The 400/425X17, 400 X 17 or 425 x 17 Longstone Tyre have been designed very much with the Austin 7 (seven) Ruby in mind. The Austin 7 Ruby fitted a tyre in the size 400x17. Today because there are no tyres of the size 425X17 being made Longstone have made a dual marked tyre called 400/42X17. The new Longstone 400 - 17 Austin seven Ruby tyres has a tread pattern designed to look very similar to the tyres that the Ruby left the factory with.