Zebrafive
Super Member
I believe poster #2 and #8 are right when they say the 75% is to keep the wheel fully covered to prevent air from getting to the rim and causing rust. This was from the days of CC. This would also be the maximum fill lever to leave room for air.
Since most fill tires because it cheaper than adding cast iron weights, they are looking for the most weight possible, hence the 75% fill. If you do not need that much weight you can fill to a lesser %.
Since most fill tires because it cheaper than adding cast iron weights, they are looking for the most weight possible, hence the 75% fill. If you do not need that much weight you can fill to a lesser %.