Is my airgun 5% slower in the winter due to the specific heat of the air?

[Caliber 22]

Their normal pressure IIRC was ~190psi at sea level where he lived. Lord only what that reached at 35,000 feet.

190 psi ? That is 13.1 bar.
Wow, I did not know bicycle tires are pumped that hard.

Anyway, atmospheric pressure is around 1 bar and that is pressing from the outside of the tire. Vacuum is 0 bar. The pressure inside the tires will stay the same as the tire contain it less a little flex. The difference is that at 0 bar outside pressure it will be as if the tire has a pressure of 14.1 bar on ground level. If the tires exploded because of that they were close to or over the limit to begin with. Am I wrong by thinking like that?

The same the atmospheric pressure will not influence the pressure inside a pcp reservoir as the reservoir is not flexing as a tire do. (Not as much.)

But, like said, it is the regulated pressure that matters.

 

[Caliber 22]

I initially thought the decrease was temperature but maybe it's not that simple.

Spring energy change with temperature, but I don't know how much and if it is enough the change the hammer force to make a difference.

 

[Scotchmo]

Spring energy change with temperature, but I don't know how much and if it is enough the change the hammer force to make a difference.

For steel, it’s a very small amount. And it goes down as temperature goes up. So that’s not the cause.

 

[Mycapt65]

190 psi ? That is 13.1 bar.
Wow, I did not know bicycle tires are pumped that hard.

Anyway, atmospheric pressure is around 1 bar and that is pressing from the outside of the tire. Vacuum is 0 bar. The pressure inside the tires will stay the same as the tire contain it less a little flex. The difference is that at 0 bar outside pressure it will be as if the tire has a pressure of 14.1 bar on ground level. If the tires exploded because of that they were close to or over the limit to begin with. Am I wrong by thinking like that?

The same the atmospheric pressure will not influence the pressure inside a pcp reservoir as the reservoir is not flexing as a tire do. (Not as much.)

But, like said, it is the regulated pressure that matters.

Yes racing tires at the time we're tubular and glued to the rims. There was no tube or rim bead so they reduced weight. They were very thin to limit rolling resistance so they had to be pumped up to very high pressure. They were almost exclusively used on competition bikes. Tour DeFrance and triathlon stuff where any reduction in weight and rolling resistance would be appreciated against a tight competitive field for hundred miles or more. I've since got fat and old so I've lost touch with cycling technology. That's how it was back in the 80s and 90s

 

[Caliber 22]

For steel, it’s a very small amount. And it goes down as temperature goes up. So that’s not the cause.

Will that very small spring tension difference not make a difference in the regulator, more tension = lower plenum pressure? I am asking to learn as well.

 

[Scotchmo]

Will that very small spring tension difference not make a difference in the regulator, more tension = lower plenum pressure? I am asking to learn as well.

Maybe a 2% difference in modulus over a 100F spread. So no. And again, wrong direction. The spring in a regulator is in compression, trying to push the regulator open, against the piston which tries to keep it closed. Less spring force means less pressure gets through to the plenum.

 

[Caliber 22]

Yes, that is correct. Last night I was half asleep and did not think it through and had everything in reverse.