[Closed] Fox 36 Air Spring

Avalanche dampers are fantastic so as you say, unlikely to be that. Try removing the damper and see how the air spring cycles on its own. Perhaps there's a trapped seal or twisted lowers causing the fork to bind.

I gave up on my air spring and fitted the PUSH coil conversion along with Racing Brothers Lycan seals .  Not ridden it yet(have you seen the state of the Downs lately) but forks stiction has almost completely disappeared.

I have a thread called Harsh feeling 36’s on here but due to my Luddite IT skillz and STW forum “improvements” I cannot post up a link.

How much do you weigh OP? And was the damper cartridge brand new and tuned to your weight?

Possibly too much oil in the Avvy cart slowing it all down?

That said if it's the same problem you had with MRP then it sounds like you have eliminated that and it's probably Air spring related.

I'll second that Avvy carts are awesome. They usually are fit and forgot, I always think they ride different to other carts as I find I'm not really aware of it working / moving so to speak. The rider specific settings they send with the cart are usually pretty bang on, don't think I've ever had to go more than 5psi either way and no more than 1 or 2 turns more or less rebound or compression. They do really just seem to work.

Thanks everyone for the replies,

Onzadog - thanks I will give that a go, had no idea you could run it without the damper, but would be interesting to see if its still slow.

The thought had occurred to me to get those PUSH springs, I've heard on that other thread that they're excellent, its just at what point do you stop chucking money at something really. TBH I have BOS Devilles on a 26" bike and am sort of kicking myself now for not just getting another set. Performance of the BOS damper is first class, its just I'd hoped that the 36 chassis combined with the Avy damper would be awesome.

I'm about 82kg and the cartridge is brand new. As you've all said, Avvy cartridges have a great reputation so its unlikely to be that. This thread does give me some ideas though, so thank you.

Oh actually 1 thing to say having gone out today. I tried that burping technique whereby you pop a zip tie under the seal. After this they did seem a bit better, but don't blow you away. Plus its warmer today, I don't know if the Fox air spring gets affected by the cold?

Not really sure how the air spring could cause this.

It is after all just a piston with a seal on.

Might be a bit out there but you sure the fork isn't bent or the bushes are binding?

Does it cycle up and down smoothly with the top cap on the air spring off?

what fork oil are you running in them?

my avalanche damper felt rubbish with standard 5wt in..

switched over to Maxima fork FLUID (not their fork oil) as thats the closest you can get in the UK to the spectro stuff Avalanche recommends.. and it improved it a fair bit..

it works even better now i've tweaked the compression and rebound stacks to speed things up a bit..

that said.. Avalanche stuff doesnt feel plush and lovely and boingy like a magic carpet ride in my opinion.. and does feel kind of wooden if you are just pootling about..

I thought it was rubbish when i first got it.. to the extent i strapped a gopro onto the downtube to see if it was actually working properly!!

push it hard though.. and it is very good.. once setup properly..

Ah yes, could be the oil. I was fanatical about finding the Maxima stuff but I could imagine the wrong stuff could make it a bit of a dog.

My Fox 36 2016 have been harsh as hell since I got them, they bind in the first part of travel and the stiction is terrible. No amount of re shimming, servicing or messing around with pressure and tokens has made a blind bit of difference. I recently had a PUSH tune that made them feel a lot better but still not like a top of the range and very expensive forks. Talk to TF I reckon that the best money thrown at them is the PUSH coil upgrade as it removes the problem.

Did you know that Fox will rebuild them with the 2018 internals (Air spring and damper mods) for a pretty good price? They'll even throw on new graphics. Having been smashing about on some 2018 forks for a little bit they are very good. You could sell your mods for probably the same price as a complete rework of the fork internals both air and damper. Just a thought.

Buy a MRP FulFill adapter for £40, fit it and be delighted with the results. Don't bother with the Ramp Control cartridge, just use volume spacers.

It's your air spring combined with a shit damper tune on the part of avalanche, with a custom tune you should absolutely not be in the position whereby you have to put lighter oil in it. My 2018 RC2s did not bind and definitely do not bind with my ACS-3 coil conversion. My Pikes on the otherhand, were improved by a FAST tune and a coil - but still tracked nowhere near as smoothly as my 36s. I'm running 20 percent sag with my coil, 6 clicks from fully open on both LSC/HSC and 14 clicks from full closed on the rebound side.

It's lovely.

Don't bother with a full rebuild to 2018 spec by Fox, sell your avy damper, then put the same money on an ACS-3 cart,  put your stock RC2 damper back in and have it PUSHED. Preferably have it all done at once by TF Tuned.

The standard 2018 RC2s are the best air fork that I've ever ridden though.

Think you might have missed the point re the oil. No one is suggesting running lighter oil, what we're saying is make sure to use the exact oil that the damper and the tune were designed to work with.

If you can't get the oil that it was designed for, in the UK - why bother, one 5WT from one company is different to a 5WT from another - it's just a crapshoot as to whether the damper is going to work as designed.

It seems like some people have had to reshim them, themselves as well. I think that the standard RC2 damper in the 2018 fork rides nicer than any other fork I've used, the closest to it is the FAST damper. But my tune had an odd digressive feel where it would feel supported and then open up completely and blow through everything on harder hits.

One of the bonuses of the Avvy cart is that it is user tunable not that you should have to re-shin it just to make it work it's just that you have the option to fiddle if you should so desire. That said the factory tunes in my experience have been bang on in the past.

Where abouts in the UK are you?

Avalanche recommend two oils, one of which you can't get in the UK. As you rightly say, a 5wt designation is pretty pointless due to inconsistency.

The advice about the oil is to the OP in case they are unaware of that fact. It could be, if the wrong oil has been used, that this could be quickly and simply resolved by using the second oil avalanche suggest which is the maxima which is relatively easy to access in the UK.

I'm using the maxima fork fluid, so as I understand that's as close as you'll get to Spectro over here.

I am just really wondering if it's affected badly by the cold. On Saturday, when it was approx 7 degrees and after burping with a zip tie they felt much better. Stupidly I should have tried them on Saturday without burping, so now I don't know whether it's the warmer weather or the burping that's improved them. They still don't feel amazing, but at least I have a few things to try.

My comment about the weather is because on Weds evening it was about -3 and they felt utterly terrible. As previously mentioned that was without any compression or rebound on.

Thanks for the suggestions

I have read reports (I think on MTBR) of some air spring pistons being a bit oversized causing the issues you describe.

Mine are great - had the MRP fulfill kit in for 8 months now, so sounds like something is amiss in your fork.

I've been running a couple of avy cartridges in 36s for over 5 years and never noticed any dramatic change in cold weather.

Oils can become less viscous under cold temperatures, I know that Fox Gold lower oil can do this. Not sure about the Avy bath damper though.

Craig at avalanche and PUSH have both in the past stated that the best thing you can do for an air fork is drop a coil in it. Before blowing 300 quid on a custom damper, I really would try a coil conversion or something akin to a luftkappe.

It might be worth getting in contact with geometronbikes as when Chris was at Mojo, the custom tuned 36s with extra bath oil, sized bushings, older style seals in the damper and some custom tuning were considered the best single crowns on the market by some reviewers.

Newly serviced forks need time to bed in as well.

I think the main problem is the Fox NA airspring. I switched my 2015 34's from TALAS to NA and performance has been jekyll and hyde since installation in mid-2016. Following a conversation with Rick (he's already posted in this thread) I'm now waiting for Ison to get stock of the MRP FulFill valve kit as the more I read about this conversion (on mtbr.com) the better it sounds and cost-to-performance ratio looks excellent on paper.

Update to my previous post:

The 'big' overhaul of my 34's (which uses the same NA airspring as the 2015-17 36's) is now underway after gathering LOTS of data and speaking to various sources including Fox, Rick/SlickandSlide, Geometron (or whatever the 'new' Mojo call themselves now!) and Vorsprung.

Findings so far:
- NA air pistons can either be oversized due to poor machining tolerances OR in some instances swell due to exposure to oil or grease > measured my air piston and it is fractionally oversized compared to Factory-spec so I'm going to have it reduced down using a lathe.
- The quadring seal in use on the air piston is too big in comparison to the stanchion bore > I'm going to switch from a 213 to 212 quadring.
- Switching from Fox Gold 20wt to Fox Green 10wt and also increasing the oil volume in each leg may also help overcome small-bump stiction.

I've now got the MRP FulFill valve and now also waiting on a new FIT4 adj. damper to arrive (replacing the current CTD damper) so looking forward to the rebuild and the results.