Riders climbing a mountain in the 1930 Tour had only two gears. They had to physically stop and remove their rear wheel and turn it around to engage the gear/cog on the other side of the wheel. This is Route N91, climbing the Col de Lautaret from Grenoble during the 16th stage of the Tour from Grenoble to Evian. The mammoth 331km stage was won by Tour leader André Leducq in a time of 13h39’23”.