</font><font color="blue" class="small">( I have a TC33D with R4 tires. The valve stems on the front tires are on the outside (like on an automobile), but the valve stems on the rear tires are on the inside (which makes it difficult to reach). Is this normal for R4 tires? )</font>
Every tractor I've ever owned, no matter what type of tire, had the valve stems on the inside of the rear tires. That's to keep them out of the way of brush and other obstacles that could break them off. They are far more protected on the inside of the wheels. My front wheels have guards around the valve stems, doesn't yours also have this feature?
I had an old industrial Ford with wheel weights mounted on the inside of the wheels. The weights had cutouts for the valve stems to stick out. That was a 1964 model tractor. My 1954 Ford Jubilee also has the stems on the inside.
I have a MTD lawn mower with the front wheel valve stems on the inside too.
It's all about giving the stems the most protection. It is harder to get to them, but not as hard as having one snapped off while working in brush. /forums/images/graemlins/frown.gif