I can’t wait to ride it now and am really hoping this helps relieve my hand numbness. I really appreciate all the replies/help given.
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up in the lower. When I removed the lowers, the nut on the bottom of the air spring side was not very tight. It was just a bit more than hand tight. I wonder if that created a small gap when the fork would extend that sucked air into the lower? The air would not be able to escape on compression because the force would close the gap? I just can’t figure out how the problem would have developed so quickly any other way.
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up...
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up in the lower. When I removed the lowers, the nut on the bottom of the air spring side was not very tight. It was just a bit more than hand tight. I wonder if that created a small gap when the fork would extend that sucked air into the lower? The air would not be able to escape on compression because the force would close the gap? I just can’t figure out how the problem would have developed so quickly any other way.
Did you try the zip tie trick first?
It’s possible the fork had air buildup from experiencing a variety of pressure changes (temperatures changes, altitude changes, etc) between the time it got assembled at the factory and when it got to you.
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up...
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up in the lower. When I removed the lowers, the nut on the bottom of the air spring side was not very tight. It was just a bit more than hand tight. I wonder if that created a small gap when the fork would extend that sucked air into the lower? The air would not be able to escape on compression because the force would close the gap? I just can’t figure out how the problem would have developed so quickly any other way.
Did you try the zip tie trick first?It’s possible the fork had air buildup from experiencing a variety of pressure changes (temperatures changes, altitude changes, etc)...
Did you try the zip tie trick first?
It’s possible the fork had air buildup from experiencing a variety of pressure changes (temperatures changes, altitude changes, etc) between the time it got assembled at the factory and when it got to you.
I did try the zip tie trick but the zip tie only went about an inch past the dust seals so I didn’t think that was far enough. Also worried this could damage the seals.
What‘s the verdict on the new Fox 38? I have one in order with a new bike.
It functions, but I wouldn't say it's exceptional in any way. If I had to choose, I prefer the '27 zeb ultimate at lower speeds, at pace they are pretty similar. My 6 year old avalanche hybrid zeb is still easily outperforming both.
It is an improvement though over the old grip 2 38's, those were not great at all.
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork lowers causes. I had my air cap off to change some volume spacers and I pushed down on the fork out of curiosity and it was difficult to get the fork to full compression with just the air in the lowers.
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork...
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork lowers causes. I had my air cap off to change some volume spacers and I pushed down on the fork out of curiosity and it was difficult to get the fork to full compression with just the air in the lowers.
i never have this problem.
My fork seals cant even keep the oil in my fork lowers, its not keeping air in them either..
Same, and I'm disappointed. I've had two forks in a row with the air release buttons and the only time anything has come out, it was oil and it went all over my gloves.
I was told they would go psst and make my fork better. I was lied to. It's like buying a turbo car that doesn't make turbo noises
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26 Fox Factory 34SL. Can anyone explain why? I know it’s not just a Fox thing. What is new/different about these forks that make them susceptible?
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26...
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26 Fox Factory 34SL. Can anyone explain why? I know it’s not just a Fox thing. What is new/different about these forks that make them susceptible?
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep the pressure in, but it is unusual for it to leak, especially in a new fork. If it comes back I would get Fox to look at it under warranty as its not normal.
The other place it can leak is the footstud to the air shaft - there is a small o-ring there but it also needs loctite to help make a perfect seal. Again its weird to leak there but it can happen if its loose or the o-ring has damage
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork...
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork lowers causes. I had my air cap off to change some volume spacers and I pushed down on the fork out of curiosity and it was difficult to get the fork to full compression with just the air in the lowers.
Was this on your 38? Even on the original Zeb which ramps up pretty hard compared to most, you should be able to bottom it pretty easily. With that fork off the bike just pushing down on the crowns with your hands is enough to bottom it out.
With my 38 on the bike bottoming it doesn’t take much effort at all. there’s added resistance for sure the last 25mm but I’d stop short of describing it as excessive.
Same, and I'm disappointed. I've had two forks in a row with the air release buttons and the only time anything has come out, it was...
Same, and I'm disappointed. I've had two forks in a row with the air release buttons and the only time anything has come out, it was oil and it went all over my gloves.
I was told they would go psst and make my fork better. I was lied to. It's like buying a turbo car that doesn't make turbo noises
Remove the foam ring next time you do the lowers service and you might get to the pssst effect you are after. Eliminating risk of dust getting past the seal and then being trapped against the stanchion by the foam is just a nice bonus.
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26...
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26 Fox Factory 34SL. Can anyone explain why? I know it’s not just a Fox thing. What is new/different about these forks that make them susceptible?
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep...
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep the pressure in, but it is unusual for it to leak, especially in a new fork. If it comes back I would get Fox to look at it under warranty as its not normal.
The other place it can leak is the footstud to the air shaft - there is a small o-ring there but it also needs loctite to help make a perfect seal. Again its weird to leak there but it can happen if its loose or the o-ring has damage
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in during extension but compression would make it difficult for the air to escape right?
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26...
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26 Fox Factory 34SL. Can anyone explain why? I know it’s not just a Fox thing. What is new/different about these forks that make them susceptible?
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep...
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep the pressure in, but it is unusual for it to leak, especially in a new fork. If it comes back I would get Fox to look at it under warranty as its not normal.
The other place it can leak is the footstud to the air shaft - there is a small o-ring there but it also needs loctite to help make a perfect seal. Again its weird to leak there but it can happen if its loose or the o-ring has damage
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in...
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in during extension but compression would make it difficult for the air to escape right?
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so I doubt that would be an issue. Even if it was, the lowers wouldn’t be able to exceed atmospheric pressure.
Or did you mean the foot stud is loose from the air spring shaft?
Those forks don’t have bleed valves, correct? Pressure is always going change in the lowers due to temperature, altitude, or even gradual migration of air across the quad ring sealing the air shaft.
As an 130 XC fork one would assume the uppers would be as short as possible. Surprised casting ramp is that much of a problem on those.
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep...
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep the pressure in, but it is unusual for it to leak, especially in a new fork. If it comes back I would get Fox to look at it under warranty as its not normal.
The other place it can leak is the footstud to the air shaft - there is a small o-ring there but it also needs loctite to help make a perfect seal. Again its weird to leak there but it can happen if its loose or the o-ring has damage
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in...
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in during extension but compression would make it difficult for the air to escape right?
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so...
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so I doubt that would be an issue. Even if it was, the lowers wouldn’t be able to exceed atmospheric pressure.
Or did you mean the foot stud is loose from the air spring shaft?
Those forks don’t have bleed valves, correct? Pressure is always going change in the lowers due to temperature, altitude, or even gradual migration of air across the quad ring sealing the air shaft.
As an 130 XC fork one would assume the uppers would be as short as possible. Surprised casting ramp is that much of a problem on those.
My fork came that way for whatever reason. I have a few rides on it since bleeding the air off and it’s still feels great. I’m hopeful it was a one time thing.
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork...
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork lowers causes. I had my air cap off to change some volume spacers and I pushed down on the fork out of curiosity and it was difficult to get the fork to full compression with just the air in the lowers.
Was this on your 38? Even on the original Zeb which ramps up pretty hard compared to most, you should be able to bottom it pretty...
Was this on your 38? Even on the original Zeb which ramps up pretty hard compared to most, you should be able to bottom it pretty easily. With that fork off the bike just pushing down on the crowns with your hands is enough to bottom it out.
With my 38 on the bike bottoming it doesn’t take much effort at all. there’s added resistance for sure the last 25mm but I’d stop short of describing it as excessive.
It was my 38, I was doing back to back testing of my TopHat and regular volume spacers.
I would describe the resistance as “notable but not excessive.” I was able to bottom out the fork, it was just more force than I was expecting. I did press the bleeder valves before doing that to equalize everything.
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in...
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in during extension but compression would make it difficult for the air to escape right?
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so...
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so I doubt that would be an issue. Even if it was, the lowers wouldn’t be able to exceed atmospheric pressure.
Or did you mean the foot stud is loose from the air spring shaft?
Those forks don’t have bleed valves, correct? Pressure is always going change in the lowers due to temperature, altitude, or even gradual migration of air across the quad ring sealing the air shaft.
As an 130 XC fork one would assume the uppers would be as short as possible. Surprised casting ramp is that much of a problem on those.
My fork came that way for whatever reason. I have a few rides on it since bleeding the air off and it’s still feels great. I’m...
My fork came that way for whatever reason. I have a few rides on it since bleeding the air off and it’s still feels great. I’m hopeful it was a one time thing.
OK yeah it might have just been the way it was assembled - if theres a big enough change in temperature or altitude it can cause an increase in pressure. Also if the damper side has the nut tightened while fully extended, it will have some positive pressure from compressing it down to the air spring.
And @Ride886 had it right - the press fit should be air tight and not able to move, plus the air spring is basically only in compression (because thats the part pushing the fork back out). If it was moving there would be a horrendous knocking and probably wind all the way loose as well
Success! The fork felt amazing and I did achieve full travel. I have a theory as to what may have caused the air to build up in the lower. When I removed the lowers, the nut on the bottom of the air spring side was not very tight. It was just a bit more than hand tight. I wonder if that created a small gap when the fork would extend that sucked air into the lower? The air would not be able to escape on compression because the force would close the gap? I just can’t figure out how the problem would have developed so quickly any other way.
Did you try the zip tie trick first?
It’s possible the fork had air buildup from experiencing a variety of pressure changes (temperatures changes, altitude changes, etc) between the time it got assembled at the factory and when it got to you.
I did try the zip tie trick but the zip tie only went about an inch past the dust seals so I didn’t think that was far enough. Also worried this could damage the seals.
It functions, but I wouldn't say it's exceptional in any way. If I had to choose, I prefer the '27 zeb ultimate at lower speeds, at pace they are pretty similar. My 6 year old avalanche hybrid zeb is still easily outperforming both.
It is an improvement though over the old grip 2 38's, those were not great at all.
I know this has been talked about a bunch but its kinda wild experiencing it yourself. Its amazing how much ramp the air in the fork lowers causes. I had my air cap off to change some volume spacers and I pushed down on the fork out of curiosity and it was difficult to get the fork to full compression with just the air in the lowers.
i never have this problem.
My fork seals cant even keep the oil in my fork lowers, its not keeping air in them either..
Same, and I'm disappointed. I've had two forks in a row with the air release buttons and the only time anything has come out, it was oil and it went all over my gloves.
I was told they would go psst and make my fork better. I was lied to. It's like buying a turbo car that doesn't make turbo noises
I have probably had over a dozen different front forks over the years and never experienced this issue with air in the lowers until this ‘26 Fox Factory 34SL. Can anyone explain why? I know it’s not just a Fox thing. What is new/different about these forks that make them susceptible?
Pressure in the lowers is almost always an air leak - the 34 SL/SC only has a single quad ring in the negative sealhead to keep the pressure in, but it is unusual for it to leak, especially in a new fork. If it comes back I would get Fox to look at it under warranty as its not normal.
The other place it can leak is the footstud to the air shaft - there is a small o-ring there but it also needs loctite to help make a perfect seal. Again its weird to leak there but it can happen if its loose or the o-ring has damage
Was this on your 38? Even on the original Zeb which ramps up pretty hard compared to most, you should be able to bottom it pretty easily. With that fork off the bike just pushing down on the crowns with your hands is enough to bottom it out.
With my 38 on the bike bottoming it doesn’t take much effort at all. there’s added resistance for sure the last 25mm but I’d stop short of describing it as excessive.
Remove the foam ring next time you do the lowers service and you might get to the pssst effect you are after. Eliminating risk of dust getting past the seal and then being trapped against the stanchion by the foam is just a nice bonus.
So I think the footstud on my fork could have been the issue as it was barely more than hand tight. That would suck air in during extension but compression would make it difficult for the air to escape right?
Even if the exterior bolt is hand tight the foot stud itself is a press fit with the lowers, and pretty much always under compression, so I doubt that would be an issue. Even if it was, the lowers wouldn’t be able to exceed atmospheric pressure.
Or did you mean the foot stud is loose from the air spring shaft?
Those forks don’t have bleed valves, correct? Pressure is always going change in the lowers due to temperature, altitude, or even gradual migration of air across the quad ring sealing the air shaft.
As an 130 XC fork one would assume the uppers would be as short as possible. Surprised casting ramp is that much of a problem on those.
My fork came that way for whatever reason. I have a few rides on it since bleeding the air off and it’s still feels great. I’m hopeful it was a one time thing.
It was my 38, I was doing back to back testing of my TopHat and regular volume spacers.
I would describe the resistance as “notable but not excessive.” I was able to bottom out the fork, it was just more force than I was expecting. I did press the bleeder valves before doing that to equalize everything.
OK yeah it might have just been the way it was assembled - if theres a big enough change in temperature or altitude it can cause an increase in pressure. Also if the damper side has the nut tightened while fully extended, it will have some positive pressure from compressing it down to the air spring.
And @Ride886 had it right - the press fit should be air tight and not able to move, plus the air spring is basically only in compression (because thats the part pushing the fork back out). If it was moving there would be a horrendous knocking and probably wind all the way loose as well
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