The Salmson AL cyclecars fitted 710 x 90 tyres however they often switched to fitting 27 x 4.40 tyres due to them being more readily available at the time and as they were the more modern well based, wired on alternative to 710 x 90 tyres.
The size description of 27 x 4.40 refers to a 27" approximate overall diameter with a tyre section width of 4.4" leaving a rim size of 19" in diameter. This description was soon out of fashion and subsequently replaced with either 4.50 - 19 or 4.00 - 19.
