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carpe mañana
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Discussion Starter · #41 · (Edited)
Hecubus said:
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
 

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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.
 

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carpe mañana
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Discussion Starter · #44 ·
B R H said:
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!
 

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carpe mañana
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Discussion Starter · #49 ·
Der Blaue Reiter said:
...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
 

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MK_ said:
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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carpe mañana
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Discussion Starter · #52 ·
Right leg is much different than the left. There is no pressure and no air spring, it is just the damper. You can just unscrew the top cap without any worries. You might end up having to release some air from the air spring, so that the negative spring compresses the fork some, before you can pull the top cap out enough so that you can add oil.

_MK
 

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Any luck on figure out why the harsh rebound? Want to get as much inpute before this here non-mechanical person tries to take a wrench to fork.

Thanks

Der Blaue Reiter said:
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!
 

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First off, hats off to the original poster of this thread. Thank you!

I just totally cleaned out and put new enduro fork seals in my 2004 Fox F80 RL (the pictorial instructions on that site are amazing!).

When doing so I figured, why not - I'll change the travel to 100mm by moving the "pin" and spacer as per the instructions on this thread.

I haven't had much time to ride it yet, but so far it seems to have worked perfect. The stantions seemed plenty long to support the extra 20 mm (and I think the crown will hold up to the change as well).

I hope it works ( I need 100mm for the terrain here and my frame is built for 100mm of front travel). I'll keep you posted.

Anyone else have more feedback on this change?

K
 

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Does changing travel change the AC height? I've just got a 2006 F100RLT to replace a rigid fork that has AC of 420mm. At 100mm it's a pretty dramatic change to the geometry so if I drop it to 80mm would that be better?
 

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carpe mañana
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Discussion Starter · #56 ·
slaw said:
Does changing travel change the AC height? I've just got a 2006 F100RLT to replace a rigid fork that has AC of 420mm. At 100mm it's a pretty dramatic change to the geometry so if I drop it to 80mm would that be better?
Naturally. You subtract the reduced travel amount from the AC.

_MK
 

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It worked... almost

Hi,

This is my first post on this forum. I just bough a "used" Specialized SJ 2005 with Crossmax SL wheels and Hayes 9 carbon brakes to get back to mtb after 5 years spent mostly on the road.

Inspired by the original post of this thread (thanks a lot to this guy by the way :thumbsup: ), I went ahead and increased the travel of my F80 RL. (By the way, I used a 7/64" allen key to bang the pin out and it worked very well :thumbsup: ). So I thought everything was fine after putting the fork back together until I tried to compress the fork... When springing back after being compressed, it now makes a "klunk" when reaching the end of the extension. Its like there is nothing to smooth out the end of the travel (when releasing it). Any idea as to what I might have done wrong or what I could do.

Also, I had to lower the pressure down to 65 psig before being able to get 80mm of actual travel and a reasonable amount of sag (15-20 mm). I'm 160 lbs and 80-85 psig got me 65mm of actual travel and a 10-15 mm of sag before increasing the travel. Is this normal :skep:

Thanks for your help !
 

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The fork broke before I had the chance to make the modification. However, I did talk with the guys at PUSH about doing the modification. I don't remember all the details, but do remember it was not a one for one modification. In other words, pulling the pin and putting it in a different spot does not give you RL 100. Yes you do get 100 mm, but you don't get all the functionality of a RL 100. There are some internal workings that are different.
 

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Update

Thanks for your reply but I'd like to know if I can run my fork like this even if there is no solution for the sound.

BTW, I forgot to say (see original post above) that I have already tried every trick posted on this thread (servicing and fully extending the oil damper, adding more oil, etc.)

I also measured the extension of the oil damper at 100 mm which tells me that there should be no problem running the fork with that amount of travel.

Anybody got longer term experience with running the F80 with 100 mm travel ? Should I worry about the clunking top out sound or can I ride my fork like this without damaging it ?

Thanks again for your help.
 

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carpe mañana
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Discussion Starter · #60 ·
cereal_monster said:
Thanks for your reply but I'd like to know if I can run my fork like this even if there is no solution for the sound.

BTW, I forgot to say (see original post above) that I have already tried every trick posted on this thread (servicing and fully extending the oil damper, adding more oil, etc.)

I also measured the extension of the oil damper at 100 mm which tells me that there should be no problem running the fork with that amount of travel.

Anybody got longer term experience with running the F80 with 100 mm travel ? Should I worry about the clunking top out sound or can I ride my fork like this without damaging it ?

Thanks again for your help.
My guess would be to look at the negative spring. See if you have two little coils below your air piston on the spring side. Make sure, also, that it is functioning properly.

_MK
 
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