40mm forks re-sprung -- huge improvement

[nuevototem]

Hi to all,

 

Today I mesure the static sag.

 

I am on 82 kilograms = 180 pounds with all equipment.

 

Now with these settings:

 

Mazzocchi 40mm: SAE 10

EXTENSIÓN: position: 7 (MAX:16) (1 more than last time)

COMPRESSIÓN: position: 4 (MAX:16)

 

Sach-Boge

EXTENSIÓN: posición:21 (MAX:34) (1 more than last time)

COMPRESSIÓN: position: 10 (MAX:43) (bottle) (2 more than last time)

 

RESULTS:

 

REAR: 58mm (Ohlins recomends 25 to 40mm)*

FRONT: 47mm (Ohlins recomends 35 to 50mm)*

 

More info:

 

http://www.ohlins.com/pdf/07282-04.pdf

 

What do u think?

[Guest ratchethack]

And the consensus is that the stock springs are 0.70? Or are they 0.90?

Docc, I looked around for a suspension shop that could measure the rate, but wasn't able to find one. So I manually compressed them on my bench and compared 'em side by side to my new Wilbers .7 - 1.0 kg/mm progressive springs right out of the box. The stockers are significantly weaker right from the first few mm of compression. I estimate they're ~.6 kg/mm.

[Guest ratchethack]

Hi to all,

 

Today I mesure the static sag.

 

I am on 82 kilograms = 180 pounds with all equipment.

 

Now with these settings:

 

Mazzocchi 40mm: SAE 10

EXTENSIÓN: position: 7 (MAX:16) (1 more than last time)

COMPRESSIÓN: position: 4 (MAX:16)

 

Sach-Boge

EXTENSIÓN: posición:21 (MAX:34) (1 more than last time)

COMPRESSIÓN: position: 10 (MAX:43) (bottle) (2 more than last time)

 

RESULTS:

 

REAR: 58mm (Ohlins recomends 25 to 40mm)*

FRONT: 47mm (Ohlins recomends 35 to 50mm)*

 

More info:

 

http://www.ohlins.com/pdf/07282-04.pdf

 

What do u think? 

71806[/snapback]

Nuevo, my 40 mm Marz has different compression & rebound damping ranges, only 3 positions available each, so I can't comment on your damping settings. Best set this aside until you get proper sag settings IMHO. When undersprung, the tendency is to over-preload and over-damp in an attempt to compensate, which just starts you off down a bad road that gets worse and worse the further you ride.

 

You weigh the same as I do and your laden sag measurements are very close to what I had with stock springs. I hesitate to assume you're using stock fork spacers, but if so, and if you're looking for an opinion, I'd say you're more'n likely as far undersprung on both front and rear as I was (and still am on the rear). The guys above (Chris Beauchemin & Chris Jedi) and many others have found essentially the same thing. It looks like you're within Ohlins' acceptable laden sag range on the front. I would not assume that these ranges apply to the Marz fork. 47 mm laden sag on these forks MAY BE a little soft, even for non-racing "Road Geez" purposes - you see, it depends on how you've got your preload and unladen sag set up with your fork spacers. By my experience, I'd expect your unladen fork sag to be on the low side.

 

You didn't note your unladen sag measurements. Per posts above, this is as important as the laden sag IMHO, and I would advise you not to respring without understanding how to use preload to set unladen along with the laden sag. You'll not be able to achieve a proper match of spring rate to load without getting BOTH in the right range. The only way you'll achieve a proper match is to go with stiffer springs front & rear.

 

You had asked previously about 7.5 wt. fork oil. IMHO, either 7.5 wt. or 5 wt. would be preferrable to 10 wt. in the Marz 40 mm fork, but 125/150 fork CARTRIDGE FLUID (a somewhat different animal altogether) would be my first choice - at least for "Road Geez" purposes.

 

Good luck!

[dlaing]

Yah, what Ratchet said....

I will add that the Ohlins measurements are larger than what Traxxion, Computrack, LE, or RaceTech would recommend.

And I would start by backing off the compression damping and cranking up the rear pre-load untill you get a sag reading about 25mm.

Then let us know your laden and unladen sag measurements.

You are probably going to need to lengthen your fork spacer about 10-15mm.

But let us know all your sag measurements before you dig into the fork.

If the numbers are out of an acceptible range, you will want new springs.

But without doubt, just changing your preload will make a huge difference.

[nuevototem]

Hi dlaing, ratchethack & docc,

 

I will post all my measured numbers (left them at work).

 

ratchethack: You had asked previously about 7.5 wt. fork oil. IMHO, either 7.5 wt. or 5 wt. would be preferrable to 10 wt. in the Marz 40 mm fork, but 125/150 fork CARTRIDGE FLUID (a somewhat different animal altogether) would be my first choice - at least for "Road Geez" purposes.

 

Why you recomend the 125/150 fork CARTRIDGE FLUID? whats the diference? witch oil are u using?

 

Please can you confirm the settings we have to put on the suspensions to measure the sags? I mean do I have to put all the settings on full open to check that the springs are right for me?

 

Thanks!

[jsciullo]

Ok you skinny guys... what would be the recommended set up for someone around 230 lbs???

Thanks,

Jim

[Guest ratchethack]

Why you recomend the 125/150 fork CARTRIDGE FLUID? whats the diference? witch oil are u using?

 

Please can you confirm the settings we have to put on the suspensions to measure the sags? I mean do I have to put all the settings on full open to check that the springs are right for me?

 

Thanks!

Nuevo, FORK CARTRIDGE FLUID is a specialty oil that was developed specifically for the unique valving, anti-stiction, and anti-foaming requirements of cartridge forks. It's formulated and graded on an entirely different scale and has entirely different properties than FORK OIL, which uses the traditional SAE grading by weight (wt.).

 

Now some will no doubt say that it's splitting hairs, and that there's no real-world difference in operation between a 5 wt. FORK OIL and a 125/150 FORK CARTRIDGE FLUID. It might boil down to the equivalent of looking at the difference between dino and synthetic motor oil.

 

It makes sense to me that cartridge forks would benefit from a specialty oil due to the way they function. Suspension guys say that CARTRIDGE FLUID is overall much higher quality oil and lasts longer. I like the idea that it's formulated not to break down over time with the unique shearing forces the long-chain hydrocarb molecules are subjected to in a cartridge fork. Guys who race might have other reasons for preferring it (or not?). The cost difference is minor, so to me it's mostly a matter of preference. I think of it this way - I change it out every 10K miles. Why scrimp to save a few dollars? I'll go with the "good stuff" here and in my trans and bevel box...only the very best synthetic.

 

As far as damping settings when you're setting the sag, it doesn't make any difference, since damping only functions on a suspension when the suspension is in motion, and your sag will settle out in the same spot regardless of damping.

 

Hope this helps.

[Guest ratchethack]

Ok you skinny guys... what would be the recommended set up for someone around 230 lbs???

Thanks,

Jim

71947[/snapback]

Jim, this may open a hornet's nest, but here's my

 

The V11 is notoriously undersprung, both front and rear, for most riders over about 150 lb., IMHO. If you've got stock springs, you're no doubt riding around on something like the last 40% of available suspension travel or even less. Your stock suspension was designed for you to ride on ~70% of available suspension travel. The good news is that there's SO MUCH improvement to be had in making your suspension better that LOTS of things you can do will all be big improvements. You might think of it as a "target-rich environment". If you do a good job, it'll be a brand new world if you can get anywhere near the handling that your Guzzi is capable of. Yep, you can do this, do it very well, and you can get there many different ways.

 

There are many riders of your (ahem) gravitational achievements (and larger) who have improved their situation immeasurably with entirely new "racing" forks and new "racing" rear shock. Many specialty suspension shops cater to this kind of business and seem to do VERY well. I have no doubt that this is a very good way to go, and for some it's the best choice.

 

An alternative to the above is to have a qualified suspension shop re-spring and re-valve the fork cartridges and shock. It's less expensive than all-new gear, but IMHO, it's a bit hit-or-miss in terms of results. Again, many around these parts have gone this way and seem very pleased with the results. Others have not been as happy.

 

Speaking for myself, as a dedicated Road Geez (no land speed record aspirations, no budding GP racing career, and no interest whatsoever in chasing Hyperbike-mounted HyperSquids over the armco in the local mountains) my approach is a little different.

 

Now this is just me, but I believe you can get in the neighborhood of 90%+ of the real-world improvement in handling for the road that an all-new or re-sprung AND revalved suspension setup would provide. You do this by giving the suspension gear you've already got the first and likely only chance it's ever gonna get to operate as it was designed to operate with your weight. This is achieved only with a proper match of spring rate to load using properly matched springs and getting the preload settings right. The stock damping now has it's only chance of working properly.

 

The cost of new springs is somewhere between 5-10% of what you'll shell out for end-to-end "racing suspension". I don't know about you, but since I'm merely a Road Geez, and I don't use anything like racing tires, am at least aware enough to know that I don't have anything close to a chassis that could fully benefit from "bolt-on" racing tackle, and I'm not, in fact, racing...well, the stock suspension, properly sprung and preloaded, is plenty good enough for my purposes. I reckon only a few Pro's would be capable of riding beyond the limitations of my stock suspension on the roads I ride (limitations of the spine-frame chassis notwithstanding), and I ain't ever gonna be anywhere near the same league.

 

Some of the Forum regulars might have some suggestions on spring rates that will match your load requirements.

 

BAA, TJM, & YMMV

[dlaing]

Ok you skinny guys... what would be the recommended set up for someone around 230 lbs???

Thanks,

Jim

71947[/snapback]

Everyone has different preferences, but you would probably want about a 500 to 600#/inch shock spring and 1.00 to 1.10 Kg/mm fork springs.

You may even be in the right ballpark to try a HyperPro progressive spring on the rear shock.

[nuevototem]

Hi to all,

 

I have all the measured numbers!

 

I am on 82 kilograms = 180 pounds with all equipment.

 

SETTINGS:

 

Mazzocchi 40mm: SAE 10

EXTENSIÓN: position: 7 (MAX:16)

COMPRESSIÓN: position: 4 (MAX:16)

 

Sach-Boge

EXTENSIÓN: posición:21 (MAX:34)

COMPRESSIÓN: position: 10 (MAX:43) (bottle)

 

RESULTS:

 

Without rider:

Rear: 25mm (R1-R2) (Ohlins recommends 10 to 20mm)*

Front: 37mm (F1-F2) (Ohlins recommends 15 to 30mm)*

 

With rider:

Rear: 58mm (R1-R3) (Ohlins recommends 25 to 40mm)*

Front: 47mm (F1-F3) (Ohlins recommends 35 to 50mm)*

 

*) More info: http://www.ohlins.com/pdf/07282-04.pdf

 

What do you think I have to do with the rear and front suspension?

[Guest ratchethack]

Nuevo, now you've got the data to get yourself on track! May I first suggest that you let those with Ohlins suspensions use the Ohlins recommended numbers! IMHO, they provide no value to you.

 

Per previous post, compression and rebound damping are independent of springs and sag settings. You can set these aside until after the sag is set.

 

Let's assume your total available travel front and rear is 120 mm. (By my calculations, swingarm travel is closer to 124-128 mm including shock bumper compression, but let's just use equal round numbers F & R for rough calculations.)

 

Rule of thumb laden sag is 25-35% of total available travel. This is 30-42 mm.

For racing purposes, go closer to 25%.

Ror Road Geez purposes, go closer to 35%.

 

Rule of thumb unladen sag is 15-20%. This is 18-24 mm.

 

You could immediately benefit from more preload front and rear. You might take a first step and add preload to get laden sag at TARGET (see below). I suspect that you'd immediately get partially improved handling. However, your unladen sag numbers will then be substantially out of range on the low end, and your usable travel would still be considerably less than possible to achieve with stiffer springs.

 

IMHO you could substantially benefit from significantly stiffer springs in both the fork and shock. If you select the right springs, this would allow both laden and unladen sag numbers to be in acceptable ranges, and you'd experience a much more comfortable, plush, less-stiff ride, and you'll wonder how you ever tolerated so much brake dive. Sound counter-intuitive? Yep. But true.

 

May I suggest you decide before selecting springs what TARGET sag settings are best for the kind of riding you do. "Medium" TARGET sag settings from the rough numbers above might be:

 

Front & Rear - laden 36 mm, unladen 20 mm

 

Next, you need to select spring rates that are most likely to allow you to get as close as possible to your TARGET sag settings. Once you commit to springs and get 'em installed, it's simply a matter of adjusting preload until you're happy with how close to the TARGET sag settings you can get.

 

Have fun! May I also suggest getting as many opinions as necessary from many sources, and go with what makes most rational sense to YOU!

[nuevototem]

ratchethack:

 

"As far as damping settings when you're setting the sag, it doesn't make any difference, since damping only functions on a suspension when the suspension is in motion, and your sag will settle out in the same spot regardless of damping."

 

Hi, but when I change the compression and the extension of the forks and the shock the measured values changed! With a few clicks I can change the results of the laden and the unladen sag. Please can you explain this to me?

[Guest ratchethack]

Nuevo, as you stated it, this makes no sense to me whatsoever.

 

You are referring to compression and rebound (extension) DAMPING settings?! You might try fully backing off both settings but it shouldn't make any difference as long as you give the damping a second or so to settle down?!

 

Maybe there's another difference between the Marz 40 mm forks besides damping setting gradient? I doubt it...

 

You're not referring to preload adjustment of the shock, are you?

 

Stiction will tend to throw sag measurements off by as much as a few mm, but this has nothing to do with damping. It's a relatively small, but well-known consideration when setting-up. If you compress the fork beyond it's resting point and gently allow it to extend until it stops moving, stiction will hold it below it's proper sag point. Conversely, if you extend the fork beyond it's resting point and gently allow it to compress until it stops moving, stiction will hold it above it's proper sag point. Dave Laing and I did this when we measured his sag awhile back, and took a "half-way" measurement between the two to establish the measured sag point. Another way to defeat the stiction factor is to "bounce" the bike a bit. It should settle consistently within 1 mm of the same point.

[dlaing]

What you've got:

Without rider:

Rear: 25mm (R1-R2) (Ohlins recommends 10 to 20mm)*

Front: 37mm (F1-F2) (Ohlins recommends 15 to 30mm)*

With rider:

Rear: 58mm (R1-R3) (Ohlins recommends 25 to 40mm)*

Front: 47mm (F1-F3) (Ohlins recommends 35 to 50mm)*

Target:

Front & Rear - laden 36 mm, unladen 20 mm

 

 

Regarding the Rear:

if you add enough preload to decrease rear with rider to 36mm that would give you about 3mm without rider. This would improve things, but you would be much better off with a stiffer shock spring....maybe a 475# spring would be about right for your weight.

Ratchet is closer to your weight, so he may have a better clue. I have a 475# spring and it is still just a little light for my 210#+++ It is fine if I sit all the way forward, but if I slide to the back of my Corbin seat, it is too light for bumpy roads.

 

Regarding the Front:

If you add enough preload to decrease front with rider to 36mm, that would give you about 26mm without rider. Assuming your measurement is correct, you do NOT need a heavier spring in the front. I suspect either you forks are different than Ratchet's or you are measuring incorrectly.

 

(my measurements were off until Ratchet came over and helped!)

[Guest ratchethack]

Regarding the Front:

If you add enough preload to decrease front with rider to 36mm, that would give you about 26mm without rider. Assuming your measurement is correct, you do NOT need a heavier spring in the front. I suspect either you forks are different than Ratchet's or you are measuring incorrectly.

Dave, you might've missed the fact that Nuevo's not using an Ohlins fork, but a Marz 40 mm? He's also got a Sachs-Boge shock. Perhaps he latched onto Ohlins recommended numbers for lack of published Marz/Sachs-Boge recommendation numbers. I suggested the Ohlins numbers don't apply. There's no reason to expect that they could have any value here and may in fact be quite misleading. I sure wouldn't use 'em. But that's just me...

 

Per my post, 26 mm unladen fork sag would be out of the rule of thumb range by my calculations, and considerably off the TARGET 20 mm "medium" sag I used for illustration purposes.

 

A stiffer fork spring would allow much improved unladen sag, and improve handling very substantially IMHO. Since his situation is nearly identical to my own, I can speak from direct experience, 'cause I've BTDT.

 

Stiffer fork springs were among the most cost-effective of all the mod's I've done, and I've done quite a few...

 

BAA TJM, & YMMV