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.41 vs .44 springs

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I am in the process of getting my forks as plush as possible, I weigh 185lbs and according to Race tech's spring calculator I would require a .40kg/mm spring, however the bike came with .438kg/mm springs and the softest available spring I can find is .41kg/mm.

 

Is it going to be worth the money to change my springs or should I just do valveing?

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You have to get springs for your weight, you can't valve around the problem

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If you don't get your basics right with suspension, then you may aswell ride it as it is. Being on the right spring rate is as important and less hassle than any other modifications that you will do. 

lol I never see mog posted, let me tell ur, mog is as tight as arse holes, and he's saying u need springs. Lol

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I'm more free with other people's money!

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Ok so would there be much compromise if i get .41 instead of .40 springs? 

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Ok so one last question, could someone calculate the spring rate i have now. The spring wire is 5mm thick, i get the feeling it is a heavier spring than oem. If so them i should really see great benifits from new springs

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When I was racing full blown I ran 50 in front 5.8 rear with stock valves.  I was 205 expert class mx. Yz250's.  But stock valves worked good enough for me anyway 

Edited by Motox367
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You will be hard pressed to tell the difference between 0.40 and 0.41 kg springs.  Keep the springs currently in your forks in case you decide the 0.41 kg springs are too light for your liking.  I agree with the earlier post that you cannot "valve" your way around incorrect spring rates.

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So other than Sag, what will a fork with 0.44kg/mm springs do or feel like differently than with 0.40kg/mm?  The ride height will be different but what else?

Fork spring rate contributes to fork compression resistance along with the air gap, determined by fork oil level.  Bottoming is controlled by the air gap.

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Overall, the fork will stroke farther and transmit less shock to the handle bars for a given impact with the lighter spring rate.   In addition, the fork will rebound more slowly which can lead it to "pack down" on rapidly repeated impacts.

Edited by GlennRay
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5 minutes ago, GlennRay said:

Overall, the fork will stroke farther and transmit less shock to the handle bars for a given impact with the lighter spring rate. 

I've experimented with lowering the fork oil level and got to a point, about 25mm lower than normal, where my forks would bottom effortlessly over small to medium debris at slow to medium bike speed with 0.46kg/mm fork springs, which are on the firm side for my weight of 180lbs.  This has changed how I understand the contribution of the spring and the air gap.

Compression damping also contributes but has to blow off on big hits or it will feel harsh.

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Keep in mind that the "compression resistance" of the air in the fork goes up as the square of the reduction of the air volume.  You can reduce the spring rate to give a softer action through the "1/4 to 3/4" stroke range and put the oil level back to stock, or even increase it a bit, to resist bottoming.  As you have noted, this is really fine tuning.

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And of course your compression and rebound dampening settings will also affect things, as well as the weight of the fork oil.

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24 minutes ago, GlennRay said:

Keep in mind that the "compression resistance" of the air in the fork goes up as the square of the reduction of the air volume.  You can reduce the spring rate to give a softer action through the "1/4 to 3/4" stroke range and put the oil level back to stock, or even increase it a bit, to resist bottoming.  As you have noted, this is really fine tuning.

Yes indeed, the fork spring is doing all the work until the air gap gets compressed so more rate will keep you riding higher in the stroke.  I don't think fork springs contribute to compression harshness, that is to say that a 0.38kg/mm fork spring will not feel softer than a 0.46kg/mm fork spring on a big hit.  Not sure it would feel much if any different over smaller stuff either.  The spring and air gap do not create the sudden spike in compression rate like fork oil does moving thru an orifice.  Bottoming will produce harshness but I think the nice increasing rate of compression resistance a spring or air gap provides will not.

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The lighter spring will "feel" much better over the lighter, smaller impacts, it will let the front wheel track the terrain much better.  All of this depends on the compression damping of the fork how ever.

Edited by GlennRay

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It's all a trade off in the end anyway.  You will never get a suspension that is supple over small to medium stuff in trail riding and still be able to handle big g-outs or over shooting a triple.

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1 hour ago, highmarker said:

don't assume racetech calc gives you the "right spring"

This times 72!

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1 hour ago, GlennRay said:

It's all a trade off in the end anyway.  You will never get a suspension that is supple over small to medium stuff in trail riding and still be able to handle big g-outs or over shooting a triple.

I can say it can with the exception of a triple, I have never jumped a triple. And won't!

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