Odd. I've got a Mk2 172 7x15 wheel I bent when I hit a pothole in the Northern Territory outback where there are no speeds limits.
I put in on the scales. It weighs 8.0 Kgs. That's just the bare wheel.
I'll weight the spare wheel with tyre when I get the Clio back from the dealer tomorrow.
I'm driving a loan car at the moment. Its a Megane. Its spare wheel is a 6.5x16 (ET49) steel wheel fitted with a 205/55 tyre. Wheel+tyre weigh 17.0 Kgs. I know alloy is less dense than steel, but its also weaker so alloy wheels can't be as thin, and they are generally designed for style and durability when banged into kerbs rather than light weight. I wondered whether the average mag was actually lighter than the average steel wheel. Doesn't look from that like there's any saving.