Mountain Bike Reviews Forum banner
1 - 20 of 73 Posts

·
I can ride a two-wheeler
Joined
·
647 Posts
Discussion Starter · #1 ·
Would it be beneficial to fill a DHX 5 with nitrogen (or another gas) instead of just regular surrounding air?

If so, what would be the benefits and how could I go about doing so?

:)
 

·
Glad to Be Alive
Joined
·
43,005 Posts
Nitrogen has thicker molecues then air so it stays in the chamber longer (less chance of it slowly leaking out)

that is the only benefit.....IMO I would just stick to air unless the nitrogen is easily attainable
 

·
Equal opportunity meanie
Joined
·
2,781 Posts
Ignore the assclown.

Nitrogen CAN seep out less if a system already has a problem with normal air leaking out. Bike stuff gets the pressure checked often enough for it to be a non-issue.

The more noble reason is to keep the shock running cooler. Nitrogen can transfer heat out of the shock oil much more effectively than normal air can.
 

·
Its got what plants crave
Joined
·
5,933 Posts
Nitrogen is also less affected by temperature changes if I recall, although a shock will probably warm up pretty quickly during usage anyway.
 

·
外国人
Joined
·
412 Posts
nitrogen = less prone to heating up, that's why race teams use them for air in their tyres, to maintain the optimum PSI on their tires.
 

·
Registered
Joined
·
593 Posts
One of my friends had his rear shock rebuilt by his moto mechanic with nitrogen and im pretty sure thats what screwed his shock up
 

·
I can ride a two-wheeler
Joined
·
647 Posts
Discussion Starter · #7 ·
I think the moto guys use nitrogen for heat reasons, and it apparently makes a huge difference in their shocks...

but would it really make a difference in a DH shock? anyone have experience?
 

·
Banned
Joined
·
19,198 Posts
Air is 78% nitrogen , you would reap very little benefit from using 100% nitrogen .
 

·
~Disc~Golf~
Joined
·
16,496 Posts
The reason nitrogen gets used in shocks is because of the lack of moisture.
Dried air could be used for the same reason.

If a shock filled w/ 'normal' is cycled fast and often enough, it will begin to heat up. Moisture will expand and change the dynamic of the shock (basically increase spring rate).
MTBs typically do not go fast enough to heat up the shocks significantly and warrant nitrogen (or other arid gasses)
 

·
Glad to Be Alive
Joined
·
43,005 Posts
Metanoia said:
nitrogen = less prone to heating up, that's why race teams use them for air in their tyres, to maintain the optimum PSI on their tires.
no less chance of seeping out
 

·
P-51 Crew Chief #38
Joined
·
603 Posts
highdelll said:
The reason nitrogen gets used in shocks is because of the lack of moisture.
Dried air could be used for the same reason.

If a shock filled w/ 'normal' is cycled fast and often enough, it will begin to heat up. Moisture will expand and change the dynamic of the shock (basically increase spring rate).
MTBs typically do not go fast enough to heat up the shocks significantly and warrant nitrogen (or other arid gasses)
Ah yes very good answer. This is one of the main reasons we use it on aircraft. Moisture can also form corrosion on the internal components and start to wear things such as seals much quicker. It is also effected less by altitude changes. The only thing I will disagree with is that a MTB shock runs hotter than most because they hold a smaller volume of oil and have more duty cycles due to their short stroke compared to a moto or something like that.
 

·
Equal opportunity meanie
Joined
·
2,781 Posts
2nd that. Hit a run that is 10 minutes long or more, and rough as hell - constant suspension activity. Then reach down and touch the reservoir of your shock.
 

·
Registered
Joined
·
276 Posts
SMT, you need to take a chemistry class. Nitrogen gas is (obviously) ~100% Nitrogen. Normal air, that would surround a tire for instance, is ~78% Nitrogen. Gas will diffuse from high concentration to low concentration, meaning the Nitrogen in the tube will diffuse out of the tire. Also, because nitrogen is fairly low in molecular weight, it will diffuse fairly quickly.

As someone correctly noted, Nitrogen gas is used because it is anhydrous.
 

·
Glad to Be Alive
Joined
·
43,005 Posts
Diggidy said:
SMT, you need to take a chemistry class. Nitrogen gas is (obviously) ~100% Nitrogen. Normal air, that would surround a tire for instance, is ~78% Nitrogen. Gas will diffuse from high concentration to low concentration, meaning the Nitrogen in the tube will diffuse out of the tire. Also, because nitrogen is fairly low in molecular weight, it will diffuse fairly quickly.

As someone correctly noted, Nitrogen gas is used because it is anhydrous.
contrary...the reason they use nitrogen in car tires is it seeps out slower because they are thicker molecues....therefore tire stay at same pressure longer then just air...
 

·
Go back to school
Joined
·
648 Posts
SHIVER ME TIMBERS said:
contrary...the reason they use nitrogen in car tires is it seeps out slower because they are thicker molecues....therefore tire stay at same pressure longer then just air...
I'm sure that's an advantage SMT but it's not the primary reason people use nitrogen in their tires. Highdelll hit the nail on the head. Really, the only reason nitrogen is even used over other gases is because it's the easiest to isolate. CO2 is cheaper but it has other downfalls.
 
1 - 20 of 73 Posts
Top