The controversies of the 1920s and the overt commercialism of the Tour put many people off the race when this new decade dawned.
War marred the end of the 30s
The lack of French success also did not help the race in its homeland.
There were experiments with team time trials and then national squads in the late 1920s, including substitute riders coming "off the bench" if someone was injured.
But these were cosmetic changes and still left teams run by cycle-makers in charge, an appalling situation for race founder Henri Desgrange.
He believed 1929 winner Maurice Dewaele had won by default, because of his team's strength rather than individual ability.
After almost three decades the Tour's father announced radical changes for 1930:
Cycle manufacturers' teams were replaced by national squads of eight riders, picked by Desgrange and paid by the Tour itself
- Everyone would ride identical bikes
- A publicity caravan was introduced to make up the cash shortfall from the absence of the cycle-makers and their teams.
The 1930 changes had a happy result for the French, uniting a group of exceptional riders in a common national cause.
Home riders took the first five Tours of the 1930s, with two wins each for Andre Leducq - "le joyeux dédé" ("the happy dude") - and for "le taciturn" Antonin Magne.
Such were the home country's riches that by 1934 Magne's second victory was not universally popular - many thought the wrong Frenchman had won.
1930: Andre Leducq (Fra)
1931: Antonin Magne (Fra)
1932: Andre Leducq (Fra)
1933: Georges Speicher (Fra)
1934: Antonin Magne (Fra)
1935: Romain Maes (Bel)
1936: Sylvere Maes (Bel)
1937: Roger Lapebie (Fra)
1938: Gino Bartali (Ita)
1939: Sylvere Maes (Bel)
Young rider Rene Viatto won three stages but was forced to help Magne in the overall standings.
The whole of France shared the 20-year-old's tears as they read how he had cried when forced to ride back up a mountain to help Magne repair his machine.
The young rider never achieved such heights again and World War II cut short his chances of winning a Tour.
Before the conflict, the Belgians ended the French glory years.
And there were further changes before the end of the 1930s.
Many had said the win by lacklustre Dewaele in 1929 was because his team leader had been unable to change his broken bicycle after an accident.
Desgrange rejected such thinking, and was deaf to calls to allow a weaker rider to lend a strong team-mate a machine.
But he relented over technological changes which even the most humble cyclo-tourist had taken on board.
Until 1937, popular new Derailleur systems were not allowed.
This design, which lives on to this day, allowed riders to change gears without removing their wheels.
DURING THIS ERA
The most long-lasting of the 1930 changes was the publicity caravan
Radio coverage also began in 1930
The first experiments with time bonuses took place in 1932 - the top three on each stage got up to four minutes
In 1935, Maes wore the yellow jersey throughout the race
Bartali was not allowed to defend his title in 1939 - with Europe on the brink of war, the Italians were prevented from competing
Until then competitors had to get off and turn their wheel around every time the road changed from uphill to downhill.
The result of the change? Another French winner - Roger Lapebie.
Not surprisingly - since his time off the bike was cut so much - the triumph was in the fastest average time to date.
Of the 1930 changes only the publicity caravan and the changes in gears have survived.
National teams disappeared in the 1960s, another era in which the Tour proved itself adaptable to circumstances and difficulties.
Rules over the use of the same bike were rapidly relaxed - France's Georges Speicher won after designing an improved braking system as early as 1933.
But what this decade proved was the Tour had learned how to adapt to survive.