400ex rear shock

[jelrod05]

i was wondering if they are rebuildable and what i would need to do it i have all the nitrogen and gauges for it. just not sure on seals and where to get them from

[3400ben]

Yes you can rebuild them.

[mlabarca240]

I rebuilt my 450r front shocks. The rear shock is a rezzie shock just like the 450r shocks. I only weigh 145 lbs and I pumped the bladder up to 140 psi with regular compressed air. As long as the air is dry it doesnt matter if you use regular compressed air or nitrogen. The only difference is nitrogen doesnt react as much to air temperature changes as regular compressed air. Nitrogen is more of an inert gas. When the outside temperature is higher on a hotter day, the charge in the shocks will change with regular compressed air. The change may be insignificant.

[06typeS]

yes you can rebuild them, but if you don't have experience doing so i would take it somewhere.

[trailrider894]

Originally posted by mlabarca240
I rebuilt my 450r front shocks. The rear shock is a rezzie shock just like the 450r shocks. I only weigh 145 lbs and I pumped the bladder up to 140 psi with regular compressed air. As long as the air is dry it doesnt matter if you use regular compressed air or nitrogen. The only difference is nitrogen doesnt react as much to air temperature changes as regular compressed air. Nitrogen is more of an inert gas. When the outside temperature is higher on a hotter day, the charge in the shocks will change with regular compressed air. The change may be insignificant.

Hey, i have never heard of people putting air into a shock before that wasn't designed for air. I can not see this working very good at all. Please correct me if i am wrong, but i don't see this as a wise descision. I will call up my buddy who works at race tech and ask him about this.

[greencow]

Originally posted by trailrider894
Hey, i have never heard of people putting air into a shock before that wasn't designed for air. I can not see this working very good at all. Please correct me if i am wrong, but i don't see this as a wise descision. I will call up my buddy who works at race tech and ask him about this.

I was also wondering about this. It came up when we recently went ridding and no one had a definitive answer. Please post what your buddy tells you, im very interested.

[trailrider894]

Originally posted by greencow
I was also wondering about this. It came up when we recently went ridding and no one had a definitive answer. Please post what your buddy tells you, im very interested.

I'll give him a call tommorow.

[3400ben]

Nitrogen performs betting than air. It does not react to heat and cold like air. If you put air in a tube and heat it up the air pressure will go up. As it cools the psi will go down. That is why they put nitrogen in airplane tires. It keep the close to the same pressure. If you use air in the bladder you would have to set the shock very soft. As a race would go on the bladder would heat up, the psi. Would increase and the shock would stiffen. Please correct me if I am wrong.

[greencow]

Originally posted by 3400ben
Nitrogen performs betting than air. It does not react to heat and cold like air. If you put air in a tube and heat it up the air pressure will go up. As it cools the psi will go down. That is why they put nitrogen in airplane tires. It keep the close to the same pressure. If you use air in the bladder you would have to set the shock very soft. As a race would go on the bladder would heat up, the psi. Would increase and the shock would stiffen. Please correct me if I am wrong.

Sounds right to me haha.

[mlabarca240]

There has to be a significant amount of change in the shock temperature to change the air pressure in the bladder. I can see if you start out in 40 degree weather and finish in 70 degree weather, but just heat from riding wouldnt be enough to change the pressure to make a noticeable difference on a stock rear shock. And these shock bladders are filled with nitrogen and the shock bodies are filled with oil. The two never mix or make contact with each other because of the bladder. I'm at sea level and the air temperature is pretty consistent here so I dont have to worry about too much. You shouldnt have to soften anything just because you use air instead of nitrogen. Its all just pressurized gas.

[mlabarca240]

If I had access to nitrogen when I rebuilt mine, then I would have used it. But seeing as I didnt, the pros and cons of air vs nitrogen didnt really outweigh each other.

[3400ben]

Originally posted by mlabarca240
There has to be a significant amount of change in the shock temperature to change the air pressure in the bladder. I can see if you start out in 40 degree weather and finish in 70 degree weather, but just heat from riding wouldnt be enough to change the pressure to make a noticeable difference on a stock rear shock. And these shock bladders are filled with nitrogen and the shock bodies are filled with oil. The two never mix or make contact with each other because of the bladder. I'm at sea level and the air temperature is pretty consistent here so I dont have to worry about too much. You shouldnt have to soften anything just because you use air instead of nitrogen. Its all just pressurized gas.

Read this http://www.thumpertalk.com/forum/archive/index.php/t-738830.html

[mlabarca240]

I just read it. It states the same insignificant differences between dry compressed air and nitrogen that I had already stated. Even some of the guys on that thread said it doesn't really make a difference because air is 80% nitrogen anyway. And the talk about molecules being bigger and whatnot, it doesnt matter either. The bond between the rubber molecules, wether it be covalent or ionic, is stronger than the bond in the nitrogen or air molecules. The bonds would have to be broken in order to have the air/nitrogen molecules pass through the rubber molecules. Look, if you have access to nitrogen and the spare 10 bucks to have it filld..by all means. If not, such as in my case when I rebuilt my shocks, then compressed air can be used.

[3400ben]

It is hard telling how much it does effect the shock.

[fearlessfred]

air temps are not going to have much difference but the difference in shock temp will be extreme and u will definitly feel from air to nitogen. if there was no diff between the two than i can asure you that the makers of shocks would not waste the money on nitrogen.if u are going to do it do it right

[Hasteloy-X]

I talked to the guys at custom axis, they said argon, nitrogen, and even compressed air could be used. Whatever is used has to be dry; no moisture in it.

[3400ben]

Originally posted by Hasteloy-X
I talked to the guys at custom axis, they said argon, nitrogen, and even compressed air could be used. Whatever is used has to be dry; no moisture in it.

Good info. Thanks

[fearlessfred]

Originally posted by Hasteloy-X
I talked to the guys at custom axis, they said argon, nitrogen, and even compressed air could be used. Whatever is used has to be dry; no moisture in it. i cant image them recommending compressed air ,and argon if inhaled is deadly and nitrogen is not.most shocks need 170 pounds or better for filling .who here has a compresser that goes that high and im asking because i dont know mine does not. also wandering who has a dryer on there compresser. to me it sees simpler to do it the correct way ,with nitrogen and i dont beleive any maker of shocks is recommending using compressed air.it also requires a speical tool to put it in the shock and not just your air chuck

[2001400exrida]

u can use compressed air, i've seen guys do it before at the track, straight out of an air compressor.

the difference is slim to none.

[fearlessfred]

well hasteloy x ,you must be right because god has spoken i bet you got wheel spacers on the front of your bike to.because other people are doing it

[trailrider894]

Hey, i talked my buddy at Race Tech. He said that he would never use compressed air. He said that there is no real way to get all moisture out of the air. Nitrogen is easily accessed at sporting good stores that sell it for paintball guns. He also said that when doing races such as GNCC and races that go from morning to mid-day will have temperature changes which will change shock performance. He said that nitrogen maintains a temperature better than air. He also said that because nitrogen has a better inertness to moisture and oxidation than air. I totally realize that this is very complicated and probably the variables between the two won't matter, but if you wanna do it right then get nitrogen... Its easily accessed and worth the money in the end.

[Hasteloy-X]

Do you think before you type???

You flunked high school science didn't you...

The reason argon will kill just as well as nitrogen is that it displaces oxygen in the body. You will die by asphyxiation if inhaling large quantities of either gas.

Our atmosphere is aproximately 20 % oxygen and the the rest being nitrogen and other nobel gases. Argon happens to be one of the other gases in that same mixture but only accounting for 1-3%. If the oxygen percentage a person breathes in drops below 18%; death can occur.

If you "READ" my post I stated compressed air "FREE OF MOISTURE" can be used. There are commercial grade dryers that can dry compressed air.

The moisture in the air is the main reason for pressure change at tempurature.

As far as compressed air is concerned, if the air is DRY, you could use medical grade air from a tank, or scuba tank type air. Places that fill tanks for scuba divers use an air compressor with a dryer on it. That may not always be the case though.

The tool you mention is called a shrader chuck. I've seen people use both the air chuck type (same used on tires) and the special high pressure type with the pin depresser built in.

Try running a shock with less pressure in it. It will make the compression softer. The same thing happens as the shock ages because the gas will leak by the seals. This is true on Decarbon floating piston shocks anyway. Not sure about the bag type shocks.

My cheapy farm & barn air compressor will goto 150 p.s.i.. Which is enough to get by.



Originally posted by fearlessfred
i cant image them recommending compressed air ,and argon if inhaled is deadly and nitrogen is not.most shocks need 170 pounds or better for filling .who here has a compresser that goes that high and im asking because i dont know mine does not. also wandering who has a dryer on there compresser. to me it sees simpler to do it the correct way ,with nitrogen and i dont beleive any maker of shocks is recommending using compressed air.it also requires a speical tool to put it in the shock and not just your air chuck

[trailrider894]

Originally posted by Hasteloy-X
Do you think before you type???

You flunked high school science didn't you...

The reason argon will kill just as well as nitrogen is that it displaces oxygen in the body. You will die by asphyxiation if inhaling large quantities of either gas.

Our atmosphere is aproximately 20 % oxygen and the the rest being nitrogen and other nobel gases. Argon happens to be one of the other gases in that same mixture but only accounting for 1-3%. If the oxygen percentage a person breathes in drops below 18%; death can occur.

If you "READ" my post I stated compressed air "FREE OF MOISTURE" can be used. There are commercial grade dryers that can dry compressed air.

The moisture in the air is the main reason for pressure change at tempurature.

As far as compressed air is concerned, if the air is DRY, you could use medical grade air from a tank, or scuba tank type air. Places that fill tanks for scuba divers use an air compressor with a dryer on it. That may not always be the case though.

The tool you mention is called a shrader chuck. I've seen people use both the air chuck type (same used on tires) and the special high pressure type with the pin depresser built in.

Try running a shock with less pressure in it. It will make the compression softer. The same thing happens as the shock ages because the gas will leak by the seals. This is true on Decarbon floating piston shocks anyway. Not sure about the bag type shocks.

My cheapy farm & barn air compressor will goto 150 p.s.i.. Which is enough to get by.

But in the end nitrogen is still better, because it is pretty cheap compared to a 200 dollar air dryer you would need for a tank. I am not really trying to argue your point. Just stating the facts.

[2001400exrida]

trail you don't have to buy the dryer. My friends have a scuba tank looking deal that they take to the track with them. They have it filled with dry compressed air at the local dive shop, and that's what they use to fill their shocks.

Nitrogen is not that cheap when you're filling a tank like this.

i thought paintball guns used CO2? the new ones must be nitrogen i guess? that's pretty sweet.

nitrogen might be what comes in it stock but i've never heard these guys complain about the air that they use and they've been racing for quite awhile.

your buddy at racetech are a little off. Compressed air can be used and it can also be almost no moisture, so there's no ill effects as far as i've seen and heard.

[trailrider894]

Originally posted by 2001400exrida
your buddy at racetech are a little off. Compressed air can be used and it can also be almost no moisture, so there's no ill effects as far as i've seen and heard.

Well i maybe air can be done in the right way, by doing the scuba tanks or a method like that. I know that living in the middle of missouri, that a dive shop is not to be found for atleast 150 miles from here. I'd spend 40 dollars in gas to fill a tank. Besides nitrogen can be accessed at almost any welding shop or maching shop. I know that since race tech has been in the buisness for what seems like decades, there must be a reason they would recommend nitrogen over air. So, seeing that nitrogen is so easily accessed and cheap around here why not just get some?

[2001400exrida]

my friends have nitrogen put into theirs and they adjust it with this air tank that i'm talking about i think.