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  1. #1
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    easy fork oil change?

    I wonder which company makes oil changes the easiest and least expensive - why can't there just be a "plug" to unscrew, drain, refill, and screw the plug back on - and ok, I don't mind putting on a new crush washer. It's nearly hilarious that Fox expects me to change my fork oil every 25-30 hours of riding - that's every 2 - 3 weeks depending on the weather, and their kit costs $40. Just trippin' I suppose...

  2. #2
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    Re: easy fork oil change?

    Rs had speed lube on the Totem but that's it.
    Here is the thing about equality, everyone's equal when they're dead. - Gavroche, Les Misérables

  3. #3
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    You really only need to change or lube the seals. You can do this easily with a screw driver and some fox float fluid. Shimmy up the stopper until you see the seal, clean and re lube it and plug the stopper back in. I'll do a full service maybe once a year if that.

  4. #4
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    While I change my fork oil maybe three times a year, which is at least 10 times the number of hours between oil changes that Fox recommends, when I do change it I find my fork is way smoother. The clearance between the bushings and stanchions is in the order of a nanometer or less, and dirty oil makes a big difference in performance.
    As well, pulling up those seals even with a protected screwdriver blade is still way easy to slip and score a stanchion. Fox no longer recommends removing the seals that way.

  5. #5
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    Speedlube on the Totem is amazingly easy, it's a pity that sort of thing isn't more common.

    Quote Originally Posted by rshalit View Post
    ...The clearance between the bushings and stanchions is in the order of a nanometer or less...
    I'm no engineer, but I think you might be off by a few decimal places.

  6. #6
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    I believe he may be! Typical clearance for fork bushing-to-stanchion outer diameter is closer to 0.035mm. Tolerance is + or - 0.002mm

  7. #7
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    easy fork oil change?

    Magura TS8 fork

    1x or 2x per year 20 minute oil change.
    That's a top reason I went with Magura over Fox. 2014 model will be grease only which seems cleaner and even easier.
    Selma Ti.

  8. #8
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    rough calculations for dirty oil

    Quote Originally Posted by SpecialWarr View Post
    I believe he may be! Typical clearance for fork bushing-to-stanchion outer diameter is closer to 0.035mm. Tolerance is + or - 0.002mm
    I did exaggerate a bit with the words "...or less" (than a nanometer), and decided to attempt to quantify my thoughts with some very rough calculations based in part on Ben Franklin's published research around 1760, in which he found that 0.10 mL of oil spreads over the surface of water of about 40 m^2 in area, forming a monolayer of oil on the water. The length of an oil molecule (diameter, if it were spherical) can be calculated, since: Volume = area × thickness of monolayer:

    Volume = 0.10 mL x (1 liter/1000 mL) x (10^-3 m^3/1 liter) = 1.0 x 10^-7 m^3; since:
    Volume = area x thickness = 1.0 x 10^-7 m^3, then:
    thickness = volume/area = 1.0 x 10^-7 m^3/40 m^2 = 2.5 x 10^-9 m = 2.5 nanometers for the diameter of a single "oil" molecule.

    From: the Particle Size chart at Particle Sizes, I find that atmospheric dust particle diameters range from 0.001 microns - 40 microns (or 1 nm - 40000 nm), and metallurgic dust (perhaps in fork oil after initial break-in) from 100 - 1000000 nm.

    Taking SpecialWarr's information regarding distance between bushings and stanchion of 35 nm, that leaves room for roughly 14 layers of oil (which I suspect is a maximum # of layers - there are many other nano-details -ha-, such as the high temperatures found inside a fork, which means fewer oil molecules can pack into the volume (space) between bushings and stanchion).

    From here, letting my imagination take over (if you're still reading - not to bore you further with more calculations):

    as "dirt" particles migrate through seal and foam ring with stanchion movement, I envision that the 30 mL of oil required for each leg of my Float 36/160 RLC indeed allows for a lot of continuous oil changes between bushings and stanchions as the fork is in use, but as "dirt" particle size in the 0.001 - 10000 micron range become trapped in the oil, oil molecules must be displaced in the space between bushings and stanchions so lubrication will necessarily decrease.

    As I said, I can "feel" the smoothness in the travel decrease after time, especially depending on where I've been riding, ie, how much dust accumulates, and when I do change the oil, I immediately notice the smoothness in travel increasing. I wonder if Fox has collected data when they are saying 25-30 hours between changes; again, I change fork oil at most after approximately 200 - 300 hours of riding, but I only spend about 2 months/year traveling to places that have high dust, the rest of the time I'm on fairly tacky soil.

    Disclaimers:

    1. I'm not an engineer, just a chemist who would rather be riding (-ta ta!).

    2. Franklin likely used olive oil; motor oils (such as Fox 10w) are mixtures, and the molecular size of the molecules in motor oil mixtures can be somewhat smaller or larger than olive oil molecules; furthermore, pure oil vs) oil on water will vary greatly in its actual 3-D structure depending on how the molecules interact with each other on the nanoscale.

    3. As I said this is both rough and imagined - I'd love to find a scholarly article.

    4. OCD: I meticulously clean stanchions, esp. around the top seal, after every ride - I, ironically, hates just the thought of dirt getting into them little spaces - possibly stemming from years ago wearing a hole through my rim with rim brakes in mud....
    Last edited by rshalit; 07-06-2013 at 11:24 AM.

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