Heres a stupid question but why do octy vrs estate come with 16s while the hatch had 17s?

Apparently the estates arn't as ridgid as the saloons, plus the saloons have the braces behind rear seats,

Hence why they never not the bigger wheels as it wouldn't ride aswell on them, also 17's were a no cost option on the saloons so i've heard

Extra weight from the estate needed the plumper side walls of the tyres afforded by running 16s to keep the ride quality maybe?

But yes early hatches got 16s too until 17s were a no cost option and then standard fit.

I suspect from an engineers point of view, it has less to do with the bracing that the Estate lacks, but more to do with the extra weight it carries, and lack of rigidity of certain components, rather than the actuall shell/chassis.

The Octavia isn't the best of designs. It has too much rear grip, and a standard Golf MkIV rear axle which is pretty floppy, and has a tendency to flex a lot under steering. With the extra weight of the Estates, I would suggest that the larger tyre walls are retained to allow more flex in the tyre walls, rather than transmit all that extra energy into the axle itself. It is in attempt to keep the ride quality, but a bit of a compromise. The better option would have been sway bars (which even the hatchbacks need in all honesty).