Fox forks: FIT just as harsh as CTD?

Evening all, it would be much appreciated if you could read the ramble below and give me your thoughts.

The fork: I recently bought a Fox 32 dirt cheap from a mate. This is the first Fox product I’ve owned so I’m not too au fait with the workings, but from what I can tell it’s a 32, 140mm, Float, FIT damper, RL model. It’s got rebound and some sort of lock-out/compression dial at the top, which is non-indexed, just says FIT on it. They’re off a full bike, so may be OEM. My mate didn’t show these too much love, so when I dropped the lowers they were pretty dry. I’ve since cleaned them out, soaked the foam rings in float fluid and put 30 mL of Fox green in each side lower.

The issue: Goddam these things are harsh. I’ve tried a range of pressures to go from 20-40% sag, but it doesn’t make a difference. They actually work fine landing drops and bigger hits, but they refuse to absorb trail chatter, and ping my front wheel of small to medium hits. I’ve ridden enough to know that no fork will make the trail a pavement, but when I’m wishing I had my 10+ year old, 80 mm travel Marzocchi’s on, I think there’s a problem. They don’t seem to have an unusual amount of stiction during a car park bounce, and I can feel the really thin layer of oil on the stanchion, so I don’t think the seals are dry.

Solutions: I’ve done the usual search and have come across several discussions on Fox harshness. However, these seem to refer to the CTD damper, and the TALAS models in particular, neither of which relates to my fork. I’m reading suggestions of putting in the Float system, or that the FIT damper is much better. So, I’m at a bit of a loss as to next steps. Do I just need to keep riding them and let the new oil do it’s magic? Should the FIT damper be pretty smooth, or was it just a relative improvement over CTD? If it’s stiction in the damper, is there anything I can do myself to free things up?

Any advice appreciated.

Hi, as a long term fox user (now on RS Pikes) I can offer a bit of experience.
The older fox (non Fit) open bath forks wern’t bad, but feel a bit out dated by modern standards.
When I got my first set of 140 FIT Floats I thought they were a big step forward, mostly in the small bump general trail chatter stuff, they had more grip.
They suffer from a common fox problem tho, it always seems to be a compromise between a nice soft fork for the small bump that dives through the travel on bigger hits. Or, pump up the air spring to cope with bigger hits and loose the plush feeling.
Yours sound worse than normal, lets assume there not working at optimum.

Is the rebound wound right up? Lower leg red cap.
Have you stripped the damper assembly?
This is using separate oil form the 30ml of fox 10wt green in the lower leg.
If the oil has been lost or is contaminated the damper is going to feel poor.
There’s good info on Fox how to on how strip and bleed the bladder. You need a few special tools i made my own its not too big a job.
Alternatively one of the damper guys that post here offered to strip & bleed my damper assembly if I could’t do it myself for about £40.

From fox

http://service.foxracingshox.com/consumers/Content/Service/QuickTech/32FITFullServiceProc.htm

In a word “Mojo” they made my 36 work beautifully

I run a few fit damped forks. You don’t necessarily need to fully strip the damper to refresh the oil and a strap wrench is all you need really. To get into it and refresh the oil. Try this first before sending them off. As above the instructions are on the fox site. ?

What about the 5ml of float fluid that keeps the air piston and inner stanchion lubed, did you renew that?

Bet you didn’t, no one does, don’t know why.

Oh, and Fox 20wt gold lower leg lube works much better than their 10wt (do it all) green damper fluid

Do it again 😉

Got a FIT and a CTD fork in 32 flavour, both perform very similarly (with the CTD in D mode), quite supple over small bump, and not too much dive under braking. My original FIT cartridge (now sat on the bench) is a different story, worked just like the others for a long time, but now feels like yours despite having it bled twice. I think it may have smething to do with the low speed compression setting, as I vaguely recall it starting to happen shortly after experimenting with more, deciding it wasn’t better, then backing it off to no avail. Should really get it sorted sometime.

Different air spring systems in the older FITs forks and the CTDs the later being the far more linear, although they could probably due for a full service, sounds as thought there could be some fluid transfer and the oil in the damper is probably due a change too .

Thanks for the replies chaps, I am taking note, just haven’t been able to reply until now!

NorthCountryBoy, yeah, I think if CTD were a step *back* from these, you may as well have run rigids! Only servicing I’ve done is as mentioned, just dropping the lowers and doing the foam rings and lowers oil. The rebound isn’t done all the way, no. It seems to work quite well, adjuster does what it says and no quirks in the rebound stroke. Do the compression and rebound circuits work on the same oil volume, as this may suggest the damper side has sufficient oil?

I’m quite impressed Fox put that level of servicing detail online. I prefer to DIY bike jobs, and I’d like to think that full strip down is something I could do with a methodical approach, but I’m time poor at the moment. Working on my bike just eats into ride time, and if it was going to be a full service I may just send them away.

However, as dirtydog suggests, I haven’t touched the air spring side either. Very good chance this is bone dry given my mates lack of servicing, and looking at the online guide for the air spring lube (http://service.foxracingshox.com/consumers/Content/Service/QuickTech/AllAirSpringQuickService.htm), looks like something that would only take an hour or so? Would I be right in thinking that a dry air spring would have a more pronounced impact on fork sensitivity than the compression assembly, give the larger diameter seals and possibly tighter tolerances to create the seal?

Would I be right in thinking that a dry air spring would have a more pronounced impact on fork sensitivity than the compression assembly, give the larger diameter seals and possibly tighter tolerances to create the seal?

IMO The inner stanchion sliding up and down over the air Seal head makes up a good portion of the overall stiction, even if it’s not dry the old fluid will have broken down to some extent and lost some of its lubricating properties.

Only a ten minute job to unscrew air cap, have a wipe around and refresh fluid.

Not much help but CTD are not a step back from Fit as most of them use the Fit damper. Evo series open bath, Performance and Factory Fit.

I’d suggest you change the seals on the air shaft as well as they may well be leaking. 😉

I think Loco already referred to this as “fluid transfer” but it might also be worth emptying the air chamber (let all the air out) and see if fluid also comes out. My FIT forks had a habit of letting the lowers lubrication fluid in and needed regular draining/ lowers services before Loco swapped the offending part for an updated version (small o-ring that was foam but should be rubber iirc)

Oh and that generation damper is either “divey” or “harsh” with very little middle ground

Thought I’d give a post strip down update. Dropped the lowers. The damper side, plenty of oil still in the lowers, smooth action from the push rod, damping all the way through the stroke. Seems fine.

Air spring side. Barely any oil in the lowers, where’s it all gone? As mentioned above, forced up into the air chamber. Also has the foam ring mentioned above. What I’m trying to get my head around is: the oil moving into the air chamber will reduce the air volume, so if anything you’d expect the bigger hits to ramp up harshly, but these are fine. Also, with the amount of oil passing through, the presumably knackered seal should be well lubed, so not sure why so much stiction?

Anyway, I’ve redone the spring side with 5-10ml of float fluid in the chamber and lubing up the seal, but haven’t put the 30 ml of u10 wt into the lower as it won’t stay there anyway. Quick test in the street and they do seem a fair bit smoother, but will need to get on a trail. Will email Mojo for options on the air piston seal.

Air seal will have part number ending 010 or 018, foam ring replacement will need year and travel of fork.

Feel free to give us a call as we hold all this in stock 😀

What I’m trying to get my head around is: the oil moving into the air chamber will reduce the air volume, so if anything you’d expect the bigger hits to ramp up harshly, but these are fine.

It’ll be harsher all around won’t it? Maybe worse on the bigger stuff but these Fox ramp up so much anyway I think you’d struggle to see any difference here.

Will email Mojo for options

LOCO or TF Tuned will look after you much better

the presumably knackered seal should be well lubed, so not sure why so much stiction?

But with the wrong spec of oil, float fluid is much thicker, something like 85wt and is fortified with molybdenum.

10wt green is general purpose, ‘do it all’ damper fluid and as such not designed specifically as a lube.

For best results use 20wt gold in the lowers and fox fluid in air spring, anything else will be a compromise.