Not cold tire pressure question (1 Viewer)

[CharlieS]

Thanks to @gaijin for the always generous sharing of RCTIP info. I’ve found it very helpful for inflating my larger than stock tires.

My question is whether there are any rules of thumb or correction factors when airing up a tire that hasn’t been sitting for hours.

What makes me think of this is airing back up after airing down and driving trails. The tires and air inside them must no longer be “cold”. When I inflate my tires back up to my standard RCTIP, they’re a bit off when I return to check the cold pressure.

Of course, I can just recheck and adjust back down the next day after things cool off, but it’d be sweet if I didn’t have to.

My example is a RCTIP of 41 psi, aired down to 20 psi, but I’m looking for more rule of thumb than a specific answer for my specific tires.

Thanks in advance!

 

[gaijin]

Thanks to @gaijin for the always generous sharing of RCTIP info. I’ve found it very helpful for inflating my larger than stock tires.

My question is whether there are any rules of thumb or correction factors when airing up a tire that hasn’t been sitting for hours.

What makes me think of this is airing back up after airing down and driving trails. The tires and air inside them must no longer be “cold”. When I inflate my tires back up to my standard RCTIP, they’re a bit more firm than I’d like.

Of course, I can just recheck and adjust back down the next day after things cool off, but it’d be sweet if I didn’t have to.

My example is a RCTIP of 41 psi, aired down to 20 psi, but I’m looking for more rule of thumb than a specific answer for my specific tires.

Thanks in advance!

It's a good question, and one which I wondered about... but decided I was overengineering the problem.

Basically, there are too many variables to give a simple answer - ambient temperature, tire temperature, total volume of air, moisture content of air, etc., etc., ad nauseum.

Best course of action is probably just as you outlined in your post. Air back up to RCTIP and re-adjust when tires are cold - easy peasy.

HTH

 

[TLC2013]

I try and shoot for 1-2 PSI above the RCTIP when airing back up from 15PSI to 41PSI. Seems to work well and I am usually dead on or worst case within 1-2 PSI of the RCTIP.

 

[TeCKis300]

I likewise air up past my target after a trail run. This will vary depending on these major variables:
1. how hard the tire was run (speed)
2. how hot the day is
3. how efficient (hot) the pump is

It'll be hard to factor these in objectively. But I usually go 2-3 PSI past target after most trail runs. If baja running or similarly faster speeds on fire roads/dry lake beds, the tires heat up quite a bit more than just crawling, so may need to air up even further past the target.

 

[CharlieS]

Thanks everyone.

 

[grinchy]

+2 or 3 psi here as well. So I'm targeting 37psi on my current tires, so I'll stop the inflation as it hits 40.

I'd rather be overinflated than under as well, as that doesn't require getting the inflator out for adjustment, just a quick valve push.