Proper spring rate

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2/10/2020 4:15 AM

so If I set my race sag at 100mm, I’m getting about 52mm free sag,
If I set my fee sag at 40 mm, I’m getting 90mm race sag,
So to get my race sag at 100mm, and free sag between 30 & 40 mm, I should go down 1 spring rate! Correct?

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2/10/2020 4:45 AM

DB505 wrote:

so If I set my race sag at 100mm, I’m getting about 52mm free sag,
If I set my fee sag at 40 mm, I’m getting 90mm race sag,
...more

Yes . If your static sag is too high then your spring rate is too stiff

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2/10/2020 5:06 AM

That’s what I thought!
Thanks!

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2/10/2020 11:15 AM

Don't think 1 rate is enough, 2 rates.

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2/17/2020 8:37 AM

aees wrote:

Don't think 1 rate is enough, 2 rates.

So I think you may be right, tried a 4.8 & not much change maybe 5mm,
But I’m sure the stiff valving ( for my weight) has an impact on sag setting,

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2/17/2020 9:35 AM

I recently spoke to Race Tech about static sag regarding a setup. They stated that with some modern bikes yz specifically that they now use preload on spring more that static sag as the leverage curves on modern linkage can make it hard to lock in both race sag and static sag.

Also I was told if you run any type of lowering linkage that you should add the drop from the linkage to your sag numbers to get your true sag? Makes sense.

Curious to see what the other On here have done or pro mechanics on here do?



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2/17/2020 11:46 AM

aees wrote:

Don't think 1 rate is enough, 2 rates.

DB505 wrote:

So I think you may be right, tried a 4.8 & not much change maybe 5mm,
But I’m sure the stiff valving ( for my weight) has ...more

Valving has little to no effect on sag, if it is with in reasonable normal settings. Piston in shock can affect some as well as bladder pressure of you take out 40% or more

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2/19/2020 5:19 PM

Is there a baseline for static sag? I think I need to drop a rate in my 19 rmz 450. The collars were actually rattling around just about in order for me to get sag, with a link

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2/21/2020 10:42 AM

Some say between 30-40mm. Race tech claims at least with the 2014 yz250f that they dont go by static sag but buy shock preload at about 6mm. They alluded to Suzukis as well. Maybe some suspension gurus will chime in. Race tech claimed modern linkages have more leverage at the end of the curve.

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2/24/2020 10:07 PM

4-10mm is where you should be in preload on a rear spring with optimal at 5-8mm

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2/25/2020 7:17 AM

Depends on what spring you have. A factory spring with end coils not touching, can ne set up to as much as 12mm. Generally with aftermarket springs, where coils touch, i set them in 3 to 8mm range. Mechanical springs twist as they compress, so less preload is favored. Static numbers vary, but no less than 30mm, and no more than 50mm are range we've used. 35 to 45 optimal. Newer 450s, we are using 95mm to 100mm on some, and 102 to 105mm on others.

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