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question re: setup with stock fork springs

Old 06-09-2006, 07:58 AM
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question re: setup with stock fork springs

I have just replaced the fork fluid, along with a leaky fork seal and got everything back together. I went through a suspension setup and am wondering about the fork springs in my bike.
Don't know if they are factory or aftermarket (I bought the bike used).

I read and hear everywhere that the factory .58 springs are too light.
FWIW: Racetech's calculator comes up with .85-.90 springs for my weight.

Here is what has me wondering.....
I set my preload and have approx 29 mm unladen sag, and 19 additional mm of laden sag on the front forks.
Based on a max fork travel of 130 mm (which I read somewhere was the max travel for the factory forks) the sag numbers I have are in the correct % travel range based on 130 mm travel. All sound/looks good.

So, IF I have factory springs, why would I change them? All numbers work out fine. Since I do not know what springs I have, I am not inclined to make a change at all, based on the unladen and laden sag.
I realize the final test will be measuring how much of the max fork travel I am actually using when I do my next track day.
If I am at 100 % then maybe stiffer springs and/or some minor tweeks with oil might be in order.
Any opinions same or different based on my assessment?

For those of you who have setup your suspension and have ORIGINAL factory springs:

How much do you weigh? (I'm 180 lbs)
What is your unladen and laden sag? (mine is 29mm and 19mm)
How many lines are SHOWING on the preload adjust shafts? (mine = 3 lines left showing)

For those of you with lots of experience with the SH front end, would you guess I have factory springs or aftermarket of some unknown spring rate?

Thanks all!!
Brian
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Old 06-09-2006, 09:51 AM
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Honda likes to use progressive springs where as racetech and ohlins use straight rate springs. Can anyone confirm the stock units are progressive wound?
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Old 06-09-2006, 09:55 AM
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Originally Posted by superbling
Honda likes to use progressive springs where as racetech and ohlins use straight rate springs. Can anyone confirm the stock units are progressive wound?
Stock springs are progressive.
They look different from RaceTech springs.
The stock have some coils closer together on one end and change gradually to further apart.
The RaceTech coils are all spaced the same distance apart.
Also the Racetech have the spring rate number marked on them somewhere.
My .90 were marked on the end.
My .80 were marked on the side near the end.

Hope this helps
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Old 06-09-2006, 09:55 AM
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I have wondered the same thing myself.

Mine seem to act linear, but I am no suspension expert. Without a test setup to measure travel -vs- applied force, I am only guessing.

If I really want to find out, I guess I could pull the fork springs and see if I could determine by visual inspection.

I am actually more interested in sag and preload settings that others have arrived at.

Thanks.

Brian

edit: thanks Bill! You were posting while I was typing.
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Old 06-09-2006, 06:04 PM
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Brian,

Take a look at my website and the section titled Suspension Setup. The Superhawk will benefit from aftermarket fork springs in the following ways:

- Less dive in the front end while braking
- More consistent compression and rebound damping throughout the range of travel
- Less possibility of bottoming the forks
and
- Provides more usable fork travel

Generally speaking (and this applies to most bikes prior to the latest generation Showa forks since 2004) you should aim for an unladen sag of 10-15mm and a rider sag of 30-35mm for the street. 5mm less for the track will minimize bottoming during very hard braking. This is achieved both by purchasing the correct spring rate and also putting the correct amount of preload on the springs via spacers when reinstalling the springs.

With much heavier springs, you will find that the damping circuits will be overloaded and you must either a.) use heavier fork oil, or b.) revalve the forks.

Hope this helps answer the questions you were asking.
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