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Old 07-29-2013, 06:59 PM   #79504
eakins
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Joined: May 2002
Location: Fort Collins, Colorado
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none taken. i just might have worded it funny, but we are saying the same thing.
that is a solid guide.

race/rider sag is just how much the suspension drops from fully extended to when you sit on your bike (actually standing on the pegs centered to be exact)...using measurement points on the bike. this is needed as the suspension needs to have room to expand back out in addition to compress down.

static sag is how much your bike drops down by its own weight.

the reason i'm asking others about sag #s is there are several "rules of thumb" that exist out there for sag depending on who you ask and what terrain you are on. i've even gotten a range just google searching for DR threads out there.

just wanted to hear what others are using.

as for getting good test results i own this stand.
http://www.harborfreight.com/motorcy...ock-97841.html
i opposite the opposite end i'm measuring in place and use use light pull on straps to stabilize the bike perfectly upright and secure.
i then pick marks on the bike and lift the end i'm testing up in the air with a car jack under the skid plate.
then i measure the extended length #. next i remove the jack and sit on the bike and have my wife measure those same marks.
i take the larger # and subtract the smaller # and get race sag.

anyway,
i'm setting my rear race sag to 95mm (3.5"), per Rick, and seeing how she rides in the back tomorrow.

These are the #s i have for travel (oem high/regular position assumed)
Front suspension – 10.2” travel
Rear suspension – 10.2” travel

using these #s and Rick's he likes 34% (3.5") of travel for rear dirt race sag, so he goes slightly plusher.
i'll work 25% upfront or 2.5"/65mm




Quote:
Originally Posted by Ride Now View Post
I think you got the terminology a little bass-ackword here; no offense. Rather than me messing this up also, I blatantly stole this from a suspension website.






Its in most manuals, its all over the net and most of your riding buddies know how. You’ll probably need an extra hand doing this, make sure they know how to read a ruler. Its much easier using a metric one too, but maybe that’s just us. Have the rider sag (sometimes referred as “race” sag) measurement from your manual for reference.






Consistent, repeatable measurements are essential. First, make yourself a reference mark, centered over the axle with a cross hair. You will eliminate the visual variations that occur when you use the center of a hollow axle.









Your next reference mark will be a location that you can easily hook your tape measure to. For this machine the forward inner fender bolt works out great for more than one reason. The reference mark on the swing arm and this reference mark are very close to parallel with the shock angle. This allows for precise repeatable measurements.









With the machine on a stand and the wheels off of the ground, you can measure the unloaded specification. This is the distance from your top reference point to the reference point you made on the swing-arm.







Record your value, you might want to consider keeping this for future reference. This value is 600 mm, you might note that this is recorded 2 images up directly inside the rear fender. Its handy where & when you need it.











Take the machine off the stand and take your loaded measurement. You will need your gear on and a helper to do this. You must be careful to keep your weight bias front to rear very consistent. It is preferable to weight the pegs standing in your attack position. If you are doing this measurement sitting on the saddle, the measurement will change depending on how far back or forward your butt sits, not very repeatable so avoid doing this.





Now you have both measurements you need. The loaded value was 495 mm, subtract this from the unloaded value of 600 mm and you get a difference of 105 mm, this is your rider sag measurement. If 105 mm was the number you were after, lock things down. If you were after 100 mm, you would put the bike back on the stand and apply more pre-load to the spring to achieve your desired result. If you were after 110 mm, you would remove spring pre-load. We will be adding information on this subject to obtain certain handling characteristics and rider sag settings very soon.





Once your rider sag is set and everything locked down, you can check your static sag. Note we said CHECK not adjust. Static sag is a checking value to reasonably verify proper spring rate, its not an adjustment.





Static sag is measured by letting the machine sit on the ground with only the weight of the bike. Measure the distance between your reference points. Subtracting the static value, 575 mm from the unloaded value of 600 mm will equal the static sag of 25 mm.








To my limited knowledge "race" sag should be about 33% of total suspension travel for the rear; 25% for the front. So if at stock settings, the rear would be 10.2" X 33% = 3.36". Front would be 10.2" X 25% = 2.55". I took the 10.2" from the DR650 Wiki webpage. http://dr650.wikia.com/wiki/Specifications


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eakins screwed with this post 07-29-2013 at 07:33 PM
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