Fox forks not using full travel ?

As per title , my 2011 floats won’t use the last inch+ of travel , they are well serviced have the new skf seals and ran at 75 psi ( with full gear on im about 200lb ) even on 2 foot drop offs/ jumps it won’t go any further into the travel , fork feels great but is now doing my head in. Any ideas ???

I have had several pairs of floats and never gotten full travel even off large drops etc.

With all air out can you get full travel – ie is there a mechanical reason.
Try a little less air.

But to be fair if my forks bottomed out on a 2ft drop I’d be putting more air in

Is the sag correct?

Thanks people , sag correct and will use full travel if no air pressure !!! Not happy my 140mm travel forks are only using 100mm at best !!!

Fox design most of their air forks with rising rate springs that make it very difficult to use full travel. Many people chop down the length of the spring push rod on fox air forks to achieve a more linear spring rate.

I cut off 15mm from my spring side rod and was achieving more travel, still not quite full travel. This was on 2009 F120 RLs. Effectively you are increasing the size of the air chamber, so allowing the air to not compress so much when using the full travel.
Its straightforward enough, although I got a mate to drill the hole through the rod dead centre for me.
http://forums.mtbr.com/shocks-suspension/fox-air-forks-modifying-volume-get-full-travel-468341-3.html

You can also try taking some fluid out of the air chamber, you may have too much in there (reducing the chamber size)

How do you get into the air chamber to remove or add fluid?

It mentions in the fox service instructions to put 5ml of float fluid in the air chamber but I cannot see how to do this?

My new 32’s had way too much oil in the air chamber which stopped them using the last inch.
You need to remove the lefthand top cap to remove excess oil.

let air out of forks. Take a suitable socket and undo top.

Id check the sag, i only run 65psi and am much heavier than you!

I found with my old floats that they needed running at a much lower pressure than what the fox manual said otherwise they had no small bump sensitivity and got no where near the recomended travel.

Dont forget setting the sag make sure you are in your actual riding position not leaning over the front or back more than you normally would.

A friend has exactly the same problem with his forks. Will pass this info on. Thanks.

On my my older F100s, I could get full travel if I used low pressures, but the forks felt too soggy with no support if any weight was put on them. I took about 15mm off the air shaft and that worked a treat

I am surprised this is still an issue on newer models though so a simple air tweak may be all you need before you start chopping your lovely 2011 fox forks! Don’t be afraid to let a little air out. (but dont go mad)

edit. Have you taken all the air out and made sure you get full travel?

Sussed mine out so thought I’d post on here to confirm what kiwijohn said above.

Fox manual says 5ml Fox Float Fluid in Air Chamber, mine had 20ml in!

http://service.foxracingshox.com/consumers/Content/Service/oil_volumes.htm

Result? Perfect, I can now get full travel when forks set to correct sag for my weight.

The annoying thing about this is that mine is an ex demo bike bought direct from the manufacturer, so I’d say only Fox or the bike manufacturer’s staff have ever worked on this fork (judging by the lack of any oil in the lowers I’d hazard a guess that the 2011 fork has never been serviced so may have been Fox who put the wrong volume in there from day 1?) Who knows but it’s not good enough really is it.

Hope this helps others.

I’ll bet it wasn’t because it was incorrectly filled at the beginning – the lowers oil migrated past the air spring seal into the air chamber. This is a common fault with that era of Fox floats, causing exactly the symptoms you describe – ie. not gettig full travel, not much oil left in lowers, and too much oil in air chamber.

Simple fix is to exchange a part in the air spring, but you need to order the new part from Mojo. If you don’t fix it, same will happen again over time.

See my post on page two of this thread if you want all the gory details and pics of the offending part.

perthmtb – I think you are probably right actually, had been thinking more about it whilst out riding this aft. Well I’ll see for sure in a few months when they get their next oil change.

Will have a look at that link cheers.

If you are getting oil migrating into the air chamber, then you need to take the foam ring off the piston rod, and replace it with a lip seal, it was a few quid from mojo. I had heaps of oil getting into mine and that’s what I did and they’ve been perfect. A mate just removed the foam ring and didn’t put the lip seal in and his has been fine ever since as well……don’t ask me why!

A mate just removed the foam ring and didn’t put the lip seal in and his has been fine ever since as well……don’t ask me why!

Because the cause of the problem was the foam ring holding oil next to the wiper seal. In theory this was a good idea as it lubricated the seal and made fork travel smoother. However, in practice every time the forks compressed a little bit of oil would stick to the walls and pass by the wiper seal into the air chamber – never to return. Over time all of the oil in the lowers could migrate into the air chamber this way.

The ‘quick’ fix was to just remove the offending foam ring so there was no oil being held there, but better to go the whole way and replace it with another scraper seal with the lip facing the other way so there’s no chance of oil getting past the piston again.

Here’s a pic of the air piston showing the upper scraper seal (black) and the foam ring (yellow).

I got more travel out of my F120s by reducing the amount of float fluid in the air chamber.

I got more travel out of my F120s by reducing the amount of float fluid in the air chamber.

Yes, but thats the nub of the issue – there’s only 5cc of float fluid in the air chamber, which isn’t enough to have any impact on travel – it barely coats the sides of the tube.

So, if there’s enough fluid in the air chamber to affect travel its because the lowers oil is migrating past the air piston into the air chamber and adding to the float fluid. Easy to check – float fluid is dark blue, float fluid plus lowers oil is blue/green colour – turn teh bike upside down and press the schraeder valve – see what colour the stuff that comes out is?

Sure, removing the excess fluid will get your travel back, but – it’ll just happen again until you fix the root cause of the problem, by removing the foam seal and replacing it with another scraper seal. Meanwhile the bushings in your lowers are also wearing out through lack of oil!

The problem with running bugger all air is they seem to dive like mad going downhill, tragically I think the best Floats I’ve had were old 2008 oil bath ones. My new 2012 RLC kashima ones I can’t quite get into the happy medium with. Running them a bit too hard at the moment so don’t get full travel.

Perthmtb – How do I get to that offending foam ring? Only taken lowers off and unscrewed nut off the top of the air chamber so far.

EDIT: And while I waited for your answer to this question, I googled FIT to see what it meant…

http://www.ridefox.com/technology.php?m=bike&t=fit

FIT

FOX Isolated Technology
Air and oil do mix, and in the world of suspension, it degrades performance. Our isolation technology employs a bladder system that simply keeps the oil and air from mixing to provide optimal performance in all riding extremes.
Doesn’t do exactly what it says on the tin!

Soooo, if there’s supposed to be a bladder system in my fork, how come oil can migrate into the air chamber? Presumably a bladder would have to have a hole in it to let the oil in, even if it did migrate past a seal.

The FIT cartridge is on the damper side. The oil migration issue is affecting the air side (i.e. the opposite leg to the damper). No idea how to get to it though I’m afraid.

Lowers off then push the compression rod on the air side out of the leg once you’ve removed the top cap.

Guys above have answered your questions already, so all I can add is that there’s good step by step guides on the Fox service website to show you how to get the air piston out.

Is this the newer Kashima forks or older Fox Floats? My 2009’s ride better than my 2012 Kashima’s – or seems to feel that way (old one’s on HT, new on FS).
Expected the Kashima’s to feel plusher – to me it feels as though the old forks offer better plushness through the travel, the Kashima’s just seem to feel a bit harsh in comparison.

Is this the newer Kashima forks or older Fox Floats?

I understand the foam ring was a ‘feature’ of 2010-2012 Floats only.

Link for air spring removal instructions on the Fox website for anyone else who needs it

http://service.foxracingshox.com/consumers/Content/Service/QuickTech/AllAirSpringQuickService.htm

Anyone got a part number for the appropriate seal for the 2011 float 32 model? I’ve got a set of these and am suffering from the oil migration problem, most frustrating.

First of all I thought it was just that they needed to be serviced constantly – because after servicing and emptying/refilling them they would feel perfect again, then gradually get worse…

Speak to Mojo, they should send you out a new seal free of charge as it’s a known issue.

Sorry, don’t have a part number.

Thanks dirtydog – i’ll give them a try. I’d got so fed up with the inconsistent performance I was considering a switch to Rockshox. Will be dead pleased if it’s a simple fix!

I know this is a stupid question but in the vein of there are no stupid questions only stupid people…
I have the replacement wiper seal to get rid of the foam ring, but it’s clearly designed to go in one way round not the other…
If you imagine it as an arrow shape (ish) presumably the wide end needs to go at the top so the “arrow” points down (from the perspective of the bike being right way up)???

Look at Perthmtb s post ^, there’s a picture with the seal fitted in the correct orientation(should be wide side up). The air pressure opens the seal up when inserted this way.

I’m pretty sure you are supposed to remove the yellow foam ring in that picture and replace it with the new seal are you not? That’s not shown the pick above…

I have however just seen the text saying it should point the other way to the one in the pic! Doh!

Yep the foam ring is replaced with new seal which goes on the opposite way to the top seal.

even on 2 foot drop offs/ jumps it won’t go any further into the travel , fork feels great but is now doing my head in. Any ideas ???

Ride bigger drops 🙂

My head hurts from reading all that tech stuff, I’m useless with it all!

Same problem as the OP, Floats not using all of travel so I wouldn’t mind seeing how much fluid is in them to see if we’ve got 5ml in there or more… how do I do this please folks? Sorry for the daft question.

1) let all air out
2) Take an adjustable spanner (or big socket if you have one) and undo the top of the lh fork
3) remove oil (I had ~40ml in mine!)
4) put in 5ml of float fluid
5) re-install top

Literally took me 2mins, if you can undo and tighten bolt you can do that

1) let all air out
2) Take an adjustable spanner (or big socket if you have one) and undo the top of the lh fork
3) remove oil (I had ~40ml in mine!)
4) put in 5ml of float fluid
5) re-install top

Step 6) If there’s 40ml of oil in your air chamber, ask yourself where it came from as it only starts off with 5ml?

Hint: it came from the lowers, which seeing as they only have 30ml in the first place are now running bone dry and scoring your stanchions and wearing your bushings into dust, so…

Step 7) Give the whole damn thing a proper service, replace the foam ring with the new scraper seal, replace all the fluids, or if you don’t feel mechanically capable to do this yourself, send it to someone who can.