250X spring question
  • User avatar
    Codeman00
    Posts: 745
    Joined: Wed Nov 21, 2007 9:17 am

    by Codeman00 » Sat Feb 06, 2010 4:57 pm

    (posted in a related thread, but I will post it here too)

    I worked on the suspension a lot today. I found out the biggest part of my problem (abnormally high static sag, a large amount of stiction and non-repeatable measurements). The problem was that I was balancing the bike by my hand on the seat and this was giving me free sag that was more than normal. :roll: Amazing how much a little touch of the seat was throwing the measurements off. I didn't realize it until today and after that, things started to make a bit more sense.

    My final numbers are below for anyone that ever reads this thread in the future:

    Rear Spring / Race Sag / Free Sag Up / Free Sag Down / Free Sag Ave / Spring Length
    5.1 kg/mm / 100mm / 27mm / 33mm / 29mm / 9 7/8"
    5.2 kg/mm / 100mm / 29mm / 36mm / 33mm / 10 "

    Anyway, neither of the springs show a free sag under 25.4mm..... I think 25-35mm is a better target range...a more correct range for the springs that Race Tech and MX-Tech are going to recommend. Remember, their recommendations was a 5.1 and 5.3 respectively, so I averaged it out to use a 5.2. It looks like I could go to a 5.3 and still have a spring with a 10.2" length or so, well within the 9.7-10.4" range.

    I think I'll stick with what I have, the 5.2.
  • Adewhitmarsh
    Posts: 1
    Joined: Mon Oct 07, 2019 1:01 pm

    Re: 250X spring question

    by Adewhitmarsh » Tue Jan 14, 2020 1:59 am

    Hi,would standard crf250 springs be ok on a crf250x 2007 ?? Are the spring rates the same standard??
  • User avatar
    JimDirt
    Posts: 3860
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: 250X spring question

    by JimDirt » Tue Jan 14, 2020 10:20 am

    Welcome to the site !! \:D/

    Actually , you could have started your own topic about this , as this is a 10 year old post ...... but with that said ......

    Yes , the spring will fit , the spring size is for your weight and/or speed/skill , not for the bike weight .... for the most part ........ The stock spring rate for a 250R for the Fork is 0.45 or 0.46 (depending on year) , and for the Shock is 5.3 ..... The 250X standard spring for the Fork is 0.42 and for the Shock is 4.80 , they run a softer spring to keep the suspension plusher in the initial part of the stroke but the 250 is sprung for someone no more than about 150 lbs max , but if you are re-springing for your weight , then go with what spring is required for your weight , so if you weigh 180 for example , you would want a 0.46 or 0.47/5.5 . but the springs will fit , both fork and shock for 250 and 450's you can swap springs around , if you are in the target weight of the 250 stock springs are fine , if not then look for a 450 spring , or aftermarket ...

    Since you did not give your weight , I can only speculate as to what spring you actually need , .... Personally , I spring heavier on the X because the bike itself weighs more , so when compressing the suspension , it actually compresses farther on the same obstacle than the R , and usually when riding a X you have a backpack full of stuff that makes your (guessing) 150 actual weight , seems like 165 to the bike , because you have 15 lbs of extra stuff on , as opposed to riding MX ..... Again , if you are just simple trail riding and nothing more , then you don't need a real stiff spring to compensate for the extra weight of the backpack etc. , just heavy enough for your weight ........ ;)

    For a example , I run a 0.52 fork and a 5.5 shock on my 450X .... But.... I revalved it basically like a Endurocross setup , so it is sprung heavy to keep the forks up in the stroke , but valved very soft with fast Rebound , to hit obstacles hard (watch a Endurocross race and watch the suspension work , that is how I setup my X .... My 450R , I have it valved soft in the initial part of the stroke , and somewhat firm in the middle and end of the stroke , I have it sprung 0.47/5.8 , I am around 200 lbs .... Valving does play a part in spring rate choice , as does the type of riding you do and your skill level , faster rider , stiffer springs , heavier rider , stiffer springs ....... with stock valving , spring for your weight unless you are really abusing the suspension like would be in Endurocross .... For simple trail/off-road riding , you do not need real stiff springs as they will beat you to death .... unless you are really fast....

    The softer the springs , the softer the ride ... to a point , if you are compressing the suspension more than 1/4 the way while just sitting on the bike , you are too far in the stroke and need stiffer springs to bring the forks (and shock) back up in the stroke , the mid stroke is usually harsher , so if you are starting there , the bike will feel harsh when hitting stuff and deflect all over the place in ruts and in rocks , clickers won't help much ....the correct rate spring will eliminate most of that , and you can be at close to stock clicker settings .... ;)
    2020 CRF450R
    02 CRF450R
    2006 CRF450X
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    Weiser , Idaho

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