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Everybody on the board is always talking about tire pressure and how much to put in. For you very smart tire members, how do you know when you have the right amount of pressure due to the fluctuation of temperature in your garage and the outside temp?
:popcorn:
 

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I'm not all that smart, but I check mine in the morning before riding and the inside of the garage is normally between 60-70 degrees. We all have our own idea of what a reasonable pressure is, but for me its 40/40 in the winter, in the summer; 38/38 because the tire gets real hot and the tire pressure goes up a lot as well.
 

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Out of all the hoopla about putting nitrogen in your tires, that's the one factor that rang true for me; nitrogen doesn't expand/contract with temperature changes so the pressure remains the same all the time (barring any leaks, etc., of course.) A side benefit of constant pressure is constant tire profile, so nitrogen is how I deal with the issue your question addresses.
 

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I have always assumed that tire pressure recommendations anticipate the increase due to increasing temperatures as we get underway. So, if you're going to use nitrogen, perhaps you should run several psi higher than you might start out with air.

Note, this is based on an assumption. I have no special knowledge of vehicle manufacturer's expectations, and I'm not an engineer. I'd be interested in other's opinions about this, especially anyone with special knowledge on the subject.
 

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I have the Smart Tire pressure system on my 06 GoldWing and I run N2 in my tires and can tell you that I have an increase in tire pressures just like all the air users do. In the summer at 90*F OAT running 2 up and pulling a trailer I have seen 170*F on the readout. If it's a gas it expands with heat.
Ride Safe
Ken
 

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Measure tire cold . I live in south Texas so cold is when I first pull it out of the garage. Usually anywhere from 50-90 degrees.
 

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I have the Smart Tire pressure system on my 06 GoldWing and I run N2 in my tires and can tell you that I have an increase in tire pressures just like all the air users do. In the summer at 90*F OAT running 2 up and pulling a trailer I have seen 170*F on the readout. If it's a gas it expands with heat.
Ride Safe
Ken
Hey Ken
I'm just as eager to learn as the next guy - so please don't take this the wrong way. But you're posting temperatures, not pressures. I don't think anyone is going to argue a temp increase. What pressure increase do you see?

You say: "I have an increase in tire pressures just like all the air users do".
My first thought after reading that is: Hey, waitasec! If nitrogen acts like normal atmospheric air, then why use it? Certainly the added cost is offset by some desired effect?
 

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As all the gas laws state: Pressure of gas increase with temperature. That is all gasses not just air we breath. Some more than others but all gasses.
Tire pressure are usually based on 65 deg ambient and anything over that temp it will be higher as the temp rises.
 

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Dr2
Yes I should have stated that when the rear tire temps got up to 170*F I had about 9-10# increase in tire pressure. Most of the hype about N2 is just hype. I use it because I have a big industrial size bottle left over from my days in aviation. the major benefit of using N2 is that it does not support combustion in the event of fire - pretty important in an airplane in a GoldWing not so much. The other advantage is it is drier and as a result there is less wheel corrosion - again in a GoldWing you are changing tires often enough it should never be a problem.
Ride Safe
Ken
 

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Out of all the hoopla about putting nitrogen in your tires, that's the one factor that rang true for me; nitrogen doesn't expand/contract with temperature changes so the pressure remains the same all the time (barring any leaks, etc., of course.) A side benefit of constant pressure is constant tire profile, so nitrogen is how I deal with the issue your question addresses.
Wrong. The laws of physics apply to Nitrogen just like any other gases. PV=nRT
 

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:doorag:pressure in a container(tire) increases as temp. increases or volume decreases. Your tire pressures are recomendations by the manufacture before riding. :p
 

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OK, so off I went to do some research on what I had taken to be true, that nitrogen doesn't expand/contract with temp. changes.

BUSTED!

So, I'm embarrassed :oops: that I posted incorrect information and apologize for that, and embarrassed :oops: that I let myself get scammed, but I appreciate you guys (once again) getting me back on the straight and narrow.
 

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Just an observation. I find that I get about 1# change in tire pressure for every 10*F from 65*F, both + or -. I also see that the rear tire temp runs about 30*F higher than the front tire in temps above 60*F while crusing down the freeway.
Ride Safe
Ken
 

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+1.....10% increase is the magic number. If the tire is too low it will run hot and the increase will be greater than 10%.

This is nonsense (urban myth). The amount or % of increase is DIRECTLY related to the increase in temperature discussed above. I'll guarante that a tire that is anywhere close to the correct cold (65 degrees) temperature will increase WAY more than 10% when riding at sustained high speeds and/or on a warm/hot day. I've seen a tire go from 40 PSI to WELL over 50 PSI in these situations.

The only way you would hold the increase to 10% in these situations would be to start with a tire that was VERY overinflated at 65 degrees. It would probably have to be AT LEAST 50 PSI at 65 degrees. This would significantly reduce the flex of the tire (which is what causes the heat and temperature increase).
 

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Out of all the hoopla about putting nitrogen in your tires, that's the one factor that rang true for me; nitrogen doesn't expand/contract with temperature changes so the pressure remains the same all the time (barring any leaks, etc., of course.) A side benefit of constant pressure is constant tire profile, so nitrogen is how I deal with the issue your question addresses.
Wrong. The laws of physics apply to Nitrogen just like any other gases. PV=nRT
Dr2
The other advantage is it is drier and as a result there is less wheel corrosion -
Ken
I don't think you were very far off the mark Tank.....Your N2 filled tire pressures stay more stable than most compressed air tires.

As mrbrabec says.... the gases expand. But as cakeman says..... there's water in them thar tars.:roll:

The reason for the N2 pressures staying more stable is that as the tire with air in it heats up....
the water changes state to a vapor and adds a pressure change that just won't happen in the n2.

Similar problem with brake fluid and water. The water works as a hydraulic just like the brake fluid....
but when the brakes get the fluid hot.... the water turns to a vapor and becomes compressable...
defeating the power of the brake hydraulics.

So in my opinion everyone was right to some extent.:thumbup:
 

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Discussion Starter #18
This is nonsense (urban myth). The amount or % of increase is DIRECTLY related to the increase in temperature discussed above. I'll guarante that a tire that is anywhere close to the correct cold (65 degrees) temperature will increase WAY more than 10% when riding at sustained high speeds and/or on a warm/hot day. I've seen a tire go from 40 PSI to WELL over 50 PSI in these situations.

The only way you would hold the increase to 10% in these situations would be to start with a tire that was VERY overinflated at 65 degrees. It would probably have to be AT LEAST 50 PSI at 65 degrees. This would significantly reduce the flex of the tire (which is what causes the heat and temperature increase).
So am I to assume that 65 degrees is about the median temp to correctly check the pressure in your tires?
 

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It's not only the temperature but the altitude you have to take into consideration.

Race tracks will underfill cold tires knowing that at operating temps the pressure will be where the manufacturer wants. Serious road riders or canyon carvers will warm up the tires then take a pressure measurement.

Altitude differences will cause tire pressure to change almost as much as temperatures.

As for N2, since air is 78% N2 and there are far more stations with air compressors, adding air to a 100% N2 tire dilutes the nitrogen making that $20 fill a waste, imo. If I were running race slicks I'd consider it, but not for my wing.
 

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Most all of the tire pressure sensors I have seen also have temperature sensors built into them, and they automatically compensate the pressure readout for the internal tire temp, or they display a differential correction factor.

Here is a chart the should help you better understand the relationship between temp and pressure. Normally the placard pressure should be set at around 65 degrees F.


 
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