Pumping a basketball?

[flobadob]

I bought a basketball a few days ago. It says on the ball to pump it to 8-9 pounds. When I was pumping it I stopped at around 6 pounds as I felt it was firm enough. However the next day the ball had lost some air and was not bouncing as well. I'm just wondering whether the reason for this could be anything to do with the fact I didn't pump it enough out if it is just a problem with the ball?

[Old_Geezer]

Losing air I'd have thought, would be unlikely to be caused by being underinflated to start with. But it makes no sense to me to not follow the manufacturer's instructions to pump it to 8 minimum. Why not try it and see what happens ?

[peter_jameson]

Hello flobadob

If the ball is made of an elastic material then if might have continued to stretch very slowly after your inflating it to only 6 psi. This would result in an increase in volume thus reducing the pressure over time.

Peter

[tonyav]

Or a dodgy valve.

[rojash]

The valve is kept closed by the internal pressure. Once the pressure falls below a certain level, the valve is no longer a perfect seal, and air will leak out slowly.

[flobadob]

Thanks for the answers. Yes, I will pump it to the 8 to 9 pounds as directed the next day it stops raining.

[boxtops]

LOL, can't you do it if it's raining?

[MASS1961]

Must be really a big basketball if you have to blow it up outside, or is it not waterproof?

[flobadob]

It's the principal, I'm sticking it to the universe.

[BillyBB]

but then even more air will have leaked out so more pumping

[flobadob]

It must just be the ball cos I pumped it to 9 and it still went down. Maybe it's because it is getting left outside.