Best Deal on front fork springs

[NCFRC]

After some research , the original Kawasaki springs are by far the best buy at $60 pair and their .37's for a 190+ rider are equivalent to most aftermarket .40's.

One set of aftermarkets I bought fit the tubes very poorly, not impressed. Plus their rates were way off. Buyer beware. :ride:

 

[Okiewan]

Ah ha!, Yes. But what about rear forks?

 

[glad2ride]

"their .37's for a 190+ rider are equivalent to most aftermarket .40's."

Uhhhh, .37 does not equal .40. Springs have rates that are measurable. Did you measure the aftermarket springs you have? Which brand did you buy?

.37 Kg/mm rate springs WILL NOT be stiff enough for someone who weighs 190 pounds, even before they put on 15 pounds of riding gear.

If you use a normal amount of preload on the springs, the front end will sag too much. If you use way too much preload, such as the stock amount, the forks will blow through the stroke on any hard hit.

 

[porterdog]

Used springs out of the front of an '00 or later XR400 are probably the best deal if you can find them. I just got a set for $55/delivered. They're hot wound and require a much smaller preload spacer due to thier longer overall length.

 

[NCFRC]

"their .37's for a 190+ rider are equivalent to most aftermarket .40's."

Uhhhh, .37 does not equal .40. Springs have rates that are measurable. Did you measure the aftermarket springs you have? Which brand did you buy?

.37 Kg/mm rate springs WILL NOT be stiff enough for someone who weighs 190 pounds, even before they put on 15 pounds of riding gear.

If you use a normal amount of preload on the springs, the front end will sag too much. If you use way too much preload, such as the stock amount, the forks will blow through the stroke on any hard hit.

I'm just quoting from the Kawasaki spring chart , we all know that different manufacturer's don't rate them the same.

 

[Rich Rohrich]

, we all know that different manufacturer's don't rate them the same.

How's that? :coocoo:

A spring's rate is a repeatable standardized measurement. It's basic physics that hasn't changed in our lifetime, at least here on earth where most of us reside. :rotfl:

 

[IndyMX]

I'm just quoting from the Kawasaki spring chart , we all know that different manufacturer's don't rate them the same.

So, let's see this chart.

 

[glad2ride]

OK. Good luck with it.

 

[sr5bidder]

I have Race Tech 38's and 170lbs and thier a bit too soft
sounds like someone at the kawi shop or kawi engineers are coo-coo

I would have thought this thru a bit better befor posting....../....
... putting neck on chop block....
/\/\/\/\/\/\/\/\
Peace

 

[txkawboy]

It has been my experience that yes, often medium-grade/priced springs are not "exact"...I even know that most serious 4T tuners will measure every valve-spring on a mulit-v head, so---??

 

[IndyMX]

It has been my experience that yes, often medium-grade/priced springs are not "exact"...I even know that most serious 4T tuners will measure every valve-spring on a mulit-v head, so---??

There's a difference between verifying a spring length, and saying that a spring rate between two different mfg's that have the same number are actually different..

You're not comparing the same things here.

 

[adam728]

There's a difference between verifying a spring length, and saying that a spring rate between two different mfg's that have the same number are actually different..

You're not comparing the same things here.

Springs can easily measure out to a different rate than specified, due to variances in the wire diameter, outer diameter of the winding, quality of the steel (or titanium), etc etc. It's pretty easy for a compression spring to vary +/- 10% in rate from the spec, although I'd hope most suspension spring manufacturers would try to hold it a little tighter than that.

 

[IndyMX]

Springs can easily measure out to a different rate than specified, due to variances in the wire diameter, outer diameter of the winding, quality of the steel (or titanium), etc etc. It's pretty easy for a compression spring to vary +/- 10% in rate from the spec, although I'd hope most suspension spring manufacturers would try to hold it a little tighter than that.

True, and that doesn't dispute what I'm saying here..

 

[mudpack]

All manufactured items have tolerances, or measurements that fall within an acceptable range for that requirement.

While it may be that a spring on the low end of the tolerance for a .40 might approach another spring (in actual rate) that is on the high end of the tolerance for a .37, to say that a spring rated at .40 from one manufacturer is the same as a .37 from another manufacturer can only be true if one...or both...of those manufacturers is in (gross) error.
Since few manufacturers have the time to actually measure and grade each and every spring they make, it's possible that...on occaison....two springs designed to be two different rates may actually measure (if one were to measure) very close to the same. Instead they make springs that calculations (based on pitch, wire diameter, and material) show will produce the desired spring rates.
These springs in that particular batch will show a bell-shaped curve, if/when measured, that places the majority within the tolerance parameters for that requirement.

In other words, chit happens.

Oh, yes, there is a requirement difference between fork springs which operate a a frequency of several cycles per second (cps) for several thousand cycles in their lifespan, and valve springs with operate at a frequency of several hundred cps for several million cycles in their lifespan. Suspension springs are highly understressed vs. valve springs which are stressed to the breaking point in many instances. As IndyMX said: "apples and oranges".

 

[IndyMX]

All manufactured items have tolerances, or measurements that fall within an acceptable range for that requirement.

While it may be that a spring on the low end of the tolerance for a .40 might approach another spring (in actual rate) that is on the high end of the tolerance for a .37, to say that a spring rated at .40 from one manufacturer is the same as a .37 from another manufacturer can only be true if one...or both...of those manufacturers is in (gross) error.
Since few manufacturers have the time to actually measure and grade each and every spring they make, it's possible that...on occaison....two springs designed to be two different rates may actually measure (if one were to measure) very close to the same. Instead they make springs that calculations, based on pitch, wire diameter, and material show will produce the desired spring rates.
These springs in that particular batch will show a bell-shaped curve, if/when measured, that places the majority within the tolerance parameters for that requirement.

In other words, chit happens.

Which is perfectly acceptable in my opinion, but to say that a manufacturer claims that their .37 springs are the same as everyone elses .40 springs as a matter of course, I find a little hard to believe.

 

[mudpack]

to say that a manufacturer claims that their .37 springs are the same as everyone elses .40 springs as a matter of course, I find a little hard to believe.

That's what I was trying to say, in my own obtuse way, earlier. :cool:

 

[glad2ride]

For the weight of the original poster, a perfect .37 Kg/mm rate spring won't be stiff enough for YOU.