Marz Fork Springs

[Guest ratchethack]

What is the reason for the new assertion of incompatability?

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I don't know exactly, and evidently it's not a "new assertion". Jason was pretty sheepish about it. I didn't want to embarrass him by nailing him to the wall for publishing what he acknowledged was wrong, and had been on GuzziTech for over a year. I didn't ask. You might give him a call for the details if you're interested.

[dlaing]

Dave, Jason at Moto International had incorrectly posted 18 months ago on GuzziTech that FZ1 springs fit the Marz forks.  When I spoke with Jason a few months back, he confessed that this turns out not to be the case.  I suggested that he update GuzziTech, which he finally got around to doing.  See:

 

01.14.04 - V11S Fork Spring Upgrade Info by Jason of M.I.  ***Revised***

 

I would expect the Hyperpro to be softer in the first few inches of travel than a comparable straight rate spring - why wouldn't you?  What I wouldn't expect is that the Hyperpro graphs as close to the stock spring as this graph shows.  I do like the differences I see, however.

I do too. What I was suprised about was how the HyperPro spring was so close to the OE spring, and how it was more likely to bottom out. Like you said, we don't know the details, but the sales guy you talked to would not give the details either. I believe I would want a heavier spring than the one they show there. I think my sag would be 2.25 inches with the hyperpro that they show. I suppose they have a good return policy, but it would be a lot of work to go through to find the sag is wrong. I know that if I get a 1.0 - 1.1 I will be very close to the right sag.

But OK, I can add preload to get the sag right, but adding pre-load is a pain it the butt and if I give it too much, is that bad? I don't understand why there is such a thing as to much spring pre-load, I guess you could get spring binding

Maybe I am doing something wrong, but I had to manually compress the spring while my girlfriend turned the bolt. Is there a safe way to lock the rod so that you may tighten the bolt?

Now Gents, leave us not fly off the handle here.   There appears to be potential for unfair and misleading aspects to this graph.  Brian, the data accompanying the graph doesn't include part numbers, so we don't know which of the many available springs - and rates -  from Hyperpro and Traxxion Dynamics are being compared.

I think we can safely assume that the Traxxion is a 1.0 Kg/mm.

I would call the Hyperpro and the stock a 0.78/1.43 or more likely a 0.75/1.5 as they probably standardized the spring, and we are not seeing every increment of measurement.

Assuming I am correct,(who knows, they could be 0.70/1.45 ) than I would have liked to order a 0.85/1.6.

For the rear, I want a #500 or #550 straight rate.

What might this translate to in HyperPro? a #450/700 might be about right.

I submit that without knowing exactly which of the many available springs from each mfgr. are being compared, the graph is not entirely useless, but pretty nearly so.  For example, I don't think it's at all fair to make a blanket statement that Hyperpro springs are "softer than stock", unless we know what we're looking at. 

You are 100% correct.

What bugs me is that the sales guy won't share the data with you....either that or he just does not have the data. Perhaps with every sale they ask, sport or street, and how heavy you are and then send the sales slip to the guru that makes the guesstimate.

Are they taking into consideration that we are riding a #500+ sport bike?

I'm not defending any spring here (I ain't got no dog in this fight to defend yet!)   However, by this graph, the Traxxion D. spring appears to be LESS progressive than the stock FZ1 spring, AND it has an significantly lower (end to end) rate than the stock spring tested.  Again, since we don't know which springs we're looking at, I'd be unfair in saying that TD springs are softer than FZ1 stock springs.

The Traxxion is not just LESS progressive, it is non-progressive and is a straight rate spring.

It is fair to say that the Traxxion 1.0 will bottom out more easily than the stock FZ1 and the supplied HyperPros springs.

I would also point out that we have no kind of comparison data whatsoever here that would graph the stock Guzzi springs in comparison to alternatives that we know for sure would actually fit the Marz forks, let alone be matched up correctly by rate from the many available from each mfgr.

 

But this is great info, and I'll take it up with the Hyperpro distributor.

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Since Jason retracted his recommendation, it does make going to a stock FZ1 spring a bit of a gamble.

We do know that the stock Guzzi spring is significantly less than a 1.0, and it is a straight rate.

So assuming they sent you the Fz1 hyperpro spring, and it fit, or they sent you one with the same rating, we could be sure you would be much better off than stock...

For me, I think the hyperpro spring in that chart would be too soft. For you I think it would be just about right....But I could be wrong.

Let us know what you find out with Hyperpro!

[Guest ratchethack]

I just spent a half hour on the FZ1OA discussion board at the link you provided, Dave, at:

 

http://www.yamahafz1oa.com/forum/showthrea...p?threadid=6694

 

I was looking for any intelligence on the topic that is the subject of this thread. Well yes, I found some evidently well-informed and well-qualified discussion but - OMG - what you have to wade through to get to anything of value over there.....

 

What I really want to say after that experience is this:

 

Please accept my most sincere THANKS to the members, posters, and moderators - especially Jaap - for providing such a pleasant, professional, courteous, polite, enjoyable, mature and informative forum HERE!!!

 

I am, (along with the rest of us) in debt to the high value and integrity of this forum! Your efforts - and high standards - are most greatly appreciated!

 

Best Regards,

 

Ratchethack

[dlaing]

...but - OMG - what you have to wade through to get to anything of value over there.....

 

That was my impression, too.

I mostly skimmed the messages and went for the charts.

I was looking for something definitive on Progressive vs. Straight, and found some interesting information, but alot of opinion just for the sake of opinion.

Ditto on the thanks to everyone who makes this forum what it is!

[BrianG]

But OK, I can add preload to get the sag right, but adding pre-load is a pain it the butt and if I give it too much, is that bad? I don't understand why there is such a thing as to much spring pre-load, I guess you could get spring binding

Maybe I am doing something wrong, but I had to manually compress the spring while my girlfriend  turned the bolt. Is there a safe way to lock the rod so that you may tighten the bolt?

 

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The two significant issues in fork-spring determination is Free sag and Loaded sag. Ideally, Free sag is in the 10-15% of full stroke range, while Loaded sag is in the 25-30% range. The value picked within this range is the first contributor to suspension compliance.

 

The trouble with too much preload, in the pursuit of proper Loaded sag, is that it will decrease the Free sag number as well. Too little Free sag results in the fork prematurely "Topping Out" during rebound motion. Coil-bind generally isn't an issue in a street bike fork.

 

Mostly, this discussion has considered the Compression side of the fork/damper cycle, but the rebound side is equally important in a high-performance environment, and that's where pre-load fits into the picture.

[BrianG]

Maybe I am doing something wrong, but I had to manually compress the spring while my girlfriend  turned the bolt. Is there a safe way to lock the rod so that you may tighten the bolt?

 

53924[/snapback]

 

I wonder what "BOLT" you are referring to? If you mean the "NUT" on the damper rod, you are assembling the spring/damper-rod/fork cap improperly.

 

This may well be presumptuous, but here goes anyway.

 

The Nut is simply a Jamb-nut to fix the fork cap on the damper rod. You should back off the nut, way down the threads of the rod and spin on the fork cap. Then run the nut up flush to the bottom of the cap. You can then remove the cap and slip the spring over the damper rod. I fix the brake caliper bracket of the fork leg into a vice (with soft jaws) and then attach a piece of tie-wire to the damper rod above the nut. I slip the spring over the damper rod and attach a bungee cord from the loose end of the wire to the ceiling, to keep the rod extended. I then compress the spring below the damper rod nut, and slip in the retainer/collett. Then I remove the wire and spin on the fork cap. Then I use wrenches to jamb the nut agains the cap.

 

Hope this helps somebody out there, and didn't offend anyone with the presumption.

[dlaing]

I wonder what "BOLT" you are referring to?  If you mean the "NUT" on the damper rod, you are assembling the spring/damper-rod/fork cap improperly. 

 

This may well be presumptuous, but here goes anyway. 

 

The Nut is simply a Jamb-nut to fix the fork cap on the damper rod.  You should back off the nut, way down the threads of the rod and spin on the fork cap.  Then run the nut up flush to the  bottom of the cap.  You can then remove the cap and slip the spring over the damper rod.  I fix the brake caliper bracket of the fork leg into a vice (with soft jaws) and then attach a piece of tie-wire to the damper rod above the nut.  I slip the spring over the damper rod and attach a bungee cord from the loose end of the wire to the ceiling, to keep the rod extended.  I then compress the spring below the damper rod nut, and slip in the retainer/collett.  Then I remove the wire and spin on the fork cap.  Then I use wrenches to jamb the nut agains the cap.

 

Hope this helps somebody out there, and didn't offend anyone with the presumption.

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Thanks, I was just going by the workshop manual, which is apparently giving improper instructions. It did not seem right that I would turn the Jamb-nut and the rod would spin endlessly unless I took the spring load off it.

Which is why I asked!

I'll have to give it another go. I had gotten everything right except for the now obvious fact that slipping in the collett is a lot faster while holding in a compressed spring than spinning on the Jamb-nut!

The manual also instructed us to remove the damper rod for just a simple maintenance.

It seems to me, that all that we have to do is pull the forks, remove the cap, drain the oil, refill, and re-assemble. It seems to me that there is no need to remove the spring or the rod.

Do you agree with this assertion?

[dlaing]

Oh, and I went back and read that entire thread....took forever

And what a tease!!! I thought they were going to have a test ride shootout between a straight rate and a progressive spring but they bailed because of personallity disorders. INCREDIBLE!

But I did notice a company called HyperCo sells "Hypercoil" springs for the rear shock that offer very mild progressiveness. (good for people like me who are on the fence regarding progressive vs. straight)

Note, as far as I know, HyperPro and HyperCo are not related....but I could be wrong....

HyperPro says they have a spring for our Sachs.

HyperCo, I believe you would have to match it from the dimensions.

I am not sure if the inches refer to shock travel or axle travel....

FWIW this data was provided by a financially biased proponent of straight rate, a Traxxion rep.

 

HyperPro:

10mm Preload

1" 517 #/in.

2" 640

3" 728

 

HyperCo "Hypercoils" 7x550:

14mm preload

1" 530 #/in.

2" 550 #/in.

3" 565 #/in.

 

FZ1 Stock:

Preload 17mm

1" 420 lb/in

2" 422 lb/in

3" 424 lb/in

[Guest ratchethack]

The manual also instructed us to remove the damper rod for just a simple maintenance.

It seems to me, that all that we have to do is pull the forks, remove the cap, drain the oil, refill, and re-assemble. It seems to me that there is no need to remove the spring or the rod.

Do you agree with this assertion?

Dave, I also found the shop manual pretty incomplete - even misleading at times, especially on forks. I've had my forks apart 3 times now for oil changes and new seals. After the first go-round, I found that I could get the 400 ml old oil out without removing the damper rods and cartridges as the manual indicates you need to do by doing just as you suggested. I pump out the cartridges and let 'em drain overnight upside down.

 

Brian, re: your comments on free sag & loaded sag, and preload. This fits with the common wisdom from everything I've read also.

 

FWIW - As I mentioned before, despite Jason's (Jason at Moto Int.) retraction of his recommendation of stock FZ1 springs for the Marz fork, it wasn't clear from my discussion with him why. Yesterday I discovered that the FZ1 springs are available from my local Yamaha dealer at $26.50 ea. This intices me to want to give Jason a call for more details, since I could easily return the FZ1 springs to my dealer for any reason if I don't like 'em. I suspect that they may fit, but might be too long and therefore require excessive preload in the Marz fork. This would explain why the TD springs may be a mfgr recommended replacement for the FZ1, since a greater length reqmt in the application for the FZ1 could easily be made up with spacers. Speculating now, will get smarter on this when I can and will advise.

[BrianG]

The manual also instructed us to remove the damper rod for just a simple maintenance.

It seems to me, that all that we have to do is pull the forks, remove the cap, drain the oil, refill, and re-assemble. It seems to me that there is no need to remove the spring or the rod.

Do you agree with this assertion?

53997[/snapback]

 

Quite right on the draining technique. I don't even leave it sit over night. Just pump it out really well, upside down. Leave it upside down while pumping out the other one, and then go back to refill and re-assemble the first one.

 

I have a "tool" for compressing the spring/spacer that facilites the placement of the collet. It's too simple to explain, but I could post a pic if anyone's interested. It still takes 2 people to do it, but the wife can be #2. (although NEVER tell her I said that!!)

[BrianG]

FWIW - As I mentioned before, despite Jason's (Jason at Moto Int.) retraction of his recommendation of stock FZ1 springs for the Marz fork, it wasn't clear from my discussion with him why.   Yesterday I discovered that the FZ1 springs are available from my local Yamaha dealer at $26.50 ea.  This intices me to want to give Jason a call for more details, since I could easily return the FZ1 springs to my dealer for any reason if I don't like 'em.  I suspect that they may fit, but might be too long and therefore require excessive preload in the Marz fork.  This would explain why the TD springs may be a mfgr recommended replacement for the FZ1, since a greater length reqmt in the application for the FZ1 could easily be made up with spacers.  Speculating now, will get smarter on this when I can and will advise.

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FYI.... The straight-rate springs we used, as supplied by Traxxion Dynamics, were FZ1 spec. So, physically, they are the right size. I cannot comment on the OEM spring's rate in our application.

[dlaing]

Ratchet,

I can easily pull my fork spring if you would like to borrow it for a comparison witht the Yamaha spring.

FWIW on the Yamaha list classified, some guy from British Columbia put his up for sale, and will toss them in the garbage if he does not get an offer, so I am sure they will sell cheap.

http://www.yamahafz1oa.com/forum/showthrea...?threadid=36807

What I don't understand is that the commong consensus from the FZ1 riders is that the stock spring is too soft, but on that first chart it appears to be firmer than the straight rate 1Kg/mm spring....sure the Yamaha spring needs more pre-load, but that is just an adjustment, and as long as it does not lower the free sag too much, it should be fine.

Perhaps the FZ1 community only attempts the external pre-load change, and that is not enough.

Thanks again, Brian, for the insight on assembling, draining, and the perils of pre-load

I currently have near zero free sag on my OE rear shock, and a fairly large loaded sag number.

Compression damping is set to help keep it from bottoming.

So any spring is going to help the rear.

Now I am just debating Hyperco #500 vs. Hyperco #550 vs. HyperPro's mystery spring, which is likely to be something like a 500/700. I guess I could give HyperPRO a call... Or wait for RatchetHack to be the guinea pig.

HyperCo is $75 and HyperPro is $109, not a huge price difference, but it could leave me money for weekend worth of riding.

[Guest ratchethack]

Dave, many thanks for the offer. Having your spring on hand to measure might save me from not being able to ride while my forks are apart - but how long do you think you can be without your spring? Assuming the FZ1 springs look like they could be a match to my needs (that is, if they're not too long and they seem to match up with my weight, etc.), I'd like to get some real measurements on them on a spring rate analyzer to plot curves and map them against the stock spring. I might be able to reciprocate for the courtesy by being your guinea pig on the HyperPro rear spring. Get back to me on a timeframe that your spring might be avbl. to measure, and let's see what I can come up with to make things work out, maybe nxt weekend.

[dlaing]

but how long do you think you can be without your spring? 

At the moment my forks are off the bike, assembled, but oil-less.

So, they are ready to have the springs pulled in ten minutes, I mean one minute(since Brian clued me in on the proper technique)

My Ohlins forks should be here any day....

So, the short answer is a couple phases of the moon, or until I bend the Ohlins on the back of a mini-van...Knock on wood.

And even then, I'd upgrade the springs, anyway.

So, absolutely no rush.

If you want, I can send rough measurements, but all I have is a tape measure.

You probably need accurate ID and OD measurements.

Spring wire gauge measurement might also be useful.

[Guest ratchethack]

Ack! I'm not yet entirely befuddled by analysis paralysis, but I can see it approaching now, and it ain't pretty. Who'd have imagined a device as simple as a spring could be spun into such analytical permutations? I suspect that some of this is marketing-driven, and that's what's starting to annoy me.

 

Though HyperPro won't publish graphs of their spring rates , I managed to get the following data out of them on their "standard rate springs" for the 40mm Marz fork and Sachs-Boge rear shock:

 

Front - Start rate = 7.20 Nt/mm. End rate = 15.05 Nt/mm.

Rear - Start rate = 90.13 Nt/mm. End rate = 144.2 Nt/mm.

 

I spent enough time with conversion tables trying to convert Nt/mm into something I can use for comparison purposes to hurt myself. As it turns out, this didn't take long. I've never done many calculations in Newtons, and it seems that other spring mfgr's don't either...

 

HyperPro also doesn't provide any data on the length from start to end rates. I'm afraid I'm starting pick up the distinct aroma of marketing mysticism.

 

Any thoughts on what we're looking at here? Anybody want to take a shot at converting this into more standard measurements?

 

Thanks in advance.