I asked a similar question on another thread without an answer so would love to hear what others can reccomend.
Float X2 IFP pressure
Hey
I know fox has low ifp pressures i believe 100-125 depending on year. And they have a lot of problems sucing air in the damper shaft and I believe raising the IFP pressure seemed like a good solution.
Has there been a tried and true IFP pressure that helps this problem?
I know fox has low ifp pressures i believe 100-125 depending on year. And they have a lot of problems sucing air in the damper shaft and I believe raising the IFP pressure seemed like a good solution.
Has there been a tried and true IFP pressure that helps this problem?
1 - 20 of 26 Posts
When the seals in the IFP fail, and they will, the shock will suck air no matter what pressure you're running. I just had mine rebuilt last month.
the current shock i am working on is a 2021 model, has the slurp since day one, but seems like the common culprit is sucking air in the main damper seal. This has the newer urethane seal since its a 2021. But i also do feel as per many other threads 125 is to low but obviously you would assume fox knows what they are doing.
I am feeling 175-200 might be the sweet spot just based on what the majority of other piggyback shoxs run
I am feeling 175-200 might be the sweet spot just based on what the majority of other piggyback shoxs run
the current shock i am working on is a 2021 model, has the slurp since day one, but seems like the common culprit is sucking air in the main damper seal. This has the newer urethane seal since its a 2021. But i also do feel as per many other threads 125 is to low but obviously you would assume fox knows what they are doing.
I am feeling 175-200 might be the sweet spot just based on what the majority of other piggyback shoxs run
I dropped my RSD down from stock 250 to 170 psi without any noticeable ill effects.
My understanding from other threads is if your main chamber psi is lower than the IFP it should be good.
Hey
I know fox has low ifp pressures i believe 100-125 depending on year. And they have a lot of problems sucing air in the damper shaft and I believe raising the IFP pressure seemed like a good solution.
Has there been a tried and true IFP pressure that helps this problem?
Mine was doing the same thing. Slurping was coming from both foamed oil after heavy riding and no maintenance, plus the IFP height was way off from settling the foamy oil. an oil and seal change plus resetting the IFP biscuit solved the issue. I also added 7wt high-use Maxima over the 5wt fox fluid (forever sold out) I run 150psi in my 2020 x2.
IFP seals almost never fail. The air in your oil comes in the main shaft seal. IFP pressure is a huge factor in preventing that. If you need an example, just drop IFP pressure and go riding. The shock will suck so much air in it'll pressurise the oil.When the seals in the IFP fail, and they will, the shock will suck air no matter what pressure you're running. I just had mine rebuilt last month.
Okey dokey, so did we get to the bottom of what is the best ifp pressure to use ? The question has sort of been skirted around so still none the wiser !
I recommend looking at all of the factors affected by IFP pressure and testing things out for yourself so you have a grasp of how much things are going to change. For example a 9mm damper shaft has a very small cross section so the spring force applied by the gas pressure is very low. So increasing the IFP pressure has a relatively small influence on the spring/preload effect. That gives you a fair bit of margin to increase it substantially with very little negatives. Conversely a shock with a 1/2" or 14mm would need much more careful consideration.
last tip -Changing something by at least 10% a very basic rule of thumb you can apply to just about anything if you are unsure of how big of a change to make. This is the average minimum change a person can percieve in a lot of cases so is a useful starating point if you have nothing else to go on. Therefore 130psi is not going to be enough!
last tip -Changing something by at least 10% a very basic rule of thumb you can apply to just about anything if you are unsure of how big of a change to make. This is the average minimum change a person can percieve in a lot of cases so is a useful starating point if you have nothing else to go on. Therefore 130psi is not going to be enough!
Start by adding 25psi to the recommended pressure. See what happens. I think you can safely assume the reservoir can handle a fair bit more. At higher pressures you may need to reduce air sleeve pressure slightly, as you'll have extra spring force from it. You may experience more seal friction, but I have a hard time believing it's much compared to the air sleeve seals.
It seems like the only downside to going too high on IFP pressure is making your spring rate too firm. I think you can safely just increase it until you you perceive some harshness and then back down slightly.
Also if the shock is twin tube v mono tube it makes a big difference.I recommend looking at all of the factors affected by IFP pressure and testing things out for yourself so you have a grasp of how much things are going to change. For example a 9mm damper shaft has a very small cross section so the spring force applied by the gas pressure is very low. So increasing the IFP pressure has a relatively small influence on the spring/preload effect. That gives you a fair bit of margin to increase it substantially with very little negatives. Conversely a shock with a 1/2" or 14mm would need much more careful consideration.
last tip -Changing something by at least 10% a very basic rule of thumb you can apply to just about anything if you are unsure of how big of a change to make. This is the average minimum change a person can percieve in a lot of cases so is a useful starating point if you have nothing else to go on. Therefore 130psi is not going to be enough!
All great advise and suggestions, however, the last thing I ever want to do is experiment with a customers shock.
Understandable. I wouldn't do it in that context unless you have a clear picture of their maintenance and riding habits. If you have that information, and it looks like it could address an issue, try it. Probably something to talk about with a buddy or regular you can get feedback from.All great advise and suggestions, however, the last thing I ever want to do is experiment with a customers shock.
To expand on that, the last thing I would ever want to do is employ a method I had only ever read on a forum in a customers shockAll great advise and suggestions, however, the last thing I ever want to do is experiment with a customers shock.
To expand on this has anyone ever experienced blown X2's on Evil Wreckoning/Followings ? Are they some frames that X2's dont play nicely with ? Thanks Richie
IFP has very little spring-rate, but high starting preload. It gives you extra friction by loading up the shaft seal more.It seems like the only downside to going too high on IFP pressure is making your spring rate too firm. I think you can safely just increase it until you you perceive some harshness and then back down slightly.
You can buy an X2 that fits your own bike and practice. They've been around for a long time now.All great advise and suggestions, however, the last thing I ever want to do is experiment with a customers shock.
Even at trade or 2nd hand price I can think of much better ways to spend my money than on a shock just to practice on simply to see what ifp presures work and what dont, but each to their own I guess ! I had hoped that a difintative answer may have come my way from the knowledgeable guys on here that know there stuff ? Afterall, this is what I thought forums are for ? P.s. I'm not trying to be a smart arse here by the way, was simply asking for advice.IFP has very little spring-rate, but high starting preload. It gives you extra friction by loading up the shaft seal more.
You can buy an X2 that fits your own bike and practice. They've been around for a long time now.
You got plenty of advice & information. What you choose to do with it is up to you.
Speaking from personal experience on my own bike. Dropping the pressure made a very significant difference to the end stroke. Basically took the harshness out of my ride after all other adjustments failed to do so.IFP has very little spring-rate, but high starting preload. It gives you extra friction by loading up the shaft seal more.
You can buy an X2 that fits your own bike and practice. They've been around for a long time now.
1 - 20 of 26 Posts
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