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Discussion Starter · #1 ·
I have a 2005 Fox Float 100 RLT that is only getting about 3" of travel best case. It does compress fully (1/4" stanchion remaining) with no air, but I suppose this fork isn't open bath, so this probably doesn't tell me anything about the oil level (which I suspect is the problem). What should I check next?
 

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B R H said:
I have a 2005 Fox Float 100 RLT that is only getting about 3" of travel best case. It does compress fully (1/4" stanchion remaining) with no air, but I suppose this fork isn't open bath, so this probably doesn't tell me anything about the oil level (which I suspect is the problem). What should I check next?
Try opening left leg of fork at the top and check there s no more than 5cc of oil in there, that was the issue with my F80RLT
 

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Full Travel

I agree

There should be just enough oil in the left leg to cover the top of the air piston. Too much oil in this leg lowers the volume of the air chamber and will make the spring rate more progressive. After a rebuild I had too much oil in there and did not get full travel until I removed some. BTW for big boys with bottoming issues you can add oil to tune the progressiveness of the spring and control bottoming.
I'm 165 lbs and run about 65 psi to get full travel on my float 100 rlc.
 

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Discussion Starter · #4 ·
5 cc or less in left leg, now what?

Should I actually remove more or look at something else? Sure would be nice if Fox had an exploded view diagram of this thing available so I could know what I'm getting into before I take the right leg apart!
 

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Lurking Homer
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That side is that easy to work on...

Just unscrew that aircap, depressure the the valve then unscrew the top. You will be looking down onto a black peice of plastic which is the top of the air piston. On top of this there will be fluid. Take something like a wooden teriyaki stick and touch the top of the piston to get an idea of how much fluid is on. This amount will probably not be visable without putting something down inside the leg like the teriyaki stick. If it appears that there is barely any fluid then there is the proper amount. If it looks like there is probably enough fluid then there is too much. 5cc(the recomended amount) is not much.

Good luck,
L-Dogg
 

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Discussion Starter · #6 ·
Too much oil in damper?

OK, I measured the max actual fork travel = 88 mm using a zip tie. The uncompressed exposed stanchion (from top of wiper to bottom of crown) measures 105 mm. If I let all the air out of the fork and compress it fully (continuing to let the air out), there is 8 mm of exposed stanchion remaining. Based on these measurements, it appears the max travel should be closer to 105 - 8 = 97 mm. Am I expecting too much to get this travel out of this fork?

My Noleen Mega Air and Marathon S forks both get more than 100 mm of travel, so I expected at least 100 mm when I purchased the Fox.

Could too much oil in the right leg cause reduced travel?
 

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L-Dogg said:
Just unscrew that aircap, depressure the the valve then unscrew the top. You will be looking down onto a black peice of plastic which is the top of the air piston. On top of this there will be fluid. Take something like a wooden teriyaki stick and touch the top of the piston to get an idea of how much fluid is on. This amount will probably not be visable without putting something down inside the leg like the teriyaki stick. If it appears that there is barely any fluid then there is the proper amount. If it looks like there is probably enough fluid then there is too much. 5cc(the recomended amount) is not much.

Good luck,
L-Dogg
Okay, what the hell is a teriyaki stick? Is that like a Slim Jim? At least I'm hungry again.
 

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B R H said:
OK, I measured the max actual fork travel = 88 mm using a zip tie. The uncompressed exposed stanchion (from top of wiper to bottom of crown) measures 105 mm. If I let all the air out of the fork and compress it fully (continuing to let the air out), there is 8 mm of exposed stanchion remaining. Based on these measurements, it appears the max travel should be closer to 105 - 8 = 97 mm. Am I expecting too much to get this travel out of this fork?

My Noleen Mega Air and Marathon S forks both get more than 100 mm of travel, so I expected at least 100 mm when I purchased the Fox.

Could too much oil in the right leg cause reduced travel?
Here's how I fixed my Float 100 RLC, which was also getting only about 3" of travel:

1) Remove top cap from stem.
2) Slide fork out of head tube.
3) Remove brakes.
4) Replace unit with replacement part seen in fig. 1 below.
 

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Discussion Starter · #10 ·
I may have to do the same thing because I can't find any reason for the problem other than that the fork is just too progressive in it's travel. It also feels a bit low on ML7 anyway, so maybe the Float 130 will be just the ticket. If it behaves like the 100, I should get the same travel out of the 130 as I do out of my other 100 mm forks that weigh 200 grams less! Hmmm...
 

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B R H said:
I have a 2005 Fox Float 100 RLT that is only getting about 3" of travel best case. It does compress fully (1/4" stanchion remaining) with no air, but I suppose this fork isn't open bath, so this probably doesn't tell me anything about the oil level (which I suspect is the problem). What should I check next?
I'd say you almost certainly have too much oil in the damper side, take the top cap as per the instructions on the Fox website and take a couple of CCs out... repeat until you get full travel.
 

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Discussion Starter · #12 ·
I thought the damper side (right side with lockout & rebound control) was just a damper cartridge and had nothing to do with the spring rate. The left side, air spring side, is the only side with an air valve, and I've already checked the oil level there and it barely covers the top of the air piston when level. Am I misunderstanding how this fork works?
 

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B R H said:
I thought the damper side (right side with lockout & rebound control) was just a damper cartridge and had nothing to do with the spring rate. The left side, air spring side, is the only side with an air valve, and I've already checked the oil level there and it barely covers the top of the air piston when level. Am I misunderstanding how this fork works?
Yes and no.

Fox Forks are open bath, so the oil covers the damper in the right hand side. Theres an air gap above the oil on the right hand side, this is needed because oil doesn't compress very easily (for our purposes, lets say it doesn't compress at all). As the fork compresses this air gap will get smaller as the oil gets moved into it, this means the air pressure will increase - creating a secondary spring effect. This is a good thing because it stops the forks bottoming out too easily, but if you have too much oil in there, the air chamber is too small and its very hard to compress the air into that small a space. If this is the case, you need to make the chamber bigger. ie. take some oil out.

To cut a long story short, the more oil you have in the right hand side, the more progressive the spring rate, however too much will make it too progressive and it will be very difficult to achieve full travel.

Hope this helps.
 

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Discussion Starter · #14 ·
Thanks, but are you sure this applies to the 2005 models? I just want to be certain before I pull it apart because otherwise I'm just going to get rid of it. The owner's manual doesn't have an exploded view and Fox tech support never mentioned this either. I didn't think it was open bath on the right side although the progressive feel is just like my Marathon when it has too much oil. I tried asking these same questions in as many ways as possible and Fox tech support just never give me a straight answer. Very frustrating.
 

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B R H said:
Thanks, but are you sure this applies to the 2005 models? I just want to be certain before I pull it apart because otherwise I'm just going to get rid of it. The owner's manual doesn't have an exploded view and Fox tech support never mentioned this either. I didn't think it was open bath on the right side although the progressive feel is just like my Marathon when it has too much oil. I tried asking these same questions in as many ways as possible and Fox tech support just never give me a straight answer. Very frustrating.
Well I haven't actually seen an 05 model, but I'm pretty sure it's still open bath. I'd recommend opening them up and giving it a shot. You don't have anything to lose, its a very simple operation.
 

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Discussion Starter · #16 ·
I've messed with enough forks that I shouldn't have any problem doing this. I just didn't want to mess with it unless I was pretty sure there was something I could do about it! Now I am more convinced there is hope! Thank you very much!
 

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Discussion Starter · #17 ·
Well, it is indeed open bath, but oil level doesn't appear to be the problem. The right leg oil level was way down in the fork. I needed a 12" piece of tubing on my syringe to extract some. I removed 10 ml and it made absolutely no difference at all. Judging by the rather large volume of air in the right leg, I can't imagine it making much difference anyway. Should I try removing even more? At some point don't I risk drawing air into the cartridge or is the cartridge sealed?

My gut feel is that this steeply progressive behavior is by design. The air chamber in the left leg (main air spring) is quite low volume to begin with. I'm pretty sure I could shorten the rod that holds the air piston in place to increase the volume and make the fork more linear.

I have to go way down to 60 psi to get a whopping 88 mm of travel. The correct air pressure for my weight is 80 psi and there I get a mere 82 mm. At 80 psi there is about 18-20 mm of sag, which is about where I want it. 60 psi is way too soft. Either way the fork bobs like crazy when out of the saddle.
 
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