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  1. #76
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    Quote Originally Posted by PMK
    That's the thing, once you run something decent, any improvement is so subtle it is almost not measurable. In a perfect world, stiction is only a problem setting a precise rider sag, which is almost useless on forks. Underway, in theory the fork never stops moving so dynamic drag is the concern.

    The foam rings play a big part in keeping seals lubricated.

    PK
    On my fork, a major difference would have to come from a mechanical change like reshimming or changing the spring characteristics.

    In terms of lubrication, I think that stiction is critical and dynamic drag is actually not that important. The fork is moving 99.9% of the time, but there is a tiny fraction of a second when it transitions from rebound to compression where the velocity is zero. If there is pure damping only the force is zero but if there is stiction or friction the force is finite. This creates a little extra jolt, and makes the difference between moving 99.9% of the time and moving 99.95% of the time. Hey, that's 2x less jolting.

    The dynamic friction only contributes to the damping forces and offsets the dyno curves a little bit. So it is a small effect on top of a larger one. It would be similar to adding a tiny bit more preload to your high speed shim stack, or however motorcycle valving works.

    This here is a dyno plot of a Bilstein car shock that I revalved, zoomed in to very low velocities. The extra 4 lbs of seal drag don't matter much at high speeds when the shock is making 200 lbs, but matter a lot when the shock is supposed to be making 0 lbs. (The force is offset due to gas pressure.)



    Engine oils are designed to have very low friction at high speeds. Way oils are designed to have very low friction at low speeds.

    As for the foam rings, I'm not sure about how things work on the Fox forks, but on my Reba, it is wedged between the oil seal and dust wiper. That means that it basically makes oil seep out the dust wiper for about an hour or two before it dries out. What is the point of that? Am I supposed to lube my stanchions like I lube my chain?

  2. #77
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    Quote Originally Posted by tiSS'er
    I think this is very true. Now that I have some time on the Bar oil, the fork feels about the same as it did with M1. I think the first few weeks the fork still had the nicely lubed seals and wipers. I have put a lot of miles on the bar oil in the past few weeks and it seems to feel normal again. Not bad, but not necessarily better than M1. Chances are I will go back to M1 as the quality of the oil is better. I have used it for years and my bushings have always lasted, telling me that it is doing its job. A coupl more hard weeks on the bar oil and I will see how it looks.
    Did the B&C oil break down or something?

  3. #78
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    Quote Originally Posted by beanbag
    As for the foam rings, I'm not sure about how things work on the Fox forks, but on my Reba, it is wedged between the oil seal and dust wiper. That means that it basically makes oil seep out the dust wiper for about an hour or two before it dries out. What is the point of that? Am I supposed to lube my stanchions like I lube my chain?
    Take the foam ring out and throw it away. In the Rock Shox implementation it does nothing but catch dirt and hold it against your stanchion.

    Where could I buy some way oil to try?

  4. #79
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    Quote Originally Posted by bad mechanic
    Take the foam ring out and throw it away. In the Rock Shox implementation it does nothing but catch dirt and hold it against your stanchion.

    Where could I buy some way oil to try?
    Try to find a friend that works at a machine shop or some other kind of shop with large moving machinery and bum some off of him. Machine shop tool suppliers or industrial suppliers also sell it, although I have not seen sizes smaller than 1 gal. BTW, the viscosity of the one I run is called ISO 68, or sometimes #2. The most common one is Mobil Vactra, but I have read that the one I have, called Vacuoline, is supposed to be better.

  5. #80
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    FWIW, I actually take great extents to put foam rings in my KTM forks. Yes these I lube prior to each serious ride. Use a syringe with a plastic needle.

    In regards to the dyno run on the Bilstein, yes the seal / piston drag is shown but don't discount the hysteresis upon the fluid / valving. Any chance of running the same Bilstein with no fluid, entirely seal drag? Those are very small IPS along with moderate force.

    PK

  6. #81
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    I guess I will use my fork for a week or so without lubing the seals on purpose, and then suddenly lube them to see if it makes any difference. Now that I think about it, maybe what I have is not a foam ring, but a felt ring. In any case, I recall from my old Marzocchi fork that the oil seals caused more drag than the dust wipers. Is it really that helpful to lube the upper side of the oil seals as well?

    Bilsteins have very low hysteresis because the fluid is pressurized. I didn't bother to measure without fluid because fluid does not create drag at very low velocities because the bilstein design has a orifice in parallel with shims. I assume this is the same with my Reba's Motion Control, and whatever Fox uses. Yes, those are low IPS on that plot. I did that on purpose to measure seal drag, not fluid damping.

  7. #82
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    update

    I have also tried the Fox Float fluid (similar to gear oil, I assume) and Torco RFF 7 as seal lubes, i.e. the lube you put on the foam ring above the oil seal and below the dust wiper.
    This was to test what effects the viscosity of the oil had.
    In all cases, the lubes lasted around 8 hours, which is probably due to the foam rings giving a slow release. The Float Fluid lubricated ok, but it seemed to dry out a bit and made the dirt into a thick sticky mud that was actually somewhat hard to scrape off the stanchions. The RFF7 actually did not lubricate all that well, and also turned the dirt into a thinner pasty sludge that hung around the wipers.

    In the end, I went back to the way oil, Vacuoline 1409. It also has this nice property that it does not try to dissolve or suspend dirt. What you get is a ring of oil, and you can see the individual dirt particles in it. I assume that this means the dirt particles are bigger and thus have a harder time making it past the wipers. I think as a way oil, it is designed to run into little bits of dirt or chunks of stuff and not try to dissolve (detergent) them into smaller specks, but rather keep them as larger chunks so they fall out of solution and get pushed out of the way.

  8. #83
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    anyone used royal purple fully synthetic oil for the lowers? was thinking that if mobil 1's ok, then so is royal purple. but im afraid that it may have seal swellers that may affect my revelation's seals and/or bushings.

  9. #84
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    Quote Originally Posted by crudscraper View Post
    anyone used royal purple fully synthetic oil for the lowers? was thinking that if mobil 1's ok, then so is royal purple. but im afraid that it may have seal swellers that may affect my revelation's seals and/or bushings.
    This is what testing is about. Give it a go and report back, initially everything is great, then report after some time on the fork.

    In a worse case, you trash a set of seals and they are a wear item needing occasional replacement.

    PK

  10. #85
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    I've been using it in fox40,totem,lyrik,for about a year and a half.No problems.I use their synthetic gear lube in my totems air chamber also.

  11. #86
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    Since this was the best thread I've found on fork oil, I figured I'd add my findings for reference.

    I was approaching the problem from the standpoint of stiction. My Fox 32 F120 has never been really stiction free since new (2009 Giant Trance X3). It wasn't bad, but it was never as smooth as my friend's rockshox reba race, which to me is the ultimate in stiction free suppleness. Or even as good as my roommate's Lyric coil. I'm glad to say I achieved almost Reba levels of suppleness on my fox, better than the lyric, and it feels way, way smoother out on the trail, doesn't rattle my teeth out on the rocky, gravely fire roads, for example.

    I'll just jump to the conclusion. For assembly, I used the new low friction fox seals, new air spring seal (it seemed there were several slightly different sizes in the full rebuild package, and I used the smallest one), finish line fluoro stanchion lube rubbed on the stanchions, fox 10wt green for the damper side, Oregon bar and chain oil in the spring side, and fox float oil on top of the air spring. I soaked the foam rings in bar and chain oil before assembly.

    For my measurements I used a contraption made of household electrical wire and a digital scale to measure the amount of force necessary to break stiction of the seal on the stanchion. You can see the contraption in the pics below. The finger dyno was not very useful. This way I got some hard numbers out of it. The numbers were not very consistent, but by re-measuring the same controls over and over (like dry, and fox green), I saw that my method was repeatable within the same ballpark. I tried every lubricating (and non-lubricating) substance I had on hand, but I only recorded the promising ones, or ones what were representative of a group.

    Here's the pictures of my "dyno", and the array of crap I tried:

    Fork Oil Stiction Photos by steel_3d | Photobucket

    And here are the numbers (in grams). Multiple numbers represent high/low numbers I was seeing on the scale by repeatedly pulling slowly till stiction was broken, noting the highest reading on the scale, stopping, pulling again, etc., till the seal got to the end of the stanchion. I re-measured several times up and down the stanchion to make sure I was getting repeatable numbers. It was tricky to keep the seal square, so I repeated many times. I wiped down the stanchion and the seal thoroughly with a rag between each lubricant, but I didn't use any solvents. Cross-contamination didn't seem to be much of an issue.

    -------

    Dry 700 650 600
    Fox 580 550 510
    Float 600 530
    Float plus fluoro 600 580
    Dry 650 550
    Mobil 1250 1000
    Dry 650 600
    Amsoil 5w40 1250 1000
    Dry 580 600
    Maxima 1100 1000
    Fox 725 650 550
    Smoothie 900
    Dry 725 620
    Fox 630 560
    Fox plus fluoro 650 530
    Fox plus grease 680 560 600
    Bar and chain 600 580

    Stiction of the spring only with chain oil plus grease: 1400 1000 800

    Stiction of fully assembled lowers, 1cm off negative spring (don't want the negative spring helping) with 0psi in air spring: 2200 2000

    -------

    The most surprising thing to me was that the motor oils were very bad for stiction. I tried a lot of them, didn't record them all, cause they were all in the same ballpark, over a kilo of stiction seen. The Maxima wasn't great either, though I've heard great things about it. It was a lower weight at 5... The motor oils and maxima actually had worse stiction than a strawberry smoothie! Much worse than a dry stanchion and seal. The automotive gear oils I tried were not great either. Not as good as float fluid or bar and chain oil. Greases were decent on stiction but caused significant dynamic drag according to my finger dyno. Note that I could not measure dynamic friction. You'd need a proper data logging instrument for that, and you might get some interesting results. I'll say that the motor oils felt pretty slick once stiction was overcome.

    Note that I didn't measure lubricating properties (I would call the plastic bushings self-lubricating anyway), I only concentrated on seal stiction for the most supple suspension action. It worked out for me. Would it have been just as good with straight fox green oil as the factory recommends? I'll never know, because I'm not redoing this again. But I tried to maximize my results based on my measurements, and findings from this thread, so the setup I described above is what I went with. I'll go one step further to say that I really wanted to ditch the fox oil due to my experience with this fork from new, and most people's comments that fox can never be plush. I was even considering converting to a coil spring! But I had to go with the numbers, and the end result definitely did not disappoint! I am now fully satisfied with my fork, and I recommend a refresh like this to everyone I talk to.

    Good luck! And let us know if you get different results from a similar experiment.

  12. #87
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    Some great info in this thread. I figured I'd add my own anecdotal results. Pretty much all in 32mm Manitou forks (sherman, nixon, minute etc) but also a smattering of others. Seals I have run many for comparison including Enduro, SKF and Manitou.

    I've used:
    Fork oils, motorex, silkolene, PJ1, Fox, maxima, castrol.
    ATF from Valvoline.
    15w40 diesel engine oil. Several brands.
    5w30 semi synthetic engine oil. Valvoline.
    fully synthetic engine oil.
    Motorex Supergliss.

    The ATF I ran for a year to see if it would eat the seals. It didn't. Lubrication was on par with the slippery fork oils and better than the 15w40 and 5w30 above. There are many fork oils on the market which will give your fork a stiction problem even if it's open bath.

    The best bushing lube I have tried, bar none, is the Motorex Supergliss. This is an industrial slide-way lube. Essentially a competing product to the Mobil that Beanbag mentioned.
    The fully synthetic engine oil works just as well as the supergliss if there is enough of it. But when volumes reduce the stickability of Supergliss is noticable.

    These have reduced bushing stiction to the point that I started to notice the rod seals in the damper cartridge grabbing. Since I've sorted that too I've had to retune compression and rebound damping.
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  13. #88
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    How did you sort out the damper seals? The amount of stiction in the cartridge was annoying me, and no oil, even fluoro, seemed to make a bit of a difference. Unfortunately, I didn't measure the stiction of the damper, but I was assuming it would change once it's in the bath anyway.

  14. #89
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    Quote Originally Posted by steel_3d View Post
    How did you sort out the damper seals? The amount of stiction in the cartridge was annoying me, and no oil, even fluoro, seemed to make a bit of a difference. Unfortunately, I didn't measure the stiction of the damper, but I was assuming it would change once it's in the bath anyway.
    PM sent.
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  15. #90
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    Btw, Fox 20wt Gold oil is available now.. and it feels better than Fox Green

  16. #91
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    Quote Originally Posted by Dougal View Post
    PM sent.
    Would you mind posting it?

  17. #92
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    Quote Originally Posted by bad mechanic View Post
    Would you mind posting it?
    Sure. Removing the energizing rings from shaft seals can reduce the preload and stiction.
    I didn't post it because it isn't applicable to most forks and needs careful consideration of which oil you are trying to contain in which chamber.
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  18. #93
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    I wouldn't mind using way oil in my fork, but the stuff really is pretty expensive. Even at the best prices I've found it's more expensive then good fork oil.

  19. #94
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    Have anyone tried silicone for the bath oil in their fork? Something like this:
    TowerHobbies.com | Associated Silicone Shock Fluid 10 Weight 2 oz

  20. #95
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    Fox are warning not to use the new 20wt Gold with anything other than their new, approved-for-use seals.

    Not sure how true this is in the real world, but thought I'd just warn people.....

  21. #96
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    Quote Originally Posted by bad mechanic View Post
    I wouldn't mind using way oil in my fork, but the stuff really is pretty expensive. Even at the best prices I've found it's more expensive then good fork oil.
    It's very expensive to buy. But you only need a few cc per fork, so the cost per job isn't a problem.
    If you need more than a few cc of lube oil, then you don't need slide-way oil.
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  22. #97
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    Quote Originally Posted by cws196 View Post
    Fox are warning not to use the new 20wt Gold with anything other than their new, approved-for-use seals.

    Not sure how true this is in the real world, but thought I'd just warn people.....
    "FOX 20wt. Gold is compatible with all 34mm, 36mm, and 40mm FOX Low-Friction wipers (manufactured by SKF). "
    "FOX 20wt. Gold is only compatible with the latest version of the 32mm FOX Low-Friction wipers (803-00-878). The label indicates specifically that these wipers are compatible with 20wt. Gold."

  23. #98
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    Quote Originally Posted by Dougal View Post
    It's very expensive to buy. But you only need a few cc per fork, so the cost per job isn't a problem.
    If you need more than a few cc of lube oil, then you don't need slide-way oil.
    At what volume do you think the cut off is?

  24. #99
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    Quote Originally Posted by bad mechanic View Post
    At what volume do you think the cut off is?
    For me it's about 20cc per leg.
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  25. #100
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    Quote Originally Posted by Dougal View Post
    For me it's about 20cc per leg.
    Great information, thank you. I guess I'll be picking up some Valvoline ATF to try out.

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