Yeabut.

Yes, however, the bike rolls better with new rubber, perhaps on account of the new casing is more resilient.

Other than the weight and thickness difference prath pointed out, the shape is flatter, and has "shoulders," hmmm... and the outside of the new rubber is tougher and slicker.

New tyres are faster, says I, but no empirical ebidence do I know of.

It is January, and the weather is inclement.