Anyone got the goods on IFP pressure/height for RP23's?
Fox RP23 info
- Thread starter wood booger
- Start date
The IFP is what seperates the nitrogen in the damper from the oil yes?
W/O it you would get a foamy, slurpy mess of a shock.
W/O it you would get a foamy, slurpy mess of a shock.
Yeah, Fox is pretty tight lipped about that stuff.
Was hoping someone here would know.
Maybe I'll try the Push guys?
Was hoping someone here would know.
Maybe I'll try the Push guys?
The 2010 BoostValve-equipped ones have an internal nitrogen chamber, located at the bottom of the shock's shaft. However, the pressure is only known by Fox and the bike manufacturer, and its acces is sealed, since Fox does not feel it could be user-serviceable. The aftermarket ones should be available starting at a nitrogen pressure of 125psi, with 25psi increments from what I have read in some magazines.
Trust me, this info not even known to bike manufacturer in many cases. We have asked.
The rebound fades so bad on this thing afer 10 minutes of rough trail that I have to stop and add 3-4 more clicks to keep from getting bucked. Then it cools off and is uber slow. I figure the oil is cooked and I wanted to play around w/ different weights/valving to try and alleviate the problem. It seesm worse now then when it was new. Air sleeve service doesn't help.
How old is the shock? Still under warranty?
I have the 2010 RP23 w/boost valve and absolutely love it.
I have the 2010 RP23 w/boost valve and absolutely love it.
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2010 shock w/o boost valve.
It's got some hours on it though (around 200).
I have access to all the equipment to pull it apart and play w/ it, I like to work on my own stuff so I have a better idea of what is going on w/ it.
I guess it could go back to Watsonville as a last resort.
It's got some hours on it though (around 200).
I have access to all the equipment to pull it apart and play w/ it, I like to work on my own stuff so I have a better idea of what is going on w/ it.
I guess it could go back to Watsonville as a last resort.
Since heat/fading/oil thinning is the problem I don't see any solution. Small oil volume surrounded by an insulating air can is the issue. I feel this on my Mojo but it's the price you pay to descend hard on a lightweight shock. I think Push's staged rebound cures this some but it will still get faster when the shock heats up. Rockshox's thermally sensitive, expanding rebound needle is a novel solution and my friend who's testing it says it works great on long DH runs. I think that you'd still feel the compression damping fade and the air spring get stiffer from heat. Basically, if you want a shock that is consistent on long descents you need a coilover with piggyback (lots of oil to absorb heat & lots of surface area to lose it).
Any changes you make to the pressure will only affect the progressiveness/overall spring rate. Changes to oil weight will affect the feel of the shock at all temperatures and the damping will still get lighter as it heats up. Are there any brands of shock oil that are known to be significantly more thermally stable? I'd think not, or wouldn't Fox use it?
Any changes you make to the pressure will only affect the progressiveness/overall spring rate. Changes to oil weight will affect the feel of the shock at all temperatures and the damping will still get lighter as it heats up. Are there any brands of shock oil that are known to be significantly more thermally stable? I'd think not, or wouldn't Fox use it?
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Yeah, pretty much what I figured, except that when you get oil hot a bunch of times it can break down and get worse. Does seem like it heats up quicker now.
On a side note, lots of friends running new X-Fusion shock on this bike say that the heat fade is much better w/ X-Fusion. I would like to try one out.
I think I am headed towards my 3rd RP 23....blew the 1st one, got a 2010 free under warranty and now the same issue has resurfaced - oil spewing out of schraeder valve when putting air in (shoots right up into the shock pump)...
The only thing on the other side of that schrader valve is the air volume inside the can. Maybe that's just some lubricating oil coming out because the valve is at the bottom? Fox didn't used to put oil in the can but a lot of use do to keep it slippery so maybe they've followed suit?
This was previously theorized, but no dice. I mean,the oil sprays out quite a bit when the actual valve is compressed via my finger or pump. Why else would Fox stealthy send me a new shock? Must have been a major malfunction. As of last night, I'm also noticing I have an oil leak around the juncture of the schaeder valve down by the body of the shock. Hmmm.
There is oil in the air can. It's that thick Fox Fluid and it is blue. I have a bottle of it and use it when I do air sleeve maintenance. I get seepage past the main seals which turns up on the shaft but that's not a problem as I never seem to loose any air. I can't say that I have noticed any spitting out the shrader valve because I always use a shock pump so there is nowhere for any oil to go other than into the pump.
But it is entirely possible that the oil you saw was from a blown damper which is encased within the air sleeve. What colour was the oil?
But it is entirely possible that the oil you saw was from a blown damper which is encased within the air sleeve. What colour was the oil?
You only use a very small amount of Fox Float Fluid in the canister.
That's what I'm thinking. Taking off the air can will solve the mystery.
The color of the oil is (I believe) red. I literally have to hang my shock pump (not that it matters, but it is a "Fox brand" pump) to drain after checking air. My temporary solution? Don't put any air in it! Seems to be holding thus far, I always have at least 1/4 inch left on the shaft/not bottoming out.
So if it feels fine the damper probably didn't leak. That must mean that you just have a lot of lube oil in the air can. It can't be a bottomless supply though so this should stop. Again, pulling the can will solve this.
I found a russian website (I can not find it again, sorry) that has the blue print of the RP23 specifing torque, presion, IFP and oil volumes.
I did repair my own RP23 succefully using this website instructions but it is a very long story indieed, I am in a testing period rigth now but untill i solve some problems I just put presurized air instead nitro.
Let see if I can find the url again.
I did repair my own RP23 succefully using this website instructions but it is a very long story indieed, I am in a testing period rigth now but untill i solve some problems I just put presurized air instead nitro.
Let see if I can find the url again.
Any news/info about making the internal service ?
Thanks
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Just in case anyone comes looking....
I had a similar issue with my RP23 from a Specialized Enduro while on holiday in New Zealand.
The mechanic at the MTB park had a look, thought he recognized the issue and called Fox to confirm. Apparently it is a known fault - the fault isn't that common but it happens in the same way each time.
Apologies in advance for the description - I didn't really understand anything I was told!:
- The issue is with the device that keeps the damper air(nitrogen) and damper oil separate.
- Once it fails, damping gets progressively worse.
- Once the oil is really well mixed with air, the shock will make a very quiet 'squish' noise when moving through the very first few millimeters of travel (that's the damper air/oil moving past the seal and mixing with the damper oil/air.)
- Shock moves through that first few millimeters quickly, way too quickly.
- you may also feel a slight knock when you stop (related to above symptom).
Repair from Fox only apparently that included:
- damper service
- air sleeve service
- boost valve seals or o-rings or something (can't remember)
- etc etc.
So, if you know how to service a damper that uses nitrogen and can get the parts, then it's user serviceable. For mere mortals like me though, it's a shop trip no two ways about it.
I had a similar issue with my RP23 from a Specialized Enduro while on holiday in New Zealand.
The mechanic at the MTB park had a look, thought he recognized the issue and called Fox to confirm. Apparently it is a known fault - the fault isn't that common but it happens in the same way each time.
Apologies in advance for the description - I didn't really understand anything I was told!:
- The issue is with the device that keeps the damper air(nitrogen) and damper oil separate.
- Once it fails, damping gets progressively worse.
- Once the oil is really well mixed with air, the shock will make a very quiet 'squish' noise when moving through the very first few millimeters of travel (that's the damper air/oil moving past the seal and mixing with the damper oil/air.)
- Shock moves through that first few millimeters quickly, way too quickly.
- you may also feel a slight knock when you stop (related to above symptom).
Repair from Fox only apparently that included:
- damper service
- air sleeve service
- boost valve seals or o-rings or something (can't remember)
- etc etc.
So, if you know how to service a damper that uses nitrogen and can get the parts, then it's user serviceable. For mere mortals like me though, it's a shop trip no two ways about it.
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For those who dare to open the shock as the last resort before sending it out for repair: http://huckingkitty.com/forums/viewtopic.php?f=11&t=680
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For what it's worth, the Monarch Plus rear shock is WAY more robust than the RP23 unit. That external reservoir makes a huge difference when plowing through dh runs. It'll heat up, sure, but it's never faded on me at 'shoe or Creek.
If you get a '12 unit, make sure you replace the lower air can seal (just above the wiper) with a quad seal instead of the stock o-ring. '13 rear shocks have this change already but the '11 and '12 stuff doesn't. It'll lose air in about 20-40 cycles with that stupid o-ring. The Fox Float rear shock air seal kit has a quad ring in it that works.
mk
If you get a '12 unit, make sure you replace the lower air can seal (just above the wiper) with a quad seal instead of the stock o-ring. '13 rear shocks have this change already but the '11 and '12 stuff doesn't. It'll lose air in about 20-40 cycles with that stupid o-ring. The Fox Float rear shock air seal kit has a quad ring in it that works.
mk