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  1. #1
    MK_
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    Changing travel on Fox F80/100 forks

    I remember this question coming up before, whether it was possible to adjust the travel on these forks. There was no certain answer and the best I got from Fox was that I needed to purchase a new assembly for the left leg (air spring side). Quoted at $30. Not bad, but not free. A while ago I picked up a used F80 RLT to use on my race bike. The frame was designed around a 100mm fork, but I figured to give 80mm a shot anyway, since it would drop the front end a bit and give faster steering. I didn't like the ride so I decided to open up the fork and check out the guts, and change the travel and oil. I was happy to see that the person who sold the fork to me did a complete overhaul prior to the sale and the oil inside was pristine. Anyway, onto the travel adjustment.

    In Floats and Vanillas travel adjustment is as easy as a rearrangement of spacers. In Floats it is easierst, since there are less springs. In case of the F series forks, this is more complicated, because in order to save all possible weight there are no spacers, simply, the travel adjusters, if you will, which are pinned into the assembly.

    In order to change travel, you don't need to touch the right leg at all, the one with rebound/lockout/threshold adjustment, only the left one, where the air spring is. Simply unscrew the bolt in the bottom of left leg with a 10mm wrench, and unscrew the top cap with a 26mm wrench. It will also help to remove the air valve cap before undoing the leg cap. Remember to let all the air out before doing any of this, otherwise you might have a little explosion of high viscosity oil. Let the oil drain out and remove the plunger assembly from the leg. This is also a good time to wipe down the inside of the slider and stanchion. The assembly will look like so:



    Examining more closely you will see a hole obove a black ring, like this:



    The black ring has a hole in it as well, through which a pin is inserted. In the picture it is sitting in the 80mm position. At first glance I was pessimistic as to my ability to do anything about it, however, I took a nail and flattened the end, inserted it into the hole in the black ring and banged at the pin with the hammer. (I would advise against a use of a sharp tipped object because the pin is hollow on the inside and the last thing you would want to do is to make the thing expand) After a bit of banging here's what it looked like:



    and a closeup:



    Now, just bang it out further until it almost comes out of the black ring. Try not to get it all the way out, because it might be difficult to insert back into the ring, but I am not sure. You will see when the pin leaves the shaft because the ring will be loose. Slide it to the upper hole and bang it back in:



    Voila! Your F80 fork is now F100. To lower travel just do the reverse. Assemble your fork back up, fill with proper amounts of oil. 20ml in the bottom, 7wt oil, like Maxima. 5ml of Float fluid at the top, to form the air seal.

    _MK
    Last edited by MK_; 03-28-2005 at 03:59 PM.

  2. #2
    nnn
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    It's funny how they provided a hole for increasing travel really cool

  3. #3
    MK_
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    The interesting thing is that the sliders are the same length as the rest in the Fox lineup. It makes me wonder if one could drill a hole a bit higher up and have a longer travel F fork, which would probably ride smoother due to increased air volume, not to mention longer stroke. At the same time, the construction of the F series forks is noticably weaker than that of the rest. The truss brace on the stanchions isn't present, the upper crown has a bit of material removed and the steerer is weaker. Makes me wonder about the feasiblity of the idea.

    _MK

  4. #4
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    Cool pix. My question is that if I want to lower my F100RL to 80mm, do I need to order a spacer from Fox or is it as easy as just re-arranging the spacers inside?

  5. #5
    MK_
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    Quote Originally Posted by Enoch
    If you have a travel adjust spacer I would use it, otherwise you can move the roll pin as described above. The spacer is just easier.
    Exactly. Also, if you're an ultra weight weenie, move the pin.

    _MK

  6. #6
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    If you have a travel adjust spacer I would use it, otherwise you can move the roll pin as described above. The spacer is just easier.

  7. #7
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    thanks...

    Quote Originally Posted by MK_
    Exactly. Also, if you're an ultra weight weenie, move the pin.

    _MK
    Thanks MK, a long time ago, I had the same question and nobody answered it, so looking at your pics, I cleared all my doubts.

    Something I need to know about forx user`s is how thick your drop-outs are. I ask this, because the "service frame" that appears at the first pages of the user manual, saying that they must be 6.20mm or thicker got me thinking. Mines are something like 6.22-23mm, (1 year of use). How thick are yours?

    Tanks a lot!
    bye

  8. #8
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    Nice post. Are the stanchions and lowers the same as an F100? I was under the impression that the stanchions were shorter and in-turn would make it so that there was not enough contact between the bushings and the stanchions. Does the fork seem to yeild any play now? Also, what year is it?

    Thanks for the great pics and descrip.

    L-Dogg

  9. #9
    MK_
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    Quote Originally Posted by fran
    Mines are something like 6.22-23mm, (1 year of use). How thick are yours?
    I haven't measured them, but this is stricktly because the fork that I got had almost zero use and the dropouts are the 2004, beefed up ones (vs 03 and earler).

    Quote Originally Posted by L-Dogg
    Are the stanchions and lowers the same as an F100? Does the fork seem to yeild any play now? Also, what year is it?
    The entire fork is identical, the only difference is where the spacer is pinned. No play in the fork, it is also much smoother due to increased air volume, much smoother. Year is 2004. Also, the only difference between this and the X series or innertia valve forks is the addition of the innertia valve in the damper leg.

    _MK

  10. #10
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    get the right tool

    Harbor Freight has a set of roll pin punches for $3.49:

    http://www.harborfreight.com/cpi/cta...emnumber=32954

    They have lots of other uses, too.

    Dave
    www.davewilson.cc

  11. #11
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    This is good info, thanks.

    I'm curious what the air volume chamber measures. It would be easy to measure from the top of the stanchion tube to the top of the air piston with the fork fully extended.

    So the cartridge was obviously long enough to extend to 100 mm as well? I wonder if this means it is the same cartridge as used in the 100 mm and maybe even the 130 mm versions?

  12. #12
    MK_
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    Quote Originally Posted by B R H
    I'm curious what the air volume chamber measures. It would be easy to measure from the top of the stanchion tube to the top of the air piston with the fork fully extended.

    So the cartridge was obviously long enough to extend to 100 mm as well? I wonder if this means it is the same cartridge as used in the 100 mm and maybe even the 130 mm versions?
    The cartridge wouldnt' extend much past 100mm, if you wanted to go higher, you would need a new one. Sliders on the other hand looked to be the same length as the rest of 32mm Fox brethren. As of the air volume, I would love to help, but Float fluid is so damn expensive, I dont' want to open up the spring side again, also, you would need to measure from the bottom of the threads to the top of the plunger, not top of the crown/slider, since the air valve that screws in with the cap goes in to the end of the threads. You could probably estimate it as 100mm + a few times the internal diameter of the slider or 80mm + a few...

    _MK

  13. #13
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    You shouldn't lose any fluid.

    Unless yours is different than my 2005 F100, all I have to do is unscrew the top cap, drop a rule in there, and extend the fork. In fact, I just did this and I get 144 mm from the top of the crown (flat machined sealing surface - top of threads) to the top of the air piston. It took less than 5 minutes.

  14. #14
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    My 2005 F100 measure 7.3-7.4 mm. There is no visually obvious wear, other than no paint, to the dropout clamp area.

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    that`s too thick (i think...)

    Quote Originally Posted by B R H
    My 2005 F100 measure 7.3-7.4 mm. There is no visually obvious wear, other than no paint, to the dropout clamp area.
    Thanks B R H. But did you measure them right?. No offense, I mean, 7.4mm seems to thick. Mine is a 2004 float model OEM. Are you measuring it, in the part where the hub and the QR go (clamp area)? Or the whole drop-out?

    Thanks again!

  16. #16
    MK_
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    Quote Originally Posted by fran
    Thanks B R H. But did you measure them right?. No offense, I mean, 7.4mm seems to thick. Mine is a 2004 float model OEM. Are you measuring it, in the part where the hub and the QR go (clamp area)? Or the whole drop-out?

    Thanks again!
    I wouldnt' be surprised if they were that thick. I got an 05 vanilla and the dropouts were massive compared to 04 Float.

    _MK

  17. #17
    MK_
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    Quote Originally Posted by B R H
    Unless yours is different than my 2005 F100, all I have to do is unscrew the top cap, drop a rule in there, and extend the fork. In fact, I just did this and I get 144 mm from the top of the crown (flat machined sealing surface - top of threads) to the top of the air piston. It took less than 5 minutes.
    Well, there's your answer I don't think that 04 is any different in volume. Also, a better measurement would be from the bottom of the threads, to get the actual air volume of the inside of the fork.

    _MK

  18. #18
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    Most excellent post! Thanks for the info. I have an F80 RLT 2005 and was wondering the same exact thing. My biggest concern was that the stanctions might be shorter to save weight and that would make it very difficult to increase the travel. I did pretty much the same mod to my Manitou Black. I found they had the notches drilled into the piston shaft precisely were you would need to put the stopper to change the travel. The difference is manitou did shorten the stanctions to save weight so you could reduce travel but not increase it beyond the original spec without a new set of uppers.

  19. #19
    MK_
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    Quote Originally Posted by Hecubus
    Most excellent post! Thanks for the info. I have an F80 RLT 2005 and was wondering the same exact thing. My biggest concern was that the stanctions might be shorter to save weight and that would make it very difficult to increase the travel. I did pretty much the same mod to my Manitou Black. I found they had the notches drilled into the piston shaft precisely were you would need to put the stopper to change the travel. The difference is manitou did shorten the stanctions to save weight so you could reduce travel but not increase it beyond the original spec without a new set of uppers.
    Next time I do an oil change, I should measure the length of the sliders (per Marzocchi manual, circa 2000, stanchions are the parts that are commonly called lowers and sliders are what is commonly called stanchions. I am confused as to what is proper so I will use Marzocchi terminology). It appeared that the sliders were standard length, however, the limiting factor is the damper, anyway, not the sliders, therefore, you can't really go above 100mm without spending money.

    _MK

  20. #20
    WC3
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    Close to full travel at 80mm?

    I have a Fox F100RL and the most travel I have been able to get out of it is 75-80mm, so I was wondering when you had your Fox Fork set for 80mm did you get near 80mm of travel? Good post & pictures! I think I'm going to change my Fox to 80mm and see how it rides.........

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    By stanchions I'm refering to the upper tubes that attach to the crown. The bottom leg castings(is this what you refer to as sliders?) are the same on all models regardless of the travel. My concern is with the stanchion length because if they are shortened to save weight there will be less bushing overlap when the travel is extended.

    Quote Originally Posted by MK_
    Next time I do an oil change, I should measure the length of the sliders (per Marzocchi manual, circa 2000, stanchions are the parts that are commonly called lowers and sliders are what is commonly called stanchions. I am confused as to what is proper so I will use Marzocchi terminology). It appeared that the sliders were standard length, however, the limiting factor is the damper, anyway, not the sliders, therefore, you can't really go above 100mm without spending money.

    _MK

  22. #22
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    More measurements.

    On my 2005 Fox F100 RLT OEM: stanchions measure 300 mm in length (not including the portion that is pressed into the crown). The air chamber measures 144 mm (top of crown to top of air piston).

    On my 2005 Fox Float 130 R: stanchions measure 300 mm in length (not including the portion that is pressed into the crown). The air chamber measures 174 mm (top of crown to top of air piston).

    The only difference I can see between the 100 & 130 is the extra material removed from the arch on the leg castings of the 100 (565 vs. 538 grams, but neither are perfectly clean yet). The steerer is black on the 130 & silver on the 100, but both are aluminum and seem to be the same otherwise. The air piston is white on the 130 and black on the 100, but are otherwise appear identical.

    The Stratos ID cartridge is the same for the 100 & 130 but different for the 80.

    It would be really nice if someone could provide these same measurements for an 80 mm fork.
    Last edited by B R H; 03-29-2005 at 04:22 PM.

  23. #23
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    It's correct.

    I just checked it again.

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    My understanding is 2004 is different.

    Fox advertises that they made the spring rate more progressive for 2005 models. In other words, I believe the air chamber is smaller for 2005 for a given amount of travel.

    PS. At this point I don't really care what the actual volume is. I'm just looking for an easy to repeat measurement to encourage others to post info on the other Fox models. If I wanted to get the exact volume, I'd probably measure it with fluid instead, but it's really not that critical.

  25. #25
    MK_
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    Quote Originally Posted by WC3
    I have a Fox F100RL and the most travel I have been able to get out of it is 75-80mm, so I was wondering when you had your Fox Fork set for 80mm did you get near 80mm of travel? Good post & pictures! I think I'm going to change my Fox to 80mm and see how it rides.........
    First, make sure the air spring is set to your body weight. If it is, open up the right leg, the one with the lockout lever and take out 5ml of oil. close it back up, and go for a short ride, you should be getting more travel already, if it still isn't full 100, take out another 5, until it is. It is comon that forks have too much oil in them from factory.

    _MK

  26. #26
    MK_
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    Quote Originally Posted by Hecubus
    By stanchions I'm refering to the upper tubes that attach to the crown. The bottom leg castings(is this what you refer to as sliders?) are the same on all models regardless of the travel. My concern is with the stanchion length because if they are shortened to save weight there will be less bushing overlap when the travel is extended.
    On the contrary. Stanchions are the bottom leg castings. Sliders are the upper tubes. and they are not any shorter on F80 than F100.

    _MK

  27. #27
    MK_
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    Quote Originally Posted by B R H
    On my 2005 Fox F100 RLT OEM: sliders/stanchions measure 300 mm in length (not including the portion that is pressed into the crown). The air chamber measures 144 mm (top of crown to top of air piston). ...
    I think that this makes sense that the sliders are the same on all florks, since that's what bottoms out. If they were any shorter it would result in the damper or the airshaft taking the impact of a bottom out, and they are far less robust structures. I would imagine the air chambers to be identical on all floats. Dampers on F forks are probably a bit shorter to save weight, so they don't extend full 130mm. There is some material taken out of the crown and the steer is different. I remember talking to a Fox guy on a phone a while ago and he mentioned that it is weaker. Also, on 04 and below, not sure about 05, there was no truss brace on the arch connecting the two stanchions, which results in a less torsionally rigid fork. I will take the measurement of the air chamber when I get home.

    _MK

  28. #28
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    Quote Originally Posted by MK_
    On the contrary. Stanchions are the bottom leg castings. Sliders are the upper tubes. and they are not any shorter on F80 than F100.

    _MK
    Trust me, its the other way around. Go here for example http://www.answerproducts.com/items....id=1&itemid=17 qnd see they refer to stanchions to the upper 30mm tubes. The lower castings are the sliders, as in they are the part that slides up and down, not the fixed part of the fork to the bike.

  29. #29
    MK_
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    Quote Originally Posted by Hecubus
    Trust me, its the other way around. Go here for example http://www.answerproducts.com/items....id=1&itemid=17 qnd see they refer to stanchions to the upper 30mm tubes. The lower castings are the sliders, as in they are the part that slides up and down, not the fixed part of the fork to the bike.
    ok ok. I'm throwing away the Marzocchi manual.

    _MK

  30. #30
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    Quote Originally Posted by MK_
    I think that this makes sense that the sliders are the same on all florks, since that's what bottoms out. If they were any shorter it would result in the damper or the airshaft taking the impact of a bottom out, and they are far less robust structures. I would imagine the air chambers to be identical on all floats. Dampers on F forks are probably a bit shorter to save weight, so they don't extend full 130mm. There is some material taken out of the crown and the steer is different. I remember talking to a Fox guy on a phone a while ago and he mentioned that it is weaker. Also, on 04 and below, not sure about 05, there was no truss brace on the arch connecting the two stanchions, which results in a less torsionally rigid fork. I will take the measurement of the air chamber when I get home.

    _MK
    Yes it makes sense they have to be the same length since it is the part that bottoms out. However some manufacturers such as Manitou make them shorter and put a sort of spacer at the very bottom of the shaft to effectively raise the bottom of the lower leg castings to correct amount so the stanchions will bottom out properly.

  31. #31
    MK_
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    Quote Originally Posted by Hecubus
    Yes it makes sense they have to be the same length since it is the part that bottoms out. However some manufacturers such as Manitou make them shorter and put a sort of spacer at the very bottom of the shaft to effectively raise the bottom of the lower leg castings to correct amount so the stanchions will bottom out properly.
    Man, this post is starting to get impossible to follow, even finding an emailed response is hard. Anyway, I see what you're saying about the Manitou, but I don't remember seeing any bumpers. I think the castings (per Manitou website ) are odentical for all foxes, only color differs and presence of V brake bosses.

    _MK

  32. #32
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    Air chamber volume measurement.

    Quote Originally Posted by MK_
    I will take the measurement of the air chamber when I get home._MK
    Measure the distance from the top of the crown to the top of the air piston with the fork fully compressed It's much easier to do that than to fight the negative spring trying to hold the fork extended while taking the measurement! The fully compressed (remaining) volume is what actually matters the most anyway.

    Thanks for taking the time to do this!

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    Bushing overlap measurements.

    On both my forks (2005 130 & 100), the bottom of the lower bushing is 165 mm into the leg casting (measured from the top of the seal lip). This means that if the bottom of the stanchion were aligned with the bottom of the lower bushing (maximum extension with stanchion 100% contained in bushings), a 300 mm stanchion would be 135 mm out of the legs. In other words, either of these forks could be made 130 mm travel with 100% bushing overlap. The last 2 or 3 mm of the stanchion is tapered, so that's probably the reason for the 5 mm extra in this case.

    Earlier models could be entirely different and so could the 80 mm. At this point, it sounds like the only real difference is the cartridge length. If the 80 mm stanchions are 300 mm long and you have the right (i.e., long enough) cartridge, I see no reason an 80 couldn't be made into a 130.

    We really need confirmation on the 80 mm measurements.

  34. #34
    MK_
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    Quote Originally Posted by B R H
    It would be really nice if someone could provide these same measurements for an 80 mm fork.
    on my 04, fully compressed, I measure 48mm from top of crown to the air piston. I also have about 6mm of exposed stanchion. It is worth mentioning that the cap for the air chamber, rather the threads are 10mm tall and the cap is machined 4mm deep on the inside (looking from the bottom, up).

    _MK

  35. #35
    kee
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    Good Infos. Thank You.

    I have been wondering if it is possible to change the travel of my F80RLT to 100mm travel. It is indicated in the Fox manual that F80RLT and F80X are 80mm specific. The travel cannot be increased. The 100RLT and F100X on the other hand could be reduced to 80mm travel, with a spacer. I have recently emailed to Fox. The reply was that If the decal actually says "Float" on it and not just F80RLT then it would be possible. Mine did not come with the "Float" decal

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    Any more details on why?

    I'm really curious what is different on the forks Fox claims cannot be changed. I don't see how it can be the leg casting because any shorter here and tires wouldn't fit. I doubt the stanchions could be different enough to prevent a fork from being extended at least 20 mm. The extra hassle involved in making the fork different in this respect just wouldn't be worthwhile anyway. I don't see any real weight savings with shorter stanchions, The tubes just don't weigh very much to begin with, especially considering the extra stuff that would have to be added to make them work. It must be the cartridge length. If that's the case, the fork is still "upgradeable" - you just need to purchase the longer cartridge (from Fox, Stratos, or wherever).
    Last edited by B R H; 03-30-2005 at 10:16 AM.

  37. #37
    MK_
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    Quote Originally Posted by B R H
    I'm really curious what is different on the forks Fox claims cannot be changed. I don't see how it can be the leg casting because any shorter here and tires wouldn't fit. I doubt the stanchions could be different enough to prevent a fork from being extended at least 20 mm. The extra hassle involved in making the fork different in this respect just wouldn't be worthwhile anyway...
    I will have to take some pictures of the castings to show you the difference, or something, because it is in plain sight that the brace that connects the two lower parts is different. More light weight, without the truss on the inside of it. I am not sure how much torsional rigidity you lose there, but you do. Going 130mm with those lowers might expose that weakness dramatically. I already had issues with the 05 Vanilla RLC flexing and ended up replacing it with the Z1 FR and I'm 170lbs. Furthermore, Fox themselves told me that the steerer will not withstand the forces exerted on it by a 5" extension. A notch over 4 might still work, however. Then, if you replace the damper with the plain Float damper, the quarter pound weight difference between the two (as reported by weightweenies.starbike.com) will be reduced dramatically. I don't know what's your reason for thinking about doing this. Whether you want a longer travel fork, but don't want to shell out the money? or you wanting an even lighter Float? At any rate, for what it's worth, I am certain that this is doable, just drill a hole above the 100mm one and get a new damper and you'll be set. You might actually get away with getting just parts for the damper, I remember replacing a few elements on my old TALAS damper and it wasn't that big of a headache. Once you finish it up, I assume that you'll need to be a tad more gentle on it than a plain Float, be nice to see someone do the test, actually.

    _MK

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    More on differences.

    I think I already know what the difference is with the arch. My 130 and 100 are different too. The 130 has "webbing" and the 100 does not (obviously machined out afterwards - i.e., it had webbing in the original casting). The difference in rigidity between the two castings is easy to feel by hand - the 130 casting is quite a bit stiffer. However, the 130 fork is a noodle at 130 mm, in my opinion - the casting improvements don't help enough at that length. I also have a Noleen Mega Air and the castings are very nearly as stiff as the Fox 130, definitely stiffer than the Fox 100, and weigh almost exactly the same (actually would be less if bossless like my 130). As I reported above, the weight difference between the two Fox castings that I have is ~25 grams - probably more than just the webbing (normal variances elsewhere too).

    I don't think there is enough detail on the Weight Weenies website to really know what the true weight difference is between an 80 and 100 mm Fox. Oil volume is just too variable. I don't believe it is 1/4 pound. It should be more like ~25-30 grams due to a shorter shaft on the cartridge and less oil.

    There may be one more difference on the 130 - the steerer. The tubing on my 130 does seem to weigh just a bit more per mm than on my 100. I don't have enough of a sample to be sure though. The 130 steerer seems to have ~0.25 mm thicker wall. It also makes sense that it could be heavier in light of what you say Fox told you regarding the steerer strength.

    My reasons for asking these questions is to simply get all the info out here so people can make better choices rather than always buying new & expensive forks. The Fox forks have alot of aftermarket support (Enduro, PUSH, Stratos), so they should have long useful lives. I am also considering reducing the travel on one of my forks to 80 mm, so I want to know what trade-offs I'll be making.

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    Great, thanks!

    That is slightly larger than on my 2005 100 & 130. I measured them extended, but if I subtract the actual stroke, both end up at ~46 mm. The top cap & crown may be different enough to matter too - I'm just not sure. I haven't tried to work out how much volume really matters yet. I'll do this and also measure these values again (compressed volume, top cap volume, etc.) and report back. If people can really feel the difference in 5 mm oil level on the right (damper) side, the exact volume may matter more than I think it does. On the left (air piston) side, a few mm may make a noticeable difference since it is a larger percentage of the entire volume.

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    One other detail on differences to note. The 80mm RLT has crown material shaved away around the stanchion joint. The 100mm does not. I have a feeling Fox's unwillingness to admit the F80 RLT can't be upgraded has more to do with this than with anything else. They probably just prefer you get the 100 with the slightly beefier crown to run 100mm. This is probably what accounts for all the weight difference between the F80 and F100 since all else appears to be the same.

  41. #41
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    Quote Originally Posted by Hecubus
    One other detail on differences to note. The 80mm RLT has crown material shaved away around the stanchion joint. The 100mm does not...
    I didn't realize that this was the case. Maybe this is stricktly due to the fact that if they didn't do so there would be 0 difference in the two forks otherwise, other than travel. During my conversation with Fox, I received no warning about an issue of increasing the travel of the 80mm to 100mm. Also, 100mm Foxes do ship with the spacer under the travel stopper (although not all, to my understanding), which would account for a few extra grams there as well.

    edit: Actually it makes no sense for the 100mm to be shipped with the spacer, because it would make them 80mm travel, so it would have to be the 80, but these are meant to be lighter, so that's improbably. I was just thinking about what a Fox rep said to me, when I asked about changing travel and didn't think it through.

    _MK
    Last edited by MK_; 03-30-2005 at 11:21 AM.

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    No spacers in my 2005 F100 RLT OE or Float 130 R.

    But they did come with spacers to reduce the travel to 80 or 100 mm, respectively. Both air piston shafts have the full array of holes for setting the travel to 80, 100, or 130 mm.

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    The crown on my 2005 Float 130 R is shaved, but the one on my 2005 F100 RLT OE is not! Sort of strange hey? I can't feel any difference in stiffness between the two uppers by hand, but the difference in the lowers is considerable (130 w/webbing is noticeably stiffer). The uppers on my Noleen Mega Air feel just slightly stiffer than either Fox and the lowers on the Noleen are nearly as stiff as the 130.

    I doubt any of the casting differences on the Fox forks amounts to more than ~25 grams total - magnesium is light! As a point of reference, brake bosses weigh about 12 grams (on a 2002 Marzocchi Marathon anyway - I shaved them off).

    So it looks like the reported weight differences must be due to normal casting variation (as well as slight design differences), different oil levels, slightly different steer tubes (at least on the 130), and the use of spacers on some forks.

    The 2005 Fox manual shows the same oil levels for all the air forks (30 ml left under air piston, 155 ml right, 5 ml top of air piston). It lists different U-cup (air piston) seals, but they look the same on mine. Any idea what this is all about (maybe a different durometer based on stroke for wear)? Also, what about the negative & top-out springs? Are these the same on all the forks? Mine look identical between the 100 & 130 and it seems logical that they would be the same on the 80 as well.

  44. #44
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    Quote Originally Posted by B R H
    The 2005 Fox manual shows the same oil levels for all the air forks (30 ml left under air piston, 155 ml right, 5 ml top of air piston). It lists different U-cup (air piston) seals, but they look the same on mine. Any idea what this is all about (maybe a different durometer based on stroke for wear)? Also, what about the negative & top-out springs? Are these the same on all the forks? Mine look identical between the 100 & 130 and it seems logical that they would be the same on the 80 as well.
    I think that from a perspective of a mass produced item, the less you vary between one item and the next, the more you profit. This most likely leads to all 32mm Fox forks being nearly identical. I think that in our conversation we have uncovered all of them. I do think that the negative spring is identical in all 32mm Fox offerings, could even be the same in the 36 and 40 for all I know, but I don't want to venture into uncharted territor (at least by me). The fact that the new crowns are shaved on the Floats probably suggests that the design passed long term reliability concerns and is safe to use throughout. I would imagine if all crowns are shaved around the outside, then it equals one less cast and cheaper production. I don't now why the different U-cup seals, and why they appear to be identical, your guess is as good as mine. So it all boils down to the spring, wheather air, coil or talas, assist spring on the damper (vanilla), length of the damper (F series), the steerer (thinner on F series), presence of v brake bosses, shaved crown (looks like it varies, not shaved on Vanilla, I've got one of the new ones), shaved truss (F series), hard annodized internal area of the stanchion (Float) and finally, R, RL, RLC variance. All these little details are pretty minor, which makes me believe that Fox guys are brilliant at marketing their nearly identical forks, which vary very mildly between one another and vary in cost substantially. It seems funny now that the F costs so much more than the plain Float, where the main difference, in terms of production steps is the machining of the truss off of the connector between the lowers, while the end result is an inferior fork in terms of performance.

    _MK

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    Thats interesting that your float 130 has a shaved crown. The pics I've seen have no shaved crown and my friend has a F100RLT with no shaved crown. Seems to show the crown is more than capable of handling 130mm in any of its form and Fox just uses it as a means of differentiating their products on some models.

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    Either that or someone is having fun with a grinder along the assembly line! Ever notice the poor finish work at the bottom of the legs? They don't take spend much time cleaning up the castings.

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    Stumpjumper Change

    I was wondering if anyone has changed their Float on the 2004 Stumpjumper hardtail over to 100mm from the 80mm and if it still handles well enough/you got any benifit from it before I decide to do it.

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    topping out

    Hey MK_,
    I tried this with mine last night. I have the 2005 F80RLT and i noticed that mine has three holes on the leg(where spacer goes). I set on the 100mm one, put fork back together, but now it tops out harshly. Do the springs need any rearrangement?
    I never touched the right leg, but was wondering if maybe I need to open it up to let the air equalize for the new length?


    For the record, My fork was making clunking noice(similar to loose headset) when breaking.
    I figure it is a bushing issue and plan on sending it for repair.
    That's why I decided to at least take a look and try this modification.
    Thanks!

  49. #49
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    Quote Originally Posted by Der Blaue Reiter
    ...tops out harshly.
    One thing that will help is adding more oil to the right leg. It stopped the harsh topout on mine, but it did limit travel, with enough oil. I eventually took the fork apart for service, oil change, seals, etc. and when I put it back together, it was fine. I believe that big part of the problem is that the damper leg has never extended this far before and it needs to be broken in. You can try to manually pull the damper rod as far up as it will go. The topout went away on mine precisely after I did that.

    _MK

    Before you diagnose yourself with depression or low self-esteem, first make sure that you are not just surrounded by a*holes

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    Quote Originally Posted by MK_
    One thing that will help is adding more oil to the right leg. It stopped the harsh topout on mine, but it did limit travel, with enough oil. I eventually took the fork apart for service, oil change, seals, etc. and when I put it back together, it was fine. I believe that big part of the problem is that the damper leg has never extended this far before and it needs to be broken in. You can try to manually pull the damper rod as far up as it will go. The topout went away on mine precisely after I did that.

    _MK
    thanks for the info.
    can i do that from bottom of right leg or do I need the open up top cap to pull the damper?

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