Hollow spoke question
#1
Racer
Thread Starter
Hollow spoke question
I was tweaking tire pressures on my car after its winter hibernation (I do drive it some when roads are dry so I don't pump them up high to avoid flat spots) and had a thought. My pressures seem to have stayed more constant over time compared to other cars. Could that be because the total volume of air in the tire includes the hollow spoke volume so it is greater for the same size tire than with a normal wheel? If this is not the case, wouldn't it be a good idea if it did? ......just wondering.
#4
Pro
This is true. I had an intersting experience when i pulled the valve stems out of my hollow spokes the other day. When I unscrewed the nut on the stem, and disturbed the rubber gasket, a tiny amount of air escaped. I wonder if there isn't some porosity that allows air pressure in the spokes? Or there was just different barometric pressures when the valve stems were installed from when I removed them. Obviously there was no tire on the rim at the time, but there was pressure in the wheel itself
#5
That's right, no air from the tires in the spokes themselves. You don't want them open because you don't want water (condensation) and any crud getting in the spokes. The crud would spin around in the spokes and get stuck, throwing off wheel balance making the wheel useless. I have a set from a 996TT that was refinished and crud somehow got inside the valve stem opening on one of them during the refinishing; the wheel had to be replaced as it was impossible to balance it.
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#9
Racer
Thread Starter
I did a little search on the 959 and you are correct sir. There was indeed extra air in the spokes for the tires. This must be where I got the idea. You can read about it here: http://auto.howstuffworks.com/porsche-959-history.htm
#10
This is true. I had an intersting experience when i pulled the valve stems out of my hollow spokes the other day. When I unscrewed the nut on the stem, and disturbed the rubber gasket, a tiny amount of air escaped. I wonder if there isn't some porosity that allows air pressure in the spokes? Or there was just different barometric pressures when the valve stems were installed from when I removed them. Obviously there was no tire on the rim at the time, but there was pressure in the wheel itself