Buick vintage whitewall tyre.
Early automobile tyres were made entirely of natural white rubber. However, the white rubber did not offer sufficient traction and endurance so carbon black was added to the rubber used for the treads. Using carbon black only in the tread produced tyres with inner and outer sidewalls of white rubber.
Over time, single-sided whitewalls superceded double-sided ones.
Beginning in the early 1950s whitewall width began to diminish as an attempt to reduce the perceived height of the wheel/tyre, during the decade increasingly lower vehicle heights were in vogue.
Nowadays, whitewalls have become a hallmark of traditional luxury.........Wikipedia
NRMA Motorfest, Australia Day, Macquarie Street, Sydney, Australia (Tuesday 26 Jan 2010 @ 10:47 am)