According to Henry Fairlie, Black wards in Cleveland gave the following percentages:
1928 - Smith - 30%
1932 - FDR - 24%
1936 - FDR - 49%
So I'd say 1932, Hoover.
It's ironic that Hoover won the black vote considering he was a virulent racist himself. He opposed anti-lynching bills and was also a fervent supporter of the Lily White Policy. He intentionally did his best to drive blacks from the Republican Party by segregated them and refusing to be photographed with any black leaders. The GOP was never really the party of Civil Rights...even Taft was a racist who sought to remove blacks from the party.
I think you are a bit unfair to Hoover. I base this on various portions of V. O. Key's Southern Politics, which primarily discusses the Democratic Party in a one-party region, but has a chapter "A Note On The Republican Party" which explains the nature of the Southern GOP back in the days of the Solid South.
The Republican Parties of the various Southern states did not serve as parties whose purpose was to contest elections. They contested very few. Eastern TN traditionally elected two (2) Mountain Republican Congressmen, and the GOP was occasionally competitive in areas of Western NC and the far western reaches of VA, but there was no pathway for these folks to ever gain significance in any of there states. These party organizations DID play a role in nominating Republican Presidential candidates, and they DID serve as the dispensers of Federal Patronage in those states during GOP Administrations.
By 1928, the Black and Tan Republican organizations were out of power (although there were still some prominent black Republicans in the South). Hoover supported the factions of the GOP in the South that had the juice and swept the South 161-6. What's more, the GOP was actually competitive in the Southern States in 1928 due to Democrat Al Smith's Catholicism. There were a number of prominent Hoovercrats, most of them in the Upper South (VA, NC, TN) and in TX, but there even some in the Deep South. V. O. Key points out that rebellion against the Smith ticket in the South was the greatest where blacks population was the lowest (NC, VA, TN, FL, TX). The states that stayed Democratic were the states with the highest black percentages (AL, GA, MS, LA, SC) and AR, whose own Sen. Joseph Robinson was Smith's running mate.
There is evidence that Hoover held racial views that would certainly be considered racist today. His wife did have the wife of black Rep. Oscar dePriest over to a White House gathering for Congressional wives, and if that doesn't sound like a big deal to folks here, they have no idea of the firestorm that occurred when T. R. had Booker T. Washington over for dinner at the White House. In his lifetime, Hoover did much legitimate humanitarian work, a good deal of it at his own expense, and he did it for all sorts of groups of poor and starving people. The balance of Hoover's life deserves a bit more leniency in its assessment; a leniency I would not give to, say George Wallace or Strom Thurmond.
