I think it was a 48×20 (mid
I think it was a 48×20 (mid 60’s), he started with an 18 on the back, but the 20 made a bit more sense (to him at least!).
Mr. Obree taught him the pleasure of the zig-zag method of getting up the steeper sections, (of which there were many), and he would often overtake a group of French or German roadies on compacts, zig-zagging across the road on a 14% incline after a couple of hours of non stop climbing out of the saddle!
The fact he made the top of the Cime de Bonette was amazing, the top loop is a km of about 14% at just under 3000m high after hours of climbing. He really is a machine, and the funniest bloke I know.