Author Topic: Setting SAG  (Read 7763 times)

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Offline Paul

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Setting SAG
« on: December 05, 2003, 02:11:46 AM »
Setting Static and Race sag

1. Put the bike on a stand (with wheels off the ground) and measure the distance from the axle to a set point on fender (I suggest you mark this spot with a marker for future reference). We will call this measurement ?A?.

2. Take the bike off the stand.  With full riding gear on, sit on the seat in the ?attack? position (or you may stand, just be consistent whichever you choose). You?ll need some assistance to balance the bike.  Compress the suspension a few times and let it come to rest naturally (do not bounce it up).  Measure from the axle to the mark on the fender, this we will call ?B?.

3. The race sag is calculated by calculating the difference between ?A? and ?B?.

4.  Using the preload collars on the rear shock spring, adjust to provide either more or less preload, in order to get the target race sag numbers.  This may take a couple of tries as you determine how much preload to add or subtract.  Re-measure after preload adjustments.  The recommended range is usually 90-105mm

5.  Now that you have your race sag set, it?s time to check the static sag.  For this you will simply measure the distance from the axle to the fender without you on the bike.  This is just the bike under its own weight, this we will call ?C?.  Subtract this measurement from your ?A? measurement to give you the static sag.

6.  You can use this static sag number to determine if you have the right spring for your weight.  Static sag numbers should be approx 15-25mm.  If your number is less than 15mm, you may need a heavier spring.  If it is greater than 25mm, you may need a lighter spring.

AZSingletracker

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Setting SAG
« Reply #1 on: December 05, 2003, 02:28:46 AM »
on your last sentence, shouldn't it be the other way around with the heavy/light springs?

Offline Paul

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Setting SAG
« Reply #2 on: December 05, 2003, 03:08:08 AM »
Nope :wink:

Reason being if you have less than 15mm after you get the SAG with you then the preload on the spring is too much for the static sag. A heavier spring corrects this problem by needing less preload.

Rowdy-Yates

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Setting SAG
« Reply #3 on: January 08, 2005, 06:45:01 AM »
Im not sure but is this assuming that your suspension is set up already or close to how you ride. Becase you can adjust your rear shock to what ever #'s you want. Then are you considering your front forks I am sure this would affect your rear. I am just looking for more info on setting up both front and rear.  Due to me being very light.

Rick

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Setting SAG
« Reply #4 on: January 24, 2005, 02:48:00 AM »
Actually, setting your sag is the first step in setting your rear suspension.  As Paul noted in his original post, setting the sag helps you determine if you have the correct spring for your weight.  If not, the suspension will not work properly no matter what you do with the clickers.  Once you have the correct spring for your weight, you can move to setting the sag and clickers for your riding position and style.

As for the rear affecting the front, you are 100% correct, which is one reason the correct spring for your weight is critical.  As a note, rebound is the pimary factor in the rear, while compression is the primary factor in the front.  This is not to say that front rebound and rear compression are not important, just less critical.  When we purchase new bikes, it usually takes 2-3 months to get the suspension dialed in to be able to go fast with confidence.

Rick

Rowdy-Yates

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Setting SAG
« Reply #5 on: January 24, 2005, 05:25:09 PM »
Rick how do you determine what rear spring you would need. Should I do what Paul has said???

Rick

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Setting SAG
« Reply #6 on: February 01, 2005, 02:11:25 PM »
Once you find out you have the wrong spring, selecting the right spring will depend upon several components:

1. What spring rates are available for your machine.
2. Determining the current spring rate (If I remember right, this can be determined using a weight and tape measure, but I would have to think about this a little to remember the proper steps)

The Race Tech site used to be a great tool for helping find the right spring rate.  I have not looked at the sight in awhile, but if they still have the section that helps in selecting spring rates, it's a good place to start.

Once you check your static and race sag, post up the numbers and we can help with the selection.

Rick