Ever wonder about fork oil?

Discussion in 'Thumpers' started by meat popsicle, Nov 19, 2007.

  1. invader

    invader Adventurer

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    I did. And this was my response: http://www.advrider.com/forums/showpost.php?p=11869987&postcount=42
    Luke also mentioned this: http://www.advrider.com/forums/showpost.php?p=5827973&postcount=36]this :evil

    At any rate, I'd like to try Silkolene's Pro RSF next time... Fuchs Silkolene (Denmark) is the largest independent supplier of lubricants in the world. Their synthetic Pro RSF (OEM Suspension Fluid- Fox Factory Inc and Penske Racing Shocks) "Utilizing synthetic technology, this high Viscosity Index (VI), racing suspension fluid was developed to exceed the requirements of today’s competition systems."
    2.5W has a VI of 464, 5W: 372, 7.5W: 322, 10W: 303, and 15W: 235.

    Silkolene's newer 02 and 05 full Synthetic Racing Fork Fluids "based on 21st century Electrosyntec technology, and developed extensively with Factory race teams and Suspension Companies in both 2 and 4 wheel competition including motorcycle, ATV, snowmobile, world rally cars, rally cross, desert racing, and Formula One" are also interesting, although I can't find their actual viscosity and VI numbers.

    http://www.silkoleneusa.com/suspension_fluids.aspx?SECTION_OBJ_ID=1048906
    #61
  2. meat popsicle

    meat popsicle Ignostic

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    Luke also mentioned this:
    http://www.advrider.com/forums/showpost.php?p=5718204&postcount=6
    :augie

    Silkolene's VI numbers look very good.
    #62
  3. MisfitToy

    MisfitToy Adventurer

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    I know its a old thread Blah blah blah... information is still relevant and this is one of the more thorough threads.

    A call to PC about my XR and a few questions about product later I came out with they use Silkolene and only that in the bikes, Now I have used Maxima in the past and it seemed to do alright, but I could tell my forks where having a hard time, It seemed like they where much harsher with Maxima 5wt.
    #63
  4. meat popsicle

    meat popsicle Ignostic

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    If the manufacturers would drop the use of lubrication specs and use hydraulic then you would have a better idea of how a fork "oil" - maybe we shouldn't call it that? Either way, SAE must go. Maybe we should start a petition for VI!

    ps - Redline also has very nice fork oils, and they tell you the Viscosity Index.
    #64
  5. dsauer

    dsauer Been here awhile

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    Another resurrection of this thread - BMW fork oil/susp fluid isn't listed, so who makes it and what VI is it?
    #65
  6. Kawidad

    Kawidad Long timer

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    Old thread, but a goodie that's always nice to bump up the list. :evil
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  7. meat popsicle

    meat popsicle Ignostic

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    If nobody posts the info ask a dealer and let us know :beer
    #67
  8. 2Short

    2Short Adventurer

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    Quick question
    My KTM Freeride manual tells me I need to use SAE 4 oil when servicing the forks, but I can only find specifications as 2.5W or 5W. Anybody has any idea what I should choose?
    #68
  9. JensEskildsen

    JensEskildsen Long timer

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    You can mix it up to get 4w if you really want to.
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  10. 2Short

    2Short Adventurer

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    Pardon my ignorance, but in the end is SAE 4 the same thing as 4W?
    #70
  11. Hipster

    Hipster Long timer

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    With fork oil, it's more important to look at viscosity rather then weight. One brands 2.5w fork oil may have the same viscosity as another brands 5 or 7.5 weight oil. Take a look at this fork oil viscosity chart near the bottom of the page http://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid
    #71
  12. meat popsicle

    meat popsicle Ignostic

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    Maybe not: http://www.engineeringtoolbox.com/iso-grade-oil-d_1207.html (there is a 20 and a 20W, which have different properties... :scratch)

    I think the link from Post #1 that would have helped you most is "The Secret World of Fork Oil", which is dead... so I used the Internet Archive and found the text:

    #72
  13. slideways

    slideways España

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    I like the Redline 2.5 wt in my KTM forks.

    KTM forks seem to be more sensitive to oil height than viscosity.

    Most of my KTM's have a mid stroke harshness that usually can be eliminated by the 2.5 w and lowering the oil level.
    #73
  14. meat popsicle

    meat popsicle Ignostic

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    I'll second Redline 2.5w fork oil. Great Viscosity Index.
    #74
  15. zomby woof

    zomby woof Been here awhile

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    This is a great thread. I'm glad it got bumped up. The relationship between viscosity and damping is an obvious one to me, but you wouldn't believe the people who either don't get it or don't believe it.
    I've been told in the past that you can't tune suspension with oil weight, and last year suggested on a Husky forum that another member change the oil in his new KYB forks to a lighter one to both try and correct the harshness, and set a baseline from which to work in the future. Holy cow was I beat up over that. Pretty much everybody told him that the only solution was to have it revalved, and anything else, especially changing the oil, was a waste of time.

    This past weekend I decided to change the oil in my Enduro Engineering revalved (not me, previous owner) closed chamber KYB's on my Husky CR150. They were OK for motocross, but just OK, and horrific in the woods. I thought knew what oil was in them, and planned to use some Maxima 3W shock oil, a drop of only 3 cSt @40, but I needed a baseline. Well, I was wrong, and didn't have enough 3W to do the job, but I did have 3 bottles of Redline clear. It only has a cSt of 5, compared to the 17 of the oil that was supposed to be in there, but I thought I'd take a chance and see what would happen. Oil's cheap, and the forks are so simple, it would be a quick and easy experiment.

    I didn't know what to expect, but was prepared to have to run the damping adjustment near the top of the range with that thin oil just to keep it from bouncing all over the track. I started off in the middle, and it was fine. it felt better than before, and much less harsh. I increased the C and R but it didn't get better, so I started backing it off. I'm now backed out most of the way on both adjustments, and it's the smoothest, most plush suspension I've ever felt.
    It was the strangest feeling going down that chopped up hard pack straight, through the braking bumps and into the turn like I was riding on the road. I thin k the clear is going to be my new fork oil of choice.
    #75
  16. davesupreme

    davesupreme grand poobah

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    the Silkolene 2.5wt works great in my KTM OC forks.... much nicer than Maxima 5wt....

    that's all i got.... :D
    #76
  17. wadenelson

    wadenelson Rider/Writer

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    All I've got is a salad fork so I prefer an oil & vinagarette...
    #77
  18. wrk2surf

    wrk2surf on the gas or brakes

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    Fork OIL or fork FLUID ???? lets get this party started again..

    [​IMG] [​IMG]

    Cant forget SUSPENSION FLUID too

    [​IMG] [​IMG]
    #78
  19. Mattithyahu

    Mattithyahu Adventurer

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    #79
  20. meat popsicle

    meat popsicle Ignostic

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