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Display Mesage #111260

Nitro Fill?
Written by boysrus_racing on 3/13/2012 at 04:29 am

I have and use nitrogen in my shifter kart tires, but I've not filled the PC
tires with it.

Nitrogen greatest benefit is that it is dry and so doesn't expand like air. A
kart tire going from 70 degrees to 240 degrees may gain 10 or more psi using
air, but only maybe 3 psi on nitrogen. When we start with, for example, only 9
psi, going to 12 psi is going to change handling, but nothing like going to 20
psi would do (initially bind the chassis, then overheating the tire and
decreasing traction, eventually blistering the tire)! It is much easier to
control pressure, therefore the tire's contact patch and heat, using nitrogen.

Bike tires heat up more on the street than a typical automobile radial tires,
but nothing like the temp changes in a racing environment where nitrogen is a
must-have. Street-driven MC tires get warm to the touch, so may go from 70 to
110 degrees, but as such will not have the potential for significant pressure
gain that nitrogen would help control.

That said, nitrogen is easier on rubber than air, and is a larger molecule so
tends not to leak out as quickly. The downside is that it is inconvenient for
most folks, possibly costly and probably isn't going to provide any noticeable
performance or longevity benefit if pressure is checked regularly (monthly).

If you choose to use it, you need to fill and purge the tire at least a couple
of times to get as much air as possible out of it. You are not going to get the
benefits by just adding a few PSI of nitrogen to a pressurized tire.
Preferably, purge the hose before filling the tire. Remember that nitrogen is
heavier than "air", so when purging the tire, keep the valve stem at the highest
point possible.

As I said, though even though I have ready access to it, I don't bother to use
it in my street cars or bikes.


--- In, "dave_hiett" <dehiett@...> wrote:
> Anyone done the nitro fill on your tires? Any difference in performance or
tire life?

Message Thread for message #111260