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Q - NItorgen and Air expansion in tyres


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My dealership insists on putting nitrogen in the tyres when fitted new, but I wonder if there are consequences from doing this.  My theory goes like this:

The tyres are fitted and filled with Nitrogen to 22PSI, the left (L) tyre goes down a little so I top it up with the compressor.  I now have two tyres with different gasses inflating them, and hence have different rates of expansion.  As the tyre heats up the (R) gets to X PSI, where as the (L) gets to a higher pressure becuase of the different effects of heat oin he Nitorgen/Air mixture

Over time the and on a hot day the (L) Tyre would have say 50% nitrogen and 50% atmosphere/air would get to a hgher pressure from heat expansion of the inflating gas, than the (R) whic is still at 100% Nitrigen

Am I on track here?  Would I be better off having air thatn the mixes

Edited by mbkitmgr
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Air is roughly 80% Nitrogen already-- so even if  you filled one tire entirely with air, the difference is only 100% vs 80%.  Also, Nitrogen and Oxygen have similar properties.  I haven't done the math but suspect the difference between 80% nitrogen and 100% nitrogen is trivial from a pressure standpoint.  Maybe someone who has the numbers will weigh in on this (and correct me if I'm wrong).

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Thank you to all responders.

This came about after I installed Tyre Pressure Sensors on the bike (Can AM Spyder 3 wheeler).  I had to top up the (L) front tyre having used it to sync all three sensors.  Since then the (R) front tyre has pure Nitrogen, and is always cooler (22 deg C) according to the sensors than the (L) front 23 deg C.

Ironically my quest for accurate tyre pressures has created a conundrum.  Without the sensors, I'd check pressures with a pressure gauge and top up as required, where as now new tyres + Nitrogen  has meant standing in the garage I have 2 different temperatures and pressures at the front.

At present standing in the garage presures/temps are:

  • (L) 18.2 PSI @ 23 Deg C - Air/Nitrogen mix
  • (R) 19 PSI @ 22 Deg C - pure Nitrogen

Am I too fussy?  Well maybe but the manufacturers max pressure is 22 psi and i find one half a psi difference affects the handling

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