Fork woes

[docc]

Having upgraded the rear shock on the Sport to the Ohlins I moved to respring the front as well. Traxxion Dynamics recommended 1.0 kg/mm straight rate springs 1.35"x10.6" with 120mm spacer for my 185 pound riding weight. (Marzocchi spring: 1.37"x11.6")

The ride is improved and sag is respectable. With 3/4 tank of fuel: 23mm static/37mm laden.

1)There is still a good bit of initial dive in sudden braking which I thought would be much improved going from 0.65 springs to 1.0. (Although the TD springs come up 0.85 on the "calculator"). Perhaps a stiffer spring is in order?

2)Worst of all, jouncing the front sounds like a squeeky swingset. TD suggested there should be a washer between the spring and spacer. My forks didn't ever have one and I'm not sure I can see how that would change the squeel. The surface of the new spring is quite nodular, or rough, compared to the original which is smooth. I wonder if springs from another source would be 'smoother' and won't squeek?

TD offered to send me some 1.1 springs to try. They have been very cooperative and helpful. Yet, I do hate taking the forks apart again and again.

[Guest drknow]

Having upgraded the rear shock on the Sport to the Ohlins I moved to respring the front as well. Traxxion Dynamics recommended 1.0 kG/mm straight rate springs 1.35"x10.6" with 120mm spacer for my 185 pound riding weight. (Marzocchi spring: 1.37"x11.6")

 

The ride is improved and sag is respectable. With 3/4 tank of fuel: 23mm static/37mm laden.

 

1)There is still a good bit of initial dive in sudden braking which I thought would be much improved going from 0.65 springs to 1.0. (Although the TD springs come up 0.85 on the "calculator"). Perhaps a stiffer spring is in order?

 

2)Worst of all, jouncing the front sounds like a squeeky swingset. TD suggested there should be a washer between the spring and spacer. My forks didn't ever have one and I'm not sure I can see how that would change the squeel. The surface of the new spring is quite nodular, or rough, compared to the original which is smooth. I wonder if springs from another source would be 'smoother' and won't squeek?

 

TD offered to send me some 1.1 springs to try. They have been very cooperative and helpful. Yet, I do hate taking the forks apart again and again.

 

Not so sure you'll need more spring, but you'll need a heap of compression damping to keep that thing from diving like a U-boat at the sight of a sub-killer. Have you adjusted your forks compression damping yet? I'd crank that thing to 1-click or a 1/4 or a turn off of all the way in and see how if feels.

 

dk

[Guest ratchethack]

Docc, you've been thru a bit of a wringer with the forks, haven't you??

 

The good news is that you seem to've made great progress!

 

IIRC, you solved an unseated cartridge rod assembly and wound up with greatly improved sags. I presume handling has improved greatly. You can't be disappointed with this, my friend!

 

WRT your comments on fork dive, have you measured the amount of actual fork travel you're getting via the ol' zip-tie method? This will give you an "index" to shoot for whilst setting the air gap. By incrementally decreasing the air gap, you can increase resistance to dive. I've set my air gap so that by howling the front tire with the big brembo's while hitting a speed bump, I get 115 mm fork travel out of the available 120 mm. This works well for me at 100 mm Luftkammer (air gap). In my case, I found that all the objectionable previous fork dive with the stock springs became a distant memory. O' course, YMMV.

 

I don't recall any kind of washer separating springs from spacers in the Marz 040 fork. FWIW, the drawing in my Service Manual doesn't show one, and the separate photo of disassembled nut, spring retainer, spacer, spring, and "support washer" (goes under spring) on the cartridge rod, doesn't show one either.

 

FWIW, I can see how not having such a thing could cause your squeak/scrape symptoms under various spring and spacer diameter scenarios -- particularly if your spacers were not cut square. I can tell you that I've cut my own spacers from PVC that aren't the same ID or OD as the stock spacers, and I distinctly recall that the PVC spacers sit in the top of the spring retainers directly under the blue anodized nuts differently than the stock ones due to their smaller diameter than stock. Neither the old nor the new spacers I cut -- or the springs -- make any noise wotsoever.

 

Replacing springs is again a matter of 10-15 min. tops. No need wotsoever to dismantle the forks.

 

Since we weigh the same and have the same forks, by my experience I'd be hesitant to go for stiffer springs, unless you're after track-oriented sags. o' course, should you do this, you will loose the "respectable" (your word) sags you have now in favor of even "tighter" laden to unladen numbers, and likely have to decrease preload with shorter spacers to get the new sags back in range.

 

BAA, TJM, & YMMV

[Tom M]

Doc,

Did you remember to put the fork oil in? Sorry...

 

I agree with RH that the 1.1 springs would be too stiff for you. Better to crank up the compression damping as Dr K suggested. A little more preload might not hurt either.

 

TD stamps the spring rate on the end of their springs. If you suspect they sent you the wrong ones look for for the stampings if you pull the springs again. My 1.1 springs came in a box marked 1.0 on the outside so I called them and they told me to check the stampings. Springs were right, box was wrong.

 

IIRC my 40mm 'zokes didn't have the washer between the spring and spacer either, but I've seen one in other forks. It wasn't just a flat metal washer, it was plastic with a lip in the center on both sides to keep the spacers concentric with the springs, and it kept the end of the spring from rubbing on the damping rod.

 

FWIW the 43mm 'zokes manual shows the spacers on the bottom, springs on top. Maybe it wouldn't hurt to try them that way and see if it helps your noise.

 

It's strange that you're having these problems when my installation went so smoothly. The only other TD spring user that I know of besides me was Guzzijon who, like me, had an '02. I wonder if the 2000 year forks are different than the 02's? If you can't get the TD's sorted Todd at Guzzitech has a new line of fork springs available that are "shot-peened for strength and durability and then polished to reduce friction and eliminate fork oil contamination."

http://www.guzzitech.com/store/HyperPro-FS.html

[docc]

I would think it could be the spacers are out of square, but the beautiful counterbored aluminum spacers that TD sent did it too.

I'm thinking more and more it's the nodular surface of the wire material and the ribbed inside of the fork housing. Maybe polishing the spring surface would do it.

I've asked Todd at GuzziTech for his input regarding the Hyperpro product. I really didn't think I wanted a 'rising rate' spring, but (obviously) what do I know?

I left the oil in the forks that I had changed during the unseated cartridge debacle. Looking at Peter Verdone's charts I'm sure I could do better at choosing oils. This "centistokes@40 degrees centigrade" looks like a remarkable tool for fine tuning. "Thicker" for compression and lighter for rebound, ya think?

I'm vague ( does it show ) on the luftkammer. I set mine to 100mm with the froks in the vice. Can it be set in situ ( with the forks on the bike)? With the spring and spacers in place, forks fully compressed?

[Dan M]

 

IIRC my 40mm 'zokes didn't have the washer between the spring and spacer either, but I've seen one in other forks. It wasn't just a flat metal washer, it was plastic with a lip in the center on both sides to keep the spacers concentric with the springs, and it kept the end of the spring from rubbing on the damping rod.

 

http://www.guzzitech.com/store/HyperPro-FS.html

 

Hard to imagine how a spacer will change a squeak.

 

The 02 fork has more range of damping adjustment, don't know if there are other differences. I don't have much dive trouble with the Wilbers springs and 100mm air gap. (or "luftkammer" as Ratch so much likes to say) I did have to increase the spacer size considerably to get proper sags and I keep the compression damping closer to the low (soft) end of the range.

 

This month's Motorcycle Consumer News has a good article on suspension set up. Nothing that hasn't been covered by the "technical collective" here but it is good info and all in one place.

[Guest ratchethack]

I left the oil in the forks that I had changed during the unseated cartridge debacle. Looking at Peter Verdone's charts I'm sure I could do better at choosing oils. This "centistokes@40 degrees centigrade" looks like a remarkable tool for fine tuning. "Thicker" for compression and lighter for rebound, ya think?

Docc, per "Best Practices" in setting up, IMHO best get basics out o' the way first. Sags (done in your case) and Luftkammer should be set with no damping at all to begin with. O' course there are probably more opinions on this than there are riders. . . YMMV. The way I've come to think of this, damping is simply fine tuning. Sags and Luftkammer are the "foundation" that you build your damping settings on.

 

I'm vague ( does it show ) on the luftkammer. I set mine to 100mm with the froks in the vice. Can it be set in situ ( with the forks on the bike)? With the spring and spacers in place, forks fully compressed?

Luftkammer can be set in situ (gotta like those medical terms too ) with springs and spacers out, fork blocked up as high as it goes. Measure the height of the oil (or cartridge fluid as the case may be) at the SIDE of the fork -- that is, the point at which the air gap measurement is exactly halfway between the gap at the front and the gap at the back of the fork stanchion.

 

If you put some miles on the fork since you set the air gap in the vise, I'd be a little surprised if you didn't find the level low (that is, the Luftkammer HIGH) on the rebound side, just because this is wot I've found -- but NOT every time! IMHO It's a good thing to check every time you're in there.

 

BTW -- One o' the great advantages of Wilbers fork springs is that you get to say, Luftkammer.

 

It's nearly as fun as saying Ausgezeichnet!

[docc]

I'm looking forward to simply trying a smoother spring surface.

 

I'm sure I've drug some fluid out of the forks everytime I pull a spring out. Next time in I'll recheck the luftkammer and reset. TD spoke to me about the 'WD40 cap measure'. Dan equated this with about 10mm height and the point at which most of us could tell a difference.

 

I haven't yet quantified the WD40 cap measure. I'm not sure I have one of those caps . . .

[dlaing]

I'm sure I've drug some fluid out of the forks everytime I pull a spring out.

Apparently the oil level drops because it does not appear to be possible to get oil level correct without riding it to pump the air out of the cavities.

Maybe the noise will go away when the oil level is corrected.

I suggested a method of setting the oil level before changing it and then replacing with the identical amount of oil, but the method was poo-poo'd by Herr Ratchet.

In your case it should be easy to just top it up, ala method Ratchét.

 

Did you verify that the diameter of the springs was identical?

As for the spring calculator, I have my doubts.

Your sag numbers appear to verify that they are about 1.0KG/mm springs...of course weight distribution can throw the estimate off.

I am curious what your sag was with the OEM springs.

 

As for the Blue nuts, the stock setting on the early V11's Marzocchi's blue nuts is 22 mm.

If this is off, it effects the seating of the damping adjusters, and far as I can guess, might cause NOISE.

[docc]

Certainly possible that the oil levels have dropped and are too low. I guess the spacers and springs have to come out to recheck and correct the oil levels. If the air gap is too big it would help explain why the dive seems little better than the stock springs when the forks were overfilled.

 

The Marz springs are 1.37" and the TD are 1.35". ( and 1" shorter than the stock springs).

 

The original sag was 39mm. I increased the spacer length from 109mm to 118mm to get a laden sag of 30mm. The higher ride height concerned me as I didn't want any increased rear weight bias so I dropped the triple trees 9mm. (I've left them there for now.)

 

I couldn't find that 22mm blue nut setting anywhere. Is that 22mm from the top of the blue nut to the top of the threaded cartridge rod?

 

I tried emailing Todd at Guzzitech but haven't heard back on the polished Hyperpro spring. Again, I didn't think I wanted a rising rate spring. I know it's been debated here before, but I missed the pros and cons.

[dlaing]

I couldn't find that 22mm blue nut setting anywhere. Is that 22mm from the top of the blue nut to the top of the threaded cartridge rod?

I could not find it in the owner's manual nor the workshop manual, but I seem to recall reading it in the workshop manual

But it is in the forum

http://www.v11lemans.com/forums/index.php?showtopic=10281

and other threads.

I think you are correct that it is 22mm from top of the blue nut to the top of the threaded rod, and thus the threaded rod is threaded 22mm into the top cap.

But you might wait for Ratchet or someone to confirm, as my memory is foggy and I could not confirm from the manual.

[docc]

Reading the TD instruction it is emphasized that the retaining ( blue) nut must be threaded on far enough that the cap then bottoms or shoulders fully before moving the blue retaining nut back out to lock the cap.

 

It makes sense that if the cap is prevented from shouldering then the adjuster rods will not be seated.

 

I have renewed my hope that my forks are just low on oil. Must ride this am, but I'll check levels this afternoon.

 

One can hope!

 

BTW, which was the thread with the debate on 'progressive' vs straight rate springs?

[Guest ratchethack]

Reading the TD instruction it is emphasized that the retaining ( blue) nut must be threaded on far enough that the cap then bottoms or shoulders fully before moving the blue retaining nut back out to lock the cap.

 

It makes sense that if the cap is prevented from shouldering then the adjuster rods will not be seated.

Docc, the Traxxion Dynamics instructions may well be correct, and I wouldn't say otherwise. But I've always been successful in setting the blue nuts as Dave mentioned above to the exact position they came from Mandello, that being 22 mm from the end of the cartridge rod ass'y, with the counterbored end of the blue nuts on the bottom (you can't even get them close if they're upside down).

 

By my experience, I distinctly recall that this is NOT the same position as would be had with fork caps bottomed, though it is within a mm or 2, IIRC.

 

It was only years after I had been re-setting them to 22 mm many times that I was able to verify by the experience of others (on this Forum) wot happens when you set them to OTHER than 22 mm. That is, of course, that you lose all adjustability on compression and rebound settings.

 

By my experience, the effect of seating the caps fully would be UNKNOWN -- could be none, could be something different.

BTW, which was the thread with the debate on 'progressive' vs straight rate springs?

Coupla comments:

 

This one's raged in bars and around rally campfires ever since the (relatively) recent introduction of progressive springs. Old-time race guys tend to insist that progressively wound springs are Satan's own spawn, suitable only for wimps and little old ladies riding scooters to church on Sunday. Why? "They coil bind!" is the usual grossly oversimplified and poorly informed response, (as if this were necessarily "a bad thing") -- though since they're designed to coil bind , and this is wot gives them their progressive action, this would seem to be a completely irrational condemnation! The Old School thinking of progressive springs as Beelzebub's Binders also runs counter to current Sport Bike OEM and racing trends in recent years, which have both evidenced a widespread shift toward progressive springs in forks, following on the heels of the trend toward rising rate linked rear suspensions, which seems to've preceded acceptance of progressive springs in forks by many years, perhaps as the lag time for tooling and procedures for manufacturing progressive springs of different rates gets caught up, which still seems to be a ways behind that of straight rate springs, at least in the hard-scrabble cottage industry that typifies aftermarket motorcycle suspension components. Of course, rising rate suspension is not possible to achieve with straight rate springs without a rising rate linkage, and there's no option for this with telescopic forks.

 

The general advantage IMHO is that progressive rate springs provide a wider range of capability -- both in terms of riding weight, or load carrying capacity, and in terms of handling the variable terrain one typically encounters on the road (as opposed to the more carefully controlled and predictable surface of tracks), thereby retaining correct chassis geometry over a wider range of variance of both than possible with straight rate springs. In other words, the theory (borne out on the road IMHO) is that progressives make suspension work better with lots more load and road variables without having to fiddle around as much with preload and damping to achieve desired results. I tend to do lots of fiddling up front, then prefer to confidently leave it alone once dialed-in, though I still tend to go on fine-tuning damping long-term.

 

My own personal take, from having installed progressive fork springs on 3 bikes, including the Guzzi, comparing them back to back with straight rate springs many times over many years, is that I prefer progressives for the kinds of riding I do -- as long as I can get a set with the rate correctly matched!

 

I must stay that in the grand scheme of things, the progressive vs. straight rate argument is really a minor consideration compared to getting sags correct with the correct overall rate to start with! The call here is actually pretty close to a toss-up for most riders, IMHO, and hardly seems worth all the fuss. With air springs being current industry standard in forks, you get a nice progressive action on the fork regardless, though the rising rate effect of the air spring is only realized at the extreme compression end of fork stroke, and with progresive springs, you get a MILD rising rate throughout the entire fork stroke. If you look at the rate vs. travel graphs posted previously, the lines described by straight rate and progressives aren't all that different, and it's really a matter of some subtlety in the long run.

 

NOTE: Lest anyone misinterpret anything I've said here (as has happened so many times it seems in all the previous discussion of this!) I am NOT saying that one type of spring is "better" than another, nor would I, nor have I ever suggested such a thing for any person under any particular circumstances, and I've never made the slightest suggestion or inference of this as if I were some kind of authority on the subject, which I most certainly am NOT! I've simply shared my own choices and attempted to explain the reasoning behind my choices based on my own understanding gained from many years of study and real-world experience on my own bikes.

 

Think of it this way. Either choice amounts to a set of compromises anyway, and there's no perfection to be had here. You picks y'er own poison and lives with it. I don't know anyone who ever fretted about the choice and wound up with progressives (who also got their overall rate properly matched to riding load!) who hasn't been 100% pleased with the results, but o' course, that's just me.

[dlaing]

I agree with Ratchet on the Pros of progressives.

And I really want to try a HyperPro shock spring.

But there are negatives:

1) spring choice. Although progressives are more forgiving, there are fewer choices, so a progressive might be a bad choice for a 90# rider and for a 350# rider. But your average 180-210 pound rider is probably within ideal range of the spring,

2) matching damping with spring rate. it is more challenging to get right.

With a progressive spring there will be a tendency for too much rebound damping on small bumps and not enough on big bumps.

I don't understand how compression damping behaves, but Jim Lindemann of Lindemann Engineering told me that getting it set right was a problem. My guess is that you would have to reduce high speed damping, but that would compromise stability in small sharp bumps.

3)If your road conditions are predictable and not very variable with no potholes, speedbumps or dips, and you never ride two up, a straight rate spring is much easier to tune and will suit your needs best.

[docc]

Thanks for the replies, guys.

 

I guess I'll open the fork and take another look at the oil level.

 

I am considering polishing the outside of the spring with some 600 then 1500 grit paper. Any thoughts?