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Offline axehole54

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nitrogen in my forks
« on: July 06, 2010, 06:11:29 PM »
I'm planning on changing fork seals this weekend and installing fittings for schrader valves and a a balance line... does anyone know if nitrogen makes a significant difference  or if I should worry about balance...I have plenty of access to nitrogen as my dad runs an air conditioning specialty shop and they use it for pressure testing
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Online Jerry Rxman Griffin aka MuthaF'er

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Re: nitrogen in my forks
« Reply #1 on: July 06, 2010, 06:22:42 PM »
IMO it's a new fangled gimmick. Snake oil. Nothing wrong with free available air (even though you have the line on nitrogen). Only REAL advantage I see is it will be moisture free but will that really matter?! What will you do when you need to top up and you're not local? 
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Offline gmonkey

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Re: nitrogen in my forks
« Reply #2 on: July 06, 2010, 07:13:12 PM »
How would you fill the forks with nitrogen?  Fit a bleeder screw to the drain hole and add one to the cap?  Assemble the forks inside a nitrogen filled plastic bag?
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Offline GammaFlat

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Re: nitrogen in my forks
« Reply #3 on: July 06, 2010, 07:40:12 PM »
I'd assume he's put schrader valves on the fork tops (caps).  I bought some and have not installed them yet. 
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Offline axehole54

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Re: nitrogen in my forks
« Reply #4 on: July 06, 2010, 07:47:33 PM »
planning on putting them in the top caps... if i should choose to do this i'm fairly certain I can hook the schrader's to a vacuum and pump in nitrogen (a/c filling equipment)
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Re: nitrogen in my forks
« Reply #5 on: July 06, 2010, 10:16:44 PM »
There are still some aftermarket fork caps with air valves floating around.
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Offline axehole54

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Re: nitrogen in my forks
« Reply #6 on: July 07, 2010, 02:25:21 AM »
Back when I used to motoX I had an old CR250 that I was running 8-12lbs (I think) of nitrogen in the forks after having run straight air for a while.... It seemed to compress and rebound differently (better) than the air... or was I imagining things. As for a  top up away from the source I could always use regular air if I had to my CR used to maintain air pressure consistantly but of course it was engineered to take air from new
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Offline Franken750

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Re: nitrogen in my forks
« Reply #7 on: July 07, 2010, 03:20:03 AM »
G'day Axelhole.

Jeez - just as well that is an "x" in your handle....  ;D

Nitrogen: pure nitrogen, as compared to atmospheric air (78% Nitrogen plus Oxygen and water vapour and other 'stuff' ) conforms far more closely to what's-his-faces gas law of PV/T = a constant than does atmospheric air contaminated with water vapour. When water vapour is heated / cooled it undergoes large pressure changes as it transforms from liqid to vapour and and back again.

In all improbability you may not even notice this effect unless you're racing at Superbike level at the pointy end of the field.

It's offered at many wheel/tyre shops, where it MAY have a slightly more discernable result given the comparitive volume difference between forks and four wheels. Well hey - at $5-10 per wheel then why not? Yee haaaa all the way to the bank.

As for me, I've found that by making slight rebound tweaks on my Konis I've gained more corner speed than I could have imagined.

FWIW  and not meaning to sound like any sort of put-down, spend your $$$ on professional riding lessons. I did. I've never regretted a moment of it.

Cheers

John C.


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Offline axehole54

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Re: nitrogen in my forks
« Reply #8 on: July 07, 2010, 06:56:22 AM »
Thanks john compressed air it is :)
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Offline turboguzzi

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Re: nitrogen in my forks
« Reply #9 on: July 07, 2010, 10:52:04 AM »
pressuirzed forks were a common solution back in the 70's - 80's to soft springs and bad damping, nobody uses them anymore. you'll be doing much better by fitting stiffer springs. if you really want to save, you could simply shorten your current ones and fit longer pvc spacers to bring up the ride height back to stock.(that's what i did on my racer and street bikes)

you can later tune stiffness further by playing with the oil level.

current motogp and wsbk run pressurized cartridges to stop cavitation but those are totally different internals

TG

 
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