12 990 Adv R Rear Preload

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by The Griz, Feb 3, 2013.

  1. The Griz

    The Griz North Forest Rider

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    Hi all. When trying to set my race sag on my 2012 990 Adv R today I came across some strangeness. Going off of the general rule that your sag should be 30% of total travel, my race sag should be 171.6mm. When the rear wheel is off the ground, as in when the bike is on the center stand, the max travel measured is 572mm, +/- 2mm. 30% of that is 171.6mm. So, when setting my race sag I had to keep backing the preload adjuster knob out more and more in order to try and reach 172mm of sag. Finally I had backed the preload adjuster wheel all the way out. However, even with the preload all the way out my race sag is still only 67mm (505mm measured while I am sitting on the bike)!! Do I need a softer spring? Seems strange. This is the first bike I've owned that had a stock spring on it that was too stiff for me. I am 190lbs (86Kg) nude. Usually I have to buy a stiffer spring right off the bat. Is this normal for the 990 R? Usually bikes are set up stock for someone much lighter than me (typically 170lbs or so).

    Any knowledge or help would be much appreciated. Thanks.
    #1
  2. slackmeyer

    slackmeyer Don't mean sheeit. .

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    Your rear wheel does not have 22.5" of travel. That's the main mistake- I'm not sure what the travel of a 2012 990r rear wheel is- KTM says it's 245 mm, so your sag should be around 74 mm. The fact that you can't quite get there is not too surprising, the adventures are undersprung in the front and oversprung in the rear. You might be ok if you travel loaded up somewhat often, but I ride an S model (had a softer spring than the normal 950) and I still had to go to a softer spring to make my rear shock work right.
    #2
  3. The Griz

    The Griz North Forest Rider

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    Thanks for the help! By mentioning the number 572 I didn't mean that that meant I have 572mm (22.5") of travel. I meant that that's what I measured from the axle bolt to my measuring point on the rear fender when the bike is up off of the ground. When I am sitting on the bike I measure 505mm from the rear axle the my measuring point on the rear fender. That's a difference of 67mm, therefore 67mm of race sag.

    I get it now. Total travel is 245mm. 30% of that is 73.5mm. At 67mm, I'm ballpark which is good!

    What I did wrong is take 30% of 572mm. :rofl 572mm is not the total travel of the rear shock, it is what I measured from the rear axle to my measuring point on the rear fender.

    Thanks again!
    #3
  4. slackmeyer

    slackmeyer Don't mean sheeit. .

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    Yep, you've got it now. And I'm not at all surprised that you would be running 0 preload to get the sag right, so don't worry about that.
    #4
  5. The Griz

    The Griz North Forest Rider

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    Cool, thanks!
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  6. catalina38

    catalina38 Long timer

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    When I got my 990R I was convinced the rear spring was too stiff even though the R models have a softer spring than the standard 990. When I went to get the front revalved and resprung the tuner convinced me the rear spring was fine but it was the valving was causing the harshness and difficulty using all the rear travel. Sure enough the revalving of the shock was a huge improvement. FWIW I weigh about 210 with gear.
    #6
  7. The Griz

    The Griz North Forest Rider

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    Very interesting. Good info. I'm still learning about this bike! Thanks.:thumb
    #7