I've been too long waiting for this...

[spook]

So check with wilbers, traxtion, elka, and others you can also just cut down the springs and space... This creates a higher rate.

[hotcam]

Doesn't cutting down the springs and spacing create the same rate,
but adds preload and the possibility of coil binding?

[spook]

Here's a link to sort of what I'm talking about. Preload (sag reduced) is added by making your spacers longer than the space available. There is a chance depending on spring type that they 'may' bind, but you can work it out so it doesn't.

Also if you by new, buy linear.

http://motorcycleinfo.calsci.com/Suspension2.html

[hotcam]

I see - he's got a few things I don't agree with in that website springs
page. For starters, he shouldn't need to cut a spacer longer and then
shorten it to suit - if his calculations were correct he could just cut
it once to the correct length. Darn theoretical physicists. Get a
mechanical engineer onto the job!

Hotcam's Notes on springs:
If you cut a single-rate spring you end up with a single-rate spring
of the same stiffness, just shorter.

If you cut a dual-rate spring you end up with a shorter dual rate spring,
that transitions from soft to hard sooner.

However if you cut the closely-wound end off a
progressively-wound spring, then you will have a rate increase.

I can bandy around maths a bit, it all is pretty simple
for straight rate springs which is one reason racers love them.

F = k x and conversely x=F/k or k=F/x

where F is the force on the spring (and the force with which
the spring pushes back).
k is the stiffness or "rate" of the spring
x is the distance by which the spring is compressed.

Example: motorbike/rider with 100kg on the front end,
two of 1.0kg/mm spring = 2.0kg/mm total stiffness.

x = F/k = 100/2.0 = 50mm spring compression when loaded.

Therefore if we want our forks to static sag by 20mm we
need to "preload" by 50-20= 30mm total.
Some of this is done by squashing the spring into the forks during
assembly (depending on the bike), the rest done by adjuster or spacer.

It is similar when using a dual-rate spring, basically
you have to do the calculation twice to account for the two different
parts of the spring.

With a progressive rate spring, k becomes a variable dependent on x
which begins to get a little more complicated.

F= x(k+Kx) where K=rising rate value (finish rate - start rate)/d.length

(This is the same formula for a straight rate spring but for straight
rate K=0 and can be ignored leading to F=kx which we saw earlier)

If you cut 10% of the length off, you don't get a 10% increase in rate.
You get an increase to the starting rate only, and a decrease to length,
which is equal to a fraction of the difference between the starting
and ending rates, depending on the old and new overall lengths of
the spring.

For example if you have a 500mm free length spring which
starts at .5kg/mm and ends at 1.0kg/mm when coil bound,
and the coil bound length is 200mm, K=.5/300=.0016

So at 100kg we will get around 140mm compression for a single spring;
or 88mm for a pair of springs (notice how it's not half, because the
springs are progressive).

More preload is not as good as a stiffer spring - a stiffer spring will have
a smoother action over small bumps and is more supportive over
large dips or bumps, compared to a soft spring with lots of preload.

I think that's all. My brain hurts.

[sweekster]

Good lord man!! Too much math for my taste. Congrats on a successful track day. All the stickers make sense now .

[spook]

Cam you could have had the job done in the time it took you to write that.

The link was only provided to give you an idea of what I was talking about. The use of spaces is only to set your sag. Cut the center out of progressives for best effect and insert a machined Delrin washer between the halves. My reference to cutting down springs was in relation to what you already have in there.... But as I said buy some linear 1.1's

[hotcam]

Yeah I think and write too much when I'm stuck in front of the computer
and wishing I was riding (or even tuning) my bike instead.
It doesn't make me any better of a rider :sad
and I hope it doesn't irritate y'all having to read through all my drivel.


It's not all writing though, last night I spent a few hours setting my
float levels to help the rich spot at 2000-4000rpm. Still goes good,
but hopefully now it doesn't blow black smoke as much at those revs.
I also put the gearing back to stock, and put the rear ride height back
to +1" overall.

As for the steering angle thing, I'm going to do what y'all say and wait
until I've got the right springs etc in and see how that goes. I found out
on the weekend that it handles much differently/better when it has heat
in the tyres it's hard to get heat into the tyres on the street.

The use of spacers is only to set your sag.

Yes

Cut the center out of progressives for best effect and insert a machined Delrin washer between the halves.

Interesting, it would increase the progressiveness.

My reference to cutting down springs was in relation to what you already have in there.... But as I said buy some linear 1.1's

Yes you are right, even with preload and spacing increase the stock
springs are just not enough. I will (obviously) let you all know when
I get new springs, they will be linear ones like you suggest.

I hope I can organise things so as I'm testing out new springs
at broadford next month, but there's money and time to figure out first

[hotcam]

Photos are up of Spook and myself on
http://www.stevenhendyphotography.com.au
Champions Ride days
Broadford 9/8/07
green group (both of us)
yellow group (spook when he got tired of going slow and showing
me the way around) (edited)

[spook]

I can't make the site work

The only shots of myself are in your group (green-med slow) I think Cam. I moved to Yellow (fast) and I think the photograph was tired by then and had retired to his caravan.

[hotcam]

Hmm, seems to half-work in InternetExplorer but not at all in Firefox.

On a related note, THST reckons they sold their last set of FZR1k
fork springs in 1.0 *an hour* before I rang. No-one else has the right size.
Damnit, have to wait for an overseas order.

[spook]

Don't sweat Cam...It quite often takes less time to get stuff from the US than it does from interstate here. So send off an order!

[hotcam]

Wanna share any postage for stuff from powersportsuperstore.com?
They seem to be the only ones who have it in stock except racetech,
and racetech's website fails at the online shopping bit. Somehow I
just can't see paying $60 postage for one item when I can get 3 or 4
for $65 postage.

[spook]

Try this mob Cam. I've spoken with him in the past and he seems to have good stock and knowledge.

http://www.asr.com.au/products5.php

[sbutler]

My eyes are watering after reading the long post Cam,.
Wouldnt it be eazy to phone Frank Ponds in Sydney, or Mick at TrackTune & ask Mick what springs he used in my bike??
It completely transformed my FZR, Frank & Mick spoke to each other & came up with the combination that they agreed would work the best.
It worked for me of that there is no doubt. So take all the guess work out & use what I have, Ive done all the testing on the track in compitition, & have the results of there work.

Doesnt matter how much you chew over what is the better option/fluid rate/spacer size/ spring rate/ spring lenth, etc, It works for me so theres no reason it wouldnt work for your FZR. I know they have different internals but they are basic forks, so without a lot of brain melting, you will have a big inprovment.

Remember the most tecnical way may not be the better way. Keep things simple is my rule, & it did me...

[spook]

Remember the most tecnical way may not be the better way. Keep things simple is my rule, & it did me...

Here here Mr butler

[FZRDude]

.....Keep things simple is my rule, & it did me...
...

I beleive that is referred to as the "KISS" Method...

Keep
It
Simple
Silly (or stupid, depending on the person using it... IE: Me)

[sbutler]

.....Keep things simple is my rule, & it did me...
...

I beleive that is referred to as the "KISS" Method...

Keep
It
Simple
Silly (or stupid, depending on the person using it... IE: Me)

You got it one!~!

[spook]

You got it one!~!

Obi-Wan?

It's not a beat up Cam lol.. How did you go with the springs?

Too bad Saturdays are out for you, as Preston MCC is running a race school at Broadford tomorrow. It's a good day... I did it years ago.

[hotcam]

It's not a beat up Cam lol..

more like a comedy roast?

How did you go with the springs?

I bit the bullet and did what all y'all suggested.
Spoke to Michael at Tracktune and um, someone, at ASR, and
Biketek too. Michael remembered Steve and his bike, and all were helpful.
Sadly there were no 1.0 linear springs available in Australia to fit until
the next container load of parts comes in 3 or 4 weeks (THST importer sold
the last set for my bike an hour before I rang ) . Apparently
the 1.0 springs will be good for what I want, and there's not much you
can do to the internals except change the oil (unless you put new
guts in the fork $$$$ ).

I usually like to buy local and all that, but I didn't want to wait that long
so I have organised with a friend of a friend for some springs
on the way via express int'l air mail, along
with a few other little things I needed (to amortize the postage cost).
Am looking forward to trying them out!

Too bad Saturdays are out for you, as Preston MCC is running a race school at Broadford tomorrow. It's a good day... I did it years ago.

Yes I'd love to be in that, am watching the discussion on another forum
with envy. Maybe next time.

On a completely different note, I got 302km out of an 18.3 litre tank of
fuel today!

[stan]

could you leave me out of this , i don't even own a bike any more

stan