Hoping I did my fox air can service ok, refiteed the shock to the bike and it needs 10psi more to achieve the same sag. Sound odd ??
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Shock needs more air presure after service ??
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Posted 2 years ago #
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ignore the gauge, I have found them only a very loose guide to what pressure you have, it could be a blob of lube from the air can pushed into your pump or something, just set the sag and it should be fine.
Posted 2 years ago # -
Ok, I was just wondering if it was easy to dislodge the seals when you reassemble it, which may lead to problems ?
Posted 2 years ago # -
No seals should stay in place as long as seated properly in first place.
As long as they are all sitting straight and the shock is working fine, it will be the pump. Set it up on the sag.Posted 2 years ago # -
Perhaps the increase in lubrication (and hence reduction in stiction) as a result of the clean and service is allowing the shock to sag more, hence there is more pressure required to prop it up?
Posted 2 years ago # -
Ah ok, perhaps it is just that its friction is reduced, its definately about approx 10 psi more required, the action seems ok, and there has been no air loss from it. just wondering whether the air is creeping past the main piston airseal and allowing it to sink down. But would this not happen
Posted 2 years ago # -
Perhaps the increase in lubrication (and hence reduction in stiction) as a result of the clean and service is allowing the shock to sag more, hence there is more pressure required to prop it up?
Yep id go for that too...its like adding lots of lsc.Posted 2 years ago # -
Cool, so the consesus is that its probably working better and not worse since the service, result
Posted 2 years ago # -
Tape over the gauge in case it ever bothers you again...
Posted 2 years ago # -
The -ve air chamber is charged when you assemble the air sleeve. It makes it quite an effort to put on.
Chances are that it had leaked all it's air out before, especially if the wiper seal was shagged.
Posted 2 years ago # -
The -ve air chamber is charged when you assemble the air sleeve. It makes it quite an effort to put on.
Chances are that it had leaked all it's air out before
I thought that the +ve and -ve chambers equalized with air passing through an air transfer port between the 2 chambers , which I am guessing only opens and allows air to pass from one chamber to another when the shock is fully extended. Common sense tells me that the transfer port must close whilst the shock is compressing or else the air spring compression wouldnt work.
Please correct me if I am wrong about this.Posted 2 years ago # -
Nope. No transfer port in a rear shock. When air leaks from +ve to -ve then the shock becomes "stuck down".
Some shocks don't have a -ve chamber, like the cheaper RockShox ones, and some have an elastomer -ve spring, like DT ones.Posted 2 years ago # -
Nope. No transfer port in a rear shock. When air leaks from +ve to -ve then the shock becomes "stuck down".
Some shocks don't have a -ve chamber, like the cheaper RockShox ones, and some have an elastomer -ve spring, like DT ones.Now I really am confused ! I just pulled this from the FOX shox website
At FOX Racing Shox we have a unique way of charging the negative air chamber in the FLOAT rear shocks and the FOX FORX TALAS system. A transfer port allows air to pass from the positive air chamber to the negative chamber at the beginning of each movement of the shaft stroke. This Patented transfer port system automatically balances the pressure for the perfect negative spring for any pressure setting.
Posted 2 years ago # -
Just wondering which is right ?
Posted 2 years ago # -
I'm not sure that's right. I've never seen anything that looks like a transfer port on any of the Float shocks I've done air can services on. There's something like a transfer port on the boost valve air cans, but that does something entirely different, increasing the chamber volume part way through the stroke... If there was a transfer port, it would be open at the position where you put the air can back on, and it wouldn't build pressure like it does when you push the can into place.
Sounds like the marketing dept haven't fully got their heads round the product.
Somebody please correct me if I'm wrong though!Posted 2 years ago # -
the transfer port is the little groove in the air can, present in every fox rear shock.
next time you do an air sleeve clean look inside the can, you will see a small 6-7mm grrove that lines up with the main quad seal when the shock is at full extension. When you pressurise the shock, the air will be balanced in both chambers. If the quad seal swells, and blocks the groove the air will not balance, and as the shock cycles it will pump more air into the negative, sucking the shock down.
If a shock sucks, or becomes 'stuck down', pop it open and change the quad seal
Posted 2 years ago # -
I got thinking about that after I wrote that. I guess I've not looked carefully enough inside the cans when I've been cleaning them.. Was thinking that a groove would be the only other way to make a position sensitive valve.
In that case it's no bloody wonder that they get stuck down, with the edges of a groove chewing away at the air seal on each cycle. It's not down to the seal swelling though, just down to it loosing it's integrity. As soon as it lets some air past it'll stop full extending to equalise and gradually pump more air into the neg chamber on each cycle.Posted 2 years ago # -
Cool weve all learned something today, thanks. Can the air only pass when then shock is in the extended position ?
Posted 2 years ago # -
Haven't you just put on a bit of weight pudding :wink:...shock was probably too clean before...hence the reduced stiction now...leave the cotton buds alone will ya!
Posted 2 years ago # -
Haven't you just put on a bit of weight pudding
Ha Ha, you know me too well mate, first thing I checked ! Jumped straight on the bathrom scales, phew, nope still the same !
Shock feels super smooth actually, I am suprised a simple air sleeve service could make that much difference, and it was nice and clean inside as well
Posted 2 years ago # -
Bugger!....yep need to swap the seals in mine..still! can't believe Ive not done it yet...massive improvement to petes& chris's (couldn't have made that worse though!)glad it worked for ya..give it a squirt of stendecs sillicon spray to keep it slippy fella
Posted 2 years ago # -
10 psi more than not very much which is all that's needed for a 12 year old boy is a lot really
Posted 2 years ago #
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