weezing shock
 

[Closed] weezing shock

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hi can any tell me if its normal healthy for a fox air shock to sound a bit weezy?


 
Posted : 16/06/2013 3:23 pm
 LoCo
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Float fluid in air can passing through transfer/neg port on initial part of the travel. Or nitrogen in the oil.


 
Posted : 16/06/2013 3:25 pm
 LoCo
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Float fluid in air can passing through transfer/neg port on initial part of the travel. Or nitrogen in the oil.


 
Posted : 16/06/2013 3:25 pm
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ok does that mean it needs fixing?

Also i emailed you about a broken reverb i have in eer parts, coul di post into you to take a look at?


 
Posted : 16/06/2013 3:44 pm
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Cods wollop


 
Posted : 16/06/2013 4:46 pm
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what is dales rider?


 
Posted : 16/06/2013 5:36 pm
 LoCo
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Nitrogen leak yes, float fluid no, emails getting done early tomorrow am!
Cod liver oil is not an effective air can lube either 😉


 
Posted : 16/06/2013 5:38 pm
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Float fluid in air can passing through transfer/neg port on initial part of the travel. No such thing in a Shock
Nitrogen leak yes as then you may get some cavitation in the shock part of the "Shock"
You dont say what type of Fox Shock it is, for instance a triad "Wheezes" when locked out and you hit a bump its the bit that shouldnt pass fluid through passing fluid through.


 
Posted : 16/06/2013 8:40 pm
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In fact they sound more like a duck 🙂


 
Posted : 16/06/2013 8:41 pm
 LoCo
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Fox air as mentioned in op, transfer port in air can....


 
Posted : 16/06/2013 10:45 pm
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*Checks*
Nope dont have one of those on my Fox Air Shock


 
Posted : 17/06/2013 8:47 am
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Dales_rider - Member

*Checks*
Nope dont have one of those on my Fox Air Shock

Which shock? It's just a little dimple on the air can


 
Posted : 17/06/2013 8:52 am
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Can't find popcorn smileyface, just imagine I added it here...


 
Posted : 17/06/2013 9:06 am
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Northwind - Member
Can't find popcorn smileyface, just imagine I added it here...

Are you implying that someone is making a mistake?!

😉


 
Posted : 17/06/2013 9:14 am
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can you guess who my money is on? 🙂


 
Posted : 17/06/2013 9:18 am
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I just happened to have an RP23 on my table here. That wee hole looks to me like a transfer port.

[img] [/img]


 
Posted : 17/06/2013 9:38 am
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Transfer port is the little bump about the size of a grain of rice on the aircan of a fox airshock unless I am mistaken. Can I also have a fiver on Simon from Loco too, being as that he is a professional and damn fine fox suspension tuner / technician..


 
Posted : 17/06/2013 9:45 am
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matches at the ready...


 
Posted : 17/06/2013 9:53 am
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So whats it transferring ?


 
Posted : 17/06/2013 11:36 am
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Takes it apart produces [url= https://googledrive.com/host/0Bxc99IsGYy4LLWJHVk5jdVlmNzg/Fox.Racing.Shox/Content/PartsListDrawingsShox/Float%20Triad_RPL%20Folder/816-72-942_RevA.pdf ]quick drawing[/url], nope cant see one.

Now my early Triad does have a hole between the main air can and the one screwed on to increase the volume but its not a Negative chamber, any air going through the air piston into the "Negative chamber" would cause a lock down


 
Posted : 17/06/2013 11:58 am
 LoCo
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[url= http://farm3.staticflickr.com/2811/9067505260_8083cd8621.jp g" target="_blank">http://farm3.staticflickr.com/2811/9067505260_8083cd8621.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/55204994@N03/9067505260/ ]neg port fox air shock[/url] by [url= http://www.flickr.com/people/55204994@N03/ ]Loco Tuning[/url], on Flickr

😉

It's also on the drawing in the top l/h you just posted the external pip at the wiper seal end of the air can, and on page 2 on the top drawing on the centre line.

Interesting you have a Fox breakdown picture too not sure these are available to the public are they? 😉


 
Posted : 17/06/2013 12:07 pm
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Tea and hob nobs, comfy chair, dog's getting the slippers.


 
Posted : 17/06/2013 12:13 pm
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Brilliant. Only on STW.

Also getting comfy in my chair.


 
Posted : 17/06/2013 1:00 pm
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Still wondering what its transferring and to where under normal operation


 
Posted : 17/06/2013 1:25 pm
 LoCo
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😕


 
Posted : 17/06/2013 1:27 pm
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You can see where it is on the cross section view at the bottom of sheet 2 and from there figure out what it'll do.
I'm not an expert on shocks but it looks to me like it'll defeat the seal on the air piston temporarily in the first part of the stroke, which will do two things, equalise the pressure on either side of the piston and since the seal isn't holding pressure it'll greatly reduce the seal friction from the largest diameter (and therefore draggiest) seal in the system as the shock starts to move.
But as I say I'm not an expert, I've never seen inside a shock before. I'm just an engineer reading a drawing 😉


 
Posted : 17/06/2013 1:39 pm
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robinlaidlaw - Member

it looks to me like it'll defeat the seal on the air piston temporarily in the first part of the stroke, which will do two things, equalise the pressure on either side of the piston

Thanks good answer. But my thinking is sat on the bike 10% sag its way past the seal, so not sure then as to why it would be transferring anything once the initial stroke is made


 
Posted : 17/06/2013 3:25 pm
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The bleed port equalises the air pressure between the positive and negative air chambers, without it you need an air valve on the negative chamber to pressurise it like some rockshox air shocks used to have,, it's the little bulge on the air can as said above..
Edit, as Loco said, its either float fluid squelching through the port (ok) or air in the nitrogen charge (not ok) the nitrogen stops the oil from cavitating (foaming) when the damper is working..


 
Posted : 17/06/2013 3:31 pm
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It won't.
Again, this is just me interpreting the drawing, so I could be wrong, but as far as I can see, it'll only do anything in that very first part of the stroke so it's purely there to ensure that the pressures on either side of the piston are balanced when the shock is full extended. As soon as the shock is further into the travel the seal will engage and pressurise the air above the piston in the normal way, providing your normal springing. Even when the seal is in line with the port, the difference in the diameters of the seals on the shaft at the left and the body at the right will still make the shock try to extend but as the seal on the body is a bit smaller than the one in the air can it'll not be extended quite as firmly, which will help the shock to move initially. Immediately after the seal moves past the port you'll still have some pressure both sides of the piston which will be helping to move the shock and then as it goes deeper into the travel the air above the piston will be compressed, and the air below will expand until it's not doing anything to help, so the spring rate will ramp up.
So overall, it's part of a system to tweak the initial break away friction and spring rate progression of the shock.
I'm sure LoCo will correct me if I'm not understanding that right.
As above, the noise might not be that, and I guess if you are getting it deeper into the travel it would suggest it's nitrogen in the oil and it's not good.


 
Posted : 17/06/2013 3:41 pm
 LoCo
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Only works at the very start of the travel/full stroke/fully extended, when you pump a shock up from flat you'll usually hear it equalize at about 150 psi when off the bike.
Stops topout clunk and in theory may help with over coming initial stiction.

Have had a few people say the shock are noisey at very start of travel that can be caused by float fluid moving through the port, but with nitrogen in the oil the gas with often sit by the piston and make a sqweltch on the first bit too.


 
Posted : 17/06/2013 3:50 pm
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Dear shock/forks experts..... looking at this maybe you can help me.... I have a RS recon solo air (silver) which I bought 2nd hand. There is some wheezing when the fork returns from being depressed (no Lithium jokes!) - does this just need a service and new seals?

cheers


 
Posted : 17/06/2013 7:26 pm
 LoCo
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It's normal for the rebound damper to make a bit of noise as the oil passes through the piston, it'll change/ disappear on different settings too


 
Posted : 17/06/2013 7:32 pm
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it'll change/ disappear on different settings too
I have tried to change rebound rate but wheezing remained :s

thanks for the quick reply loco 🙂


 
Posted : 17/06/2013 7:42 pm