Following on from the earlier thread – i thought my shock might be leaking air…

Does the air in the shock when taken outside into the cold have a different volume compaired to when the shock is inside and warm ?

I ask because i did a test ride and it was sagging about 35% in the cold.

Left it indoors and after about an hour or so of warming up the sag is now back at 30%

So when cold can i expect more sag than when its warm?

pv=nrt

the answer is yes, but without bothering to do the calcs i am not sure if the change in temperature would be sufficient to notice a change in pressure.

if its , say, 5 degrees outside and 20 degrees (celcius) inside, the air pressure inside the shock will be (273+20)/(273+5) times greater indoors. so approx 5% difference, enough to be noticeable i would think.

that -273 degrees celcius is “absolute zero”… when all atoms stop moving.. thats all from todays chemistry lesson !

OK.

Hopefully its just the colder then.

Thanks guys.

The bigger issue for air shocks is that intense and prolonged use will absolutely increase the temperature of the air and change the spring rate as well as transfer heat to the damping oil, causing performance to deteriorate drastically.

By intense and prolonged use I mean like in the Alps, doing 10+ minute descents.

thats all from todays chemistry lesson !

Sounded remarkably like physics to me 🙂

Also, your rebound damping will be slower on a realy cold day, partly from the lower air pressure, and parly from the higher viscocity of the shock oil in the extreme cold. I back my rebound off a couple of clicks if temps very low.