Nitrogen Shock Fill

Edited Date/Time 6/19/2022 11:06am
Does anyone here refill there own shocks after rebuild or take them to a shop?
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btroxler
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5/10/2021 11:15am
I do. I rebuild and re-valve suspension as a side hobby.

Is your questions in regards to doing it yourself? If so, you can get the tank from your local welding supply and buy the unit from Race Tech that allows you to charge shocks. You are going to spend ~$400 to buy cylinder, fill it with nitrogen, regulator and adapter to fill either Schrader valves or needle style.
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5/10/2021 11:37am
I do fork seals and rebuilds for guys regularly but have always told them to go to a shop to refill the nitrogen on the shock. I have a cylinder already. Good to know Race Tech has a unit to purchase. Sounds like a lot of guys say it can be a pretty dangerous process. Do you use a scale to know how much to add?
FGR01
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5/10/2021 12:57pm
Scale? You fill with Nitrogen until you reach a certain pressure, just like filling tires.

Another thread with info:

https://www.vitalmx.com/forums/Moto-Related,20/Affordable-nitrogen-tank…

This is the hose I use to adapt the Race Tech fill tool to my regulator on my tank. As good or better than the hose Race Tech sells and much cheaper.

https://www.grainger.com/product/IMPERIAL-Charging-Vacuum-Hose-6X645
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mxtech1
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5/10/2021 5:07pm Edited Date/Time 5/10/2021 5:09pm
As long as you have a certified tank and a reliable pressure regulator/valve setup, it's a very safe process to do. It's also easy to use and a great way to make another $10 bucks on the shock rebuild price.

IMO, the Race Tech version is a little bit overpriced as I am sure they are just buying them in bulk and marking up the resell price. You can get a comparable industrial grade regulator much cheaper.

I have a local SJ Smith welding supply store and they are great to work with for Nitrogen refills on the tank.

The Shop

redduk
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5/10/2021 7:11pm
I guy on ebay has a nice set up for half the price of Race Tech. It's the one I bought and had no problems
5/11/2021 2:48am
i do my own, ive raced in locals for a lota years and was looking at cutting runing costs it was always made out to be dangerous and harder to do than it is when you speak to shops etc, its as said above, like filling a car tyre, i bought my kit from ebay usa and had it shipped, come with braided hose and no loss chuck, saved me a lot of the last couple of years
5/11/2021 8:50am
redduk wrote:
I guy on ebay has a nice set up for half the price of Race Tech. It's the one I bought and had no problems
Happen to have a link to the eBay kit you bought?
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Skerby
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5/12/2021 1:55pm
Im gonna go out on a limb and suggest that you just pressurize it with air. Use an mtb shock pump. I haven't tried this on a moto shock but it is my go-to when rebuilding bike shocks.

I haven't noticed a big performance difference, usually the shock is performing much better since it needed a rebuild anyways. Air is like 90% nitrogen or something. MTB shocks get really hot too.
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HackMan162
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5/12/2021 4:41pm
I've run them with air before in a pinch, and for vet class motos (e.g. 3-6 laps) there is no discernable difference.
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Lasse
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5/13/2021 12:38pm
Skerby wrote:
Im gonna go out on a limb and suggest that you just pressurize it with air. Use an mtb shock pump. I haven't tried this on...
Im gonna go out on a limb and suggest that you just pressurize it with air. Use an mtb shock pump. I haven't tried this on a moto shock but it is my go-to when rebuilding bike shocks.

I haven't noticed a big performance difference, usually the shock is performing much better since it needed a rebuild anyways. Air is like 90% nitrogen or something. MTB shocks get really hot too.
I agree, there is no point in running Nitrogen.
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rjg
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5/13/2021 1:45pm
Nitro is not necessary. Compressed air is adequate if you have a bicycle pump.
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beamer
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5/13/2021 1:51pm
No Nitrogen? Interesting.....
DuroTools
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5/14/2021 9:01am
HackMan162 wrote:
I've run them with air before in a pinch, and for vet class motos (e.g. 3-6 laps) there is no discernable difference.
I think the only difference is that with air the PSI will vary depending on temp plus it holds moisture so not good long term but can be used in a pinch
Jeff_Brines
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5/14/2021 10:00am
Talking to a suspension engineer he laughed about the sentiment you "need" to fill with nitrogen. While it certainly is best, there is really nothing wrong with using a bicycle shock pump for all of us "normal" riders. This has been proven empirically over and over again.

I just did a bladder conversion. I ran the shock with air from a shock pump (atmosphere) for the first 10 hours. No PSI loss, worked great. I had a buddy fill it with nitrogen thereafter. I literally can't tell a difference and I'm pretty picky when it comes to this stuff.

I can cite a bunch of examples of guys using normal air to fill important suspension bits with zero problems, in moto and in mountain bikes. This is most notable with air springs. Nobody is filling with nitrogen, there are zero problems.

The nitrogen fill is becoming an old wives tale of moto, with less and less of it rooted in science. More and more of it rooted in "this is how we've always done it".

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dmm698
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5/14/2021 10:22am
Talking to a suspension engineer he laughed about the sentiment you "need" to fill with nitrogen. While it certainly is best, there is really nothing wrong...
Talking to a suspension engineer he laughed about the sentiment you "need" to fill with nitrogen. While it certainly is best, there is really nothing wrong with using a bicycle shock pump for all of us "normal" riders. This has been proven empirically over and over again.

I just did a bladder conversion. I ran the shock with air from a shock pump (atmosphere) for the first 10 hours. No PSI loss, worked great. I had a buddy fill it with nitrogen thereafter. I literally can't tell a difference and I'm pretty picky when it comes to this stuff.

I can cite a bunch of examples of guys using normal air to fill important suspension bits with zero problems, in moto and in mountain bikes. This is most notable with air springs. Nobody is filling with nitrogen, there are zero problems.

The nitrogen fill is becoming an old wives tale of moto, with less and less of it rooted in science. More and more of it rooted in "this is how we've always done it".

No problems with air forks and air pressure fluctuation? You lost me there LOL. Even in the PSF forks you'll see a change, and thats large volume low pressure. TAC forks arent changing? and those pressures are more in line with a shock than a PSF.

I fill with N2 because I have the capability. I bet some guys run race gas, but pinch a penny to fill with a bike pump. Irony
5/14/2021 2:19pm
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike that you filled with air? ie how many hours you rode on them? and i run n2, as the guy above said as i have my own bottle, and ive filled that many shocks from it now over the time, its like its for free now and ive still got half a bottle, i was was lead to beleive and im no suspention expert, that nitrogen is more stable, and that over 20 mins will heat up less, running air is not something i personaly would ever do, its a bit like saying water is as good in the rads as coolant, yes it will work, but is it correct??????????
Falcon
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5/14/2021 2:36pm
Heat will affect the pressure of plain air more than it will nitrogen. In such a high-pressure, low volume application, it will make a difference. Can you feel that difference? Maybe not. However, with nitrogen, your shock will not increase in stiffness over a moto as much as it would with air.
rjg
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5/14/2021 6:31pm Edited Date/Time 5/14/2021 6:43pm
I will tell you from measured experience. Intermediate provincial competitive woods rider. Many measurements taken. I put 139psi of air in cold. I ride sand whoops for 1hour and meassure it at 147psi. It is likely 149psi before hooking up the Guage. There is a pressure change for sure but significant enough to effect me - not at all.

When it comes to forks , I feel air pressure is more significant effect due to the seals effectice surface area. Seal deflection on a fork is very noticeable.
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DuroTools
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5/14/2021 7:13pm Edited Date/Time 5/14/2021 7:15pm
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike...
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike that you filled with air? ie how many hours you rode on them? and i run n2, as the guy above said as i have my own bottle, and ive filled that many shocks from it now over the time, its like its for free now and ive still got half a bottle, i was was lead to beleive and im no suspention expert, that nitrogen is more stable, and that over 20 mins will heat up less, running air is not something i personaly would ever do, its a bit like saying water is as good in the rads as coolant, yes it will work, but is it correct??????????
Air forks we will fill with Air and is somewhat similar in function so maybe we are idiots for not using nitrogen up front. If I get my own fill nozzle and tank I'll definitely be trying that.
rjg
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5/14/2021 7:24pm
I dare you to try air with a bicycle pump back to back with n2. You will understand after that.
DuroTools
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5/14/2021 7:30pm
rjg wrote:
I dare you to try air with a bicycle pump back to back with n2. You will understand after that.
We talking front or rear suspension?
5/14/2021 7:42pm
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike...
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike that you filled with air? ie how many hours you rode on them? and i run n2, as the guy above said as i have my own bottle, and ive filled that many shocks from it now over the time, its like its for free now and ive still got half a bottle, i was was lead to beleive and im no suspention expert, that nitrogen is more stable, and that over 20 mins will heat up less, running air is not something i personaly would ever do, its a bit like saying water is as good in the rads as coolant, yes it will work, but is it correct??????????
DuroTools wrote:
Air forks we will fill with Air and is somewhat similar in function so maybe we are idiots for not using nitrogen up front. If I...
Air forks we will fill with Air and is somewhat similar in function so maybe we are idiots for not using nitrogen up front. If I get my own fill nozzle and tank I'll definitely be trying that.
i really hope you dont think i was saying anyone is a idiot for using air buddy, there seems to be a lot that use it and i was just genuinely curios why, i do prolly 15 to 20 shocks a month as im a breaker and do a bit of cerakoting, and i fill up with air when i seat the res cap, but always drain and fill with n2, id heard of people using argon etc ie other inert gases but never straight air, hope i didnt offend anyone
DuroTools
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5/14/2021 8:11pm
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike...
im "shocked" lol that a lot of guys suggest just air above, can i ask with genuin curiosity, how long have you giys owned the bike that you filled with air? ie how many hours you rode on them? and i run n2, as the guy above said as i have my own bottle, and ive filled that many shocks from it now over the time, its like its for free now and ive still got half a bottle, i was was lead to beleive and im no suspention expert, that nitrogen is more stable, and that over 20 mins will heat up less, running air is not something i personaly would ever do, its a bit like saying water is as good in the rads as coolant, yes it will work, but is it correct??????????
DuroTools wrote:
Air forks we will fill with Air and is somewhat similar in function so maybe we are idiots for not using nitrogen up front. If I...
Air forks we will fill with Air and is somewhat similar in function so maybe we are idiots for not using nitrogen up front. If I get my own fill nozzle and tank I'll definitely be trying that.
i really hope you dont think i was saying anyone is a idiot for using air buddy, there seems to be a lot that use it...
i really hope you dont think i was saying anyone is a idiot for using air buddy, there seems to be a lot that use it and i was just genuinely curios why, i do prolly 15 to 20 shocks a month as im a breaker and do a bit of cerakoting, and i fill up with air when i seat the res cap, but always drain and fill with n2, id heard of people using argon etc ie other inert gases but never straight air, hope i didnt offend anyone
I personally wasn't offended and I was genuinely just thinking that with the stability of nitrogen it really makes sense to use it up front so not sure why I've never thought or heard of anyone doing it before. I'm not one that messes with my forks air pressure but I do notice the forks get firmer as the day goes on so I bet there is an increase in pressure that wouldn't happen with nitrogen. But about the shock, I've done it once, was selling the bike and was under a time crunch to get the shock rebuilt and back on the bike so the buyer could test ride it. Taking it to get filled would have been a half day ordeal since the closest place was am hour away and I'd have to wait a half hour at least. I'm assuming the only reason people would use air is for the same reason I did , strictly convenience and nothing else. Oh and in case anyone was wondering I did disclose to the buyer that it needed nitrogen eventually. I honestly couldn't feel the difference on the track though.
Berni
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5/15/2021 11:37am
I have had my shock filled with a bike pump for a year.... I have found no problems neither I found more change during a 2h. cross country race in sandy soil in stiffness due to heat... I am about to do a new service and will use again air for sure.... Sure nitrogen might be better, but not even close to be necessary.... At least not for my level
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5/17/2021 5:37am
My local suspension guy fills my shocks when i rebuild them myself. He told me it wouldn't be a problem to fill it with air and not a lot of people would notice a difference.
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Falcon
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5/17/2021 11:54am
The reason nitrogen isn't commonly used in forks is because they do not get as hot. The air volume is larger, the shaft speeds are slower, and forks are exposed to much more airflow. Thus, the "inert" properties of nitrogen are less apparent.
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Chuck_Below
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6/6/2022 4:24pm Edited Date/Time 6/6/2022 4:26pm
The benefit of Nitrogen is the stability of the gas. With using Air you get oxygen (an oxidizer on parts) and some hydrogen, being moisture. As temperatures rise very high in the shock, the pressure will increase in the shock bladder higher with Air over Nitrogen. I don't know how much. In road racing, only Nitrogen is used in tires for pressure stability/ consistency. May not want air in a shock long term for seasons or years.
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lumpy790
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6/7/2022 1:01pm
Falcon wrote:
The reason nitrogen isn't commonly used in forks is because they do not get as hot. The air volume is larger, the shaft speeds are slower...
The reason nitrogen isn't commonly used in forks is because they do not get as hot. The air volume is larger, the shaft speeds are slower, and forks are exposed to much more airflow. Thus, the "inert" properties of nitrogen are less apparent.
good explanation sir!

My question is .... how consistent do you guys want your suspension to be?

I personally hate shock fade
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Wiscomx
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6/7/2022 7:45pm
Road racing, and circle track they run nitrogen, a lot less pressure rise with nitrogen then air, nitrogen also has less moisture, regular air will work, I prefer nitrogen, also refill customers shocks with nitrogen, I personally feel it’s better, if you break it down it’s essentially the same result.

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