valve access holes in wheels?

[JoeDxMB]

I'm a bit confused about the valve access holes in covered WWI wheels.
It's my understanding that most WWI aircraft  wheels were solid rubber . 
In  addition, I recently saw a pic of a  a WWI wheel that was  basically just a disk of metal  with a solid rubber tire but, it still had a hole in the disk where a valve access hole would be  .

So, why all the holes?
Can anyone shed some light on this?

[uncletony]

I think they were almost always pneumatic, not solid rubber (think how heavy solid rubber tires would be!)

[uncletony]

from 1913...