis is right (I never worry about the drivel printed on the spring, I just measure them) then the rear sounds about right, and the front a little soft. Softer than I use for my 150lb self. But that would be typical of Wilbers, who trend towards being on the soft side. Actually, the rear, which looks pretty darn good, is a bit less typical for them. You're in pretty good shape, and just have a front biased more towards compliance than control. Anyway, if you took those 'believed free lengths, minus the sheet-reported preload figures, and they come out to close to the current spring lengths (plus, or minus, however much you adjusted) then you'll know Wilbers was right on both their sheet and in what they delivered.

In a couple cases with with Wilbers, they've not been able to provide very fine increments in spring rates, so sometimes you end up a bit softer or firmer than target. Might be the case that the next front spring up that they had available was much too much, so you got one erring (if at all) on the low side.

I'd have preferred a bit more rate in the front, but it's a pretty good setup you can be happy with for most normal use.
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Old 03-20-2012, 08:03 PM
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