Marz Fork Springs

[Guest ratchethack]

Now my BS meter is bouncing off the "MAX" peg. By my calculations (somebody chime in if I've miscalculated please!) from the figures provided by the US distributor (see above post), the HyperPro rear spring has a start rate of 5,047 lb/in and a end rate of 8,075 lb/in. Can you say, "rigid suspension"?!?

 

The numbers he gave me for the front work out within the range of what I might expect: 403 lb/in start rate and 842 lb/in end rate. The trouble now is that I don't trust any of their numbers. And of course, without a distance measurement between start and end rate measurement points ("that's proprietary"), for the most part, we're still just shootin' in the dark.

 

So I called Doug back. He's going to check the unit of measure on the rear spring. Will advise.

 

My current assessment of HyperPro: CAUTION until further notice.

[dlaing]

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.

 

Newtons (N) to kilograms force (Kg.f.) 0.10197

Kilograms force (Kg.f.) to Newtons (N) 9.80661

Newtons (N) to pounds force (lb.f.) 0.225

Pounds force (lb.f.) To Newtons (N) 4.448

1" = 25.4mm

 

so,

Front -

Start rate = 7.20 Nt/mm. = 0.734184 Kg/mm

End rate = 15.05 Nt/mm. = 1.534649 Kg/mm

 

Rear -

Start rate = 90.13 Nt/mm. = 9.190556 Kg/mm = 515.0929 lbs/inch

End rate = 144.2 Nt/mm. = 14.70407 Kg/mm = 824.103 lbs/inch

 

The numbers by themselves are in my opinion, far too progressive and extreme.

But, I think we can assume the start and end rate numbers shown are fully open and fully closed, and that with preload and the limitations of travel we would be looking at numbers in the middle somewhere...

Since most people go to a 500 or 550# rear, the rear spring may be too stiff.

The front could probably be set pretty well with the right preload....but a lot of trial and error.

I wish the curve was less radical.

Most of the 'experts' don't consider progressives for sport riding.

I believe if the progressiveness was cut in half they could win over more people.

But hey, maybe I am wrong and it will just work incredibly.

My biggest beef with my current setup is how the superslab 70MPH rhythmic bumps that just wear at me.

For blasting through country road, most of the roads are in good enough condition that even the stock set up is tolerable.

So, I am attracted to the HyperPro because I think it will greatly help the superslab issue.

I am just worried that it will leave me with two inches of real world used travel because it is too progressive. But I could probably completely remove the rubber bumpers that are getting harder with age...

While a straight spring would allow the suspension to utilize the travel.

Dazed and Confused.

Perhaps I'll be the guinea pig, and you can try my bike.

I am more worried that the rear spring my be too hard for your lighter weight.

[dlaing]

My current assessment of HyperPro: CAUTION until further notice. <_>

54206[/snapback]

Oh, I see you just posted again while I was calculating.

So yah, I think we have the same concerns.

But you were off a decimal.

[Guest ratchethack]

Dave, you might be the only one left on the Forum who's eyes haven't glazed over completely by now. Thanks for hangin' in and pointing out my slipped decimal point. Now I'm more determined than ever to dog this thing until I know exactly what I'm doing - AND until I know exactly what the mfgr's are doing.

 

At this point I'm pretty torqued-off with HyperPro. The numbers for the fork springs we both just calculated don't line up at all with the comparo graph you provided earlier. As I mentioned then, we don't know what springs we're looking at in that graph, because we have no way of telling which spring from each mfgr is represented there. The only one that comes in only one flavor is the stock FZ1. However, I b'leive we're safe in arriving at the conclusion that the spring Doug gave me numbers on is definitely not represented in that graph.

 

Regardless of my decimal point faux pas, the numbers I got from Doug today for the fork springs alone are pretty wild, and I just don't trust 'em. We'll see what he comes back with tomorrow after he promised to call the factory to double check when I questioned the unit of measure on the rear spring. When he said today that he's "not used to customers as detail oriented" as myself :!: , I think I started to get an idea of what business they're really in - and (unless there's been some kind of misunderstanding) today it's starting to look more 'n more like it ain't a biz I want any part of...

 

Meanwhile, Jason at MI is out sick, so I can't shed any light on what might have been wrong with the stocker FZ1 springs he tried. Hey - I'm in no huge hurry at this point. I'm gonna do this right to the best of my ability to understand what's right regardless of how long it takes.

 

"Trust, but verify." - words to live and ride by.

[dlaing]

Here is a chart of the front.

The two points for the Guzzi HyperPro correspond with the Yamaha HyperPro curve.

I am guessing at the Guzzi stock curve, but my guess is that it is about a .7 or .8 Kg spring. Can anyone confirm?

EDIT I think we need the data in front of us to understand this chart better.

We don't know how HyperPro got those numbers, but I believe it is safe to suggest that on both the Yamaha and Guzzi HyperPro front and rear springs, the numbers line up.

Hyperco for Guzzi
Probably no preload....probably measured at first centimeter or millimeter  and spring halfway point or binding point :huh2:  

Start rate = 7.20 Nt/mm. = 0.734184 Kg/mm =41 #/inch
End rate = 15.05 Nt/mm. = 1.534649 Kg/mm = 86 #/inch
Compressed to:      Pounds/In pressure   Rate: kg/mm   Total
0.5"                      41              0.73           41
6-10"                    86              1.53           350-400???

Stock Fork Spring, 15mm preload:     
Compressed to:      Pounds/In pressure   Rate: kg/mm   Total
1"                        44.0            0.78            44
2"                        54.0            0.97            98
3"                        66.6            1.19            165
4"                        73.6            1.32            238
5"                        80.0            1.43            318



Hyperpro Fork Spring, 15m preload:
Compressed to:      Pounds/In pressure   Rate: kg/mm   Total
1"                      43.2            0.78            43.2
2"                      45.0            0.81            88.2
3"                      51.8            0.93            140
4"                      75.0            1.34            215
5"                      80.0            1.43            295



Traxxion Dynamics Fork Spring, 15mm preload:
Compressed to:      Pounds/In pressure   Rate: kg/mm   Total
1"                      53.60            0.96            53.6
2"                      55.00            1.00            109
3"                      55.00            1.00            164
4"                      55.00            1.00            219
5"                      55.00            1.00            274

[dlaing]

Here is the rear shock...sorry, Ugly Graph.

I suspect the stock Sachs is very close to the FZ1 stock in weight.

But note how much stiffer the HyperPro is....

EDIT whoops, speaking of decimal points, I swear I drew in a zero next to the numbers on the vertical. So on the chart, where it says 50 it should be 500, where it says 60 it should be 600, etc.

This chart is from the following data:

HyperPro Guzzi:

515 #/in Probably at 0.5 inch

824 #/in Probably at half the spring length, 3.5 inches

 

HyperPro FZ1:

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

[dlaing]

I am contacting Hyperpro to see if they can provide me with a lighter weight shock spring than what they spec'd for Ratchet.

I did some calculations and I believe a 475# spring would be about right for me.

I estimate that the spring weight over the axle is about 40% of spring weight, so a 500# spring would need 200# over the axle to deflect it one inch. I don't sit over the axle, so I need a lighter spring.

I stood on the stock spring(detached from shock) while holding a ruler to it (A sight to see) and found that my 210#s deflected it about 5/8 of an inch indicating a spring weight in the 300-350# range. A 350# spring would require 140lbs over the rear axle to deflect it one inch.

I now think 500# is a little too stiff, even for my weight.

I am hoping for 400-550# rising rate from hyperpro.

The 515-825# rate that they quoted is toooooo stiff, or my calculations are way off.

[Guest ratchethack]

Dave, I like it lots better when you're gonna be MY guinea pig.

 

Finally reached Jason at Moto International again to get the full "skinny" on the stocker FZ1 fork spring in the Marz forks. My question was, "What exactly was the problem fitting it in the Marz fork?" He said it was too SHORT, and also that there was a fitment problem in the bottom of the fork (he was a little fuzzy on this part) but otherwise he would have used spacers to at least test it out. As I speculated, the RaceTech spring he wound up (so to speak ) using was a quick solution to his customer's problem. The stock FZ1 springs now look far too dubious to consider.

 

Next I'm either going to find a local place that can give me a decent rate analysis & graph on springs for comparison purposes, or I'll make up a spring rate analyzer myself, then order something - maybe RaceTech, maybe HyperPro - and measure them against my stock springs, with the idea that if I don't like the way it measures up, I'll send it back. The logic in this is that I gotta know where I'm going AND where I'm coming from before I have any right to positive expectations. Will advise.

[dlaing]

Dave, I like it lots better when you're gonna be MY guinea pig.

Sorry, I am gonna chicken out.

They offered me a money back guarantee that it would work, but I think the numbers show it to be a little too stiff for me.

Maybe I need to eat more and get my weight up around 250#

But for now, I am gonna give a 475# HyperCoil spring a shot.

Ordered from

http://www.hrpworld.com

$78.45 US after shipping and insurance

[dlaing]

Okay, back to fork springs.

I found some more progressive springs:

http://www.wilbers-products.net/ (in German...)

V 11 Sport

Artikel Nr. 600-062-01

 

Die progressiven Gabelfedern von Wilbers Racing Suspension machen durchschlagende Gabeln und bockiges Ansprechen zu einem Stück Geschichte. Durch ihre Konstruktion federn sie leichte Unebenheiten ebenso souverän ab wie harte Schläge oder brutale Bremsmanöver. Das ist das Ergebnis sorgfältiger Konstruktion und eines harten Testprogramms von der Nürburgring-Nordschleife bis zur Full-Speed-Autobahn.

Eine Produktionsfreigabe erfolgt erst dann, wenn die routinierten Tester ebenso zufrieden sind wie die Prüfer des TÜV. ABE und eine lebenslange Garantie dank verschleißfester Konstruktion gehören ebenso zum Lieferumfang wie eine detaillierte Einbauanleitung.

99Euro or luftballoons

Guzzitech.com sells Wilbers...perhaps they can get them

Wilbers also lists HyperPro and this other brand,

Promoto

V 11 Sport

Artikel Nr. 500-062-01

Gerade die Gabelfedern beweisen die Qualität zum Sparpreis. Sie sind ebenso sorgfältig konstruiert wie die teureren Gabelfedern anderer Produktlinien, bestehen aus hochwertigem Siliziumstahl, werden auf modernsten, computergesteuerten Maschinen gefertigt und sind in Fahrversuchen exakt auf das jeweilige Motorradmodell abgestimmt und selbstverständlich TüV-geprüft. Ihre progressive Auslegung garantiert ein feines Ansprechverhalten bei geringen Einfedergeschwindigkeiten, rettet aber auch Ihre Gabel vor dem Durchschlagen oder zu starkem Eintauchen, wenn Sie stark bremsen oder bei hohen Geschwindigkeiten auf derbe Stöße im Belag treffen.

80 euros

[Guest ratchethack]

Dave, you knew I HAD TO check this out, and I'm glad I did. Todd E. just got back to me with the following recommendation for Wilbers progressives:

 

7.0 N/mm start rate, and 10.0 N/mm end rate. $123 USD.

 

Wilbers reccomends 7.5 wt fork oil and a 100 mm air space with these for the Marz 40 mm USD.

 

Now this looks A WHOLE LOT more reasonable to me, and I'm sure you'd agree. Plotting these on your posted graphs shows these are entirely different animals. I b'lieve they may just be exactly what the MD ordered for Yours Truly. But before I commit, of course, your comments are respectfully requested, por favor.

 

BTW - by my calculations, the N/mm figures convert thusly:

 

61.9 lb./in. start rate and 88.5 lb./in end rate.

 

Gracias, mi compadre.

[dlaing]

SWWEEEEET!

It sounds like Wilbers has there act together.

The spring should progress from the about the softness of stock to what the 225# plus riders are using with a straight rate....assuming the measurements fall within the range of travel...

This should put you right in the swwwweeeeet spot!

The oil rate sounds right as you need something a little thinner to reduce high speed compression.

Perhaps 5W would be even bettter.

As for the fluid height, want to borrow my Marz for some fluid level effect tests?

[dlaing]

7.0 N/mm start rate, and 10.0 N/mm end rate.  $123 USD.

 

 

BTW - by my calculations, the N/mm figures convert thusly:

 

61.9 lb./in. start rate and 88.5 lb./in end rate.

 

Gracias, mi compadre.

54982[/snapback]

I get 39.97302 lb./in. start rate and 57.10432 lb./in end rate, per spring.

So, for two springs, that would be roughly 80lbs per inch rising to 114 lbs per inch.

Ideal sag is (according to Ohlins)

Without rider:

Rear: 5-15 mm (R1-R2)

Front: 25-30 mm (F1-F2)

With rider:

Rear: 30-40 mm (R1-R3)

Front: 35-50 mm (F1-F3)

But keep in mind, with a progressive spring proper sag for the fork is probably more like one inch bike only and two inches bike with rider.

When you are on the bike, you are probably putting 60- 80lbs over the front wheel, so the sag should be just about right after you set the preload.

[Guest ratchethack]

Ack! Looks like I'm still not getting along with Newtons... Thanks again, Dave. I just re-calculated, and now I get the same numbers you did. Now, however, the Wilbers look to me to be too under-sprung for my objectives. Damn. I believe I need a start rate that's considerably above where I am now with the stock straight-rate spring - not below. Back to analysis paralysis. Or maybe I need to find another way to look at this. Arrrrrgggghhhhh!

[dlaing]

I think you will find that the spring rate is perfect for your weight.

I seem to remember someone saying the stock spring was somewhere around a 0.6-0.7 Kg/mm.

Does anyone know for sure?

In any case the starting point for the spring is roughly the same as stock or just a little firmer, but as you compress it, you will be into some seriously firm territory.

If you add pre-load, you should be able to meet your objective.