[AdeC]

The real Rally Costa Brava 1986 was both a tarmac and a gravel event:
https://www.youtube.com/watch?v=MLbbmI6n...INGCHANNEL

The SRC knobblies are really rough, but grip is very good.
They don't collect much dust from the track, like slicks do.
To avoid further doubts, here are two more photos of that really splendid SRC Lancia: 

Hub

Yep, you've convinced me... I need this.