Fork spring recommendations

[Skeeve]

It is more than accurate enough to within a hundredth of an inch, but to within a thousandth it is only an estimate.

 

What the heck good is a plastic caliper that only measures to .010 good for? Making sure you've got the right sized fuse for your magnetic mine? No offense, but you can buy a 6" dial caliper that reads to the thou' for $15 at Harbor Freight; if that's too much, you can get an old-school machinist's vernier caliper for $12 from Enco & others. Why on earth are you bothering w/ that stupid plastic piece of... um, polymer - for?

 

Good point about paint thickness, that could reflect the difference.

 

Thanks. I can't take credit for it; it was part of the OP in the KLR forum where the link to a spring calc. formula turned up when I first went looking...

 

Do you really think spring material does not make a difference?

 

Yes, material makes a difference: that's why the spring calc formulas we're using all explicitly state "for use w/ steel springs only." Phosphor bronze, titanium, carbon-fiber: these all have different Young's Modulus values, & hence, yield different formulae. Apparently, due to the physics [don't ask me, I only work here], steel is steel is steel when it comes to making a spring: different steels may fracture of fail sooner, & others may sag or slacken in longer or shorter periods, but it's all same same wrt poundage ratings (resistance to deformation), all else being equal.

 

HyperCo boasts about how powdercoating is the ideal choice because it is thinner than paint

 

Yes, I read that too. I don't think the thickness of the protective coating is likely to have noticeable f/x when you're talking about springs in the 100s of #/in category [except in measuring them as we're now doing], but the fact that powdercoating provides a more flexible, contiguous, weather resistant protective layer than paint is certainly worthy of note: by possessing greater flexibility than true paint, powdercoating is less likely to develop points of failure [rust] down the road, which would weaken the spring & ultimately lead to material failure of the spring [cracking.]

 

But suspension springs were probably one of the first widespread uses of powdercoating, since they're small enough to fit in an oven & would benefit greatly from the superior weatherproofing P/C has to offer...

 

Ride on!

[Skeeve]

free length = 29.5 cm., or 11.614"

...

wire dia. = ~4.5 mm, or (as measured) .176"

(emphasis added)

 

Now that's just mean! (to quote James Coburn*, & using the original meaning of the word in English, ie: poor or stingy.)

& that's just pitiful...

 

Talk about bean counter engineering! How bad off does the factory have to be to choose inadequate components in order to literally save pennies! Unless Guzzi's accounting department ordered a lifetime supply of springs just once, there's no way they could have saved enough money to make a significant difference to the balance sheet**, & the cost difference of 5mm vs. 4.5mm wire to the spring manufacturer is probably only noticeable in ton lots! These things are even wimpier than the springs from my SV, which aren't suited to anyone over 70kg, and are fitted to a bike that's already at least 35kg lighter than the lightest v11 variant at that!

 

This should be added to a "New v11 Owner's FAQ" or something:

 

"The fork springs need replacement with new ones at least 20% heavier than stock if the bike is new & you're an average human male. The previous owner would have told you he already did this if he'd known about it. Go out today, not tomorrow, not next week, today & order some replacements. Best $100 you can spend on your Goose..."

 

 

* - Payback, in response to Mel Gibson's character shooting his luggage...

** - Due to Moto Guzzi's "boutique manufacturer" small production runs in the late 90s & early '0s.***

*** - Nice to see this changing, since under Piaggio's stewardship!

[Guest ratchethack]

What the heck good is a plastic caliper that only measures to .010 good for?

Not to be a picker of nits, but we ARE dealing in thicknesses of paint within .005-.010" here!

 

The problem with Dave's "caliper" is that it CAN'T measure .010" -- OR +/- .001".

 

It can only measure +/- .01". :!:

 

As I said once before, this is NOT a tool to use for measuring just about anything applicable to Guzzi's -- or anything with machine parts, for that matter.

 

It'd make a dandy sand-box toy f'er the local ankle-biters, tho. . .

(Talk about bean counter engineering! How bad off does the factory have to be to choose inadequate components in order to literally save pennies! Unless Guzzi's accounting department ordered a lifetime supply of springs just once, there's no way they could have saved enough money to make a significant difference to the balance sheet**, & the cost difference of 5mm vs. 4.5mm wire to the spring manufacturer is probably only noticeable in ton lots! These things are even wimpier than the springs from my SV, which aren't suited to anyone over 70kg, and are fitted to a bike that's already at least 35kg lighter than the lightest v11 variant at that!

I doubt if saving pennies has ever been the motivation. Guzzi isn't the only mfgr to've come up with the "strategy" of under-springing bikes to the point of limp-noodle, wallowing-sow road manners (however fleeting this point in time may've been amongst the often-checkered past and revolving door at the helm of the company). Who knows wot "brilliance" may've emanated from wot "new" marketing committee based on the fact (no doubt statistically verifiable!) that tire-kicking humpty-doofuses on showroom floors prefer soft, plushy suspension when they sit down on 'em over real-world road-worthy firmness?? I'm convinced that this is the way most Lead Wings are sold.

 

(emphasis added)

 

Now that's just mean! (to quote James Coburn*, & using the original meaning of the word in English, ie: poor or stingy.)

& that's just pitiful...

. . .

This should be added to a "New v11 Owner's FAQ" or something:

 

"The fork springs need replacement with new ones at least 20% heavier than stock if the bike is new & you're an average human male. The previous owner would have told you he already did this if he'd known about it. Go out today, not tomorrow, not next week, today & order some replacements. Best $100 you can spend on your Goose..."

 

 

* - Payback, in response to Mel Gibson's character shooting his luggage...

** - Due to Moto Guzzi's "boutique manufacturer" small production runs in the late 90s & early '0s.***

*** - Nice to see this changing, since under Piaggio's stewardship!

Skeeve, WRT these specific fork springs for the 040 Marz USD fork, I've been whistlin' this tune for years here on this Forum (see "How To" under "Fork Oil change" f'er just one example http://www.v11lemans.com/forums/index.php?...7960&st=0#). To my knowledge, there haven't been more than a handful of posters who've evidently understood it (or cared, or even noticed) -- either before or after I whinged on and on about it 8 or 10 different ways -- and took the appropriate action. Regardless o' where they gain the knowledge, without upgrading fork springs from the cheesy stock excuses for springs, there's a bit of a 900-lb. handling gorilla in the corner. . . You'd think that it'd be a little tough to ignore on the road, wouldn't you?

 

Y'can lead a parched horse to water. Beyond that, waddayagonna do?

[dlaing]

Not to be a picker of nits, but we ARE dealing in thicknesses of paint within .005-.010" here!

 

The problem with Dave's "caliper" is that it CAN'T measure .010" -- OR +/- .001".

 

It can only measure +/- .01". :!:

 

ONLY READ THE FOLLOWING IF REALLLLLLLY BORED...

Not to be a picker of nits here either, but the caliper is precision plastic that CAN measure 1.00" or 0.10" or 0.01" The plus or minus accuracy is untested, but is probably accurate to better than +/- .0025"

I can still eyeball and estimate easily to within a quarter of a .01" increment or .0025"

Combining my inaccuracy with the rulers, I suppose I could be off by as much as 0.005"

Calipers are alot like telescopes and microscopes. Just because it says it is 1000X does not mean that it is ten times better than 100X. Resolution is as important or more important than magnification. Not to say my Plastic Caliper is high rez, just that it is not worse than times the inaccuracy of a .001" caliper and it is probably better because of what I can eyeball.

If the ruler is used for comparison of a Sachs and a HyperCo spring, the accuracy is greater than if comparing against absolute true measurement.

If I had eyeballed the 0.44" and 0.42" measurements that I made of the spring "wire" thickness, I would have eyeballed them at 0.441" and 0.421" so in my opinion the spring rates would have been higher than my suprisingly high result.

My guess is that the error potential on the plastic ruler is to within a result of + or - 20 pounds. I think that is accurate enough to challenge the accuracy of the online spring calculator. But as you said, paint thickness can make a big difference in the outcome.

.01" results in over 50 pounds of different spring weight.

Of course if you believe Ratchet and think my caliper is accurate to plus or minus .01" than I could be off by plus or minus 50 pounds.

But of course Ratchet and I can't even measure the number of free coils the same way.

One of you should buy my Sachs shock with HyperCoil so you measure it

Or I can buy a better caliper and still goof the measurement

Measuring the coil width was a real pain, but the result there is less critical, but I am sure my technique resulted in greater inaccuracy than my caliper's inaccuracy.

So, I give up, because uness I chip the paint off, the measurements are useless.

And in less I buy a caliper that "Claims" to be accurate to .001 you won't believe my measurement.

[dlaing]

 

Yes, material makes a difference: that's why the spring calc formulas we're using all explicitly state "for use w/ steel springs only." Phosphor bronze, titanium, carbon-fiber: these all have different Young's Modulus values, & hence, yield different formulae. Apparently, due to the physics [don't ask me, I only work here], steel is steel is steel when it comes to making a spring: different steels may fracture of fail sooner, & others may sag or slacken in longer or shorter periods, but it's all same same wrt poundage ratings (resistance to deformation), all else being equal.

HyperCo says their springs are made of high tensile chrome silicon,

micro alloys, titanium, alloy steels and stainless.

I suspect my Hypercoils are made for a chrome silicon alloy steel.

It is significantly lighter than the Sachs spring.

Could it be thinner per spring rate?????

Is the Sachs spring powder coated?

[Skeeve]

...I can still eyeball and estimate easily to within a quarter of a .01" increment or .0025"

Combining my inaccuracy with the rulers, I suppose I could be off by as much as 0.005" ...

 

Generally speaking, it's accepted that accuracy cannot be greater than 1/2 a division. If your divisions only go to .01" [NB: thanks, Ratchet, for reminding me about significant digits... ], then no matter how well calibrated your eyeball, the rest of the world is only going to accept your measurements to +/- .005". This is the class of fit known as "coarse," & is sufficient for blacksmiths w/ hammers, files & hacksaws to turn out relatively functional copies of AK47s on the Pakistan/Afghan border.

 

Calipers are alot like telescopes and microscopes. Just because it says it is 1000X does not mean that it is ten times better than 100X. Resolution is as important or more important than magnification. Not to say my Plastic Caliper is high rez, just that it is not worse than times the inaccuracy of a .001" caliper and it is probably better because of what I can eyeball.

 

I do not want to start a p!ssing match here, but as you just stated: the key is resolution, and a pair of calipers that has 10x the resolution of another is, to all intents & purposes, 10x more valuable (better) than the other, provided they both cover the same range of measurements, etc.

 

So unless your needs for the caliper consist of mainly sorting nuts & bolts or other widgets to determine whether or not they belong in the SAE or metric bin, or organizing a pile of whatsits by 1/64", then please, shell out the )

 

But of course Ratchet and I can't even measure the number of free coils the same way.

 

Yeah, this worries me too. What is it w/ you two?

 

One of you should buy my Sachs shock with HyperCoil so you measure it

 

Actually, I'm more likely to shell out for your Sachs w/ the stock spring, since that will give me a spare shock to mount my own Hyper (not, as yet, ordered, but gonna,gotta,gettit! ) and can then be rapidly swapped out w/ minimal loss in riding time. All of which begs the question: are the Sachs stockers rebuildable?

 

Or I can buy a better caliper and still goof the measurement

 

Ah, but you'd be goofing it with fine accuracy, vs. coarse! A whole WORLD of difference, there!

 

So, I give up, because uness I chip the paint off, the measurements are useless.

And in less I buy a caliper that "Claims" to be accurate to .001 you won't believe my measurement.

 

Well, not exactly: the measurements can generate "ballpark figures," which have comparison value, ie: accurate measurement of a "known" spring like the Hypercoil unit you have generates a calculation of say, 500# for a nominal 475# spring, and an accurate measurement of the stock spring yields a calc'd. value of 450#, so we end up with a good guess that the stock spring is around 425# nominal, with the result that we now know the factory was adjusting the suspension for their test rider, the 45kg ex-jockey Giacomo Felloffadahorsey (who preferred a soft, roly-poly kind of ride, since that was what he was used to), instead of any kind of average rider. ;-)

 

And just so you know, I believe your measurements within their range of accuracy, which cannot be less than 1/2 the smallest division. It's just that we're in a realm where we need a higher level of accuracy than your measurement tools can provide. Think of it like the difference in visualization offered by Muybridge's trip-wire cameras vs. Edgerton's invention of the stroboscope. A world of difference, there.

 

Trust me, you'll never regret the money you spent on a .001" (or .02mm, if your preference is for metric) -graduated dial caliper [preferably, steel, altho' I've heard the fiberglas models that have come out lately are decent enough.] I know that I haven't had a month go by since I got my first one that I haven't really wished for it for some reason or another, even when I'm in a long dryspell between puttering about on the lathe. Yes, when I need precision I reach for a micrometer, but for most occasions, my dial calipers are the measurement tool of 1st resort.

 

Remember when you were a little boy, and first got ahold of a magnifying glass, & spent days looking at everything UP CLOSE & going around burning ants & stuff? It's like that...

 

Ride on!

[Skeeve]

I doubt if saving pennies has ever been the motivation. Guzzi isn't the only mfgr to've come up with the "strategy" of under-springing bikes to the point of limp-noodle, wallowing-sow road manners (however fleeting this point in time may've been amongst the often-checkered past and revolving door at the helm of the company). Who knows wot "brilliance" may've emanated from wot "new" marketing committee based on the fact (no doubt statistically verifiable!) that tire-kicking humpty-doofuses on showroom floors prefer soft, plushy suspension when they sit down on 'em over real-world road-worthy firmness?? I'm convinced that this is the way most Lead Wings are sold. <_>

 

In all fairness, G'wings & other full-up tourers are perfectly plush for the superslab, which is their intended environment. The vast majority of their riders do not realize that they are dangerously undersprung for anything approaching normal motorcycling maneuvers...

 

Skeeve, WRT these specific fork springs for the 040 Marz USD fork, I've been whistlin' this tune for years here on this Forum... To my knowledge, there haven't been more than a handful of posters who've evidently understood it (or cared, or even noticed) -- either before or after I whinged on and on about it 8 or 10 different ways -- and took the appropriate action. Regardless o' where they gain the knowledge, without upgrading fork springs from the cheesy stock excuses for springs, there's a bit of a 900-lb. handling gorilla in the corner. . . You'd think that it'd be a little tough to ignore on the road, wouldn't you?

 

Yes, you have been singing this tune for a long while. That 900# gorilla? Well, quite frankly, I don't claim to be a good enough rider to know when handling flaws are the bike's purview or my own lack of skill. [That's me, humble to a fault! ] so I think a lot of riders out there may just not be aware of how much better it can be. If all you've ever been fed is Purina motorcycle chow, how are you to know that there's filet mignotorcycle to be had for the asking? And the last bit is the "do I gotta?" factor, as in "if I can crank up the preload enough to make it handle kinda sorta O.K., I'll live w/ the nasty jolts going over freeway expansion joints if that means I don't have to disassemble the front end of my motorcycle to replace the cr@p stock springs..."

 

And btw, at least one pair of ears your singing fell on isn't deaf; all I've got to do now is install the new fork springs I bought.

So there!

 

[Guest ratchethack]

. . .I think a lot of riders out there may just not be aware of how much better it can be. If all you've ever been fed is Purina motorcycle chow, how are you to know that there's filet mignotorcycle to be had for the asking? And the last bit is the "do I gotta?" factor, as in "if I can crank up the preload enough to make it handle kinda sorta O.K., I'll live w/ the nasty jolts going over freeway expansion joints if that means I don't have to disassemble the front end of my motorcycle to replace the cr@p stock springs..."

I reckon ignorance is bliss. . .Throw in a big slug o' laziness and you've got a perfect cocktail for handling mediocrity on a motorcycle capable of (IMHO) very good road manners. It's not only unfortunate, it's just plain sad, and it can also be dangerous. There are so many good write-ups on suspension setup out there in "the information age" -- yet it's amazing to me that as far as I can tell, less attention is paid to it today (if possible) than it was decades ago.

And btw, at least one pair of ears your singing fell on isn't deaf; all I've got to do now is install the new fork springs I bought.

So there!

 

Skeeve, I, for one, would be interested in your setup results and before & after handling analysis.

[dlaing]

 

Well, not exactly: the measurements can generate "ballpark figures," which have comparison value, ie: accurate measurement of a "known" spring like the Hypercoil unit you have generates a calculation of say, 500# for a nominal 475# spring, and an accurate measurement of the stock spring yields a calc'd. value of 450#, so we end up with a good guess that the stock spring is around 425# nominal, with the result that we now know the factory was adjusting the suspension for their test rider, the 45kg ex-jockey Giacomo Felloffadahorsey (who preferred a soft, roly-poly kind of ride, since that was what he was used to), instead of any kind of average rider. ;-)

 

Exactly! and the point I am trying to make is that the Sachs spring reads to be firmer than the 475# HyperCo spring, despite my sag measurements indicating that the HyperCo spring is firmer than the Sachs spring.

And both calculated measurements show a much firmer spring than what they are in reallity.

My measurements may not be accurate enough to determine the spring rate to within plus or minus 15# but they are accurate enough to within maybe plus or minus 30#

So, to me this throws up a red flag about the accuracy of the calculator.

But if we take Ratchet's measurements and subtract 50# because of the paint, that would put us at about 450# which would match up pretty well with my sag measurements. So, maybe the calculator is right and my caliper is off by a full dial increment When I measured coils the preload ring was backed as far off as possible, but maybe it is still bound enough that I mis-read the free coil count. And the diameter was just plain tricky to measure.

So Ratchet is probably correct for once, and I am wrong

Or our springs are different!!!

[Guest ratchethack]

. . .When I measured coils the preload ring was backed as far off as possible, but maybe it is still bound enough that I mis-read the free coil count. And the diameter was just plain tricky to measure.

So Ratchet is probably correct for once, and I am wrong

Or our springs are different!!!

Dave, our Sachs-Boge springs are the same. It appears that you've mis-counted coils.

 

FYI - here are the first 3 sentences at the link for the GuzziTech spring rate calculator here.

 

If you have ever wanted to be able to determin what strength spring is on you rear shock you can use this information to help you figure it out.

You'll need to be able to measure the spring by itself. That means it has to be removed from the shock.

 

Then Mike Tiberio explains further down the page:

 

Do not count the coil at each end that is flatened and really used for seating. starting where the spring "takes off" from the base coil, I count full coils from this point on, and then do my best guess as to fraction of coil before returning to the base coil at the other end. Basicly once the free coils touch the base coil, the spring is done.

[dlaing]

Yah, I suppose there could be a half a coil wound up between minimal pre-load and no-preload.

There is NO WAY (short of $100) that I am pulling that spring out.

It was a major pain to get the one out that was replaced by the Hypercoil.

Ratchet's measurement is definately more accurate. I think the paint is the only problem in the calculation.

But I still think the HyperCoil does not fit the calculator model.

[docc]

The Ohlins springs are a lot shorter ( 9 5/8") and only 0.007" bigger in diameter.

 

I wonder if they can still be made to fit . . .

 

 

Nerts, Dave was right. The Ohlins springs won't go in the Marz forks.

 

I suppose I'll change the oil ( the crap that came out is nasty) and try to set my 'air spring' like a good boy.

 

I'm pretty sure I can change the sprinngs without taking the forks off the bike, so I'll have to source some springs and come back to it later.

[Guest ratchethack]

Nerts, Dave was right. The Ohlins springs won't go in the Marz forks.

 

I suppose I'll change the oil ( the crap that came out is nasty) and try to set my 'air spring' like a good boy.

 

I'm pretty sure I can change the sprinngs without taking the forks off the bike, so I'll have to source some springs and come back to it later.

So Docc -- you mean to say that + .007" dia. over stock wouldn't fit inside the stanchions?!

 

Yep, you can easily enough change out springs in less than 15 min. without taking the forks off the bike.

 

Keep us in the loop, & happy spring hunting.

[docc]

0.007" assuming the measurements were all good. I didn't take time to remeasure.

 

I didn't like the Maxima 5wt oil I used. It was clear and colorless. Not hardly as interesting as the blue Silkolene I've used before. I'm looking forward to trying the synthetics. Are they more compliant?

 

I was surprised that the volume to set the 100 mm luftkammer varied from 355 ml to 300 ml from right to left. Made me feel like I'd screwed something up.

 

Before I'd used the volume measure ( to +/- 0.1 mL). I must have had much less air spring. Should that make the forks less harsh now ( with more air spring)?

[dlaing]

Nerts, Dave was right. The Ohlins springs won't go in the Marz forks.

Judging by the measurements, I think I was Wrong and the Ohlins springs would fit fine with longer spacers.

I would do what Ratchet said and just pull the springs.