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aka Taprider
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Discussion Starter · #1 ·
I put 3wt oil in my F100X and like it much better.
I was hating the Terralogic. It would not activate easily enough for technical climbing and felt like it had more stiction than an old Mag20 or RS1 on easier trails, even with the threshold a minimum and 52 psi (I weight 150, 160 with gear).
I put in Bel Ray 3wt (12.6 centistoke) [stock FOX is ~31 centistoke, 7.5 wt.]
If you take the brain cartridge out you will note a small orifice at the top of the cartridge, this orifice is always open and allows the fork to reach sag without the inertial valve being activated and allows the fork to move a bit without the inertial valve being activated. I was hoping that lighter weigth oil would move through this orifice more easily and make it less of a kick when the fork first hits a bump before the inertial valve stays open.
Yes the fork is more plush now and when climbing a rough gravel road the fork now moves for 2 cm diameter pebbles (Stock Fox or 125/150 Golden Spectro - 7 wt oil would not allow the fork to move unless I first did a little wheel lift to shock open the brain).
The fork does bob more for rough pedalling, but rough pedalling will make a road bike with 100psi in the tires bob anyway (learn to pedal and you will be way more efficient than imagining no suspension will make you go faster).
The notchiness between open and closed valve is much less now.

An added benefit, before when using 52 psi the negative spring was sucking in 20mm of my travel, then with 20 to 25 mm of sag, I only had 55 - 60 mm of travel). Now I am able to pump up to 70 to 72 psi and still get the plushness I want and lose only 5 mm to the negative spring.
I was doing some 2 foot drops to flat concrete, landing with wheels level, and still had about 3 to 5 mm of travel left over (using 72 psi). At 60 psi I was using all my travel on a very rooty downhill with no big drops (just lots of little ones) but never felt the shock bottom out.

PS the Fox maintenance schedule might seem extreme (I think it says overhaul your fork every 50 hours) but I noticed it didn't even take that long before that Golden Spectro fork fluid was discoloured and dirty looking (where does the dirt come from anyway?, I'm using Enduro Fork Seals now and haven't seen a drop of oil or lost any air - the stock Fox seals were worse than the Exxon Valdez)
 

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Did it fubar the compression damping? I'm guessing you could turn up the rebound to offset the thinner oil but I would think that the fork would blow through the travel faster.

I just installed a 100x cartridge in my RL today and only got to do a parking lot test as it was raining outside. I put 7 weight maxima oil and did notice a 'stutter' as the valve reacted to bumps. My epics brain doesn't do this so I might have to experiment with thinner oil up front.
 

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aka Taprider
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Discussion Starter · #4 ·
undertrained said:
Did it fubar the compression damping? .
No.
I believe because now I'm able to pump up the shock to the recommeded PSI and only lose 5mm to the negative spring. Did another race this weekend near Vancouver, not as rough as North Vancouver's NOrth Shore, but still some moto cross whoop de doos, creek beds, roots and little drops. Still had 3 to 5 mm to spare as indicated by my zip tie. So could have gone a little less pressure but then would have lost more to negative spring and would have same amount of travel in the end anyway.
Last year I borrowed a Float RLC and put it on my bike for a week. It would blow through most of its travel for body movements at proper sag. So maybe lighter oil and more pressure would help a Float fork too (especially those guys not getting full travel).

Oh, another thing, you won't really know how locked out your fork is when brand new since there is a lot of seal stiction, after you have broken the seals which is only a short while before they are broken, you should get a little bit of bob when standing and pedalling before the inertial valve opens. The studder does not go away with 7+ wt oil
 

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CCM--
I've got about 15 hours on the same shock and I can feel a definite lack of initial stiction this thing had out of the box. How heavy are you (I'm about 200#) and do you think for a "semi-Clydesdale" like me an intermmediate oil would work to the same effect you got with your 3 weight?? I have had the same experiences as you with sluggish inertial valve (brain valve) "wake-up" which seems to improve over the course of any given ride.
 

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aka Taprider
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Discussion Starter · #6 ·
jennytalia said:
CCM--
I've got about 15 hours on the same shock and I can feel a definite lack of initial stiction this thing had out of the box. How heavy are you (I'm about 200#) and do you think for a "semi-Clydesdale" like me an intermmediate oil would work to the same effect you got with your 3 weight?? I have had the same experiences as you with sluggish inertial valve (brain valve) "wake-up" which seems to improve over the course of any given ride.
I weight 150lb or 160lb with gear and XC race on courses that are rough. I don't have to rely on sprinting at the beginning for position, since I rely on my downhilling or technical climbing to gain positions (this is BC after all not Europe).
I think 3 weight would be too low for you.
According to everything I've read about oil on this forum and advice from the local moto-x shop you can mix fork oil no problem (even different brands), so loosen the foot nut and allow a little oil to drip out of your right leg, refill from top cap side, you won't even have to remove cartridge and replace with an equal amount of lighter oil. Refer to Enduro Fork Seals website for directions. I think maybe a 6.5 wt mixture would be ideal, but you have to experiment. Maybe only take out and replace 20ml at a time.
 

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CCM--Thanks for your helpful reply.

I dont race but my F100X is attached to a single speed so I do occasionally do some "sprinting" during my climb ascents. In addition, here in Arizona desert country, the single track is very rock and loose. I was wondering whether you experience the "loose headset" feeling sometimes given off in this sort of riding. My headset is OK as I check it every week and it is a CK and one of my buddies who rides a gearie has the F100X and also has this sensation. Have you experienced this sensation and if so, has it persisted after the oil change?? J
 

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aka Taprider
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Discussion Starter · #8 ·
yes I had that feeling
much of it went away after the oil change (there is still some but not as much of a kick), but you get more bob standing 5-10 mm (but not wallow 20-60mm)
 
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