where the rubber meets the road
US /wɛr ðə ˈrʌbər miːts ðə roʊd/
UK /wɛr ðə ˈrʌbər miːts ðə roʊd/

1.
onde a borracha encontra a estrada, o momento da verdade
the point at which a theory or idea is put to a practical test; the crucial point of a situation
:
•
All the planning is done, now we're at where the rubber meets the road.
Todo o planejamento está feito, agora estamos no ponto onde a borracha encontra a estrada.
•
When it comes to actually implementing the changes, that's where the rubber meets the road.
Quando se trata de realmente implementar as mudanças, é aí onde a borracha encontra a estrada.