FOX FLOAT: How to get full travel (maybe?)
The following might be of interest to FOX Float/Talas users that are far from getting full travel. If you want to skip the story go to the bold character section.
I had problems with the Fox Float RLC from day one. It worked very nicely and was very comparable to my previous Vanilla/PUSH but the problem was travel. Set up with the correct sag/pressure (between 60-65 psi for my weight) there was no way to get more then 4” of travel. So I did what the MTBR forum wisdom suggests: decrease oil a bit in the right leg (150 instead of 160), and take out some of the FLOAT fluid from the left leg. Ok, now I was maybe at 4.2” (strangely enough travel decreased after a few rides) not good enough. I decided to try to install a spring in the right leg, with the idea that I could use less air pressure and gain some end of travel millimeters. It made for a nicely plush fork but it did not help with the travel.
But … while I was disassembling the fork I realized that the right leg was actually under pressure toward the end of its travel! There was a distinct psssssss of compressed air coming from the right leg if I unscrewed the right top cup after I compressed the fork completely. Could that be it? The Fox instructions tell to add oil in the RL after you inflate the LL, as a result you have a large volume of air in your RL: a whole leg worth of air (not only the leg: the cartidge is also full of air since you cannot cycle it when you add the oil, and the oil seats on top of the cartridge before you close the top cup). Who knows how many extra psi is that but I tried to get rid of all that air.
The fox instructions tell you to: inflate the LL, add the oil in the RL, close the top cup
Instead: compress the fork completely, add the oil while cycling the cartridge (to avoid trapping air), close the top cup, and then inflate the LL
Result: a sizable increase in travel, you can tell the difference just by compressing the fork. I got 5" doing my usual speed jumps, and a much more linear feeling from the mid travel onward.
The recepie above might be obvious to some but I think it is worth mentioning because there are quite a few frustrated FOX users out there ... it seems to have solved the no-full-travel fox float travel problems and let me put back some fox fluid in the LL that I was nervous to take out to begin with
Last edited by Davide; 05-08-2007 at 02:02 AM.
Thanks for the tip. Even though I'm not ready to pull my fork apart yet, I've been paying attention to the posts on this subject.
I completely removed the air from my fork, and then found that I could get total travel. But that last bit still had resistance as though it had air in it.
I think you're on to something. I usually read instructions only as a guideline, and then proceed by using what I think is the best way. It'll be interesting to give this a try.
One thing I have to wonder about without knowing what spring you used- hopefully the spring was fairly "stock" and was captive so that it didn't score the inside of the fork leg surface. I'm sure you thought of that.
Another thought is that perhaps even when you do remove the air, it'll return on it's own once vigorous riding ensues.
And thanks again, because I'm the kind of mechanic who feels a lot more comfortable with a little bit of preview of what I'm getting into. I'll never forget the time I was rebuilding a transmission and pressed a pin into a hole that was blind. And it was the wrong hole. I had to EDM the darn thing out. But forks are pretty simple. Bla bla bla. I'm off for a ride!
Hope it helps ... it seems to work. Anyway, it might be less effective but note that to try the trick you do not really need to change oil (that requires to opne the fork at the bottom too).Instead:
Originally Posted by Gregg K
- decompress the fork (left leg)
- open the top of the right leg (i.e. disassamble the RLC top and unscrew the top)
- push all the way down
- close the top of the RL (grease the cup threads first) while the fork is fully compressed: do not extend the fork, in this way you should mimimize the amount of air in the leg.
- re-inflate (left leg)
...only problem: some air might come back in, through ... the seals?
I put the spring in the right leg (not the left where there is the air chamber) and it was a FOX soft (very widely wound) with the usual heat-shrink for protection. With the spring installed, I could use a pressure of 50 psi to achieve the same sag (I usually use 60-65), the fork felt very nice on stutter but the travel was still around 4" (which makes sense if you believe the theory of the extra air in the RL, if anything the spring made the volume of the RL even smaller). I took the spring off now, and I am back with air only
Originally Posted by Gregg K
... now I am off for a ride
Last edited by Davide; 04-26-2007 at 05:05 PM.
I"m wondering if you mean to just crack the top of the right leg assy. and let the air bleed out. I am guessing you don't mean to disassemble the thing, which includes pulling the knob off the bottom of the fork leg.
It doesn't matter anyways since all of my tools are on my trucks in Humboldt county in storage. And I live in Mendocino. I just realized I can't do diddly squat.
Iam Having The Same Problem With My Float 4 Inches Of Travel. I Want 5.5 Inches.has Anybody Asked Fox About The Problem.i Heard They Had A Problem With The 36s.not All The Travel.too Much Oil.
Could you bleed the air out of the lower leg by inverting the fork and just loosening the propedal nut?
I'm only able to guess until I see the fork disassembled, or see an exploded view of the forks.
Well .. it does not seem to last
Davide, It sounds like you are creating a vacuum on the damper side with your technique.
I'm not familiar with the RLC fork internals. If you can run lower oil levels safely, it would gain more bottom travel with the same sag and be more linear.
(Go coil and live happily ever after!)
High volume fork sleeve
Yes, if (if!) all the observations I describe are real the net result should be some level of vacuum in the RL when the fork is fully extended ... and I am already using 150mm of oil in the RL, and I decreased the FOX fluid level in the LL (that gained a good half inch of travel).
Originally Posted by derby
But I think what is needed is the equivalent of the high volume sleeve for the RP3/RP23 http://www.pushindustries.com/produc...tle=Components
It should really not be that hard to have an adjustable air chamber in the LL ... or have somebody manifacture a cup that gives more volume to the LL ...
Slightly off topic, I looked on the Fox site and they don't seem to publish a tech manual showing how to tear down fork, change oil etc. Anyone have a link?
Originally Posted by Davide
Nevermind...i found it, just had to keep clicking:
for reference: http://service.foxracingshox.com/consumers/index.htm
Last edited by slcpunk; 05-29-2007 at 03:22 PM.
No Tail-Just a Nub
I have the same thing giong on, and emailed Fox - here is a copy of our exchange (after thinking about it a bit, it strikes me as rather lame, very light on explanation or helpful direction. He sent an attachment with a generic list of tuning tips):
I recently bought an Ibis Mojo with an 07 Float 32 and an RP23 on it.
Here are the issues I have (after looking at you manuals and making a number
of adjustments, and triple checking sag/pressure). First, and most
significant, is the fact that no matter how hard I jump on top of my
fork, I get less that 4" of travel out of this supposed 5.5" travel fork (and
there are many others experiencing the same thing out there). What is the
deal and how do I get it fixed?
An easy way to check if there is actually something wrong with the fork
regarding not being able to achieve full travel would be to release all
the air pressure from your fork and compress it fully.
If the fork is working, you should come up to approximately 1/4" shy of
the lip of your wiper hitting the bottom of your crown.
The same principle applies to the rear shock, on full compression you
should come up at approximately 1/4", or slightly less on full
Suspension is not designed to be bottomed out constantly, that would
defeat its purpose.
Our forks and rear shocks become fairly progressive towards the end of
their strokes to be able to accommodate aggressive riding, larger hits,
etc... but will bottom out if you run your air pressure below what is
recommended for you weight and proper fork performance.
Also when coupled with bottom out bumpers which help to soften harsh
bottoming, it will be difficult to get these to compress until they
bottom out unless a severe hit is taken
Bicycle CSR/Aftermarket Sales
Fox Racing Shox
Thanks Joey, that is helpful (and I'm not looking to bottom out, just to
get the advertised performance out of this equipment that I have paid for).
...and so the fix, if, after letting all the air out and there is still
really limited travel? Why would the fork only provide less the 4" of travel if there isn't
something "actually wrong"?
You won't get a precise measurement if you are measuring the stanchion
itself. Measuring from axle to crown, your fork should read
approximately 510mm when fully extended, and 370mm when fully compressed
if this is a Float 140mm fork. This may not be "exact" due to the
manufacturing process and slight variances & tolerances in all the parts
that make up the fork.
At that point there are those rubber bottom out bumpers I mentioned
previously which normally will limit "FULL" compression and protect your
fork from bottoming to approximately 1/4" between the top of the wiper
and underside of the crown on full compression.
If your fork is only getting 4" even after you've released the air
pressure and measuring from axle to crown, then there maybe something
internal wrong with the fork and it will need to be sent in for repair.
If this is the case, I would recommend contacting us here at the number
below to setup service for your fork.
Bicycle CSR/Aftermarket Sales
Fox Racing Shox
You are right it is a very lame reply ... The problem is that they need to have an independent adjustment for compression or bottom out (ot both) ... but they would not admit to it. Marzocchi does it and so I think Rock Shock and the only solution to this real problem is to send the fork to PUSH ...
Originally Posted by sangmatt
As I suspected my ""solution" (basically creating a vacuum in the RL) does not seem to last. Air probably seeps in the leg after sometime and one is back to square one ... I'll PUSH the fork whe I am back in September
A couple of points from FOX
We got in touch with Fox about this problem, had an email round robin and they've added a couple more tips that I'll repeat here.
The Spec. [for travel] is +-5mm…. Keep in mind with the negative spring system the travel can vary a little depending on starting air pressure.
If the fork is coming up 5-10mm short, I would suggest unthreading the air side top cap and removing some of the Float Fluid "air piston lubrication".
The Factory fill is about 5cc stock. By removing some of the Float Fluid you can increase the air volume…. This will make the air spring more linear and easier to get to the full travel mark. Leave just enough Float Fluid in the upper tube so that the fluid just covers the air piston (about 2cc).
A simple way to get the oil out is to wrap the end of a screw driver with a paper towel….. Dip it into the upper tube and soak the oil up.
Also from Fox:
The key here would be correct oil volumes and if they know how to drain the oil out of the cartridge before filling the fork back up with 160cc. If the oil is not drained out of the cartridge you will not get full travel out of the fork.
Damper side of fork: 160 CC
Air Chamber: ( above air piston) 5cc
Air Spring Side lower leg bath : 30cc
See our FOXhelp service web site for full fork service details: http://service.foxracingshox.com/
The other clue may be is that one of the people in the threads has excessive air is building up in the lower leg. This is not normal!
Maybe the ID of the upper tube has a scratch or the piston seal is cut. This type of issue will allow air to pass into the lower leg. Usually the dust wiper seal will pop out…… but not always.
The customer can always send the fork back to us and we can check see the issue first hand with out further speculation on what the issue may be or not be.
Finally, if you guys are not having any success with these tips and the website, you can get in touch with the Customer Service Manager Dustin Spencer. He can be reached at (800) 369-7469 Ext. 6520 or by email at firstname.lastname@example.org
Sorry to hear about the problems, we've had really good luck at Ibis with all the Fox products we sell. We know that the problems are isolated, because as you might image we hear when anything goes wrong.
Full Travel Floats
Here is a sure fire way to make Fox cringe, void any chance of warranty AND get full travel from your Float forks...
As Scott Nicol suggested, less oil in the air chamber will increase its volume and create a more linear spring rate — that makes it more willing to dive deeper into its travel.
In my opinion the spring rate ramps up way too much as the air chamber is too small. I got sick of not being able to ever get full travel and fixed it by making the main air chamber bigger.
The piston at the base of the air chamber sits on top of the compression rod and is held in place by a pin. The pin is simply pushed through the base of the piston and a hole in the compression rod.
I removed the piston and cut the compression rod shorter. I then drilled a new hole in the compression rod for the pin and re-assembled.
This lowered the base of the air chamber and provided a larger air volume. The result is a more linear spring curve and full travel on the trail.
I have run my 130mm Floats like this for over 12 months with no dramas.
I am a lighter rider (64kg/140lbs) and I trimmed about 10mm off the compression rod.
The amount that you trim will depend on how restrictive the travel is for you. I started by making it 5mm shorter but that wasn’t enough.
I'm not sure how this mod will work with the 140mm Float forks. It should be the same as long as the inner surface of the stanchion is smooth and consistent for a good 10mm or so below the standard position for the air piston.
Good luck if anyone wants to have a crack at it. It worked very well for me and I can't see why Fox has such a hard time working it out.
No Tail-Just a Nub
Too involved for me...but...
...what else did you try prior to taking this leap JHwick? Did you check your oil levels (air chamber and dampener?) How much float fluid did you take out and how much more travel did you get?
I'd like to hear more specifics from folks who have been working on this issue, in terms of what they are finding in their shocks, what they did, and to what effect...I hear "check oil levels" but haven't heard much in the way of specific accounts of people adjusting those levels and how it works for them...
I'm especially interested to hear from more Fox Floaters that are under 150lbs like me...
My suggestion is more scary than involved - if you can pull the fork apart and change the oil then you could do the mod that I did.
I tried more or less everything - as I said this was well over a year ago so the specifics are not clear in my mind. Wasn’t happy with the results in any case or I wouldn’t have taken to the compression rod with a hack saw
I vaguely remember that less oil in the damper leg helped but less oil in my XTT version of the Float seemed to leave the valving exposed to air pockets too often. i.e. lay the bike down on its side for a while, pick it up and the valving doesnt work until the oil works its way back down.
Less Float Fluid in the air chamber definitely helped as this is what clued me in on the modification that I did.
If you want to try my idea but are understandably worried about wrecking the fork, source a replacement compression rod for the air side first, then shorten the old rod- all you need is a hacksaw, file & drill plus other basic tools (betcha Fox hate the word 'hacksaw' being mentioned in a forum thread on fork tuning )
Not the editor of MBAustralia are you? If so, you should publish your mod in the tech section See if that gets a rise out of Fox
No Tail-Just a Nub
OK - here are the basics: 07 Float RLC on a mojo, I weigh 145lbs tops. Even with sag on the excessive sag, I could only get 3 7/8" of travel.
I took some of the FOX advice, brokered by Scot Nicol, and let all the air out and checked the travel distance (easy to bottom out...seems logical). I then took off the cap on the left side (damn that is soft metal), and dipped in a screw driver with a paper towel tightly banded around it and soaked up maybe a cc or two of float fluid. After pumping it back up and setting pressure, I could get 4 1/4" of travel
I'm am considering another round of dipping...
Question: is there an analogous trick for the RP23???
I'd say you've found him out..based in Oz, knows about Fox forks, and rides a yeti 575.
Originally Posted by ozelise
< I'd say you've found him out..based in Oz, knows about Fox forks, and rides a yeti 575. >
Weedy guy with glasses? - Nah that wouldn't be me...
< Question: is there an analogous trick for the RP23??? >
No need to fiddle with the RP23 in my opinion. Works sweet on most bikes that I have tried and gets full travel when required.
So is there an easy solution for those not so keen on pulling brand new forks apart? Or at least a simply step-by-step fix that wont challenage folks who've never disassembled forks before?
< So is there an easy solution for those not so keen on pulling brand new forks apart? Or at least a simply step-by-step fix that wont challenage folks who've never disassembled forks before? >
Less Float Fluid in the air chamber is probably the easiest band-aid fix.
Aside from that it is time to get out the hacksaw
I think that is a pity that Fox hasn’t tweaked the air volume as most riders I know of don't utilise all the available travel in their Float forks.
Still, the guys at Fox are pretty clued in so I am sure that there is some reason for it, just wish they would explain rather than offering lame suggestions as though they don't know their product.
Perhaps Fox want to have their travel 90% useable so they don't have people complaining about forks bottoming out - in my opinion they should bottom out or the travel is going to waste.
No Tail-Just a Nub
OK - JHwick, how does the extra air volume affect brake dive on these forks? Other performance issues of getting that extra travel? thanks much...
< OK - JHwick, how does the extra air volume affect brake dive on these forks? Other performance issues of getting that extra travel? thanks much... >
The larger volume allows the fork to use its travel without resorting to very low air pressures. Instead of running 70psi in an effort to gain full travel, I now run 80psi. As a result the fork is probably a touch firmer in the initial stroke with less sag.
Now this will have drawbacks with suppleness over small bumps and oter negatives as well. As with many tuning issues it comes down to personal preference. It works for me but may not work for others.
If you ran the same air pressure with the increased volume, it would have more brake dive as it would be too soft, but I dont think it should be a major issue once you up the air pressure. That said, my forks are the XTT 'inertia valve' forks and the damping would cover up any tendency to dive excessivly under brakes.
In 08 Fox has increased their low speed compression damping and state that this allows you to run much lower air pressures. This will also help you get full travel with less chance of brake dive but will probably bring about other negatives such as lower air pressure = more travel lost to sag. They will argue that the firmer damping makes the fork sit up higher in the travel, but when you sit on the bike, the damping is not going to stop it saging deeper into its travel under your static body weight.
The long and the short of it is that there are pros and cons to every set-up and no wrong and right. I simply posted my idea as it solves the issue that people had raised and it worked for me.
How about a Mojo/575 comparo? All other components being equal.
Originally Posted by JHwick